Does anyone have an idea how to test for microphonic or bad tubes?? I really don't fancy forking out cash for a big old AVO Valve Tester type of machine. Tubes are costing me a fortune lately. I use 6L6's and 12AX7's. Thanks!!

I can't seem to find any 500ma HT fuses. But I do have 1A ones available. Would these be ok to use?

As I understand, you live in Holland? I'm in the UK, so it would be a nightmare to send it to you, without the thought of the costs of shipping etc. I know a good tech that would do it for me, but he costs £££'s. I think it may be a power tube, but I'm not too sure. I will however try and bias it again with it fully operating. Thanks Erwin!

Thanks Erwin. I hope the tranny isn't damaged, thats all I need. I'm getting the HT fuse tonight to see if it works. I know it's the fuse because when I unscrewed the holder, the fuse fell apart.

Any chance of your Bluesmaster clean/OTS overdrive schematic??

Cheers guys, it was the HT fuse.

There's a chicken head knob right between the two 6L6 power tubes (50w OTS), I'm guessing this is the bias control. What must have happened is, the control must have been turned up somehow and therefore over-biasing the power tubes, they probably couldn't handle it, and hence blowing the electronic HT fuse.

I'm quite sure this isn't the OD trimmer because it makes no difference in sound when I turn it. It must be the bias control. As I said, I didn't build the amp, so don't know.

Also it seems the bias test points don't seem to work either. I tried to bias it last night with a digi multimeter, I switched the amp on and let it run a while, inserted the black and red probes and switched on the MM and nothing.....no reading what so ever. I'm sounding like a complete numpty!! ha ha ha

Ah I see. What does HT stand for? I'm pretty careful when it comes to electric....learned my lessons! What values should I look at getting as a replacement? Also why would it blow, is there something I should be worried about? Sorry for all the questions and thanks for the help!

Hi Erwin,

Looks and sounds VERY cool. Could you please email me your schematic??

Many thanks:

Email: babybearyeah@live.co.uk

Thanks for replies guys.

I have moderate knowledge of amps to be honest. I unscrewed and changed the fuse at the rear of the amp last night to what it says to do - 2A Slo Blo, but still no sound. The tubes were fully burning and lit up, if it's something I could fix, cool. I don't really want to take it to an amp tech to sort it, especially if its something as simple as a fuse. Is there anything internally that could go tits up? I understand there is an internal fuse that could have blown also??

How did he change the OTS cleans to Bluesmaster spec then?? My OTS's clean channel sucks ass. Apparently the Dumble is supposed to be a modified Fender Twin, my clean channel certainly doesn't sound Fendery at all. Zero headroom and sounds spanky than the chimey cleans Fender are renowned for. I use a strat through my OTS and the OD channel is a bit too fizzy and no bottom end at all, but when the PAB is engaged, it sounds much better, more open and harmonic. Maybe has something to do with the V30 I'm using instead of a EVM12 or G12-65??

I wonder if anyone could help me......

My new Ceriatone OTS was built for me by a well respected amp builder here in the UK. I've played through it for a few months with all kinds of guitars and setups, never let me down and I always look after my gear.

So I took the amp one night to a band practice and there was no sound coming out from it!!! It powers up, so it couldn't be the power lead, the PAB pedal lights up as usual, I tried several different guitar cables, also tried swapping my guitars with my friends....still nothing. I changed the tubes even, still nothing.

It might be the 2A slo blow fuse could have blown?? But surely the pilot light on the amp wouldn't be lit??
I've tried turning every dial up to 10, taking it off 'standby' to 'operate' to see if there's any hiss, but nothing.

Could it be the speaker?? It's a V30 and they're built solidly and reliable??

PLEASE HELPP!!!!!!