Slo Clone LDR switching issues

[ThisLifeILead]

Howdy folks,
The slo clone forums is alittle slo so i thought i would post here.
http://www.slocloneforums.com/schema...CIAL-SCHEM.pdf

I finally got to fire up my 50w slo clone. All power supply voltages seems good. I biased up the 6l6's to 38ma each.
it seems the overdrive channel isnt working properly. i have low output and the channel switching isnt working for the overdrive channel.
The clean/crunch switch is what switches the channels not the channel select switch. I verified my crunch/clean switch wiring. I think some of the LDR's are not functioning.LDR1 or LDR2 are suspect.

My question is how does one test an optocoupler LDR?

i am using VTL5C1 optocouplers. I am getting 1.65v on 2 out of 4 LDR's. no voltage on one LDR and -0.36v on the other LDR.
Should there be voltage on all of them? Do i measure the switch side for changes in resistance? (on/off resistances)

any help is greatly appreciated.

[52 Bill]

My question is how does one test an optocoupler LDR?

i am using VTL5C1 optocouplers. I am getting 1.65v on 2 out of 4 LDR's. no voltage on one LDR and -0.36v on the other LDR.
Should there be voltage on all of them? Do i measure the switch side for changes in resistance? (on/off resistances)

According to the schematic when the footswitch is off 2 of the optos are on and 2 are off. When the footswitch is turned on the 2 that were on turn off and the 2 that were off turn on.

If you are measuring the voltage across the led side of the opto, you should either get near zero voltage or about 1.5 volts, depending upon the switch setting.

[ThisLifeILead]

I found my footswitch wiring was backwards. DOH. after swapping wires channel switching works great now but my volume is still very low. time to bust out the scope.

[ThisLifeILead]

BAM! i mixed up one of the resistors on the P.I tail. i put in a 1meg instead of 10K. Plate wires were out of phase aswell. after fixing the mistakes it fired up and worked flawlessly. No squeel or over the top hum on gain channel but i never got past half volume with full gain. Dam this is a loud 50W amp.
I did find the amp to be quite bright so I installed a conjunctive filter. 0.0033uf and 5K 10w resistor.

I played the amp ALOT this weekend with various guitars and i must say this is a very transparent sounding amp. The depth control is very nice. The loop on the otherhand is very quiet.
Ive played ALOT of factory made PCB amps and the SLO really is the king. Very little fizz and a very tight low end. Very happy with this amp. time to sell my high gain pedals and my mesa DC-5.

I gotta go pick up some small zip ties to clean the amp up. once i have it all cleaned up i will post some finished pics. :mrgreen: 8)