I have used them in a few places (DAC PSU's) but I find the others mentioned here much better in general.
Muse & Fine Gold always rather warm and pleasing (like a SE 300B). Great caps IMO. Nichicons works wonders in chip stages & DAC's. 2 days ago I tweaked a chip phono pre with only 2 Nichicon Fine Gold caps in the PSU, much more authority, slam and bass - started to sound like a good tube phono pre. Then I changed the Rubycon (old) output caps to Panasonic FC: More pleasing, the splashiness is nearly gone, more neutral and more slam.
Cheers Ian,
I remember and promise to make some pictures of my amp once I get a decent camera (it's really crappy quality with my sony)
Currently have one problem with my Restek, so I'm asking you and other guys to assist me please...
I tried to determine voltage on all caps using my tester and once I got to blue 470uf I accidentally shorted smth near the left power amp section top 470uf Philips cap that is in the middle...
There was a spark and now amp doesn't go out of Protection mode. Seems that smth has died. Voltage on left channel's transistors now is from 58.6 (top 2) to ~30-35 (two Toshiba that are below) and should be 48.5v as on the all right channel's ones. And it is 0 on the one small in the middle (~3v should be)...Tried to get it out, but was reluctant, amp didn't come out from Protection mode. Tried to remove the 1st big transistor, still no changes...
If you completely remove left section's power supply from pbs, no protection mode appears. Also I assume it shouldn't be the preamp section as if you disconnect power supply (this 4 wires that go to right top corner of pbs) it doesn't affect staying in protection mode.
I guess it could be this black relay or opamp or maybe some resistor (checked all these white ceramic, seems all are fine)...
Btw, checked voltage on left & right 10000uf caps - it's 48.5v on both channels.
Is there some way how to trace possible part's death and where to start from? Maybe from LM337 regs?
Would be very glad for any suggestions or help...
I remember and promise to make some pictures of my amp once I get a decent camera (it's really crappy quality with my sony)
Currently have one problem with my Restek, so I'm asking you and other guys to assist me please...
I tried to determine voltage on all caps using my tester and once I got to blue 470uf I accidentally shorted smth near the left power amp section top 470uf Philips cap that is in the middle...
There was a spark and now amp doesn't go out of Protection mode. Seems that smth has died. Voltage on left channel's transistors now is from 58.6 (top 2) to ~30-35 (two Toshiba that are below) and should be 48.5v as on the all right channel's ones. And it is 0 on the one small in the middle (~3v should be)...Tried to get it out, but was reluctant, amp didn't come out from Protection mode. Tried to remove the 1st big transistor, still no changes...
If you completely remove left section's power supply from pbs, no protection mode appears. Also I assume it shouldn't be the preamp section as if you disconnect power supply (this 4 wires that go to right top corner of pbs) it doesn't affect staying in protection mode.
I guess it could be this black relay or opamp or maybe some resistor (checked all these white ceramic, seems all are fine)...
Btw, checked voltage on left & right 10000uf caps - it's 48.5v on both channels.
Is there some way how to trace possible part's death and where to start from? Maybe from LM337 regs?
Would be very glad for any suggestions or help...
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Hi Pal, thats not ideal! as there is no service information, its a bloody nightmare to fault find.
I would replace the whole output stage, all 4 of the larger devices and all 3 of the smaller ones on the buggered channel. You can get all of them from Dalbani electronic component suppliers and distributors, Nikko Electronics for semiconductors, transistors, capacitors all major brands of spare and replacement parts I know cos I did something similar and ended up rebuilding mine!
I cant remember the device numbers but I think you can get all original devices from dalbani rather than cheapo Chinese copy ones. I was that pissed off when I did mine, I went sick the next day and drove to the shop to collect the devices! lol
Let me know how you get on
I would replace the whole output stage, all 4 of the larger devices and all 3 of the smaller ones on the buggered channel. You can get all of them from Dalbani electronic component suppliers and distributors, Nikko Electronics for semiconductors, transistors, capacitors all major brands of spare and replacement parts I know cos I did something similar and ended up rebuilding mine!
I cant remember the device numbers but I think you can get all original devices from dalbani rather than cheapo Chinese copy ones. I was that pissed off when I did mine, I went sick the next day and drove to the shop to collect the devices! lol
Let me know how you get on
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Not the same issue but I did short something that lead to output stage failure. I was already replacing every electrolytic cap so I blindly replaced one entire output stage and managed to resolve the issue. To be honest, without the service data which I've tried to get from restek in Germany several times, you're fumbling in the dark :-(
Not so much blindly, more an educated guess!
Those regulators you are talking about are the rails for the pre amp stage which is the 3 BB2604's that run along the back of the board where the volume control plugs in and poss there is a feed from the pos reg to some of the control logic too.
As soon as you unbalance the output stage, it will blow itself up! Thats pretty standard for amps. If they are not carefully adjusted, they can go into thermal run away and just die.
When I said replace the whole output stage, there was a method in my madness. You may find that you dont need to replace it all but if you replace the lot, you know its all good. There is a possibility that you could replace a single transistor only to find another is dead and it blows the new one up immediately.
As I said without the service data, its not so easy to see exactly whats going on. I'd again take an educated guess that its not going to be the protection circuits that are causing the problem. Its more likely to be the output stage with a fault causing the protection to kick in. As for the other bits mentioned I'm not sure what they all do without puling mine to bits again and trying to work it out. You could replace the 604's but again I doubt that will be the issue. You need to be careful because the rails there are a bit high and some opamps dont like it!
looking at my parts drawer, you'll need the following but check the devices in your as Restek may have used slightly different devices if yours in not identical to mine.
2 x Toshiba 2SC5200 @£2.19
2 x Toshiba 2SA1943 @£2.19
2 x Sanyo 2SC2344 @£1.09
1 x Sanyo 2SA1011 @£0.56
Total inc VAT £13.80 plus shipping
Seriously, its worth replacing the lot as I really think thats whats likely to be giving you issues.
Those regulators you are talking about are the rails for the pre amp stage which is the 3 BB2604's that run along the back of the board where the volume control plugs in and poss there is a feed from the pos reg to some of the control logic too.
As soon as you unbalance the output stage, it will blow itself up! Thats pretty standard for amps. If they are not carefully adjusted, they can go into thermal run away and just die.
When I said replace the whole output stage, there was a method in my madness. You may find that you dont need to replace it all but if you replace the lot, you know its all good. There is a possibility that you could replace a single transistor only to find another is dead and it blows the new one up immediately.
As I said without the service data, its not so easy to see exactly whats going on. I'd again take an educated guess that its not going to be the protection circuits that are causing the problem. Its more likely to be the output stage with a fault causing the protection to kick in. As for the other bits mentioned I'm not sure what they all do without puling mine to bits again and trying to work it out. You could replace the 604's but again I doubt that will be the issue. You need to be careful because the rails there are a bit high and some opamps dont like it!
looking at my parts drawer, you'll need the following but check the devices in your as Restek may have used slightly different devices if yours in not identical to mine.
2 x Toshiba 2SC5200 @£2.19
2 x Toshiba 2SA1943 @£2.19
2 x Sanyo 2SC2344 @£1.09
1 x Sanyo 2SA1011 @£0.56
Total inc VAT £13.80 plus shipping
Seriously, its worth replacing the lot as I really think thats whats likely to be giving you issues.
Cheers!
removed all Toshiba and Sanyo transistors and made some measurements with a tester in case any of them is burned. However seems all are fine. However I've ordered them to be fully assured that the cause is not related to power tr. and will make some testing in the following days.
So I guess if that will not help the next step could be replacing all the rest of transistors (BC550C, BC639, BC640, BF470, BF469).
There is also one integrated circuit (ha12002) that is some kind of protection for power amps, maybe it's worth to replace that one too?
Please let me know if my guesses make any reasonable sense and maybe it's better to replace all the parts at once?
removed all Toshiba and Sanyo transistors and made some measurements with a tester in case any of them is burned. However seems all are fine. However I've ordered them to be fully assured that the cause is not related to power tr. and will make some testing in the following days.
So I guess if that will not help the next step could be replacing all the rest of transistors (BC550C, BC639, BC640, BF470, BF469).
There is also one integrated circuit (ha12002) that is some kind of protection for power amps, maybe it's worth to replace that one too?
Please let me know if my guesses make any reasonable sense and maybe it's better to replace all the parts at once?
dtses. Have a read through this page, it's really helpful and teaches a lot about fault finding inside amps.
Troubleshooting & Repair Guide
It may prove easier than you think to repair.
Cheers, Lee.
Troubleshooting & Repair Guide
It may prove easier than you think to repair.
Cheers, Lee.
Cheers Ian,
actually didn't even expect to receive the scheme, however wrote an email to 'ae@...' explaining the current situation with my beloved amp perhaps, they felt sorry for my amp or maybe company's name in my email was some kind of credo for them... don't actually know and don't want to know.
Regarding our MKI version, seems it will be difficult to have it as it's much older and possibly they didn't keep it. Anyway I will try and let you know if they send me anything.
Btw here are the links opened MKI and MKII versions:
- MKI
- MKII
actually didn't even expect to receive the scheme, however wrote an email to 'ae@...' explaining the current situation with my beloved amp
perhaps, they felt sorry for my amp or maybe company's name in my email was some kind of credo for them... don't actually know and don't want to know.Regarding our MKI version, seems it will be difficult to have it as it's much older and possibly they didn't keep it. Anyway I will try and let you know if they send me anything.
Btw here are the links opened MKI and MKII versions:
- MKI
- MKII
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Cheers Ian! How r u?
it's alive again just fixed it yeasterday!
the problem was in the resistor near the cap I shortened...sad thing is that I checked 3 of them right after all that had happened and forgot to test the other one that is between two 470uf caps...Anyway, now Restek is working fine
Waiting now for opams in power amp's stage (LME49710HA) as well as for 12000uf Elna caps.
Still need to decide which caps to chose for:
1) 470uf psu caps
2) 10uf PreAmp section
2) 470 & 220uf power amp sections
I was thinking that for 4 x 470uf PSU caps some decent BC could be chosen, for instance. I guess that Preamp section desperately needs to have Silmics The most doubtful for me is power amp - whether to buy Tonerex 220uf + Nichicon KZ 470uf or BC 470uf + Panasonic FCs. Alternatively replace all PA stage caps with FCs as I don't actually know will there be any noticeable difference between FCs and Tonerex + KZ (details, stage and so on. If FCs could be slightly harsh, that would be only an advantage for me as I prefer some heavy metal music)...
it's alive again
just fixed it yeasterday!the problem was in the resistor near the cap I shortened...sad thing is that I checked 3 of them right after all that had happened and forgot to test the other one that is between two 470uf caps...Anyway, now Restek is working fine
Waiting now for opams in power amp's stage (LME49710HA) as well as for 12000uf Elna caps.
Still need to decide which caps to chose for:
1) 470uf psu caps
2) 10uf PreAmp section
2) 470 & 220uf power amp sections
I was thinking that for 4 x 470uf PSU caps some decent BC could be chosen, for instance. I guess that Preamp section desperately needs to have Silmics
The most doubtful for me is power amp - whether to buy Tonerex 220uf + Nichicon KZ 470uf or BC 470uf + Panasonic FCs. Alternatively replace all PA stage caps with FCs as I don't actually know will there be any noticeable difference between FCs and Tonerex + KZ (details, stage and so on. If FCs could be slightly harsh, that would be only an advantage for me as I prefer some heavy metal music)...- Status
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