3.05.2003
Is this what I need?
(Response from Audio Asylum posting)
Yep that is the 60mF section that is left unconnected which was the first
section after the diodes. If you look at the side of your cap it will show the
values and the symbol callout that correspond to the terminals on the bottom.
It was probably bad (the voltage is highest closest to the diodes) and left
unconnect just to get the amp working at some point in it's life. The voltage
would probably be close even with this section unconnected since your power
supply resistors still appear to be in the circuit. however the AC ripple would
not be totally filtered out of the B+ voltage going to the circuit, and the
noise and hum to the rest of the circuit will be higher.
The quad cap you found could work but it will fall short of what was originally
in the amp. The original quad cap in that amp is a four section. The first
three sections being 60mF, 40mF, and 20mF all at 450Vdc for the high voltage
filtering. The last 100mf at 25Vdc is for the bias supply.
You can check out Antique electronics supply I think they have some quad caps
that will take care of the high voltage but you will have to install a modern
100-220 mF 25Vdc minimum for the bias under the chassis (new caps of this value
are small and should fit no problem). Also this quad cap is taller than the
stock one and the cage will not fit with it installed.
Or you can use a JJ or LCR 50/50mF at 500vdc clamp mount for the first two
sections (you'll have to drill holes to mount the clamp however) and hide a
20-47mf at 450vdc under the chassis for the third cap (I don't know of one but
there may be one by Panasonic or Xicon or someone else that will fit). And
you'll still have to use a modern small cap for the bias here as well. Check
out Mouser or DigiKey for the modern type stuff.
I have not found a totally stock type solution for this amp and If you find one
please post it. My Stereo 35 has the original quad cap still in it and I know
one day I will have to replace it.
(Response from Audio Asylum posting)
Yep that is the 60mF section that is left unconnected which was the first
section after the diodes. If you look at the side of your cap it will show the
values and the symbol callout that correspond to the terminals on the bottom.
It was probably bad (the voltage is highest closest to the diodes) and left
unconnect just to get the amp working at some point in it's life. The voltage
would probably be close even with this section unconnected since your power
supply resistors still appear to be in the circuit. however the AC ripple would
not be totally filtered out of the B+ voltage going to the circuit, and the
noise and hum to the rest of the circuit will be higher.
The quad cap you found could work but it will fall short of what was originally
in the amp. The original quad cap in that amp is a four section. The first
three sections being 60mF, 40mF, and 20mF all at 450Vdc for the high voltage
filtering. The last 100mf at 25Vdc is for the bias supply.
You can check out Antique electronics supply I think they have some quad caps
that will take care of the high voltage but you will have to install a modern
100-220 mF 25Vdc minimum for the bias under the chassis (new caps of this value
are small and should fit no problem). Also this quad cap is taller than the
stock one and the cage will not fit with it installed.
Or you can use a JJ or LCR 50/50mF at 500vdc clamp mount for the first two
sections (you'll have to drill holes to mount the clamp however) and hide a
20-47mf at 450vdc under the chassis for the third cap (I don't know of one but
there may be one by Panasonic or Xicon or someone else that will fit). And
you'll still have to use a modern small cap for the bias here as well. Check
out Mouser or DigiKey for the modern type stuff.
I have not found a totally stock type solution for this amp and If you find one
please post it. My Stereo 35 has the original quad cap still in it and I know
one day I will have to replace it.
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