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68.188.189.26
This the upgrade underneath with k40s and MBGs which made a monumental improvement and I still have a pair of wimas to change out.
Here you can see that I have put in motor run caps in place of the junk Rubycons that were in previously.
Im rebuilding this preamp and it has lots of gain and when I got it was putting out a DC and of course new coupling caps took care of that..There is no schemtic on this preamp but I see two adjustements inside which I believe may a DC offset adjustment for an earlier stage.
If the power supply waveform isn't pretty,neither is the sound in most cases.
Edits: 08/26/08Follow Ups:
I respect your work. But gentlemen, all the more reason that you *should* know by now not to judge a book by its cover. (To those who have heard the pre, exceptions respectfully taken).
This pre launched the longest thread on Audiogon (over 3400 posts covering 6 yrs). There have been very few issues with this pre-amp and huge accolades over its gorgeous sound.
I own a Chardonay upgraded to a Sauvignon (line stage versions of the Syrah). This pre is dead quite; no hum, na-da, zero, zip. I'm running 1944/5 Ken-Rad black glass 6SN7s and 1950's-era JAN Sylvania 6L6GAs.
I drive it with an Optima Yellow Top battery-driven Altmann Attaction R2R NOS DAC, the Savingnon driving a First Watt F4 power buffer into VMPS RM30M ribbon speakers. The F4 replaced a Music Reference RM-200. Power courtesy of ExactPower and two 2.4KV balanced transformers. Liquid and luscious. The closest I can get to a 6SN7 SET if you allow me the line on the F4.
Maybe Mick breaks the rules? I care? Proof is he's a brillant designer and has made many people very happy with *reliable*--check the data--great sounding equipment at a killer price (entry fee was still $2100 give-or-take when he recently closed shop).
Maybe you dress and route the wires and introduce hum because now you have systemic instead of random interactions? Maybe not. Maybe you expend all the good building techniques at the cost of what? Time? Money? Footprint real estate? Even higher reliablilty? My pre is quite a bit simpler inside so I can only guess that the added complexity is due to the phono stage and how Mick incorporates it into the assembly process. Good building practice--No prob; good idea, excellent rule of thumb; I'm not dis-ing that per se. But let's all first take a breath and check the data; check the Audiogon thread. All around a very reliable, awesome sounding pre.
Rabeleis
Im not knocking this preamp in anyway..Its very vintage like in its sonic demeanor and it sounds much like my upgraded mac c20.It doesn't use solid state devices in the signal path and its easy to work on and,the price wasn't bad at all..It has a separate supply and even the 2 chasiss,look like my mac mc60s..This preamp reminds so much of a mac in the bygone era.Thank god we have those resurrecting that type of gear.
If the power supply waveform isn't pretty,neither is the sound in most cases.
I had to admit when I saw the pics posted I "assumed" a good deal of hack work had been done. After seeing the 6moons site I see some of it was original (but not all).
Rest assured that most here understand that neat wiring, all tied up close to each other, isn't smart. Still guys do take pride and try to run in 3D space in a somewhat tidy fashion. We also assumed we were looking at a preamp only.
So you know what they say about assuming and it is true in this case for sure:)
Russ
I'm a bit confused, if it's a cap coupled preamp, how/why is there a DC offset adjustment.
If your doing an upgrade for a client, why leave dozens of albino monkey coffins inside.
Also, you might consider using cap clamps to secure the motor runs to the underside of the chassis.
(nt)
Dear Limono,
The KONDO M7 you saw certainly did not come like that from the AN-J factory, Kondo-san never used this type of resistor anywhere in or near the signal path and rarely in the power supply and since he is not here to defend this I feel I have to.
It sounds like the unit you saw had had some kind of after market "upgrade", I have seen plenty of those over the years.
All the Audio Note Japan products we sold, used 1 and 2 watt Shinkoh resistor pretty much everywhere, and where higher power resistors were needed Kondo selected the best possible, some of which may look like "monkey coffins" but did not sound like them.
Just for the record.
Sincerely,
Peter Qvortrup
There are some impressive designers (Kara Chafee comes to mind) building great-sounding units with White Coffin resistors, nasty electrolytics, chokes > 10ohm, etc. I remember seeing a DeHavilland preamp and thinking, How could that possibly sound any good?
Well it does, and it just shows that you don't have need Mills and Blackgates everywhere to have nice sound (necessarily). It's more about voicing IMO.
No argument here.I have also heard plenty of excellent sounding equipment that has coffins and lower cost electrolytics..Like you say,its all in how its executed.You can find 20k dollar amps with coffins in them.
If the power supply waveform isn't pretty,neither is the sound in most cases.
nt
Dear Limono,
If you are talking about me then I am happy to be the cretin that stands accused!
Unfortunately I never managed to fully get this implemented, Kondo-san only did so after Cerafine stopped production.
Sincerely,
Peter Qvortrup
Oh, no Peter -you were called "enlightened management";) I just repeated what I read a few times from the sources I don't remember.(about BG's) You also mentioned that Kondo being pragmatic used whatever parts he could source and it didn't change the voicing of his amps. M7 with "white coffins" (probably in PSU)was on Audiogon sale a few months ago and the owner claimed that it was original Kondo unit. I don't see anything to defend. It didn't mean disrespect to Kondo (opposite) nor to you. You voice your amps (and marketing campaign;0) with BG's and other parts you find necessary to achieve the sound you desire.It is a respectable activity. I just don't like when people dismiss the design or particular equipment because of use of certain parts or they load accidental (poor design) with exotica and expect miracles.
Regards,L
that dealers forced Qvotrup to use Black Gates?
To infinity and beyond!!!
I'm not talking abought enlightened management ;)
I would look at the schematic and the layout, and consider ways to clean up the wiring. Generally, rat's nest approaches like the one pictured have less bandwidth, higher noise and greater tendency to oscillation due to inadvertent capacitive feedback.
More standoffs to mount parts would be advisable. The unit should be able to tolerate UPS/Fed Ex shipping without falling part inside if you did your homework. Of course it would sound better too :)
also customers love the audio porn and the interior shots . My personal experience is wheter neat or rat nest or PCB whatever I assemble it humms like a mofo 0)
Generally, rat's nest approaches like the one pictured have less bandwidth, higher noise and greater tendency to oscillation due to inadvertent capacitive feedback.
I agree and you know,this is one of the reasons the preamps like the Marantz 7c and the mac c20,c22 and the cit one sound so dam good when upgraded..They are neatly laid out and pretty basic in design and they just plain sound good..Every time I upgrade or repair a newer preamp,it makes me appreciate my macs and citations more and more with Jim's upgrades of course and some of my own.When you get back to basics and make it nice and clean,its going to perform well if you pay attention to things like the power supply,and layout of the signal path..
If the power supply waveform isn't pretty,neither is the sound in most cases.
The owner brought it to me..He lives in Michigan so there is no shipping involved..Its sounding very good now and what I did was go down to the original 1uf value and I put in a Sangamo 1uf pio and those caps are wondrous..They are square..The amp doesnt't look as bad in real life as it does in the picture.I will reroute many of the wires but its sounding very good and its quiet but I like your suggestion ralph about the terminals.
If the power supply waveform isn't pretty,neither is the sound in most cases.
That's pretty shocking actually. I guess that's why Supratek doesn't show pictures of the inside!
Anand.
At the Cabernet Dual...
I would hesitate to plug that in. It looks like a DIY project gone horribly wrong!
That's pretty bad. The caption says PTP is more reliable, but not when it looks like that. There is all sorts of stuff floating around in there, I wouldn't feel comfortable leaving that on in my home when I wasn't present.
It makes me wonder how quiet it actually was with all the wiring all over the place...chances are it was probably very quiet...If I wired something up like that it would hum like a humming bird...
Beautiful on the outside though...
...before you started your cap changing?
And what signal caps had Mick used in it before?
REgards, Allen
take a look for your self .
I was a little shock when i first see it .
it was worse than stuff that guy around this forum make .
LT
The caption seems a bit off... given the unprofessional construction (although the 'snake pit' comment is real enough), there's no way this thing is going to be 'reliable'. I guarantee that if that thing were laid out properly, it would perform better.
Forgive me for going off like this, but having done this for over 30 years now, and paying plenty of dues for it as a result, seeing someone get away with this sort of thing is difficult. You don't glue capacitors into an amp or preamp- the first bump in UPS and you have a service issue and a shock/fire hazard (look at the photo on 6moons- the power supply filter caps are glued in place). In this case, the tip of the iceberg- five dollars of terminal strips, clamps and standoffs, plus an eye towards their use in the chassis design would have resulted in a piece with lasting value. As it sits, a unit built like this cannot be readily shipped and the performance from unit to unit will be inconsistent.
Shipping something like this would open one to lawsuit liability and servicing such a unit without fixing the obvious construction issues is unethical. I know its a bad thing to bad-mouth a competitor (even one that is out of business for what are now all-too-obvious reasons), but this is deplorable and equipment like this should be avoided! IMO I would be remiss in not saying such a thing after seeing that photo.
Dear Ralph,
I have to say I share your expressed views here and may I add that anyone owning a product that is made this way does run the risk that their fire insurance may not be valid and pay out if the insurance company or its agents decides to have a good look at causes and avoidance, a practice which is getting more common, at least here in the UK.
The other aspect is that products made this way, apart from being potentially unreliable, noisy or downright dangerous skew the competitive landscape to disadvantage manufacturers who abide by the prevailing electrical safety regulations, because our products have to carry a premium to cover this compliance.
What I also find hard to understand is how various magazines can review products like this without taking some risk that they themselves get caught up in liability suits as a result of someone buying the product based on a recommendation by a reviewer, if I was the editor I would be more than a little weary of this.
Sincerely,
Peter Qvortrup
given the unprofessional construction (although the 'snake pit' comment is real enough), there's no way this thing is going to be 'reliable'. I guarantee that if that thing were laid out properly, it would perform better.
Hello Ralph,
I understand your point of view, being a manufacturer and all but my Supratek Chenin, powered and use in the averaged of 4 to 5 hours a day and sometimes more from April 2004 up to June 2008, never have an issue. The preamp was very quiet and the phono section is superb (compared to Wright sound WPP100C and Pass Labs Xono that I owned and to the Cornet 2 that I currently own) and does not hum even at maximum volume setting of the volume pot. As I recall, I only had one incident where I thought something was wrong on one of the channel on the phono. Mick sent me an schematic, and I compared the voltage specs from it and found out it was the 6C4 tube doing the anomally. After that, fortunately, the preamp is working flawlessly up to now.
FWIW, as for the DC pot, that is for the Phono section adjusting the bias on the input FET.
regards,
Abe
Tube rectification is the key!
If so you are lucky that shipment didn't damage it. I've read plenty of positive comments about the brand in the past, but FWIW as a responsible manufacturer, you have to build your product so it can arrive safely and survive the normal handling that it is going to get over the years as it is used.
The unit pictured is built with glue.
As time goes by, the glue will perish, making the unit more and more fragile. Heat will accelerate the phenomena. In time, it will be come hazardous to use as it begins to fall apart. You have to also ask yourself 'why is this manufacturer also out of business?'. There may be any explanation from the manufacturer, but having to rebuild a number of units like this because they got dropped in shipment is the sort of thing that kills a manufacturer. I've seen other 'manufacturers' make this same mistake, although I am of the personal opinion that anytime you see something like this, a scam is taking place.
IOW the construction and the out-of-business thing are likely not coincidental. If your unit is built the same way you should be aware that its not ethical to sell it- construction like that pictured is barely acceptable at a hobby/prototype level, and is the sort of thing that should not be exposed to the public.
Hello Ralph,
Points well taken.
regards,
Abe
Tube rectification is the key!
What? You don't use 10 watt sand cast speaker crossover resistors for grid and plate stoppers? I build my mono ladder attenuators with 12 watt mills resistors, I also brush my teeth with LSD, is there a correlation?
I'd like to see what a stock one looks like. I just can't imagine it looking like that!
Russ
Allen
It looked much worse when I got it.There were a couple people that worked on it but the caps that were in it were the wimas and they were so so so so HARSH sounding and the paper in oil mbgs and k40s just took that edge off and gave the preamp depth and detail that you can hear and now its much more natural..
The motorruns I put in because it had 3 rubycons hanging in it that came unglued.
If the power supply waveform isn't pretty,neither is the sound in most cases.
....the wimas and they were so so so so HARSH sounding....
Yay! Michael and I finally agree on a cap. ;)
I'm curious how you mounted the motor run caps. I can't see any clamps.
ray
Ray
I used somthing called amazing goop..The stuff is fantastic and its an RTV but its so strong,you can pick the amp or preamp by the cap after its glued in..
If the power supply waveform isn't pretty,neither is the sound in most cases.
although they are very pretty on the outside.
Yeah, this is part of the reason I get on people's cases about using Mills resistors all over the place... There is no f-ing way all those resistors need to be 10 watt...
Mills and AB and some Rikens
If the power supply waveform isn't pretty,neither is the sound in most cases.
What are all the white sand cast resistors?
Mills, AB's, or Rikens:)
Russ
Russ
I know they aren't AB or Rikens..I was telling Black plate the resistors that I like which are ABs,Mills,and Rikens. Capiche?
If the power supply waveform isn't pretty,neither is the sound in most cases.
of the slight inductance. Not all areas need noninductive resistors. I do like the Mills though as well as the 5 watt Kiwame. And for me I do find that using larger than needed resistors is a positive for the sound.
The Elaborate DAC=Johnny's Balloon Meshplate 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
see images at: www.pbase.com/jamato8
I agree..The chasis looks typical Mcintosh.
If the power supply waveform isn't pretty,neither is the sound in most cases.
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