Hi Chris,
Sounds fine, but I'd leave the zener in there. It's working and will not be the source of your hum. The newer part may have a higher resistance. That might possibly be better, but only if the rest of the noise is lower. I can't see this myself. The film caps will be good.
I would look at the heater supply caps for sure. Also, the board to board connections are a good source of whacky problems. Have a good look around and clean out both the power supply PCB and the PCB's in the audio chassis as well.
-Chris
Sounds fine, but I'd leave the zener in there. It's working and will not be the source of your hum. The newer part may have a higher resistance. That might possibly be better, but only if the rest of the noise is lower. I can't see this myself. The film caps will be good.
I would look at the heater supply caps for sure. Also, the board to board connections are a good source of whacky problems. Have a good look around and clean out both the power supply PCB and the PCB's in the audio chassis as well.
-Chris
Hi Chris,anatech said:
All electrolytics, other than the one in the timer circuit, have been replaced already. I had already redone some of the board-board joints in the main box while working on the CR1/D3 stuff. I thought I would trace out the heater circuit from the PSU and LM350K (which has been replaced also) thru the umbilical into the preamp itself and see if I can find anything. I will probably just go ahead and redo all the board to board connections (I had focused on the ones towards the HV reg section). I have reread this entire thread, and noted your recommendation to another poster to use HV dope on the PSU board. Something like Q-Dope work for this (have some)? Did you mean on both sides?
I am not going to immediately try the IXYS part, but since I was placing an order... Since it is a TO220 and needs an external resistor, I will need the zener's real estate on the board to implement this. I don't think the HV reg. section that I have been working on with your invalauble assistance is the source of the hum.
Hi Chris,
-Chris
Yes, I do mean both sides. There is a common failure mode due to traces being too close for the voltage across the space. I even will grind a gap with my Dremel tool. Clean with Lacquer thinner before appling the dope. Removal of the socket is required. Grind out any rough or odd looking PCB material (might be starting to track). This could be the "popping noise" you heard.
I do the same thing when I see a cool part.
Thank you. I agree with you. I don't think it's causing you hum either.
-Chris
Hi Chris,
Took the PSU apart (mostly) last night and started working on it. I'd forgotten that I'd burnt the board up some when I changed out the original Sprague caps in there 4 years ago (my first foray back into doing electronics work
One of the B+ wires back to the connector is suspect. Do you recall whether the connector pins are solder cup or crimp? Just thinking I want to replace the wire all the way from the board to the connector. If you've ever replaced wires in here, how did you do it? I was thinking if they are solder cup, I could just replace the entire wire/heatshrink, etc. (I have some 22ga Teflon SPC that I used for the Cerafines in here).
BTW, the B+ and common (ground) wires from the PCB to the connector are doubled up... pins 1 and 9 for the B+ and pins 2 and 10 for the common. Someone earlier in the thread had asked about that. Its a 10 pin JAE connector, I think at one time I had looked up the part number, but hadn't found anyone who stocked it (mainly looking for the pins for it). But then I suppose I would need at a minimum the pin extraction tool, etc. for it. Would have been nice if he (M.E.) had used an Amp or something more easily sourced.
Took the PSU apart (mostly) last night and started working on it. I'd forgotten that I'd burnt the board up some when I changed out the original Sprague caps in there 4 years ago (my first foray back into doing electronics work
One of the B+ wires back to the connector is suspect. Do you recall whether the connector pins are solder cup or crimp? Just thinking I want to replace the wire all the way from the board to the connector. If you've ever replaced wires in here, how did you do it? I was thinking if they are solder cup, I could just replace the entire wire/heatshrink, etc. (I have some 22ga Teflon SPC that I used for the Cerafines in here).
BTW, the B+ and common (ground) wires from the PCB to the connector are doubled up... pins 1 and 9 for the B+ and pins 2 and 10 for the common. Someone earlier in the thread had asked about that. Its a 10 pin JAE connector, I think at one time I had looked up the part number, but hadn't found anyone who stocked it (mainly looking for the pins for it). But then I suppose I would need at a minimum the pin extraction tool, etc. for it. Would have been nice if he (M.E.) had used an Amp or something more easily sourced.
Hi Chris,
Yes, the grounds are doubled up between the power supply and the preamp chassis.
The wires are simply soldered directly to the PCB, they may have plated through holes. A solder sucker is required there. If you don't have one, you need one. The type to get has a plunger and trigger button. It's typically blue in colour with a yellow button. There is no shroud for the pump, it's a two hand operation. Get spare tips. It should cost anywhere from $10 ~ $30. The real one is a DS-01 I think, but others may use the same part number. Without this, removing the socket will be next to impossible.
-Chris
Yes, the grounds are doubled up between the power supply and the preamp chassis.
The wires are simply soldered directly to the PCB, they may have plated through holes. A solder sucker is required there. If you don't have one, you need one. The type to get has a plunger and trigger button. It's typically blue in colour with a yellow button. There is no shroud for the pump, it's a two hand operation. Get spare tips. It should cost anywhere from $10 ~ $30. The real one is a DS-01 I think, but others may use the same part number. Without this, removing the socket will be next to impossible.
-Chris
I've got a good solder sucker (the blue and yellow one) and solder braid. Already have the tube socket out, no problems (was new anyhow as I had replaced all of them w/Azuma from partsconnexion 3 years ago).
I was asking about the pins into the 10-pin connector on the back of the PSU for the umbilical... whether they are crimp or solder type, as one of the HV wires should be replaced. Or advice on how you may have replaced these (wires) in the past.
Thanks,
Chris
I was asking about the pins into the 10-pin connector on the back of the PSU for the umbilical... whether they are crimp or solder type, as one of the HV wires should be replaced. Or advice on how you may have replaced these (wires) in the past.
Thanks,
Chris
Hi Chris,
Sorry. I have specifically avoided opening the umbilical cable. I have never once seen the inside and want to have it remain that way.
This is one of those "don't bug that thing" times. Don't mess with it unless you really have to.
-Chris
Sorry. I have specifically avoided opening the umbilical cable. I have never once seen the inside and want to have it remain that way.
This is one of those "don't bug that thing" times. Don't mess with it unless you really have to.
-Chris
Yeah, I understand the feeling. My question regards a wire inside the PSU from the PCB to the back connector... how would you go about replacing one of these? I suppose I could splice it, but I wanted to avoid doing that... would rather replace the entire wire.
If splice is your vote, what is the best way to do this?
I was poking around on JAE's site (more English than I remember it) trying to figure out what connector he was using, etc. I will look at the connector more closely... one type looks like it comes apart with a) no need for a pin extractor, and b) solder cup pins. Wouldn't that be nice 🙄
If splice is your vote, what is the best way to do this?
I was poking around on JAE's site (more English than I remember it) trying to figure out what connector he was using, etc. I will look at the connector more closely... one type looks like it comes apart with a) no need for a pin extractor, and b) solder cup pins. Wouldn't that be nice 🙄
Hi Chris,
Yes, I like to replace the entire wire if needed. Thankfully, I have not had to do this yet. When looking at possible connectors, think not expensive as far as your choices go. Solder cup would seem to be likely in this case.
All you can do is look.
-Chris
Yes, I like to replace the entire wire if needed. Thankfully, I have not had to do this yet. When looking at possible connectors, think not expensive as far as your choices go. Solder cup would seem to be likely in this case.
All you can do is look.
-Chris
Hi Chris,
Well, ripped into it. The connectors are not the exact same series as what JAE currently shows here, but are very close. The actual connectors are JAE SRC02A16-10S and SRC06A16-10P. No pin extractor needed... you remove a retaining clip (which was one of the biggest pains), then the connector guts come out. There is a front and rear body, with the pins sandwiched between them. They are solder cup. The holes in the rear body are ~0.056", so many teflon 22ga wire types will not fit thru them. The stock Pacific wire of course will not. I used 21.5ga teflon wires (the pins accept 22ga), and had to solder these while they were in the connector body. Would be much better to find wire that had a small enough OD to do the soldering outside. These things had to be really labor intensive to build!
I replaced the 2 B+ wires (pins 2 and 9) and the 2 commons for this portion of the circuit (pins 3 and 10). The stock wire in these spots was strange... hard to solder to even after stripping it back and really dull conductors... almost looked like tin plated copper?
I had already resoldered/refitted most of the other wires on the PCB. Cleaned it (after scraping several areas) with denatured alcohol (didn't have any lacquer thinner around) and Q-doped the backside for right now. Will do the front after I put the main caps and the tube socket back in. I may take your advice and repace C76 (IIRC) with a 47uf Cerafine instead of the 100uf I have in there now. Or I may put the pair of Panasonic TSUPs I have in (much smaller physically). I'll take some pics and post them later.
Chris (Pars)
Well, ripped into it. The connectors are not the exact same series as what JAE currently shows here, but are very close. The actual connectors are JAE SRC02A16-10S and SRC06A16-10P. No pin extractor needed... you remove a retaining clip (which was one of the biggest pains), then the connector guts come out. There is a front and rear body, with the pins sandwiched between them. They are solder cup. The holes in the rear body are ~0.056", so many teflon 22ga wire types will not fit thru them. The stock Pacific wire of course will not. I used 21.5ga teflon wires (the pins accept 22ga), and had to solder these while they were in the connector body. Would be much better to find wire that had a small enough OD to do the soldering outside. These things had to be really labor intensive to build!
I replaced the 2 B+ wires (pins 2 and 9) and the 2 commons for this portion of the circuit (pins 3 and 10). The stock wire in these spots was strange... hard to solder to even after stripping it back and really dull conductors... almost looked like tin plated copper?
I had already resoldered/refitted most of the other wires on the PCB. Cleaned it (after scraping several areas) with denatured alcohol (didn't have any lacquer thinner around) and Q-doped the backside for right now. Will do the front after I put the main caps and the tube socket back in. I may take your advice and repace C76 (IIRC) with a 47uf Cerafine instead of the 100uf I have in there now. Or I may put the pair of Panasonic TSUPs I have in (much smaller physically). I'll take some pics and post them later.
Chris (Pars)
Hi Chris,
It looks like you are on the way to a good running preamp. You are also a braver man than I! It is good to hear that you can work on the connector. I would have considered shortening the umbilical unless you need all that length.
The wire will oxidize under the insulator. Flux helps you to solder it. I will also scrape the outside before applying flux.
Using a smaller filter capacitor is very wise. This should reduce the high frequency content of the rectified AC. Consider a bypass cap as well. This is the place to get rid of high frequency noise, not later on.
-Chris
It looks like you are on the way to a good running preamp. You are also a braver man than I! It is good to hear that you can work on the connector. I would have considered shortening the umbilical unless you need all that length.
The wire will oxidize under the insulator. Flux helps you to solder it. I will also scrape the outside before applying flux.
Using a smaller filter capacitor is very wise. This should reduce the high frequency content of the rectified AC. Consider a bypass cap as well. This is the place to get rid of high frequency noise, not later on.
-Chris
Hi Chris,anatech said:
We'll see how this turns out. I have all the time I wish on this... you, when you were doing the authorised repair work were running a business and needed to manage your turnaround. Mucking around with the PSU on this thing makes me wish I had a variac
I'm getting some wire that will fit thru the connectors yet is 600V rated teflon SPC. The best way I can see to do the connector is to do all leads at once. The pins have flats on each side which seat into the front piece (making it a PITA to get everything aligned, with heatshrink holding the pins from moving forward). By doing all at once, you could individually solder each pin/wire, seat them in the front part, and when all are in, thread the leads thru the back piece, then heatshrink, starting from the most internal pins. A higher dollar connector with pins which insert from the back would be better, but then you have the pin extractor and probably a crimper to deal with ($$). I'm wondering if it might not be wise to Q-dope the connector back, as the stock heatshrink leaves some of the pin exposed... crap looks like that shiny ratshack heatshrink.I am reverse engineering the board, as the schematics (SA5) are not accurate WRT the heaters (went from 12V to 6V), and the heaters on when unit plugged in versus just fired up on the SA5. I am in the process of laying out a PCB for this to correct some of the problems with the stock one. Much of the heater circuit does not apear on the schematic (1N5404? LED obviously has to be wired somewhere else instead of in the heater circuit... etc.)
When I get to the point of board layout, I'll post pics and hopefully you can give me some feedback as to where you say problems with arcing, etc.
Chris
Hi Chris,
You are right. When running a shop there is zero time to reverse engineer anything unless it pays money. Also, manufacturers do not take kindly to warranty shops modifying anything. They view it as a danger, and I agree with them on average. We did work with engineering departments when it came to design issues causing common failures.
One question. Why are you stuck on teflon insulated wire? I always found it a pain to use. Anything rated for 600V should be fine. I prefer fine copper stranded.
With any luck, Counterpoint designed the connector to eliminate high potentials from adjacent pins. No worries if they got that part right.
-Chris
You are right. When running a shop there is zero time to reverse engineer anything unless it pays money. Also, manufacturers do not take kindly to warranty shops modifying anything. They view it as a danger, and I agree with them on average. We did work with engineering departments when it came to design issues causing common failures.
One question. Why are you stuck on teflon insulated wire? I always found it a pain to use. Anything rated for 600V should be fine. I prefer fine copper stranded.
With any luck, Counterpoint designed the connector to eliminate high potentials from adjacent pins. No worries if they got that part right.
-Chris
anatech said:
Hi Chris,
Teflon SPC (silver plated copper mil-spec) wire is great to work with. T-strippers work great on it, no burning, 600V almost by default, 19 strand copper. What's not to like other than perhaps finer copper stranding. I don't have places locally that I can source wire easily (go figure for Chicago). I always get envious when I read posts here and on head-fi of guys in Quebec or Toronto that can walk down the street and find vendors that actually stock components and stuff... 😉
As to Counterpoint designing the connector right... pins 2 and 9 (B+, 435V) right next to that circuits ground or commons on pins 3 and 10. Don't think so, but I'm not going to change it.
Chris
Hi Chris,
I hate Toronto - unless someone else drives. 😀 Then I have to be the heck out of there before the end of day rush starts. That would be about 3:30 PM weekdays. You are toast after that.
Never looked at the Counterpoint plug pinout. He seems to mess up power supplies every single time. There is always at least one thing wrong with them. Dope the pins inside the plug. That should take care of it. Personally, I'd redo the pinout on both ends. The only problem is you'd have a non-standard preamp. 🙁 I guess it's better to leave it.
Such a simple thing to mess up. Cost to correct the design before the amp went out the door, $0.00.
-Chris
I hate Toronto - unless someone else drives. 😀 Then I have to be the heck out of there before the end of day rush starts. That would be about 3:30 PM weekdays. You are toast after that.
Never looked at the Counterpoint plug pinout. He seems to mess up power supplies every single time. There is always at least one thing wrong with them. Dope the pins inside the plug. That should take care of it. Personally, I'd redo the pinout on both ends. The only problem is you'd have a non-standard preamp. 🙁 I guess it's better to leave it.
Such a simple thing to mess up. Cost to correct the design before the amp went out the door, $0.00.
-Chris
I just want to add my grain of salt about the SA5.1
Presently, I own a SA5.1 and done many mods on it.
Many resistors were replaced by Mills ww non inductive and the wondercaps were replaced by dynamicaps. The power supply caps are now Dynamicaps. I'm still asking me why they don't name Wondercaps : Wondercrap. I hate these film caps.
Alone these mods donne great results. The sound is less veiled. Sound has more definition without being hard. Soundstage is now excellent.
Something really funning to try in this preamp is different tube rectifiers. I tried different brands of 6BW4 (with a little mod to do near the socket) and different brands of 6V4. Try a Telefunken EZ80/6V4 and you will fall off your chair. This incredible.
The cord between the power supply and preamp needs to be shielded. You can buy a shield jacket and easily place it on your new cord or the stock one.
The 1.6ma current source in my preamp was dead. I replaced it by a resistor as recommended by M. Elliot. I should perhaps try another current source but it works.
My system is a horn based system with a sensitivity of 100db/1w/1m. The preamp is only a little noisy when it is freshly turned on. After some time it is correct.
This preamp is simply marvelous. The phonostage is probably one of the best I tried. It is a way better than the SA-3000 i had before.
Be sure to clean the swiches. I used Deoxit on them and it helped.
Marc Legare
Presently, I own a SA5.1 and done many mods on it.
Many resistors were replaced by Mills ww non inductive and the wondercaps were replaced by dynamicaps. The power supply caps are now Dynamicaps. I'm still asking me why they don't name Wondercaps : Wondercrap. I hate these film caps.
Alone these mods donne great results. The sound is less veiled. Sound has more definition without being hard. Soundstage is now excellent.
Something really funning to try in this preamp is different tube rectifiers. I tried different brands of 6BW4 (with a little mod to do near the socket) and different brands of 6V4. Try a Telefunken EZ80/6V4 and you will fall off your chair. This incredible.
The cord between the power supply and preamp needs to be shielded. You can buy a shield jacket and easily place it on your new cord or the stock one.
The 1.6ma current source in my preamp was dead. I replaced it by a resistor as recommended by M. Elliot. I should perhaps try another current source but it works.
My system is a horn based system with a sensitivity of 100db/1w/1m. The preamp is only a little noisy when it is freshly turned on. After some time it is correct.
This preamp is simply marvelous. The phonostage is probably one of the best I tried. It is a way better than the SA-3000 i had before.
Be sure to clean the swiches. I used Deoxit on them and it helped.
Marc Legare
Hi Marc,
I had corresponded with you over the years regarding the SA-5.1.
What size resistor did you use to replace the current source? Around 27K or so? I know Mike alludes to this on the Alta Vista site, but he never really says exactly what he does. My CCS works fine, so I'll probably leave it.
As far as shielding the cable goes, do you just ground the shield to the PSU case and leave the amp end floating?
Glad yours is quiet... mine is getting better and will hopefully be quiet after I get done with the PSU stuff I'm doing now.
Regards,
Chris
I had corresponded with you over the years regarding the SA-5.1.
What size resistor did you use to replace the current source? Around 27K or so? I know Mike alludes to this on the Alta Vista site, but he never really says exactly what he does. My CCS works fine, so I'll probably leave it.
As far as shielding the cable goes, do you just ground the shield to the PSU case and leave the amp end floating?
Glad yours is quiet... mine is getting better and will hopefully be quiet after I get done with the PSU stuff I'm doing now.
Regards,
Chris