I have a AA-1600 with my tech, the power capacitors dont have any markings, anyone know the spec for the power capacitors ?
cap size is 64mm diam. or 2.5"
100mm tall,
spacing between screw terminals = 30mm
rail is around 70v
If the rail is 70V, the power capacitors between 70 to 100 volts ?
capacitance 15000uf ?
I got these power capacitors from ebay, for a good price
https://www.ebay.com/itm/185794552079
Max is rated to 90 surge, 75VCD
What do guys you think ?
Also does anyone knows the numbers for the bias ?
There is a schematic but not a service manual
thanks for your help
Quote Reply
cap size is 64mm diam. or 2.5"
100mm tall,
spacing between screw terminals = 30mm
rail is around 70v
If the rail is 70V, the power capacitors between 70 to 100 volts ?
capacitance 15000uf ?
I got these power capacitors from ebay, for a good price
https://www.ebay.com/itm/185794552079
Max is rated to 90 surge, 75VCD
What do guys you think ?
Also does anyone knows the numbers for the bias ?
There is a schematic but not a service manual
thanks for your help
Quote Reply
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The voltage rating is right on the edge and I would fit 100volt versions.
The value of these is nominally around 5000uF, much more and the mains transformer will suffer. The amplifier is only rated at 150Watts after all.
It is a class B amplifier and the bias setting should be between 5 & 8mV across the emitter resistors.
It may take you a while to source capacitors that fit the clamps!
The value of these is nominally around 5000uF, much more and the mains transformer will suffer. The amplifier is only rated at 150Watts after all.
It is a class B amplifier and the bias setting should be between 5 & 8mV across the emitter resistors.
It may take you a while to source capacitors that fit the clamps!
Capacitors with a surge rating are ancient. I would worry more about the age than the 75 wvdc rating versus 70 .
E-bay is a great source of ancient historic rubber. Rubber is the sealant in electrolytic caps. Notice that Pebble Beach concours for autos allows modern replacement tires?
I would buy e-caps from newark or mouser. Digikey, I once received 9 year old caps for full price. Newark when they have old e-cap stock, they lower the price and put a * next to it. 16000 uf is too big without a MOS surge supressor in the AC supply before the transformer. Be sure to charge up any old cap to >2 v with some sort of DC power supply and a resistor. This reforms any discharged aluminum oxide.
I wouldn't worry about matching the clamps. Modern caps are a lot smaller. If you use use snap-in caps, you can solder terminals to a cinch type solder terminal strip and screw the strip over the hole. You could use glue. The best rubber cement I have found these days was "shoe glue" in the shoe department. California has banned any useful rubber cement, so nobody will make it anymore. Liquid Nails is now garbage.
E-bay is a great source of ancient historic rubber. Rubber is the sealant in electrolytic caps. Notice that Pebble Beach concours for autos allows modern replacement tires?
I would buy e-caps from newark or mouser. Digikey, I once received 9 year old caps for full price. Newark when they have old e-cap stock, they lower the price and put a * next to it. 16000 uf is too big without a MOS surge supressor in the AC supply before the transformer. Be sure to charge up any old cap to >2 v with some sort of DC power supply and a resistor. This reforms any discharged aluminum oxide.
I wouldn't worry about matching the clamps. Modern caps are a lot smaller. If you use use snap-in caps, you can solder terminals to a cinch type solder terminal strip and screw the strip over the hole. You could use glue. The best rubber cement I have found these days was "shoe glue" in the shoe department. California has banned any useful rubber cement, so nobody will make it anymore. Liquid Nails is now garbage.
they amp is rated 125Watts
are you sure about the UF value for the caps ?
https://stereonomono.blogspot.com/2020/04/heathkit-aa-1600-power-amplifier.html
A few dollars more, you can get a 15000µF/100V from DigiKey.
15000µF 100V Aluminum Electrolytic Capacitor