| KBK |
I went and bought two Counterpoint SA-220 amplifiers. I decided to get two, so I could go stacked for biamp or separate mono-blocks. I am getting the schematic in a week or so, and am wondering if anyone here has ever taken a shot at modifying or upgrading the circuits in these units.
For those that are unfamiliar with the unit, it is a SS-fet based 220WPC output stage, coupled to a input buffer-predriver 6DJ8 based tube stage, that has even got a tube rectifier in it's PS!. It is very much like a tube pre-amp built right into a dual mono (single transformer, dual wound with separate caps and bridge rectification) Fet power amp. The unit weights 69lbs, and is internally strappable to a 600watt monoblock. According to what the manual says, you can upgrade the internal rail fuses to 20 amp, if you should desire to.. for low impedance loads like say.. A pair of Apogee Duettas, or the like. It runs typically blazingly-toaster hot like most fet amps.
Of course, the moment I read that the rail fuses can be upgraded to 20 amp... I spun off to Rat Shack in a cloud of hen $hit and small rocks.... and in they went!
I have to modify and tube-roll both units identically for monoblock/stereo use.
Any ideas? |
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| Dingaling |
| did you ever mod it? |
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| Dingaling |
| also, have you tried other tubes in there? |
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| KBK |
hmm. Ok. Not much action on this one! I accidentally ended up with a third. Don't ask how. :) Well, OK. I fixed one of the original two, only after I bid on a third on ebay..because I was PO'd that the fix of my second unit was not advancing at a resonable rate..
I bid high..and now 20 minutes after I bid.. I fixed the second unit. Murphy's law! It looks like I'm going to win that one, so I'll end up with three.
Anyone got a schematic for this puppy at all?
Should I hand them out, like shop class, so we each have one to work on? |
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| anatech |
Hi KBK,
I just fixed one. I will be working on modifications to make them sound good and be more reliable.
One thing you should know. Those outputs are really matched very tightly, to select a set you may have to buy 50 to get a set that is tight enough. It's not fun. That's why M.E. charges so much for a repair.
You should see where the SA-100 has got to so far. Mind you, it isn't the same circuit anymore. It has the sound people liked, only better.
For tubes, I have had great luck with the Electroharmonix 6922. I would recommend them highly. You will have to mess around with them to get the gains matched between channels.
One last warning, these units don't always match the schematic. Sometimes they don't even come close. You are further ahead to trace it out. Don't worry about the analog computer, it's jumpered at the factory at the minimum sensitivity. As close to off as it gets. I would put the lower rated fuses in if I were you.
-Chris |
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| KBK |
I was kidding about the fuses, I have 10 amp ones in there right now.
There's these 6 499k resistors in between the Wima caps in the tubed power supply for the 6DJ8 predrivers. One of them was burnt out. I replaced it with something close..and the issue is still there. it seems these resistors need to be exact, or sumpthin'.
Anyway.. I manged to pop the adjacent one during a live voltage test..my dang meter was set to resitance! FUG!
Now both channels are distorted. FUGGIN HECK! Me? I'm short on time these days to 'duke it out' with gear like I used to. Hopefully, If I get some 1 watt 499k resistors, that will fix it. It seems these puppies in some way 'balance' the voltage that goes to the tubes. (B+?, now very low?) I've no idea what the bloody resistors do, and I don't have the energy at this time to take it fully apart and duke it out. Buying the third was the easy way out. Change the silver faeplate to my black one, (to have a black pair) and be done with it. Flip to mono, and leave them alone. Yeah right. That might last a day or two.
The screwy part, is I used 5 100k 1% 1/4 watt resistors to try to hit the 500K the others measured. No go. damn.... I gots to get the schematic..
This amp is also a ba$tard to work on, with the wiring and chassis, etc. Tubes and solid state. A perfect recipie for minor bouts of shocking behaviour. Can you say 'electrocution'? and Screwdrivers stuck in the ceiling? From the reaction of the muscles in the arm....
You see, I lent out the perfect, all original minty one I had first bought. I'm getting it back tomorrow so I can finally do comparative tests. And hopefully get the dead one working..while I await the arrival of the third. Eventually I'll have three working units. By then, i'll likely be out of time to do this sort of thing altogether..but also be in the quandry of having no manufactuer I know of.. make gear to my personal standard of sound quality.
I'm sure most of us here are familiar with that particular sitaution.
In the end, I expect I might get the completed boards for at leat two of them from Alta Vista....and then.. mod from there. I can also then sell the working components. Complete board/trans assembiles. It would drop the price of the upgrade to less than $1k US, each. Each channel board, matched and working/tuned should fetch about $150US, easy, on ebay. A drop in fix, and worth every bloody cent. Then, the main board assembly, in good clean shape, another $150, for sure. The upgrade is $1400, so, deduct about $450-550US from the price... |
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| sajti |
| quote: | Originally posted by KBK
hmm. Ok. Not much action on this one! I accidentally ended up with a third. Don't ask how. :) Well, OK. I fixed one of the original two, only after I bid on a third on ebay..because I was PO'd that the fix of my second unit was not advancing at a resonable rate..
I bid high..and now 20 minutes after I bid.. I fixed the second unit. Murphy's law! It looks like I'm going to win that one, so I'll end up with three.
Anyone got a schematic for this puppy at all?
Should I hand them out, like shop class, so we each have one to work on? |
Try to search the web. Due Counterpoint is finished few years before, the founder of the company still keep a new homepage with modification kits, and general help for his amps.
I don't remeber the location, but I saw it, few months before.
sajti |
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| Elso Kwak |
| quote: | Originally posted by sajti
Try to search the web. Due Counterpoint is finished few years before, the founder of the company still keep a new homepage with modification kits, and general help for his amps.
I don't remeber the location, but I saw it, few months before.
sajti |
www.altavistaaudio.com |
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| anatech |
Hi KBK,
I was a warranty service center for Counterpoint up until the end. They still owed me $$$. :bawling: Oh well.
I would think twice about upgrading those amps. I call it the Michael merry go round. Fad central.
Those resistors do not have to be precision parts. Can you say, plate supply decoupling resistor? I think you are looking for 499 ohm parts. 470 to 510 ohm values should work fine. The plate resistor should be 100K ohms.
-Chris |
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| KBK |
Got a schematic? I'll pay you Alta Vista's price. That'll bring a few bucks in. I'm sure Michael won't mind.
That's $75US, plus $14US shippng and handling. That's $89US. Then, dollar conversion (approx 1.21)makes it.....about $110.00 cdn. |
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| anatech |
Hi KBK,
I don't have an emailable copy. And yeah, Michael would freak. The "manuals" are broken up into insanely small sections. Something that would be 6 pages is a book with Counterpoint. I will help you out. The circuits are very simple. As I said before, they may not match the printed version.
Counterpoint makes many design errors, these are created anew in some "upgrades". Please use your common sense when dealing with upgrades and general information.
The reason I have redesigned the SA-100 (slaughters the SA-220 now and I'm not done yet) is that some Counterpoint customers tracked me down. (I sold my shop 7 - 8 years ago and moved to a different city!) They needed a good tech to deal with their product. Now that I had time to spend I looked more closely at the circuits and saw the design faults. Understand that you can't modify a product while being warranty for same, so I didn't bother studying them at the time. SO after fixing the power supply and tube circuits, it's time to convert the output stage to bipolar. I am building a prototype of that now. Other things on the "fix" list are the DA-10 (after Michael mod), SA-220, SA-1000, SA-2000 / 3000.
I don't have a problem with Michael, just these products and the mods that follow.
-Chris |
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| KBK |
I'm not an EE, but I do know parts selection like the back'o'me hand. I do also know grounding, noise isolation and parts location, tracing, etc on boards for minimal interference and issues. This, of course, allows one to second guess many engineers, and create something that sounds better than their work. As they say, anyone can make something great if price is no object. And anyone can improve on any other's design work. The principle reason they tend to have computer programming 'teams', not individuals. But we both know all that, it seems.
More than anything, I'm looking at this point to do a basic parts upgrade. then, see what comes out of that effort. I need the schematic to do this properly, of course. I've always gone through the effort to do modification and repair work blind.. with no supporting schematic. This I figured was the best training ground of all. Fix that puppy with your *** blown off! Anything after that should be ridiculously simple, meaning..using a schematic, for once.
So the one is broken. Micheal was kind enough to tell me the fix I needed for the SA-220, in a few seconds. I took five secs to tell him the issue, he took five secs to tell me the fix. He stated basically what you did, but stated the caps were bad as well. I've never seen the traces (if there are any) on the underside of the main board, and can't see where anything goes due to the size of the caps, etc. A shematic is the way to go. Notice the repeat on my harping of the need for the schematic? :)
Yes, I do see you hinting at the mod stuff. But I need working amplifiers at this time. I've got others, but I'm kinda (currently) in love with the idea of the SA220/220 mono set. I always wanted them. At least until I've had them for a while. Do you need a few to work on to do the design work? I love the sound, but not the lack of extreme grunt at the bottom. My 300kuf Belles 450 does that pretty well. I go to the TO area fairly often. Where in Ontario?
I'm Itching to do that fix tonight, but I'm SUPPOSED to be working on modding the optics package for a JVC G1100 DILA for a friend......
Edit: DOH!! 500ohms. fug. |
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| KBK |
| thanks dude. I'll amble over and take a peek. |
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| anatech |
Hi KBK,
The supply section of the SA-220 is completely different to the SA-220. This is where your problem is. If you look to the left, you will see I'm in Georgetown, On. E mail me if you need help. I have a photo of the 220, but I think it's topside only.
Yes, I have hinted at mods. These are basic circuit changes that anyone should be able to see are lacking if they do any design work. I am not trying to "snipe" at Michael's designs. I have repaired a few basic, real faults in the SA-100 (design wise). I have gone further and changed the design completely as well. This is a progression (not Natural :D ).
-Chris |
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| phi70 |
I see that there is a counterpoint expert in this thread.
May I ask if there is any opinion / experience with the Natural Progression Monos?
How are they compared to the NPS series and the modified SA220s?
Thanks. |
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| anatech |
Hi phi70,
I am not a fan of the NPS series, or the newer product. Michael has yet to learn how to build a power supply. His errors got worse with newer product. The NPS series has a circuit fault in the bias circuit. He actually made a constant temperature circuit rather than a bias control circuit.
For me, I find I can modify an SA-100 and get far better sound quality (not done yet), the SA-220 is only larger so those changes will need to be scaled up somewhat, but they are the same.
I find that some newer models still suffer similar faults as the older ones in some regards, but at least they don't explode as often.
I've ignored his later mods as they tend to center on using his newer circuits so he can use bipolar outputs.
-Chris |
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| KBK |
Ok. I've got a odd situation with SA-220's again. A quick one for Chris. Once again, I've got three of these. Love those hybrids. I still have the same two, and a cranky and beat up SA-20 came my way for virtually nothing. Gonna sell the two good looking units..and keep the junker.
Swapped tubes across channels, and swapped relays.
The channel not operating is a HAIR warmer during warm up, and a hair warmer at full stability (20 min). It puts out a mild 'buzz', sonically, no DC offset-this buzz, after the relay connects. volume cranked on pre-amp, and a tiny high frequency version of the signal comes through. that's it. Last quickie I haven't done, is to try cleaning the mono switch on that side. And those schematics are a ******. Not a cleanly drawn circuit amongst them.
Any clues?
Oh yeah, the M-05. What do you think of the idea of fxing it and then blowing it out on Ebay? That's one way to get around this current issue. |
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| anatech |
Hi Ken,
Interesting fault. I would think you would have a DC offset condition or low bias current. The low, tinny audio suggests an open contact. Swing it by if you want.
I am trying to get back into the M-05. I had a shot (cortisone) in the left shoulder and am expecting one in the right. That should put me near the end of January where I can manipulate this beastie. I am also going to try and give you back the dual AC cords our previous tech combined into one.
How cheap did you get the SA-20? I need a prototype chassis and the tube section output is inferior to the SA-220 (not the same amp really). He paralleled the last tube for the SA-20 and runs the SA-220 as a pseudo constant current loaded animal. So it will have much higher distortion than an SA-220.
Take care Ken, Merry Christmas & Happy Holidays !!!
-Chris |
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| KBK |
I fixed the SA-220, now that I actually broke down and looked at the schematic. 1/2W emitters? Duh! Seems likely to be a common failure. That current starving again. All of 20 minutes once I used my head for second. Changing all of the series PS load resistors to 1 watt and raising them off the boards would be a good preventative measure.
It also improved sonically when I replaced the last two 100uf 400V caps for the final stages on either side, (C15 and C115) to 180uf 450V. I'm pushing my luck, I know, but it made a huge difference in stability, slam and liquidity of the sound. Oh, I put those russian 0.3uf polystyrene 'multicaps' on the final loading caps to the tranistors. from 1uf to 1.3uf. Worked wonders. Managed to fit them under the board. And the guys who made the boards for them should have been shot and fired, in that order, after the first year of use at counterpoint. Those boards are too fragile. I've rearely met a board that fragile, not since a 40 year old Dynaco or the like. ****. junk. Looks nice though, just don't try to pull a main snap-mount PS cap.
This amp is a pain to service! But it does not compare to the Belles 450 design. That amp is a nightmare. No pots anywhere. Biasing/DC is fixed. get it right.........no pots is good thing, though.I remember, one time, that the 450 sounded 'off' once, for about 3 months, in one channel. I broke down, and took the cover off. One of the hitachi fets had blown itself to pieces. Took it's head right off! When I pulled it, tested it... it was a dead short! And the amp still ran. Man that amp is tough! Over 15 years at over 75kuf per rail..and it still works. Good solid bass,as one might imagine. |
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| anatech |
Hi Ken,
I replace those caps all the time, no problem. ;)
Yes, the amp is a pain to service. There are no source resistors, those are gate stoppers and should never get even warm. Unless the gate shorts to drain (common) and then they literally explode. It's kinda fun to see, isn't it?| quote: | | Changing all of the series PS load resistors to 1 watt and raising them off the boards would be a good preventative measure. |
Yes, but only if you have the board up already.| quote: | | I'm pushing my luck, I know, but it made a huge difference in stability, slam and liquidity of the sound. |
Yes, but you are further ahead to fix the problem in design. Either way, it's a better sounding amp now.
-Chris |
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| KBK |
I have the rather messy looking SA-20 now, in the trunk of my car. I have to take the beast out and look at it. I took a gamble on it, as to the source of the issue from the statement on the E-bay auction, as to the nature of the failure. It is likely to be the same problem as I just repaired in the SA-220. Paid $300US for it. Some might say it is too much on a gamble, but hey... that is the nature of a gamble. To each the worth they impart and imply.
The seller was entirely honest, as this was a second auction on the same amp, the owner had stopped the original, and re-did the auction based on further evidence, not wanting to defraud anyone, or even have the appearence of doing so. A good omen. I hope.
If this is the case, then I wil have two perfect channels to sell on ebay or to keep as spares if I decide to keep one of the 220's, after asessment and repair. If that is the case, or even if it isn't, I'll likely give the blank chassis with tranny, to you. If so, I'll likely deliver it in person. The main PS Caps are yours, if needed along with wiring, rectifiers, etc. Basically, the three boards in working condition, removed, and sold on ebay. You get the rest.
At that point, what the channels may sell for, may deliver the chassis to you, at very little cost to me. This, insofar as cash outlay on my part.
You indicated at one point that the fets are suject to decay over time, and ultimately - failure. That is not a good thing, as that would mean that the Counterpoint Sa-20 and 220's are always destined to fail at some point down the line. At least, far more often and sooner than any other amp out there, possibly. Literally a limited and unrepairable lifespan. Not a good thing.
What I mean, is that, in terms of audiophile collections... Counterpoint Fet-Tube Hybrid amps, may be, 50 years from now, all ...non-working static models. Full of the spoor of magic smoke. |
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| KBK |
Broke down and opened it up. Two separate transformers, likely the original one was blown. If not, then the original units sure were ugly-***. Looks like **** in there. Chassis is fine. HV transformer is bolted to the cover! What a mess.
Should have known better than to buy it from a audiophile on ebay. Sometimes you win, sometimes you loose. Now I'm supposed to give this guy (the seller) a rating of some sort...on this? He did not mention that it was 'non-stock'. Otherwise, I would have never touched it. serial #22044 or the like. Early unit, I guess. 66,000uf in the heater supply. definitely not stock.
Oh well. If the fets are good, I still come out on top. Price for mikey's used pulls are up to $220US for the set of 8 (one channel) |
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| anatech |
Hi Ken,
It's not stock, but I can still work with those parts (I hope). The high bias tended to kill the original transformers. Then with people telling others to increase the bias current would seal it's fate.
Yes, if you can pull a couple good sets of outputs, you are in fact way ahead of the game. I am wishing you well on this.
| quote: | | 66,000uf in the heater supply. definitely not stock. |
Yet another good way to makea transformer buzz and overheat. Everyone is an expert I guess.
-Chris |
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| KBK |
I'm going to see what I can get the guy to refund me. I'm hoping he'll see that about $100US refund, is just about right.
At that point, I will break downa nd buy the transformers from ANTEK on Ebay, for the M-8 Precision fidelity hybrid. At taht point, I will also buy two of the 800VA rated 56x2 transformers at the same time. 5.4"x 2.8" in size, with clamps, pads, etc. These two will stack nicely in the Counterpoint chassis. 800VA at 50hz..+10% for 60HZ..eagles..880VA rated. Not too shabby.
At that point, you may have a choice to make. The stock counterpoint transformer from my second unit, the one you repaired... or the two separate 800VA toroids,with the small dynaco tranny for the tube section....OR.. add in one of ANTEK's small 150VA tube V rated toriods. If you choose the stock units, I'll make use of the transformer mods. I certainly would not mind, but the work involved slows me down. Heck, the price of about $180, overall, for all three trannys..nearly makes it a no-brainer. The trick is getting that tube one just right, obviously.
Mikey rates at 120-100x2 AC in, and ..uhm....284x2AC and 54x2 (x2)out, IIRC. so..the ANTEK 250x2, upped from a 115 in to 120 in, becomes...not enough. only 4.5% higher, or so. damn. Ok not for me, but how does it work for you? He has other transformers, take a look. but they are all notably larger and the voltages don't work for the stock counterpoint design.
http://stores.ebay.com/Antek-inc_Tr...3QQftidZ2QQtZkm
Here's the specs:
You are bidding on a new 150VA toroidal transformer. It is precisely made for high-end tube amp or pre amp. It has very low power loss and magnetic leak. Labeled input 115 + 115 Vac (Dual coils), outputs 250Vac x 2 (dual coils) at 250mA each, 6.3V at 3A, and 12.6V at 2A each. This item has CE certified. Mounting hardware is included. The test results are excellent. (note: Please increase 10% of rated power when this transformer use in 60 Hz power source) 4.4” Diameter x 2.1” High.
You'd have the 12V 2 amps for turn-on functions, led's whatever, and the heater, of course and the 500VAC, with 250mA, series. More VA is available, but it comes at a sizing issue. This one would present enough issue.
Maybe I should call my manufacturing bud in China and start importing toriods myself. Might be easier.
Yes, I do have a friend of (casual friend, but a close friend worked for him for 3 years) many years aquaintence, who has O/O a factory out of China, Gangzhou area, for the past 10 years, minimum. He knows the ins and outs of electronics, specifically high end audio quality manufacturing in China. I've never made use of the connection, but maybe it's finally time. he knows everyone over there. all the real people the honest ones, the reliable ones, etc... and all the dangerous people. Now that's a valuble connection. |
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| anatech |
Hi Ken,
I'd be more than happy to have a look to see what would work best for you. I'll gladly take what you do not want. Keep in mind that your amps working properly is the first concern.
Let's talk about your acquaintance in China. It may turn out to be very useful to you. I'm still dealing with sore shoulders, injections and pain management courses. So I'll bet I'm slower than you right now! This actually bugs me quite a bit.
All the best Ken, you are welcome around any time.
-Chris |
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| KBK |
| What I'm thinking, as the market is definitely 'in the groove' of using facilites out of China for component manufacturing, this angle could be used in your pursuits to organize chassis and components and deliver unpopulated chassis to Canada, and then fill out here,and have finished products. At a marketable and viable point in the current north american marketplace - this, from the lack of need for large numbers of initial purchases of the given major chassis components. Due to the pricing structure of such an endeavor, it is possible to pursue such and get past the trick of initial startup as a costing/financing factor. The connection via this friend is what makes it viable. Otherwise it is a difficult and darned near impossible task. Other than these comments, It is obvioulsy a conversation, that is best taken place off this board. :) |
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| anatech |
Hi Ken,| quote: | | It is obvioulsy a conversation, that is best taken place off this board. |
Yup. That was my intent all along.
-Chris |
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| jrdmedford |
Why dont you stuff a JLH amp, Death of Zen or some other
popular bipolar amp in there? You'll get less output power for
the same amount of heat dissipation, but it will probably sound
dearned nice!
I'd look at this article for some other ideas:
http://www.tubecad.com/2006/10/blog0084.htm
The upside with this is you could buy the Aikido boards from him
and use the power buffer stage that he suggests at the very
bottom of the article. The downside of this is that these devices
are Flatpacks (Not TO-3) which means some heatsink calculation
and mechanical adaptation needs to be done.
What trips me out so much about solid state is the excruciating
details with respect to thermal management... With tubes you
get alot of leeway and warning signs when you are pushing them
too far. Also, the output transformer behaves as an expensive but
good fuse if something really bad happens.
-- Jim |
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| anatech |
Hi Jim,
My work with these amps is developmental. I sure don't want to stick a clone of a different amp in there. I'd rather figure out how to improve the amp while retaining it's sonic signature as much as possible.
Besides, where is the fun of cloning something??
-Chris |
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| KBK |
OK. sa-20 purcahse issues resolved. The seller was insane, in the end. I attempted to reason with him, over about 7 emails.
-He said a channel was 'down a bit in volume'
-he is the seller and has ultimate responsibility for the item at the sale point, re representation.
-When the amp arrived, the t-03 covers were all off the one channel and in the bottom of the box. Which means they were pulled and tested, and the channel was known to be blown.
-The cover HAD to come off for the re-insertion of the t-03's...this means the seller or his technician KNEW the amp was a complete kludge of a mod, witha blown transformer. Does an sa-20 have boards for the outputs? This unit has only one set of diodes for the entire rail of t-03's. No output boards.
-This means he knowingly did not disclose this imformation about the amplifier. This is known as fraud and misrepresentation.
-To top it off, the guy works at a high end audio shop in chicago.
-I finally called him to see if I could keep the chassis, and he refund me $100, but he yelled at me and cut the call off. He maintained his position of it being 'as-is' so too bad for me. I told him tha ws like having a boken honda transmission and motor stuffed under the hood of the chevvy..and not telling the buyer. He eventually said that he would refund the price (in the end, after much badgering by me, in terms of getting him to see what he had done as being totally dishonest), and the one shipping, if I sent the unit back. I asked that he meet me half way, and refund half the funds and then I send the amp. I siad, I trusted you, I received this. Why should I trust you again? With the funds and the amplifier? Again?
-at this point he refused..and said that if he had to deal with one more call or email on this, he would deduct $50 off the refund for each communication. (two emails back, he says this)
-That was when, two days later, I called him with the # he supplied on the UPS shipping sticker, and tried to save him $250, but proposing the $100 refund and I keep the POS. No-one else would want it, ever. That's when he cut me off.
-He then sent me an email telling me that phoning him was unnacepptable, and was harrassment, that he was sending this email to his lawyer, and he would inform the police and authorites if I attempted to phone him again. (All I said, was my name,and hello. He then cut me off and yelled at me, and hung uup the phone, mid curse, no less). He said he was afraid for his family and friends. In this email he re-iterated that he would only accept communication by email, and that he would deduct $50 for each communication.
- at that point, after attempting 7 tries at simple reason..and being overly fair and attempting to make things good for him, ie better for him than me, and only the barest form of fairness and balance in this transaction, (also putting my reputation, name,and business reputation on the line, over a lousy $300!) I was forced to give him a very nicely worded negative strike on ebay. There goes his 100% score.
What a completely insane person. I'd hate to be one of his customers, as the man is clearly insane and sociopathic. he wanted his way, and eventually went ballistic if anyone disagreed with that, to the point of threatening to take them to court. Truly an extreme individual and a disservice and danger to the Chicago high end audio business group.
~~~~~~~~~~~~~~~~
Chris..now I have a chassis for for you. As you can see, it has a history. I think the one channel is good. I'll obviosly keep that.
I will investigate the transformers, but in the meantime, I need get this puppy to you in some fashion. A timely fashion, of course.
Counterpoint question:
On the Sa-220. The interstage 0.68uf couplers. Can I buffer those? Or does that quickly become an issue? I don't think it will, but I need to know your thoughts on that. The 0.68uf wonder cap is at a critical juncture for the signal, and I'd like to fix it up a bit. I'd like to use one of the Russian teflon 0.1 or the polystyrol caps. (0.3uf, 0.315uf, 0.339uf, 0.47uf,and 0.5uf, all 250VDC rated for the green polystyrol ones) A pair of the 0.339's might do, but the are physically to big to fit in the space. For example, the 0.5uf units are so big, they are almost the exact same can size as the wima 400V 1uf B+ rail buffers. (the six that are around the rectifier) |
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| anatech |
Hi Ken,
You are correct on all counts. He knew perfectly well one channel was toast. He also knew the repair and resale value of the amp. The repair cost for a transistor kit is well over $300 as you know from experience. You would be well within your rights to charge him a slightly higher amount for each correspondence, but it isn't worth the effort. I am sorry to hear you were lied to and ripped off.
I think the recent negative feedback will cost him well in excess of the $300, but he is too stupid to recognize that. I would have also reported this issue to Ebay - you still can. Do it.
The chassis can wait a bit, and you are welcome to the mosfets. I didn't want them in the first place. I can't do anything right at the moment but we can sit down and discuss what you'd like to do with your unit(s). I'll lend you my thoughts on this (but I want them back! :D )
As for upgrades on these......... Those coupling caps are 1 uF in the new units. The driver stage in the SA-20 isn't that good either. I don't think a magic cap would help here until the other design faults are fixed. Consider any polyprop in that location. That would be vastly better than the originals. I think Partsconnexion has a 15% off sale this month. Time to buy. ;)
-Chris |
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| KBK |
I swapped out the sovtek's for the 622EH tubes. I know these tubes! I can get these tubes, this exact manufacture (at least with a casual look,and also it's other more expensive brother)...by the hundreds, for almost dirt. I know this guy, you see....
I do have a problem with matching and testing though! My B&K Dynajet 707 does not recognize them as a 6DJ8, electrically speaking, in terms of testing for mutual conductance. I cant test, match or grade them! That's a major problem.
Does the extreme high end excess ever go away? Or is that my new design of cable? :p The new cable does everything right, in the extreme. Except, possibly, for that. IT's sooooo good, that people will begin to understand how much cables actually color their systems. It will be a major case of 'I had no idea' for every person who tries the cable, no idea that cables are responsible for that much coloration of the signal. The reason that this could not be figured out before, is that no cable that has such low levels of signal damage, in terms of all parameters of propogation itself, has ever been available....until now. We have always been forced to use a cable or wire everywhere, so there is no possibility of escaping the effect of wire, period. This means we have no possibility of understanding the effect of wire, on the whole, as no chance of escaping it's influence...exists. Kinda like folks trying to figure out time, matter, dimensionality, gravity, etc. Unable to get outside the box and take a look wholly fresh and unattached look...
Yes, I manufuactured (forged) the conductors myself, from scratch. If you want it done right....
No metallugical/refining/etc company is going to make such small experiments for some guy, without huge outlay. Besides, they have no idea what I'm attempting to do, and are not going to allow me to commandeer my own experiment, in their labs and facilities. Then they'd argue with me on the whole financial aspect ,value, ownership, rights, etc - once they 'get it'. Money has a way of making people see their own viewpoint only, when lots of it suddenly appears on the table. Cheapest and safest to do it myself by a factor of 10-20x, no matter the horrendous complexity and work that it is. This also keeps me wholly in charge of my own technology. I know it's very naughty of me, but I figured out how to make copper more conductive than copper.... :p
I'll put the Sovteks back in and see if it goes away. Problem is, I'm also modding the Counterpoint at the same time. Makes for very tricky evaluations. |
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| KBK |
good lord!
The cable has such low dc-to light speed impedance (apparently) that moving the cable a few inches..or most specifically...the resistance of the RCA jack becomes a VERY noticable issue. I was getting HF reflection between the two jacks, methinks. I re-inserted the cables on the CD...and the VERY noticable HF emphasis has nearly dissapeared. Ouch. Oh well..with more rsesolution comes more clarity of other issues. I just tried it as a RF cable in a fully modded 1080P capable CRT projection system. Flawless. This, as a single composite NTSC cable. This actually a fairly difficult test, due to the nature of the NTSC signal. It did extremely well. Right up there with the best I've seen, without any sort of controlled testing. Next, is some Audio to RF testing of square waves. That'll separate the wheat from the chaff.
The problem with this cable as far as DC to lightspeed aspects of EM and ES (field and current) propogation, unlike all other cables..it is an 'equal opportunity employer'. :) Yes, there is alot I'm not saying. Obviously. For all the right reasons. ;)
I wish these guys who made all these recordings had access to this cable, as it's making HF problems so apparent, it's extremely annoying. The fact that if passes RF so well, as a casual analysis..seems to indicate that it does not have audio freq HF resonant issues (not always true, but ..unlikely), which would tend to lead to the Audio frequency HF issues I'm hearing. I'm not sure it an issue. The clarity and dynamics up there and throughout the entire band..is extreme..from micro to macro, it's unlike anything I've ever heard. Oh well... new area of exploration....new problems!
You see, if a cable or signal transmission system does not present any issues to any component of dynamic signals..then the way the ear works is specifically in the realm of dynamics..and if all other cables funck up dynamics, and specifically in the HF range...which they do (and to all other aspects of signal propogation!)....then a cable that does not do that at all....does present..everything that currently exists and was built designed, understood, eq'ed, etc....all around that point.....it does present that entire world of audio....with a serious quandry!!. Don't shoot the messenger!
The apparent increase in extreme bass fidelity seems to also indicate that the issue of 'balance' does not lie at the bottom. I need to do some micro-resistance and capacitance tests.... run some sweeps. Dang. Now I have to buy a proper scope and bench set up. I hate that.
I'll head to the University maybe, tomorrow. Get some quick time on a reference LCR meter.
I may also be getting RF issues, as I am using a SA-220 (modded) and a sa-3.1 pre (modded). There may be feedback between the two cables, and I'm not sure Mikey did much to bandwidth limit his gear, not thinking it's an issue. But an extremely low impedance super bandwidth cable can also make a great antenna. I'll bounce out the current gear and see what happens. I tried a RF blocker, but that does not present a problem for RF to be generated on cable itself. I noted no change whatsoever when this was done.
I may just send the amp chassis soonest, via shipping it, as that may be the best way to get it there quickly. It's going out this week, for sure. I'll pull the channel and boards first, of cousre. |
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| KBK |
Feces.
Mikey's design, in terms of layout of the 3.1 preamp is apparently the culprit.
I recapped the unit in the extreme, in terms of the signal caps, all russian polystyrols now. The vast majority of the issue if not all of it...went away when I pulled the 3.1 out of the system. Loading is now different too, so I can't discount that RF possibility.
When I first looked at the unit, I was suspiscious in the extreme..of the layout, Input/output proximity was potentially a serious issue..and then... those metal boxes around the caps spoke volumes about potential RF feedback issues.
I put my 1Mhz capable Acoustat TNP fet preamp in there, and the issue seems to have gone away.
This cable is way too revealing. Oh well. I thought I was going to have to sell the 3.1 preamp. This just re-inforces that opinion. The other 99.99999999% of the population that does not have this cable in their system..will love this preamp. Me, I'm not giving up this cable for anything. Guys in the big city will only be able to use it with RF shielding..but that will destroy half of what they are paying for. Such is life.
The SA-220 is guilty too, but only in terms of RF pickup due to input impedance, is my guess.
Chris, can any of that be changed, ie, dropped without affecting anything else? I don't believe that's generally true, of course, high input impedance tends to be a part of the design aspect of tube input/ouputs..so changing that can bring on other issues. I need a bit more current domination in the equation.
Some might call my facination with Counterpoint gear Coprophilia, but that's a matter of debate. I love hybrids. The two different methods of amplification both lack in something, the hybrid seems to bridge the gap.
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| anatech |
Hi Ken,
Install RF ferrite beads and some low value caps to ground at the inputs of both the preamp and the power amp. The input impedance in the audio range will remain essentially unchanged.
If your caps are physically larger than the original ones in size, it is entirely possible they are picking up noise and ...... Try the M-caps out or some other, smaller capacitor.
-Chris |
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| KBK |
Ok. I figured it out. I accidentally turned propogation theory upside down and inside out.
Whoops.
Get thee to a Nunnery. :p |
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| KBK |
Another tiger by the tail. Too much. This will make everyone re-think progogation theory. The cables sound insanely good. Likely to turn the entire industry on it's ear..and more. This will hit the world of audio like a freight train. It's too big, I might have to shelve it like many other things I've done.
nah. ;) This one is just tooo much fun. The truth in dymanics are..absloutely ...startling. Shocking, in fact. Detail like you've never heard.
See you guys at the Fesitval Du Son in Montreal. Look for it. |
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| KBK |
Ok Chris, I'm back from the show. Physically recovered (two weeks preparing and only a few hours sleep a day in that time period), but definitely not financially recovered.
Had lots of chinese folks looking at my two chassis CD clock power supply. They had little question marks above their heads and furrows on their brows, when peering at it.
As far as I could tell, and from reports from others, we had one of the best sounding rooms at the show,and one of the most, if not the most 'analog' sounding digital set-ups at the show. Nice clock..good clock.. :D
Also had a group of blind audiophiles come through. The one (blind) guy said it was the best he'd heard in 30 years of going to shows.
Time to tape that counterpoint box up and then wrap some more cardboard around it,and ship it off to you.
A side note, the repaired 220 developed some DC at the output..I noticed it the other night after lots of loud movie stuff..right at the end of the evening at about 3:30 in the morning. ieeeeee! my A-T woofers at $300US a pop were sticking out about 1/4"!
So I shut it down and now (next day) it won't open the relay on that channel at all. It 'goes green' and turns on the one channel..but not the other. Earlier (possible explaination)... about two weeks before, I had accidentally grounded one of the transitor cases on that repaired channel, with a swinging rca cable on a fully grounded piece of gear (digital DEQX crossover). nice big arc!! whoops! nice arc scar on the t-03 package (rear set). I still hadn't put the 03 covers back on, I was looking for new ones, the originals are split and baked by the heat. my bad.
Anyways, first thing I did, is look at the schematic to see what is connected to that rail voltage. Seems the bias circuit is connected to it. hhhmmmm...measures fine, in simple in circuit voltage and resistance comparisons to the other working channel. wait..no..no bias voltage on the dead channel. dead cold (temp) channel, it is. Of course..that relay ain't opening.... All eight outputs measure the same as well, when pulled and checked with the ole' meter for shorts. They measure high resistance on all pins and directions/pin combinations.
The only spare amp I have around now, (since I sold four to get extra cash needed for the Montreal show)..is the little Belles 200.
I finally hooked it up, first time since you re-built it.
As you seemed to indicate, it does sound good! Love those simple circuits. I immediately took it apart and started swapping better caps in the pre-driver stage. My old technician friend here in Kingston doesn't call me 'cap-man' for nothing, you know. Now for the PS main filter caps and separate rectification and about 60-80uf of film bypass per rail...oh....does it ever end?
As well, I could not, and still cannot respond to Jneutron and most specifically the guys who gave me a bit of grief in the 'audiophools' thread, about skin effect and propogation theory.
I bypassed skin effect and propogation issues altogether. But I am unwilling at this time, to explain exactly how. Ah well. Such is life. Most folks read my posts and wonder how such a git like me could come up with such stuff, since I don't know the math lingo.... Simple. I understand the true essence of the fundamentals very, very, very well. That's where I concentrate, as that's where the real action is. The rest is...just..engineering. (nothing against engineers, it's simply just not the way my mind works) We all have our strengths and our weaknesses.
http://www.audioxsell.com/community...ge-2007/TEO.htm |
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| anatech |
Hi Ken,
I have some ideas about your DC offset. The last thing you should ever do is remove the outputs and start testing them. These tend to go short drain-gate, taking some resistors and zeners with them. You can't mistake that.
I'm glad the show went well for you. I am still trying to get things under control here. I am only getting about 5 hours sleep per night. I need a solid eight. There is a possible correction in sight. BTW, I have a new (to me) distortion analyzer on my bench. ;) :D :D :D
-Chris |
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| Workhorse |
| quote: | Originally posted by anatech
I am only getting about 5 hours sleep per night. I need a solid eight. -Chris |
In my view Solid Sleep must be atleast 12 hrs continuous in an unknown Place...
Not probably with Poobah
[I think he is hibernating somewhere unknown]
:D :D ;) |
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| anatech |
| Poobah has been busy. I do miss him around here. |
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| KBK |
| quote: | Originally posted by anatech
Hi Ken,
I have some ideas about your DC offset. The last thing you should ever do is remove the outputs and start testing them. These tend to go short drain-gate, taking some resistors and zeners with them. You can't mistake that.
I'm glad the show went well for you. I am still trying to get things under control here. I am only getting about 5 hours sleep per night. I need a solid eight. There is a possible correction in sight. BTW, I have a new (to me) distortion analyzer on my bench. ;) :D :D :D
-Chris |
Yes..I was looking at the other Punterpoint thread (I think it has bias and offset issues as well - an SA-100 thread). I started checking all the different 'test points', in the Mikey supplied list/'schematics' :dodgy: :rolleyes: (Ah, Mikey's OK. We can all do better, and sometimes do. I mean, did I ever make it as far as he has with amplifiers? I think not.) I gotta look at the zeners and diodes in this puppy next. Work my way up the chain. I've swapped out the relays, of course. I think I should spend a few minutes staring at the schematic and maybe it'll come to me.
Obviously, it's not in the tube section, or the power supply (main SS output rails, or any other shared source PS system) section, or the outputs themselves (did quick tests there with whoops..gotta go back and check those load resistors/diodes again..with the outputs removed maybe)..so this, overall.. limits the possible areas of concern. It's gotta be bias or offset. And at that point, there isn't all that much to check. All that extra **** on the output board maybe complicates the issue. Ugh. It certainly does in terms of figuring out what is what, in the physical/locational sense. What a mess.
After much self abuse, I'm about ready to give up on these things. Maybe move onto some units that have bipolar outputs. And maybe not Mikey's designs, either. But there is little doubt I will at least stick to hybrids.
I might go after Gilbert's stuff next. (Blue Circle) No circuit boards! Gotta love that. Big plus, right there.
Things are coming together in the audio world, but it will initially be slow going, of course...as for amplifiers...we will talk. |
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| anatech |
Hi Ken,
Look at it this way. At least you are not forced to send Counterpoint gear back to M.E. I should show you the DA-10 that went down for upgrades where they actually destroyed the PCB. It came back with different caps and a ruined PCB. I also discovered the board layout is badly flawed. Surprised?
-Chris |
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| KBK |
Nope, not suprised. But I managed to compound the problem further. Test proble slipped while checking the Mj340 on the analog computer's one +15V output. The little 7815 blew it's head off.. not suprising with 70VDC put on it's output. Thar she blows! Now I really have to fix it, no doubt there. Outputs are likely fine, though.
Time to park that amp for a while and move on to other stuff. No time to remain frustrated with it. Too much other stuff to do. |
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| anatech |
Hi Ken,
Sorry to hear that. Let me know if I can help.
Ken, I need to talk to you with regard to moving stuff bought in the US into Canada. I paid UPS $90 yesterday in clearing fees. Duty and taxes on top.
These clearing fees exceeded 1/3 the value of the items. I can't afford to do this. I don't mind paying the duty and taxes, I just want to avoid the vultures.
-Chris |
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| KBK |
OK. With regards to the funky audio cables, the feline is beginning to move from restrictive confinement.
The cable does away with propagation and skin effect issues. This may seem like a very odd statement, but it will become clear when everyone knows what I'm speaking about (re: the cables).
A few people publicly know about the cables now and the news of it's existence will travel fast.
In all seriousness, you guys will love it. Not only does the cable make serious sense in a scientific way, it also sounds fabulous. I'm not engaging in a ego trip here, with my musings, I'm just eager to share this funky new toy with you guys.
Edit
Chris: It is my intention to send you both amps. If I would remember to do so, dammit! |
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| anatech |
Hi Ken,
No problem. At the moment I have been very slow in everything I do. It's frustrating since I have not seemed to have recovered from the doctor's messed up treatment. It will take some time yet before I am up to my previous slow pace.
Be good to see you by though. Door's open if you are in the area.
-Chris |
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