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In Reply to: RE: HK Citation 2 rebuild questions posted by DAK on April 13, 2015 at 01:45:39
My advice is to leave it mostly stock. Just replace coupling capacitors and electrolytics. Use bumble bee capacitors the dry ones or sprague black beauties in the front of the amp. I would recommend Unicon electrolytics from hifi collective and CE manufacturing the paper tube ones if at all possible. They new had to build electronics back then doubtful that there will be improved musical performance and likely worse. Tune it in with respect to the geniuses that made it and you will be happy for years.
Follow Ups:
I'm sorry, but I don't think this is good advice.
Over 50% of those resistors were out of tolerance - do you really want to leave those in there?
Do you really want to leave those tired sockets and 50+ year old PVC wire in there, especially keeping in mind that it has been BAKED? It's WARM under the hood of a Deuce.
Do you really want to leave the broken fuse cap, the corroded RCAs and the tired speaker connections in the amp?
Where do you intend to get a reasonably close set of NOS power tubes? And what are you going to do when the intermittent bias winding solder joint in then power trafo lets go and takes out your $600-$800 power tubes - and maybe more?
Have you ever heard one of the Citations after they've been properly redone? You would be about the first to say musical performance hasn't made significant improvements. I've posted pics here of a Cit II amp I built for a Grammy winning jazz bassist - he says it's the best amp he's EVER heard.
I appreciate you taking the time to post and contribute, but honestly when the YOUNGEST Citation II was produced over 50 years ago "band-aid" approaches are inappropriate. Keep in mind that amp has much more in common with a Ferrari or a Porsche than a VW or a Chevy. And high performance gear needs more care than others. The amp deserves it!
Hi,
As always the challenge in any restoration, at least for me, is bringing the piece back to its previous glory and maybe goosing it a little bit in the process. The problem is that the parts they had available to them back in the day were, for the most part, FAR superior to those of today. Maybe not technically superior but musically superior. So a careful study must be performed as to what parts can be used. The biggest problem is finding electrolytics that can compete with the old Mallory cans or Astron minimites. Those electrolytics where awesome and in a lot of cases still sound good after 50 years. Pretty amazing. But I agree many are on their last electrode and are at risk for failure. The second problem concerns the issues of reliability and sound quality. It would be easy to make an amp utterly reliable by using over rated parts everywhere but that might hurt the sound quality. So what is needed is a balance. Very good reliability with the best sound quality. Sometimes one has to sacrifice ultimate reliability for added sound quality. Sound quality comes first always.
The old carbon resistors are still the best to this day so I wouldn't go around ripping those out and putting 0.1% metal films in thinking you'll hear an improvement. Same goes for couplings caps like black beautys and bumble bees. They are hard to beat if not impossible. What you get is vintage heaven. It is always important to keep the urge to over modify as when you do this you risk losing the specialness of these vintage amps. The way I look at it is every part that is changed should be out of necessity and is a necessary evil. So yes I would leave most of those things alone. The wire, tube sockets, speakers connections etc. as long as they are still functional I most assuredly would leave them alone. They will probably last another 50 years and are probably better made than much of what is available today. Remember these vintage amps are still working after 50 years. I think thats a pretty good indication of their rugged build quality and dependability don't you? They are not fragile little things about to self destruct.
As for the carbon resistors being out of tolerance, carbon resistors are always off (even when new) and as long as there is not anything egregious I wouldn't worry. More importantly they happen to sound exquisite, especially the old ones. I would cringe at the thought of changing out for modern day equivalents which will alter the sound for the worse.
Is the winding coming loose from the transformer a common problem??? Really??
Referencing the above picture, do you believe those russian capacitors compete with vintage american parts for sound quality? Likewise, how do you rate JJ or F&T against other electrolytics?
I am sure the amps that you rebuild sound really good, they are after all some of the best amps ever made. I would love to listen the one of your overhauled amps. Any videos on youtube?
Wow
Where do I begin with this? Chip covered a lot of it but it is really sad that you follow this outdated thinking because amps like the Citation 2 and the Mcintosh and the Heath W5 and W6 amps all have the best iron ever made.
There isn't any magazine or publication about vintage gear that would tell you to leave 50year old electrolytic capacitors in the circuit.They are ticking time bombs and their leakage puts an unnecessary load on the power transformer and then you risk losing the transformer that becomes very costly to replace if you can even find one.
I don't deny the sound quality of the 160p caps but if you look inside a Russian K40y pio cap,it is a copy of the 160p only it is sealed with oil and is built to a closer tolerance being a military grade cap..The 160p is a paper cap impregnated in wax or oil depending on the year it was made.You obviously never tried or heard a Russian k40y because if you did,you wouldn't make the statement that you did.They sound almost identical to a 160p being they have similar construction only they are more refined.
The bumblebee caps you say to leave in is the biggest mistake you could ever make..They crack and have moisture in them and when they become leaky,they can cause catastrophic failures and do,especially when they feed the output tube grids causing the tubes to draw excessive grid current and then burning up not only the tubes,but the output trafos as well.
I agree that the AB resistors are very good in many places in an amp,but not in a preamp.They should only be used as grid stoppers and carbon and metal film for the rest,depending on where they are used.
Why would you want to use old tired components in an amp just to say its original? The basic sound of any amp or preamp comes from the design itself. Mac and Citation amps sound the way they do because of the transformers and the design and the type of tubes used.Putting in better quality filter caps, coupling caps, and resistors, is not going to change that..It is only going to enhance and purify what is already there.
When you add more and better quality filtering,that makes the amp more quiet so you can hear more definition while lowering distortion and increasing peak power.If they had these caps back in the day,they would have used them.
The music material we listen to today is far more dynamic than when these amps were built and then you have all the digital noise on the AC line from HD tvs,computers,etc.The amp has to be purified in the power supply if you want to hear the amp the way it should sound.
You like to throw the words vintage sound out there a lot.What is vintage sound? I was born in the late 50s so I have no ideas how these amps sounded when new in the 1960s and I don't think you do either..There are way too many unknown variables but I do know that improving the specs of a Mac or Citation amp or preamp with a McShane upgrade is not going to change the original sonic intent.There is nothing wrong with using the AB resistors on the grid and there is nothing wrong with using 160p caps if they check out ok however,we have capacitors today that give the same sound only better and we don't have to fear the ultimate unknowns.Old filter caps,diodes,and bumblebee caps have to go along with noisy resistors because they do cause the amp or preamp to lose focus,increase noise,and also cause excessive distortion and if you think those are good attributes,I would love for you to hear a properly rebuilt and upgraded amp or preamp.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
Edits: 04/15/15
Ok all....I'm not quite sure how to respond. I feel like you've all just beaten me up on the schoolyard and stolen my lunch money! So here goes...
To Michael Samra-I think if you actually reread my initial post in response to DAK we agree a lot more than you seem to think. Regarding the electrolytics I specifically said to replace them, just like you. We also agree about where to put the Sprague 160 capacitors. The "front" meant away from the output tubes in the early stages of the amp. It's not about leaving original parts in to say it's original. It's about leaving the right parts in that sound better than if replaced with newer, less music-friendly parts. And in reference to sacrificing reliability for sound quality, what I mean is that older parts can lack the overall reliability that new parts have simply because they are new. Quite obviously I don't recommend using leaking, cracked or bulging caps. That's ridiculous to suggest!
Where I disagree with you is on increasing the power supply capacitance. Its not usually a good thing in a well designed amplifier. These were highly engineered and they didn't throw in random size capacitors willie nillie. Or cheap out on small caps and then turn around and spend lavishly on oversized output transformers which are of the highest quality along with everything else. Would that make any sense? Getting back to the capacitors, the problem with greatly altering the amount of capacitance is that you can hear that it changes the speed and flow of the power supply which in turn effects the speed and flow of the amp and its overall coherence. Incidentally, the same holds true for guitar amps. Increasing the capacitance often can change the responsiveness(speed) of the amp to the player.
Again these are my opinions, its what I have experienced and heard. Its not meant to be contentious.
Ping
You have to understand that the variables have changed since these amps were built.For one thing,the music material we listen to today is much more dynamic than in the 1960s.Where 40db dynamic range was the norm,most material today whether it be LPs or CDs runs between 90db and 105db dynamics.
This puts an incredible drain on the power supply under peak dynamic conditions. You also have to understand that rebuilt Macs and Citations are not powering old speakers anymore.Many of the McShaned Macs and Citations are powering modern Electrostatic speakers such as Martin Logan,Quad,and even the planar magnetics such as Magnepans and these speakers require more energy when played above moderate levels.
Even on the efficient speakers of the day,you can no longer depend on stock values because of the garbage on the power lines today from all the digital noise.You will hear that noise come thru with an anemic power supply on quiet passages and it's very irritating.
You have to also understand that these amps are capable of much more than when they were originally made.You aren't changing the circuitry by building a stout and quiet power supply with greater energy and a lower impedance.You are just purifying the wonderful sonic attributes of what is already there.You could keep the original filter cap values if you were using all film caps because they are much faster and much more efficient than an electrolytic of the same value but let face it,there just isn't the room to do that in most cases. Always remember that an amplifier is nothing more than a DC power supply that we modulate with an AC signal.The more we purify the power supply and give it more joules of energy,the happier our amplifiers and speakers will be.The stock value Mac or Citation cannot drive modern speakers in the 87db to 91db range with 95db dynamic material with stock values because on the first heavy transient,you hit the DC rail in a hurry and then you have an inferior sounding amp on your hands.Read this thread and see what I mean.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
Edits: 04/18/15 04/18/15
Hi Mike,
First off, I'm glad to hear you are feeling better!
Just one thing - while the lower ESR, DF, and other desirable factors of film caps are nice to have, the added energy storage from the larger value caps in my kits makes it possible for the amp to deliver more peak power and deliver it for a longer period of time. While the larger caps have but a minor impact on RMS power they have a significant and measurable impact (for the good!) on short term peak power. This is VERY important with wide dynamic range material!!
Think about it - the Cit II was rated by H-K at 60 watts/channel RMS power and 130 watts/channel peak power into 8 Ohms. With the Cit II OPTs that requires a swing of just under 22 volts into the 8 Ohm load, and pushing 22 volts across 8 Ohms requires about 2.75 amps of current in the secondary. This is available from the power supply continuously.
To produce 130 watt peak power requires just over a 32 volt swing in the secondary and requires a primary swing of 635 volts (yes, the primary CAN swing above the rail for short periods). 32 volts into an 8 Ohm load requires 4 amps of secondary current. IF the power supply can deliver the current, the peak power can increase and be maintained for longer periods. This means the power supply should be capable of delivering well over the current requirements to meet its RMS spec - it should be capable of supporting peaks well above the RMS rating. In the Deuce that means more energy storage - bigger (and much higher quality, if not quite to the level of a good film cap) power supply caps. This results in improved peak power performance.
Do note that yes, I left out trafo losses and frequency related issues in the explanation to simplify things a bit.
Just one thing - while the lower ESR, DF, and other desirable factors of film caps are nice to have, the added energy storage from the larger value caps in my kits makes it possible for the amp to deliver more peak power and deliver it for a longer period of time. While the larger caps have but a minor impact on RMS power they have a significant and measurable impact (for the good!) on short term peak power. This is VERY important with wide dynamic range material!I agree Jim.I was just making the point that the only possible way you may get away with using stock values would be to use film caps and even then you will run into issues.The caps that you have in your kits perform like film caps only they have the energy storage snd delivery as well. The Panasonic ED series are the best electrolytics in existence right now AFAIC and as you say peak power delivery is what it's about..If you would have told someone 30 years ago that you can power a set of ESLs or Magnepans to dynamic levels with an Mc240 or Citation 5,they would have thought we were on something,that is until your wonderful kits came along.You also use one or two film caps in your kits on the smaller values.
BTW,your kits have the lower ESR,DF,and all the desirable factors of the film caps..Just because they are electrolytics,doesn't mean they don't produce much better specs than the old 55 degree cans.I only use film caps in a few places such as off a GZ34 rectifier tube or as added decoupling at times like in the Mc240.It doesn't mean you have to use film caps and in most applications it just isn't feasible because of size restraints.In a couple places it can be a blessing.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
Edits: 04/18/15
Please go peddle the utter nonsense someplace else.
The world is not flat and the moon is not made of green cheese. Your saying so does NOT make it true.
Eli D.
"These were highly engineered and they didn't throw in random size capacitors willie nillie."
That a pretty strong assertion - you're saying that is what I do in my Citation kits? No way that's the case, no way. Back in the early 1960s Citation designer Stu Hegeman would have KILLED to have access to the parts I do now. He was limited by (among other things) cost factors, by diode durability issues, and by the parts he had access to. If he were alive today he'd be VERY pleased at how we treat his masterpiece amp.
BTW - define for me what you mean by "speed" and "flow" of the power supply.
And where in the world did you get the idea that modern parts are less "music-friendly"? Nonsense! For instance, you mean to say the fast/soft power supply diodes we now use that can handle 3 amps of continuous current and 600 volts PIV while generating near zero noise are not as good as the old "top-hat" diodes - the ones that were expensive as all get out and failed often if they pushed at all? One PRIMARY reason for the smaller cap sizes on older gear with solid state diode power supplies was that the rectifier diodes couldn't handle the currents! With today's far superior diodes capable of handling surges of 100s of amps (if need be) we are free to use cap values and caps with so much lower ESR than Hegeman could have even dreamed of.
I'm sorry, but IMHO you simply don't know what you are talking about. My comrade Don and I have redone HUNDREDS of Citations, how many have you done? How many have you heard? If you do a search and look for reactions to the performance of the "McShaned" Citations what do they say?
The preponderance of evidence is STRONGLY against you.
This post is not meant to be contentious either. But is IS meant to challenge the erroneous beliefs you are passing on and describing as indisputable facts.
My apologies to most of you on this site. I thought this was an open forum to have discussions. Clearly you only want to hear things that jive with your already established opinions. I've done a little bit of research since my original post and the responses here just to see what else is out there. There are so many other sites and forums that have similar philosophies to mine. I've found a lot! Surely this can't be the first time you've heard this! It appears to be an ongoing debate. Many many professionals believe that gutting vintage amps is the wrong thing to do.
My advice to any owners of these amps is to experiment for yourself. Try some vintage tone capacitors at key spots. Its easy to do. Maybe take some cues from what is found in vintage guitars and guitar amps. If you don't hear a difference throw in whatever industrial parts you can find from panasonic and be done with it.
And as for how many amps I've restored I pose this question to you. How many amps have you designed? IMHO the people who designed these fantastic amps that are still being used today are a bit more knowledgeable than someone who restores them.
Ping
I hope we didn't come off as condescending but many are very passionate about their Macs and Citations. Several of the caps that Jim puts in the kits are vintage paper in oil caps that are new old stock.They are sonically very similar to the 160p and I agree that the 160p caps are fantastic but when they have been in use 50 plus years,you have to realize that they may not be up to spec anymore and leak DC and this causes many problems for tubes and output transformers..The bumblebees were also a nice sounding cap when they worked but their reliability is horrible because they were made in a humid plant and that's why so many of them are cracked.If you could find a source for NOS 160P capacitors in a plentiful supply, let Jim know because I'm sure he would be more than happy to stock them. The problem is they no longer exist and the K40y pio caps sound almost identical to them in their sonic patterns only they are more reliable.
There's something else going on that nobody mentioned and it's this.Citation amps ran extremely hot and it wasn't just because of the tubes being biased at 90ma and 100ma each.That was part of it but the truth is the power supply filter bank was too small and underrated for energy storage and delivery for a class A type amp of that higher power rating.Think about this.When is a power transformer working its hardest? When it's charging the capacitors and being the filter caps were small by comparison,extra current is constantly being pulled thru the power transformer causing it to heat up more because it has to constantly refill those undersized caps much more than it would if you used modern filter caps of a higher capacitance value. OTOH when Jim designed a stout power supply to fit the Citations and the Mac amps,they could loaf a lot more because the transformer wasn't working as hard as it was when you try and play the amps at higher volume levels.The Citations run much cooler after the McShane rebuild and that way you don't have to risk ruining your power transformer from excessive heat.. How is that a bad thing?
The other problem is that the old coupling caps leaked DC overtime and this would cause output transformer failures..A good example was the Heathkit W5m. Many would say it was because the 16309 output transformer was too small but there was more to it than that.Every failed output transformer I have found in those amps had the original black cat 1uf coupling caps in them and that was mainly what caused the output transformer to fail..The caps would leak DC going to the grids of the KT66s and they would draw excessive grid current putting a huge load on either side of the output transformer causing the primary winding that feeds that one tube to open up.Many of these output transformer failures could have been avoided if people would have changed the output couplers to the KT66s.While the 16309 output transformer was smaller,having the output tubes drawing so much extra current took them beyond their power rating causing most of the failures.There is also the issue with power transformers failing in the W5ms and this was because people never changed filter caps nor the rectifier tube socket that would develop leakage between the pins. This was due to poor layout and design and if you put in a new high quality rectifier tube socket and get all those resistors off the tube socket that are hanging from it,this will greatly improve your chances of saving your power transformer and make your amps perform much better..How is this a bad thing?One more thing I want to address...Jim and I do not modify or redesign vintage amplifiers and preamps.We may address a weakness in design but that is an upgrade and not a circuit redesign..There are those that do butcher vintage gear for the iron or change the circuit to something else.
The Citation 2 was born with six 12BY7a and that's the way we leave it.
Some try to redesign the original by changing the circuit to dual triodes and when you do that,it's no longer a Citation 2..
There is nothing wrong with vintage circuitry.I have said many times before that a tube conducts the same way in 1956 as it does in 2015.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
Edits: 04/18/15 04/18/15
No, you've been civil, not at all. I think the 160 and dry( non-oil) bumblebees are pretty similar. Sure sure I am well aware of capacitors leaking d.c. So you check them of course.
Again the stout ps supply causing the power transformer to run cooler is not bad in itself, of course not. I'd be more interested in how it sounds though. But I think we can rest assured that the transformer is being safely operated with the original power supply in place. The fact that it still works after 50 yrs and potentially tens of thousands of hours of use is a pretty good indication.
I am going to go listen some tunes now.
Ping
The bumblebees did have a similar sonic nature to the 160p but being there were so many issues with them,I just replace them to be safe..The 160P caps are fine if they measure ok.
Again the stout ps supply causing the power transformer to run cooler is not bad in itself, of course not. I'd be more interested in how it sounds though.
It sounds like a Mac or a Citation 2 with a bit more refinement. Try it,I think you will love it.. But I think we can rest assured that the transformer is being safely operated with the original power supply in place.
` That would be true if we were listening to records from the 1950s and 1960s because they didn't have super dynamics in the 95 plus db range that would constantly drain the undersized power supply on peak transients. That is basically the whole argument for beefing up the power supply so we don't drain it and it keeps us from hitting the DC rail which is distortion at its worst.
Just try building one the way Jim says and if you don't like it,you can always put it back to original values.The manufacturers used smaller value electrolytics because that's all they had in those days. It was adequate for the time tho with what we listened to..You could say it's like trying to use Pentium 2 computer today.At the time they were made,they were plenty fast but since the dynamics of web browsing and internet speeds have changed,they no longer work well in today's market.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
Edits: 04/20/15
I'm surprised to see such hostility on this topic, and I don't know why you're getting so much crap for what you've said. I'm not in agreement with all of it either, but there are certainly some gray areas in this. Besides, your opinions seem pretty tame compared to most of the rotten advice that masquerades as fact on this forum. Guess you struck a nerve... :)
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Buy Chinese. Bury freedom.
T/K,
Ping is very much entitled to his opinion. What raised the hackles were statements of opinion as if it was Biblical Truth. Did you see IMO or I think?
Far too much nonsense has been "floated" on this forum, of late. :> (( It has to be opposed, less the "big lie" gain traction and people start believing it.
Eli D.
"Did you see IMO or I think?"
Eli, you can believe that I understand how you feel about this. I've been through it myself with a few other members. Still, I have to wonder if it's really necessary to always state that it's the author's opinion when discussing something other than formulated science like Kirchoff's Law or the Pythagorean Theorem. Opinion constitutes so much of what's written in forums like these, I always assume it's necessary to search out or ask for an authoritative source if it's a topic of interest to me. In this case, however, it's evident Ping is coming from a place that is not black and white, and that there will be no authoritative source. His perspective seems to be based on an opinion that the equipment should be restored, that the original performance is not only good enough, but that it consists of a sacrosanct product of its designer that should not be tampered with. I personally don't agree with that, but there's room for it in the audio community. Just as some people prefer to restore a Model T while others install a V8, it's simply different strokes. More to the point, I don't think he deserves to be vilified for this opinion. He's not preaching a deranged pie-in-the-sky philosophy like some of the Asylum inhabitants, and at the very least, his approach won't make the amplifier worse. I know you guys are passionate about this, but I think intelligent Cit II owners will understand your perspective and will appreciate Jim's wealth of knowledge and experience on this subject without the need to insult the other side. Just my $.02. :)
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Buy Chinese. Bury freedom.
"There are those that do butcher vintage gear for the iron or change the circuit to something else."
I don't see anything wrong with that. Not one bit. These are engineered machines, not carrier pigeons. :)
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Buy Chinese. Bury freedom.
Jack
If you are going to butcher a nice clean vintage unit for the iron that is factory built,I couldn't go along with that.If it's an old POS that's on its last leg,that wouldn't be a big deal.
There has been an evolving trend going on with vintage gear following that of the vintage car market.For example,you have the crowd that loves an all original 51 Merc with the flathead and the three speed manual overdrive,just the way it came out of the factory at Ford.
You then have the crowd that wants to chop,channel,and lower the car and put in a modern crate engine and auto trans out of newer Mustang,or maybe a chromed out small block Chevy or Ford engine.Is one group right and the other one wrong? It depends on whom to talk to.I like both.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
"If you are going to butcher a nice clean vintage unit... I couldn't go along with that."
That's your choice. It's my opinion that stripping the iron off a '60s amplifier and rebuilding it in a modern chassis isn't butchery. Didn't I read somewhere that Jim McShane used to do that with the Cit II amps? Correct me if I'm wrong.
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Buy Chinese. Bury freedom.
" Didn't I read somewhere that Jim McShane used to do that with the Cit II amps?"No, ABSOLUTELY NOT!! I would never do that, period. If you did read it it was either totally mistaken or a complete fabrication. IIRC a guy by the name of Mike Moffat - who was later of Theta fame - did that though.
Edited - I stand corrected, it was Bruce Moore. The mixup came about because I am currently considering purchase of a basket case Cit II that was indeed reworked by Mike Moffat - I got the names confused. Thanks for the correction.
Edits: 04/19/15
OK, I'm corrected too. :) It was a long time ago that I read that piece, must have mixed up the names.
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Buy Chinese. Bury freedom.
IIRC, Bruce Moore made a 120 monoblocks that used Citation II output iron.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
Jack
Depending on the amp,that would be your choice but would you butcher a mint condition Mac Mc275 just to get the iron?
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
Well, if your position is going to be based on a MacIntosh, using words like "mint" and "butcher", there's nothing to discuss.
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Buy Chinese. Bury freedom.
How about a clean factory built Citation 2? I don't think you would butcher that either.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
I've seen some that the only thing worth salvaging on them is the output iron. The power transformers on the Citation II are not the best to begin with. Many of those amps ran so hot the potting material literally melted out.
I kind of wished the Citation II was allowed to be designed with a pentode output. I think that wold have made a very good amp even better.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
" The power transformers on the Citation II are not the best to begin with."
I don't agree at all, IMHO those transformers were top shelf stuff. What about them was substandard?
"Many of those amps ran so hot the potting material literally melted out."
Often the heating was due to the trafo being on an amp that needed work. And early on H-K got crazy with the bias spec of 100 ma. per tube. So the transformers were worked VERY hard in many cases. But even many of those trafos that were not well treated are still running just fine today, 50+ years later.
IMHO those trafos may have been assassinated by other amp issues but they very rarely failed on their own. We've seen some issues with the bias winding in the last few years, but that's it.
If I were to get another HK Citation II, I would have to seriously consider a newly made power transformer with more reserve (overkill) to help out performance. I'm sure the original quality of the power transformer is fine. It's more the fact that it was run HARD near its limits for a lot of years, so many of them are stressed.I also wonder if a pentode output would have been better in the long run.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
Edits: 04/19/15
and they don't generate a lot of heat unless people leave old leaky caps in the unit that stress the power trafo..The Heath W6m also uses a doubler and as far as the Citation 2 running hot,that was true back in the day when they were biased at a 100ma per tube..With the McShane mods and the reduced bias on the tubes,they run much cooler than before.
I wasn't a fan of doublers either until I realized their wonderful attributes..Do you realize the power transformer in a doubler has fewer turns of wire that is thicker and heavier and therefore has a lower impedance secondary.
The biggest reason for doublers back in the day was the price and availability of higher voltage and higher current silicon diodes.I wish they would use them again.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
Edits: 04/22/15 04/22/15
Always good when you provide some good insight, Mikey. Valid points to consider.
Having said that, I still prefer not to use a voltage doubler. I'm also not a fan of cathode bias. To me, fixed bias is a better technical solution, especially in the DIY world.
I never cared much for the sound of the Mac's you mentioned. Always thought the Citation II sounded better. I have always wondered what the Citation II would sound like as a all pentode design.
Give me fixed bias pentode output any day.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
Interesting: Marantz 8 and 9's also used voltage doublers. Doublers were quite common in the old days. For modern designs, Quicksilver has almost totally ( i haven't see all his designs) gone over to a doubler system.What is interesting is Mike has used the doubler for B+ supply for the front end tubes ( 600 volt B+ = 300 volt at the half way point) or for the screen 2 taps. This, in effect, enables him to run a non ultralinear output and also enables his amps to be stable running anything from a 6L6 to a KT 120
Edits: 04/19/15
All the smaller HKs I'm rebuilding have doublers. They work very well, and I wouldn't hesitate to design one into new gear. That's a useful trick regarding the 1/2 B+ tap. Of course, it can also be done with a FWB if the PT has a center tap.
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Buy Chinese. Bury freedom.
It's just economics, in the old days, it may be fine to "butcher" an amp for its irons, but these days, an original un-molested amp of certain makes is worth a lot more than the irons. So in most cases, it does not make sense to do so anymore. Anyone continue with the practice of "salvaging" is either got more money than sense or just "out of the loop".
"Anyone continue with the practice of "salvaging" is either got more money than sense or just "out of the loop"."
Really? How about 40- or 50-year-old integrated amps with worn out pots and switches that can't be replaced, faceplates faded and scratched, and virtually every part needing replacement, including NLA capacitor cans, riveted-in tube sockets and banks of rear-panel jacks? Then there are those awful tone control PECs, sub-optimal bias designs and phono preamps that by modern standards bordered on "defective" even when they were in new working condition. Gimme a break. Anyone who strips this iron and uses it to create a modern, high performance system has done the audio world a favor.
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Buy Chinese. Bury freedom.
+1
You make many good points, however, we are not talking about beater units of pedestrian origins... Citation II, like most of Hegeman's designs are collector items, unless they are completely beyond repair, why would you want to strip them for parts? With some exceptions, these units could be brought back to life with some TLC, they are a part of electronics and American history, I think they should be perserved and appreciated as they are.
Unless you have a rare factory built that is in clean or mint condition,I let those alone.OTOH,a Dynaco ST70 turns my stomach in stock electrical condition.They are so anemic in every way they pretty much have to be modded to get real performance out of them.This is why there are so many aftermarket parts available for them,sort of like the small block Chevy.
The early ones had undersized power transformers and then you have that single GZ34 that struggled because it is being run close to its limit in that amp under dynamic conditions..The Knight KB85 used two GZ34s which made much more sense.They also used much more filtering than the Dyna ST70 which was a measly 90uf total.
Nobody ever went broke underestimating the intelligence of the American public
H. L. Mencken
Of course, I'm referring to amps in the condition I described. MOST are now in that condition or worse, due to age. I have no qualms about converting any of them into modern tube amplifiers, and I have a dozen or so in storage just waiting their turn. :)
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Buy Chinese. Bury freedom.
I've designed at least 3 from scratch, and done complete redesigns to a number of others. But that's really not relevant.
" I thought this was an open forum to have discussions."
It is. It appears however that discussions that don't fall into line with your thinking disturb you.
"There are so many other sites and forums that have similar philosophies to mine."
You are definitely entitled to your own opinions/philosophies. You are NOT entitled to your own facts.
" Maybe take some cues from what is found in vintage guitars and guitar amps."
Guitar amps are completly different beasts. They are not music reproducers, NOR ARE THEY DESIGNED FOR FIDELITY! But even in that field there are great opportunities to utilize better improved parts and so on. I am right now in the midst of rebuilding a classic early 70's Ampeg V4B for my friend and Grammy winning jazz bassist Phil Palombi. A few years back I did an Ampeg B-15N for him that he now uses in the studio and at home. He told me the B-15N "kicks the ass" of the high dollar amps he's played through. And that's why he sent me the Ampeg. The bad news for you? I used quite a few modern parts in the B-15, and I'm doing it again in the V4B. I also built him a Citation II amp 2 years ago. He and (so far) all his fellow musicians that have listened to it say it's the best they've ever heard. To be fair, these guys haven't heard every amp ever made (who has?), but they hear VERY well.
I have a TON of respect for the great designers of days passed - Stu Hegeman was one of them. I would never violate the intangible bond I feel with him and his work. Sadly, he was gone before I could ever meet him in person, but I feel very comfortable saying that he'd find what we do with his design would meet his approval.
I can't even believe I need to respond to a post like this. The number of logical fallacies in your post is astounding. You harp on the notion that I may not have my own FACTS. Well...You have stated so many opinions that YOU are trying to pass off as fact. I have never said in any of my posts that I think you should drive an audio system with a guitar amp. I was only talking about the tone caps. Using vintage guitar amps as a reference was merely an example of where one might find good sounding caps. You sound to me like you approach amps an electrical engineer and select parts that fit the bill according to engineering standards. Unfortunately, this does not always mean the "right" cap selection SOUNDS the best. I think it's great that a Grammy winning bass player likes your rebuild. However, that does not give you the authority to suggest that a legendary designer like Stu Hegeman, would love your design rebuild or think it's an improvement. That, to me, sounds incredibly bold and arrogant. I think there's an equally likely chance that he might think your rebuild killed the music. We will never know. Again he could very easily have used larger supply capacitors. Nothing stopped him; they were available. But, he didn't. And don't give me the mess that those top hat diodes couldn't handle it. They could with ease. And you talk about how good the diodes are today but many prefer the sound of the old diodes because they sound more like a tube rectifier. I think people can draw their own conclusions. You are a restorer of old amps that thinks he knows better than the original designer.
In response to your thoughts on why I felt attacked, I would like to say that your statement "It appears however that discussions that don't fall in line with your thinking disturb you" is completely ridiculous! Let me remind you that after one post stating my opinion I was the one who was attacked, called a troll and called stupid; not the other way around. One last thought...you said it's not relevant that you designed 3 amps from scratch and have redesigned a number of others. If it's not relevant then why did you ask me how many I've done?
I'm bowing out after this - think what you like.On guitar amps - I supply tubes to some of the smaller "boutique" amp makers out there. A LOT of them use TONE CAPS such the very popular Sozos that were not even around in the old days. And besides, they are not seeking fidelity; they are seeking a tone that is often based on deliberately induced distortion.
Why did I say I designed 3 amps (actually one was a preamp)? Because you asked and though I don't consider it relevant I wanted to answer your inquiry.
Why do I say what I say about Stu Hegeman? Because I HAVE communicated with a couple of today's designers who DID speak personally with Stu before he died and who HAVE told me that what we do with the Citation gear is terrific and in keeping with the original design intent he had. Now if they are lying to me then I'm off base, but I don't think they are.
BTW, he WAS limited in some of what he could do. There was a very low frequency oscillation in his prototypes that he struggled with, and he wasn't able to do exactly what he wanted to "fix" it because he had to have a design ready for production in short order. Also, I'm told by people who knew Stu that he felt that an ultralinear configuration may not have been the best choice for the amp, he preferred pentode mode. He was pushed by the sales guys to get the amp to produce very low distortion while putting out as much power as possible. The specs of the amp were a key part of the advertising pitch. Stu was a recording engineer, he wasn't a "specs" guy, so some design conflict was probably inevitable.
A quick thought about power supply capacitors - they and the semiconductor diodes were two of the most expensive small components in the amp. I'm not even sure they could be had in the day, but with the heat under the hood of the Cit II chassis I cannot imagine that Stu would not have used 105 C rated electrolytics if they were available at an affordable price. Nor would he have failed to utilize the other attributes of modern capacitors such as compact size, long life, low ESR and DF, and the myriad of other highly desirable characteristics offered today. FYI, MANY of the developments in these capacitors (and diodes) came about as the result of the switched-mode power supply and the constant demand for improved performance at less cost in less space. None of that development was present when the Deuce was deigned.
The diodes and capacitors? Please search out and read Rick Miller's 1990 (IIRC) design-changing Audio Amateur article regarding diode noise performance and the early 80s Walt Jung and Richard Marsh article "Picking Capacitors". You'll see how products not available to Hegeman made/make improved performance possible. Rick's article demonstrates using sound science that diodes like the top hats and even later pieces such as the 1N4007 sounded NOTHING like a tube rectifier due to the presence of relatively large amounts of PN burst noise generated by the minority carriers (holes) moving across the junction. That noise is completely absent from vacuum diodes (and Schottky diodes) as there is no mechanism to generate it. And it is only present at greatly reduced levels in modern fast/soft recovery diodes.
As far as mentioning what I did about the amp I sent to Phil Palombi... it is only relevant because I find that he and his comrades in the world of jazz (Phil was a classically trained bassist BTW, so he brings a lot to the table) have the ability to hear music far better than I do. So I value his opinion more than mine for that reason, and because he has no bias towards it like I may have. I did not mention that based on my reputation a number of other very well respected listeners have sought "McShaned" Citations. Dick Olsher (formerly of Stereophile and other respected publications, now writing for The Absolute Sound) sent me a Citation II amp to do for him. Sadly the core amp he sent was totally destroyed by UPS during shipping, and that project never came to fruition. My friend Dr. Norm Thagard, CNN expert correspondent, space shuttle astronaut, and audio design associate of Nelson Pass uses EIGHT "McShaned" Citation IIs in his home system. You can read about the special preamp Norm designed to drive all the amps in a back issue of AudioXpress.
At CES a few years ago a cable maker used his "McShane/Citation" at the show, and he got some amazing comments - here's just one:
""... a cable competitor, (name removed to protect the innocent and guilty), came by on a scouting mission. His interconnects start at about 6 times what our line tops out at, but he was very interested in our design and wanted a good listen. We played "freedom in the groove" for him and he said "this sounds very nice" and I started talking about the bang-for-the-buck factor with the $2k (McShane/Citation II) amp and $1k speakers and he stopped me mid sentence. "It sounds very nice at any price" he interrupted."
There's more, but no kidding - doesn't it seem like maybe there is SOMETHING worthwhile going on with these amps??
Finally, I never "attacked" you, but if you took it as an attack because as I stated before THE PREPONDERANCE OF EVIDENCE points in a different direction than your thinking it is certainly regrettable. I am sorry you took it that way, but only you can decide how to react to what I posted. Maybe I should not have said "facts", I should have just said "the preponderance or weight of empirical evidence". So my apologies for not defining my position more clearly and less controversially.
Edits: 04/19/15
I don't take measurements or base my likes and dislikes on theories or specs just listening. I have listened to probable close to 100 different brands and series of electrolytics and many many other film caps over a period of 10-15yrs. I have seen where caps that measure well sound really good and where caps that measure really well sound bad. Diodes that are supposed to be really good sound OK and generic run of the mill ones sound excellent. All of my opinions are based only on listening no measurement devices and no theory. From my experience, there are subjective qualities present in parts that aren't measured but experienced by some listeners and maybe not others. I have never listened to your products but I would guess that I would prefer the stock version with certain parts changes over the rebuild with parts with good data sheets. The main problem that is introduced by the wrong parts is an electronic sound however subtle that kills naturalness. When I listen I am comparing to the way I think live music should sound. Specs and theory are not part of the equation and are not enough to built great music makers. More capacitance is sometimes better but sometimes not. It must be judged by listening. For example, the noise you say is present in the old diodes. It may not bother the human ear such as seen with second order distortion. It actually sounds good to some but alas its a distortion so should be bad right? Not all distortion or "noise" causes problems for the listener you have to listen to find out what's what. After your post its clearer to me where the disconnect is. Different philosophies.
"he felt that an ultralinear configuration may not have been the best choice for the amp, he preferred pentode mode. He was pushed by the sales guys to get the amp to produce very low distortion while putting out as much power as possible."
I've always wondered why the Cit II and V were UL, while all the smaller amps and receivers were pentode. This also says something for the greater level of GNFB in the Citation series, something I would have thought less necessary due to UL operation. It's too bad these designs came at a time when specs ruled the day. It must have been quite stressful to design VT products under those conditions.
Thanks for the info!
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Buy Chinese. Bury freedom.
There is actually very little global NFB in the Cit II. Most of the 31 db of NFB is either the unbypassed V1/V4 voltage amp cathode resistors or one of the multiple NFB "short" loops used in the driver/PI and from the plates of the output tubes back to the drivers.
For some reason (senior moment?) I can't recall the exact number - but it's single digits, like 5 db IIRC.
BTW, the Cit V is not U/L, it's pentode. As a result, improving the screen supply regulation is a positive step. Also, unlike the Cit II most of the Cit V NFB IS global.
"There is actually very little global NFB in the Cit II. Most of the 31 db of NFB is either the unbypassed V1/V4 voltage amp cathode resistors or one of the multiple NFB "short" loops"
I shouldn't have referred to it as global. The point I was making is that the Cit II employs UL *plus* tons of NFB, much more than the smaller amps. I recently measured my A500, and it was less than 15 dB. That's enough to produce distortion numbers that are more than acceptable, but nothing like solid state. That would be quite a challenge, designing a large tube amp that could compete in a market guided only by numbers.
Thanks for the info on the Cit V. I think I knew that at one time... :)
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Buy Chinese. Bury freedom.
Some great information, Jim. Thanks for the update.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
I would rather Citation II monoblocks...that power iron is just too heavily loaded. That, and space for film caps( at equal capacitance to the upgrade values). While I am 'in there', adjust some values so as to take advantage of a current regulator in place of the tail load.
Rest assured, if I didn't settle on W6m, there would be a distributed 'Deuce running my bass horns instead.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
It is a conundrum. If you challenge the rank bullsh_t the troll produces, feeding occurs. OTOH, failing to challenge allows untruth to gain traction. :> ((
Eli D.
Eli D.
I don't get it? Do you feel better now that you've called me a troll? I think if you actually took the time to read my post you'd see I'm actually trying to have an intelligent discussion. Would you like to join in instead of throwing out useless names?
' The biggest problem is finding electrolytics that can compete with the old Mallory cans or Astron minimites. "
No, Sprague Atoms are superior in every way.
"Sometimes one has to sacrifice ultimate reliability for added sound quality. "
No, you don't. Ever. Melting OPTs are not a sonic choice.
"Referencing the above picture, do you believe those (R)ussian capacitors compete with vintage american parts for sound quality? "
Yes, they are better.
"carbon resistors are always off (even when new) "
No, no they are not.
"The problem is that the parts they had available to them back in the day were, for the most part, FAR superior to those of today."
No, that statement is false.
"I would love to listen the one of your overhauled amps. Any videos on youtube?"
Ahh!, This question would indicate you are simply retarded.
The result of this has you labeled "Troll". You are making statements of fact that are not, they are ridiculous.
THANK YOU for dealing with "Ping". I would have offended the moderators by going further than "troll".
Those who read Cyrillic will understand what I think flows from the "pen" of that "inmate".
ΓΟΒНО!
Eli D.
.
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