Sorry there are two more caps you need to buy/change
C11/C12 in the schematic
47uf/35V x2pcs
Replacing coupling caps with poly caps is usually gives a sonic improvement, but being physically much larger are sometimes very hard to fit into the space available.
dave
Just waiting on some of the caps to arrive but making a start. Just wanted to check with you more knowledge folks if these caps are ok for the power stage. They have the same values but the new ones are about half the size
Also the old ones say 50WV, my understanding is that means the safe working limit? So still a 50V cap?
Also, can the old ones be discharged whilst on circuit or is it best to desolder them first and then discharge them? If if needs to be done before desolrering how is this best done? With a light bulb?
Thanks
Also the old ones say 50WV, my understanding is that means the safe working limit? So still a 50V cap?
Also, can the old ones be discharged whilst on circuit or is it best to desolder them first and then discharge them? If if needs to be done before desolrering how is this best done? With a light bulb?
Thanks
New caps produce with new technology therefore the size will be smaller than the old caps.
yes, old cap 50WV is still a 50V cap
If the amp is working normally, the 10000uf power supply cap will discharge in a short time.
But each time before you repair or do anything to the amp you better measure the caps voltage with a multimeter. If the cap is still in high voltage, discharge it with a 100 ohm 2W resistor and check with multimeter again.
yes, old cap 50WV is still a 50V cap
If the amp is working normally, the 10000uf power supply cap will discharge in a short time.
But each time before you repair or do anything to the amp you better measure the caps voltage with a multimeter. If the cap is still in high voltage, discharge it with a 100 ohm 2W resistor and check with multimeter again.
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Do your self a favour, order parts from a reliable supplier and not eBay. AS you are in the UK, CPC are good for small orders - http://cpc.farnell.com
Bit of a dumb question maybe but....
How do you guys go about locating the solder points of a component in the underside of a single sided PCB? When looking at the cap I want to desolder from the top of the board, it's pretty hard to locate the points when the board is flipped over. I can only think of using some sort of very narrow beam light source touched to the side of the cap from above, like the small torches doctors use to shine into your eyes to dilate puplils. Other than that a ruler to measure the distance? Still not always obvious exactly where the solder points your after are though esp if lots of components in close proximity...
How do you guys go about locating the solder points of a component in the underside of a single sided PCB? When looking at the cap I want to desolder from the top of the board, it's pretty hard to locate the points when the board is flipped over. I can only think of using some sort of very narrow beam light source touched to the side of the cap from above, like the small torches doctors use to shine into your eyes to dilate puplils. Other than that a ruler to measure the distance? Still not always obvious exactly where the solder points your after are though esp if lots of components in close proximity...
There are only + and - polarities in the PCB, so that you just use short wires to connect the caps to the PCB, and fixed the caps with the original metal belt.
Careful in soldering, do not short any circuit, double check there is no short circuit for these caps before you fire up the amp.
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Success! Amp is re capped. Sounding fantastic! Was worth the effort. Had problems with the seller sending the wrong caps and hold ups with the post but its all done now. Really pleased.
Thanks very much for all your help, I couldn't possibly have done it with you
One slight issue is some unwanted noise. It seems to be something to do with my Turntable. I have the amp and the TT in the same double socket outlet. When the turntable is plugged in I get noise which I can hear on every input (phono/tuner/aux) whether the TT is switched on or not.
If I unplug the TT the noise goes away. Weirdly though, I get the noise with the TT plugged in even when that outlet is switched off by the socket switch (in the Uk we have a switch for each of the outlets in a double outlet).
I have the TT grounded at the terminal provided at the pre amp.
I am not sure if this is a new thing or if I am only hearing it now because I'm listening for potential problems. Its not the end of the world because I only hear it if the 'noise' with the power amps volume pots on over half way and a quarter of the way is plenty loud enough anyway...
I replaced the 2 volume pots on the power amp (one is Left ch one is Right ch). This wasn't easy as the leads where stupidly small and twisted and there isn't much room, its not the neatest solder job ive ever done but they seem to be working. I'm just wondering if they could be picking up AC frequency? They probably are not as good as the original Japanese pots but they where the only ones I could find with the correct shaft size...
Anyway Its sounding great and best of all I'm not getting the loud pops from the amp anymore so I'm happy! If anyone has any ideas about the noise when the TT is plugged I'd be interested to hear it.
The TT is an old Lenco Goldring GL69 by the way
Cheers.
Thanks very much for all your help, I couldn't possibly have done it with you
One slight issue is some unwanted noise. It seems to be something to do with my Turntable. I have the amp and the TT in the same double socket outlet. When the turntable is plugged in I get noise which I can hear on every input (phono/tuner/aux) whether the TT is switched on or not.
If I unplug the TT the noise goes away. Weirdly though, I get the noise with the TT plugged in even when that outlet is switched off by the socket switch (in the Uk we have a switch for each of the outlets in a double outlet).
I have the TT grounded at the terminal provided at the pre amp.
I am not sure if this is a new thing or if I am only hearing it now because I'm listening for potential problems. Its not the end of the world because I only hear it if the 'noise' with the power amps volume pots on over half way and a quarter of the way is plenty loud enough anyway...
I replaced the 2 volume pots on the power amp (one is Left ch one is Right ch). This wasn't easy as the leads where stupidly small and twisted and there isn't much room, its not the neatest solder job ive ever done but they seem to be working. I'm just wondering if they could be picking up AC frequency? They probably are not as good as the original Japanese pots but they where the only ones I could find with the correct shaft size...
Anyway Its sounding great and best of all I'm not getting the loud pops from the amp anymore so I'm happy! If anyone has any ideas about the noise when the TT is plugged I'd be interested to hear it.
The TT is an old Lenco Goldring GL69 by the way
Cheers.
It could be the cartridge acting as a radio receiver. The 1st time we had that, it was a hard issue to resolve. Can’t remember how we fixed it.
What cartridge (MCs usually are the ones that can have this problem).
dave
Unfortunately the original problem seems to be back. Finished listening to a record, I was getting another one ready to play and I heard really loud cracking/white noise from the right channel in 2-3 second busts intermittently☹️. Turned the amp off and it started again. Turning the speaker select to 'off' stops it being heard from the speakers. It seems to happen when there is no music being played. Before I re capped it I was hearing occasional very loud pops, I'm not getting these any more but the issue obviously hasn't completely gone away.
Anyone got any ideas where to go next with this?
Anyone got any ideas where to go next with this?
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