So,I wanna build another amp..

[DigitalJunkie]

Hey guys,

I wanna build another amp..
I've built a subwoofer amp from "scratch" before from stuff I had around the workshop,and a schematic of a car amp I copied.
Prolly about 150W output...then I finally blew it up while fiddling with the output stage.

This time I've got a buncha parts from a Sansui amp I've had for a while (A-1130p) 2 x 130W
It gives me grief whenever I try to fix it..So I gutted it a bit,and want to rebuild it..(reuse the chassis,and some of the parts.)


Heres what I have...
450VA/350W power tranny,secondaries 47-0-47 and 16-0-16 Vac.
And 2x 8200uf 80V caps.. (I think the rails were about +/- 70v at idle.)

Output transistors are 2SC2581 / 2SA1106
Drivers for outputs are 2SC2591 / 2SA1111
I have a bit of an output circuit worked up around those (copied from the Sansui.) But I'm willing to change it a bit..
The Sansui originally used a STK3102 for the front end,and I think,had somekind of bias servo circuit.
I guess I really just need a suitable circuit for the front end,or a schematic of a complete amp that will work with the parts I have here..

Can anyone suggest a circuit to follow?

I have this stuff available for the rest of the circuit..
ECG/NTE 373/374's
ECG/NTE 323
2SC1815/2SA1015(?)
2SA733
2SA777
2SC458
2SC711
2SC1345
2SC1509
2SC1684

I also have lots of other parts floating around the workshop..Boxes of stuff I havn't even looked through yet,who knows what might pop up!
I already found a buncha TO-3 transistors,and 10 pairs of MJ15011/15012!,so I should be set for parts,I just need a suitable circuit for the parts I have available..

Later on those MJ15011/12's might make thier way into a couple of Leach amps...or maybe one big monoblock!

Thanks guys! Any suggestions would be great.

[DigitalJunkie]

Okay,so I'm leaning towards the ESP 3a,using the parts I have on hand..
http://sound.westhost.com/project3a.htm

But,
It looks like my +/- rails are gonna be a bit (2x) higher at 65-70Vdc,instead of the 35V (42V max) specified on the ESP page..I know the output,and driver transistors I have will handle the voltage,what about Q1,2,3,4,9?
Does anybody know off-hand if any of the transistors above will survive the higher rails before I go digging through datasheets?
Is there anything else I should change because of the higher voltage?

Maybe someone knows of a ~100W amp schematic with 60-70V rails I could follow instead?

[Scribble]

From my understanding your tranny has two different secondarie voltages? one being 16 and the other 47?

If so you should Gut the whole thing and build a new shiny preamp and amp into it. No idea which one though

Just my limited input

[DigitalJunkie]

Originally posted by Scribble
From my understanding your tranny has two different secondarie voltages? one being 16 and the other 47?

Yep,one 47-0-47Vac main secondary,and a second (lower current) 16-0-16Vac secondary that was used for everyting else (preamp stuff,protection circuitry,led power meter,etc.)

If so you should Gut the whole thing and build a new shiny preamp and amp into it.

Thats the plan,I just need to find a suitable schematic to follow..