Hi

Thanks  - i am chuffed because it's also my birthday as well!!

I have some basic electronics knowledge - but after seeing the circuit diagram i realised it was a bit different. I started checking component by component from the input starting forwards. After that it was a choice of FET (which i could not source) or changing the two chips. Luckily i had a couple spare, and after changing the second one back to life!! (wish i had done that first!!)

I had difficulty with the circuit - i can follow normal amps to a degree but this one had me stumped what was doing what.

I have been playing guitar and bass on and off for 25 years and for guitar have always used tube amps (still do) but after hearing the sound quality of this i have to say that if i was to restart gigging again, i would go SS. I was really surprised at the quality this amp gives.

All i need to do now is find a couple of input jacks for this - they are knackered - even cleaning them is no use.

Cheers

Hi all

Found the problem - it was he second LM358N - replaced that and back came the volume!!

Thanks again

Paul

Enzo,

You are an absolute star!! Thanks for taking the time to do that, much appreciated.

Thanks to everyone else with your suggestions as well

Cheers

Paul

Hi,

Thanks for the replies and advice - really appreciated, thanks.

First problem is the two input jacks high and low - the switchcraft jacks were not making contact with the jack plug and seem to be wired strange - not what i was expecting at all. Even after removing them and temporarily wiring another standard socket to the hi input on the PCB the volume is very low with both master and volume up full. If i have any luck getting it fixed i will have to work out how to get new inputs as i doubt if i will ever find replacements. It seems to have complicated switching (to me!!) on the inputs that i need to work out - as i have now removed the sockets there are extra PCB lands that are not being used - running into the preamp.

I tried running out the preamp direct into another amp - and the volume seemed ok - although i still had the master volume up full. If i touch the input leads to the power amp there is the usual loud buzz.

Oh and the reverb doesn't work!!

Still, at least i am learning!!

Paul

Hi,

I stumbled across this site whilst looking for circuits - and i am new here so hello everyone.

I have decided to try to get my old Lab series L3 amp working again - there seems to be very low output from the pre amp section. I have spent all day on it with no luck so far.

Does any one have any idea where i could find a schematic for this amp? I have looked all over the web and can only find circuits for the rest of the series which seem quite different from mine.

Cheers all

Paul