Resprom EMS1511 dead :(

[DJduck]

Haven't posted on this forum for a while, but here I am again, with another problem.
So basically, I bought a Bulgarian made Resprom commercial amplifier (with the 100V line transformers removed) a while back to use it in my PA setup. But this thing ended up sounding so bloody brilliant, that I just couldn't resist using it in my main audio setup.
Then I started fiddling around with it. Recapped it and changed output wires. Now I started making it into a fully featured home stereo amplifier, which included removing all the useless wiring and connectors. The stuff that I removed is all a part of the "control" circuitry. It is only used to control the amplifier from the preamplifier of this set. But I don't have any other pieces from the set, only the power amplifier.
http://www.kn34pc.com/sch/sch_ampl/r...m_emc_1511.gif
Above is the full schematic of this amplifier. Two modules on the left are the amplifier channels. There are two channels in this amplifier, therefore two blocks. The upper schematic is for the power supply. Circuit on the right is the "control/bridging" card, that has no use when this amplifier is not used as a set. This card has been removed from the amplifier, and the amplifier still continued working after removing the card.
Well, what happened is that I basically removed all the wiring except for power supply wires and output wires. Added new input wires.
So after all that had been done, I turn it on and the power light comes one, amplifier module relays click in and "working" LEDs light up. But just in case, I hooked up my multimeter to the outputs, and boy am I glad I did. Why? Because there is 13V of speaker roasting DC on the output!
So what the hell?!
I disconnect POWER GROUND from CHASSIS ground, and the DC is gone. Reconnect them, and 13V DC on the outputs! Two grounds disconnected from each other, my multimeter measures 13V DC between the two grounds. Power ground disconnected from chassis ground, input and output grounds connected to chassis, I get a very quiet, distorted signal on outputs. Input ground and output ground connected to power ground, or power ground connected to chassis, and 13V DC on the outputs.
Remember, amplifier modules are fine, they were working just before I rewired!
So I made a stupid mistake in the wiring or something and now I need the help of you guys to get this amplifier up and running again!
Below you will find a picture of how my stuff is wired up. Marked with red is everything I removed, green marks the card that has been removed, yellow marks some points in the circuit, I labeled them because the schematic is in Bulgarian.
So please, help me resurrect it, I NEED MUSIC! :P

Cheers!

http://www.upload.ee/image/4314044/s...m_emc_1511.gif

[stj]

Re: Resprom EMS1511 dead

i think when you pulled the transformers, you should have fitted DC blocking output caps.

i'v not seen a power amp before that pretty much connects the speaker directly to the power via not much more than a transistor!

remember, transformers cant pass DC, but without one - well good luck!

[DJduck]

Re: Resprom EMS1511 dead

It worked fine without a cap before
Most good designs don't require output caps, some need inductors, but only cheap designs use output caps.

[DJduck]

Re: Resprom EMS1511 dead

Got it working!
It was a grounding issue!