I get them from Mouser in Texas. They have a great selection and ship same day, so for me I get orders from them in 2-3 days.
I know in another thread that you are looking for schematics for your amp, I saw the pre-amps posted over at ampage. Try searching there. If I get a chance, I'll try to post a link.
No the tolerance does not matter as long as the basic value is correct. I would suggest starting with the pre-amp boards and then do the power amp board.
I was surprised at the difference that changing a few resistors and a few caps made in terms of the background noise and hiss levels. Even though you will notice a difference don't expect the amp to be dead silent.
For anyone that needs the schematics for the PC105 pre-amp board or the PC703 power amp board here's the link.
yeah...that's exactly what I am going to do after reading copius amounts of posts by those who have gone before me.
I don't expect total silence but I believe I can reduce the waterfall to a trickling creek.
Thanks for the link to the schematics. I found others on that board but had Boost instead of Bright...those PDF's are good as the values are very clear.
I was reading elsewhere that you can upgrade the Output Caps and Bridge Rectifier(?) to get more headroom and possibly volume. I may tackle that after tweaking the pre-amp.
C4ster Messages: 686 Registered: June 2001 Location: Mukwonago, WI (Milwaukee...
Senior Member
Just make sure the voltage rating is the same or higher. I generally install caps that are 2 to 4 times larger. For a 2500uF I would put in 10,000uF. Typically in K100's. Or for 4700uF I would use 15,000 to 20,000uF. You might change the AGC3 fuse to a slow blow fuse. I generally don't change the bridge. That brige is very beefy as it is. But a 200VDC 25Amp bridge should be large enough.
Conrad
Changing out the filter caps and upgrading the bridge rectifier will help to get the most usable sound out of the amp, but it will not get more power from the amp.
No, it isn't shown on the PC702 drawing. It appears on the overview page that shows the pre-amp boards and the power supply. It is listed as CR1.
On your amp, it is bolted to the floor of the chassis. It is 1 1/2" - 2" round (at least if it is the original one) and has 4 terminals with 2 wires that come from the power transformer and a red (+) and green (-) wire that go to the large filter caps.
stevem Messages: 4733 Registered: June 2004 Location: NY
Senior Member
Yes, the round item with the four wires coming off it is the bridge rectifier.
They do not make FRED type as a bridge, so you will have to make it up from 4 seperate ones on a terminal strip or bread board.
I will fax you a schematic of the power supply with the preamp, but I tryed to fax the preamp one to you yesterday and that fax number did not work, so please check it for me.
pleat Messages: 1452 Registered: June 2004 Location: Belding, Mi
Senior Member
If it's any help, I have a bridge rectifier from a Kustom 3 monitor amp circa 1975 era. It is a little smaller in size but has the 4 tabs on it for hooking up the leads. 20.00 I looked on the schematic and it shows the power amp using 40.2 volts and I know the older K200 series shows 39.5 volts. Not sure if there would be a problem or if there is something else in the amps that regulates the proper voltage. The Monitor is a donor amp, Tranny is now in my K150 2x10 amp and the power amp board and transistors found a home in NC.
pleat