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Unlike the car industry that keep track of failure rates and repair costs it is often said that SETs and tubes are less reliable than SS. (aside from tube life failures which is an expectation that the owner has when buying a tube amp)
But I wonder if and how and why this might be true if it is true at all. Yes SETs get hot but that would seem to be a result of the tube getting hot and not the other components. And these days the tubes are mostly exposed in modern amps so while the tube is hot the surrounding caps/resisters etc are well enough away that they should not be affected.
And I'm not counting some of those dirt cheap rather iffy products from China that were notorious or the odd production run issue where a bunch of caps were failing. That happens to SS makers as well from time to time.
Follow Ups:
Ive had more trouble with SS gear.
Listening to my NORH SE9 now. Never had a problem, but when it was new it had PC board smell. Had a slight hum when I turned it on...traced it back to a dirty volume pot on my Quicksilver Pre-amp! A few twist's with the power of remedied it.
.
Beatnik's stuff http://web.me.com/jnr1/Site/Beatniks_Pictures.html
You've had it a while, no? Still liking it?
Big J
"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."
I've had no issues with either my 3 year old or so 219IA or my close to 5 year old 215 tube CD player or my 13 year old AN OTO Phono or my 16 year old Antique Sound Labs MG Head DT headphone amp.
Hi,
I have had several reliability issues with my Audio-Note Quest silver mono's.
Mainly bypass cap and oil coupling cap. This has happened twice shortly after the first repair.
AN has not the best track record regarding "Quality Control'. After the repair some screws were missing etc.
My dealer in Holland had quite a discussion about this with Peter Q.
But at the end I have now the best SET I have ever owned (Quest Silver mono's with M5 pre-amp / Yggdrasil dac and AN-E/SPe's)
John.
Triode 300B amp has been running without issue for 5 years.
My SE amps have all been homemade, and each has performed flawlessly and reliably every time it's been turned on. No blown tubes, no sparks or other fireworks, and no noise. In fact, my 417a--46 amps are the quietest amps I have ever owned, and the 46 even has AC on the filament!
I have an ANK kit 1 300b set amp that I just built in November.
After about two hundred hours of use and incredible satisfaction, the rectifier tube started to spark upon start up.
Then it started blowing fuses. I was guided to try a replacment rectifier tube (5v3).
I bought a pair and each worked for a little while, but then they started to do the same thing.
Now I have been guided to try a 5u4g type rectifier tube.
I built this amp to go with a set of high sensitivity speakers I built for myself last summer.
It replaced a ss amp I used to use (audio upgrades modified- 1985 Adcom 555).
It's a bummer because I love this new SET amp so much.
It smokes my old Adcom, making it sound etched and grainy in comparison.
I have since switched back in my Adcom555, but it pales in comparison to the degree that I have prefered to not listen to music at all.
I will do anything I can to get this problem rectified (pun intended)!
Hi johnny, Is the power supply for your amp capacitor input or choke input? If it is cap input what is the value of the first cap after the rectifier? A large cap will also fry your rectifier. cheers, Dak
Hey DAC.
I know that the smallest transformer of the bunch (mains, choke, outputs) on top of the amp deck/chassis is called the "choke transformer".
Does that answer your question?
Since this is a kit, they provided a schematic. Look at the schematic at the power supply and at the tube rectifier. The B+ will come off pin 8 usually, on the rectifier and after that there will be either a capacitor then the choke then another cap. This is called a Pi filter. If it is a choke input filter the schematic would show no capacitor connected between the rectifier and the choke. The choke would be connected to pin 8 and then there would be a cap after the choke.
So if you have the Pi filter what is the value of the first cap? If it is a choke filter the size of the cap following is not as critical.
So I checked both my wiring schematic and build manual.
They aren't all that descriptive, as the amp uses 3 pcb's (filament, driver, power supply). It is not all point to point wired.
So I opened it up and pulled up (gently) the power supply board.
It looks like the scenario you describe-
B+ comes off of pin 8 of the rectifier base, then directly to the choke, no cap in between, that I can see while tracing the circuit.
This connection is on the pcb, but I see the pads are connected.
.
If I can attach pics to my post, then im sure I can.
Ill get it posted a bit later.
But its like I said, more of a diagram or cartoon than an actual schematic.
There is also the build Manual.
The pcb looks to be double sided. Seems pretty easy to trace, but as you know, Im no electronics wiz.
The largest cap I see on the PS board is a 220uf. It seems its AFTER the B+ and choke.
I could be wrong, so ill post pics.
Regards!
.
DAK-
Sorry but its not working for me.
The post looks normal when I hit "preview post" with the pics attached, but when I hit "post message, it doesn't show up.
Perhaps I'm not a member long enough (6 days) :)
I ordered 20 new fuses, and a new rectifier tube.
I figured I should have plenty extra of these anyway lol.
If this doesn't do it, then ill have to send it out for sure.
I know ANK uses a builder for their kits when customers choose not to DIY, but I cannot recall who it was.
I think he calls himself "Digital Pete".
I had a couple of hurdles to cross during the build of this amp back in November,so between that and now this, perhaps I've wore out my welcome with Brian :(
I'll report back on how it goes.
Thanks for trying to help me out.
Regards!
Hello all.
I said I would report back with my attempted repairing of my ANK kit 1 300b set amp.
A few days ago, when I received my new fuses and my new 273b/5u4g rectifier tube in the mail, I installed a new fuse, installed the new rec. tube, and gave it a shot.
Once again, upon switching on the amp, the new rectifier tube would spark, and the fuse would blow. I replaced the fuse and re-tried two or three more times, with the same result.
With still not hearing back from Brian, I decided to try and reach out to "Digital Pete",
ANK's kit builder.
Well, I got lucky there,
as Pete took the time to walk me through some different voltage tests.
He came to the conclusion that I should try a 5u4gb, which apparently passes twice (approx.) the current of the other rectifier tubes I tried (including the 5u4g).
I was rained out from work today,
so I was able to confirm some final voltage measurements with Pete (which he described as "textbook"). I then tried one of my new 5u4gb tubes, which I received yesterday.
So far so good.
No spark in this new rectifier tube on start-up, and no blown fuses as of yet.
I have turned it on and off several times, and I also let it play for several hours today (getting nice and hot).
I sure hope this takes care of it.
Regards!
in this "post a message" box, go down to upload images, to the right is the "browse" box. As long as your file is in your computer you can access it for download by hitting the browse button. when your files are viewable, Click the relevant one, and it should darken to indicate that it was chosen then at the bottom of the page should be an "open" button. press that, which will send your file to this website allowing it to be posted. good luck, dak
Edits: 04/23/16
Late but as you seem interested and never got the reply I did find this manual on the net which I believe has schematics.
I'll check it out and report.
Regards!
The Kit 1 is a well-proven design with years of use by many satisfied builders. I'm suspecting something is not quite right, and that Brian could help you problem solve this.
I have been consulting with Brian.
I haven't heard back from him in a week or so.
Im guessing he is away on business or vacation, or just overwhelmed busy.
I too felt that it was a well established kit, hence why I chose it.
To Brians suggestion, I replaced the original rectifier tube that came with the kit, to a 5v3 tube.
I bought s pair.
Both began to spark upon powering on, and blow fuses, so he suggested the 5u4g next, but said the 5v3 should have worked.
I guess I'll have to give them a go.
Regards!
Tube rectifiers have a minimum plate supply resistance (Rs) for a given voltage. The 5U4G at say 450~500V (as is typical for cathode biased 300B amps) needs to see about 70 to 80 Ohms ahead of it. That is the combined resistance of the transformer's primary and secondary given by the formula: Rs = Rsec + (N^2)xRpri + Ra. It's this this last term, the additional resistance, that must be added in order to bring the Rs to the desired value.
Depending on size, a typical transformer in an amp such as yours will have a source resistance of about 30 to 40 Ohms. You would probably need to add a ~30 Ohm resistor just before each plate of the rectifier (total of 2 resistors) to bring the source resistance (Ra in the equation above) to the required level as specified in the tube data sheets. I would use at least a 10W resistor.
I forgot to mention that with these added series resistors, you should be mindful of their voltage ratings. If for example the transformer secondary is at 400V, then a 500V resistor rating would not be ideal. Resistors need to be at or bellow 70% of their max voltage rating for a long and happy life. Either up the rating, or use two resistors in series.
I also forgot to mention in the previous post that the series resistors will also have the effect of lowering the B+. If your line voltage is on the high end of the scale as is the case in many places, there should be no issue. If you were to use the 5V3 which drops less voltage than the 5U4, you would probably end up at the original B+ level with the use of the series resistors. Hope this helps. Let us know if you resolve the issue with whatever means you might try.
Thanks sonicboom.
I wish I was electronically savy enough to try an make the changes you recommend, or to even fully understand them!
I am not.
I was only able to build the amp because of its kit design and build manual, and the fact that I have some soldering experience with RC cars.
Ill have to trust that this amps initial, intended design is a proven one, and hope that I have been unlucky with THREE different rectifier tubes (the stock kit supplied 274b, and the pair of 5v3's), which I find hard to believe.
Ill report back with my outcome on this, and if indeed it is or is not the rectifier tube/tubes. Then perhaps someone here can recomend an honest repairman for my amp.
Regards!
...have not had a problem with my Chalice Audio 'Grail' SETs in 7 yrs..
Yeah, not good at all for a 3000.00+ amp. I think Mike Samra commented that the power trans for many Chinese amps have a 110/220 primary. Since USA voltage is mostly +120 that not only puts a strain on the PT but also the power supply components. So, I am still trying to track down a problem with the unit which now does not pass a signal. It went from a distorted signal to no signal. I would say if you are thinking of getting a Chinese made amp you better be sure it is made to operate at 120vac or be ready to spend about the same amount of money for repair jobs down the line. cheers, Dak
Many of the amps you buy on Ebay that are made in China,they almost have an extra wait time because they have to modify the AC input to work in the US market.If it was 240vac,there wouldn't be an issue..What some guys are doing are running their amps on variacs which is a bad idea..They aren't stable over time and there can be fluctuations in voltage by as much as 10% or more.You are better off just getting a tapped isolation trafo or getting transformer with the correct primaries.
A friend you get for nothing,an enemy has to be bought
It seems like there is no real damage done to the amp. It looks like the 845 have worn out and need to be replaced. the tube lineup is 12at7 - 2a3 - 845. If the owner subbed a 12ax7 for the at7 would that drive the amp harder? If the ax7 has more gain would not the signal to the 2a3 be more and thus working the 845 even harder? cheers, Dak
"If the ax7 has more gain would not the signal to the 2a3 be more and thus working the 845 even harder? "
Only if he turns it up. (or, to say it the other way around, only if he didn't turn the volume control down to compensate for the added gain of the 12ax7 vs. the 12at7)
Or to say it yet another way, if he listens at the same level as he always did the 845 would not be "worked" any harder.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Hi Tre, the upshot of the whole problem is that i found the bias pot on one amp was burnt out. So, i replaced both pots with beefier AB units and now the amp plays and sounds good. The bias voltage is controllable and works as it should.
I should have mentioned that I would have been seriously bummed if I was the owner of the amp. I am just trying to get it going again. It is a pair of monoblocks so one I got sorted out ok. But the one that doesn't pass a signal is a head scratcher.
"My question to customers who disparage valve amplifiers is always, "OK, so how many 20 - 30 year old transistor amplifiers can you mention that have any value (meaning someone will actually pay money for it)?" in general there is no answer to this question, as most of these amplifiers are gone long before they get this old, now the next question is "So how many 30 - 40 year old valve amplifiers can you mention that people would buy now?" This list becomes quite extensive - depending on how knowledgeable whoever is answering the question is - Quad, Radford, Leak, Marantz, Fisher, Harman-Kardon, and so many others, so what we can conclude is that while fashion favours more modern technology, time tells the opposite story, which is partly why we make the products we make."
PQ. from the article 'PETER QVORTRUP TALKS THREE-MOTOR TURNTABLES: AUDIO NOTE UK 2016, FACTORY PHOTOS & NEW SPEAKERS' , https://parttimeaudiophile.com/2016/01/13/qa-with-audio-note-uks-peter-qvortrup/
Big J
"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."
Barring catastrophic tube failure (short that can damage amp), I expect to be using these amps 20 years from now. (Provided I personally last that long.)
Built them myself from kits (DIY HIFI SUPPLY BILLIES).
Lots of upgrades early on but since about the last 10 years, just listened.
Decent tubes to start, Amperex GZ-34, Tung Sol and Ken Rad 6SL7, WE Kansas 300Bs.
All still good but could use a rebuild I am sure.
I use/own a mixture of DIY SET preamps and amps as well as modded and stock Fi amps and have never had any issues in almost two decades. This is with several hours of daily use, 7 days per week. I replace tubes (USA NOS for everything except output tubes which are Chinese or WE) every 5 years or so and that is it.
I often get replies or into conversations where there is an assumption that Solid State amps are much more reliable than SET/Tube amps and because this isn't the car industry where records are kept I wonder where these myths/legends/facts?? come from.
I've not owned tons of tube amps but I've never had a problem (except tube failure) with any of them whether they were from cheap and cheerful china or the west. Yet I have had SS amps die or begin to fall apart or my top of the line Pioneer Elite receiver that was DOA. They replaced it but...
I mean anything can fail of course - companies buy caps and the cap is dead - what can you do?
RGA,
I purchased my 421a from Don Garber in March of 2007. I listen about 10-12 hours a week. 9 years later, no hum, buzzes or breaks. Besides the sound quality, that's why I made the purchase; to get off the repair merry go round. The only tube substitution was the 6sl7 driver, I exchanged the GE for a Raytheon(Garber provided 2) (round plates) just for the hell of it, liked the response and stuck with it. The WE 421a power tube still test's new. Can't get anymore reliable than that.
mike
For some reason, the only problems i have had have been with AN(UK) products, but they have always been minor, but fatal, stupid things and have been fixed for free, locally.
My one and only tube amp experience was with an Audio Note P2SE amp that I owned for 16 years. It worked reliably on a daily basis and without any issues during the time I owned it. To this day I regret selling it.
The four 5881 tubes put out a lot of heat enclosed under the amp's cover as the tubes were not externally exposed as are some designs. This did not have a negative effect in my experience, but I believe that dissipating heat from sensitive parts can help to prolong their life.
Well there is always the Ongaku - tubes exposed - but you might need to win a lottery.I am excited to see and hear their new entry level Cobra amplifier for $3000 or so. It's not a SET I don't think - it is class A and 25 watts and will use the C-Core outputs - comes with remote control and a built in DAC. It seems like a lot for a little but the tubes are exposed!!!
My sights are pretty much on the Empress Silver 2A3 at the moment. I like them a LOT every single time I hear them. But preamp is my next move.
M3 phono or M6 line and worry about the phono stage later (maybe an M1 or M2 phono stage (but more boxes in my already stuffed HK apartment). So the M3 is kind of the front runner for a complete package. But I wish there were still a sig version or something to get the C-Core and black gates - but I guess that would make it an M6 now wouldn't it.
Edits: 04/15/16
Also, the PP version. There is now a Soro SE Signature that has double C-core OPTs, just like the OTO Signature
My understanding was that AN had some issues with a run of their caps having early failures (but that they fixed them for free with a better cap). I've had no problem with my OTO Phono SE bought back in 2003. I would not say they're exactly battleship build quality.
Chinese labor may be better - if they make a defective part they're probably taken out back and beaten. In the UK if you tell the employee he made a mistake you'll probably get sued for making them feel bad. I'm being facetious.
nt
It seemed to be issues regarding caps circa 2006-2007 where caps were failing. Peter was on this forum and Bottlehead taking them back and replacing them for free even well out of warranty. They were copper oil caps. I can't find it but Peter had a page dedicated to cap issues from that time period and that they would be replaced with newer models - Possibly why there are no AN M3 MKIII versus MKII.
I built them in 1999/2000 and have been running them ever since. One amp took a lightning hit, but I fixed that. One amp is now silent; I'm thinking it's a coupling cap, and I might fix it someday.
I'm testing out a LIO right now, used the dead amp as an excuse to make changes :)
Over the past 10-15 yrs, I mainly use military or industry grade parts that I got dirt cheap from ham swap meet, everything is overkilled, size and weight isn't my concern at all. Those parts are going to last if not forever, probably generations. I expect the only thing that need to be replaced are tubes. I run them conservatively, with good ventilation, delayed B+, I expect each set of tubes will last at least 15-20 years.
With attention paid to most details, a SET is very reliable.
I've experienced a SET failure that was built from an arrogant and incompetent guy, who sold many incompetently built products to "screwed" customers. I've repaired and modified an amplifier (6N6P-6B4G-5Z3S) built by him and I've seen many things asking for trouble:
-putting 50uF after a rectifier rated for 20uF. The rectifier was of course.. arcing. There were no damping resistors.
-The output tube was 50% above datasheet mentioned power dissipation.
-The amp was self-oscillating, too bad I don't keep the photo with the wire dressing and the grounding.
-The diodes for the heater were underrated and there were cases of shorted rectifiers, leading to the feeding the tantalum filtering capacitors with an inverse half wave. I personally experienced an explosion of a tantalum capacitor K52-2 in such a amplifier, it goes off like a gun - a scary experience.
The problem isn't much in the technology, but in the builder himself.
I build my own single ended tube amplifiers.
Any reliability problems that I've had in the past, have always been....pilot error (so I am NOT perfect).
No failures due to parts, as I do NOT purchase bottom-of-the barrel parts.
Steve
I build all my amplification, so as said it's as reliable as I build it.
Since I've been using 4P1L SETs I just leave them on 24/7. The tubes are cheap and there are just 4 of them and I have 150, so I simply don't care. I put on music before I go to sleep, which is why it stays on. My whole system goes through my SET - computer, iTunes, TV, everything.
I pretty much never have problems once the system is working - it just stays working.
I am using a pair of car radio 12AB5 tubes in SE pentode mode.
A pair of 12AV6 driver tubes, and a hybrid SS diode/6AX5GT power supply.
Steve
I want to make a Hybrid SS/tube rectifier to protect the dual tube rectifiers on the Raphaelite Sinovt amp that I am working on. Do you have a diagram of the circuit you are using? thank you in advance, Dak
I have never had any problems whatsoever with m Audionote Kageki. But, then again, I have never had a problem with ANY tube gear--linestages, my pushpull amp, my phonostage.
Most of the gear that people seem to have issues with involve gear that is either poorly constructed (including cheap parts and wiring) or being pushed hard to extract as much power from the tubes as possible. The stress on the tube shortens the tube life, and the failing tube also might cause some damage to the amp. The really well-built gear that is run conservatively will last decades, probably longer than most solid state gear will last (and most tube gear is repairable, while much solid state stuff cannot be repaired because a particular transistor or chip is no longer available).
RGA - you have a Personal Message emailed to you on 11 April regarding reliability and suppliers of LM-219IA.I've been using SETs for about 14 years and have had no reliability issues. As you say, the tubes can't be expected to last for ever, but the other electronics should be equally reliable to a similarly-built SS amplifier - and possibly more so than a Class A one. Class A tends to run very hot, whereas it's only the tubes on an SET that get hot and they should be well ventilated.
I'm presently using Chinese Consonance Cyber 845 monos, previously British Art Audio PX-25 and 845 Carissa. Others in my system were not owned by me, so no long-term experience.
I suppose one reason that SETs may be less reliable is that many are hand-built by humans in small works. The bigger brands building large runs of SS amps often use robots which may, or may not, be more reliable! However it's likely that the small producer with his soldering iron and oscilloscope will do more testing to ensure it's running perfectly before sending to customers.
Peter
Edits: 04/14/16 04/14/16
Are you talking about commercial products or home built? I build my own and I've never had a failure - I usually rob the parts for another project before too much time goes by. FYI, besides the tubes, things like cathode resistors for SET can get pretty warm and they are often close to other components like cathode bypass caps.
My SETs are warming up right now for a nice morning listening session. 4 years, 5 sets of SETs running at different times, not a hiccup. A couple are over 100 watts.
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