The Amp Garage

Yeah saves on barbers fees I guess :D Heisthl - i put a 100k before and after the loop, I hadnt anticipated any issus with it but ah well.. I guess it will be something stupid I 've overlooked. I'll get the camera out and post some pics. Dogears - I didnt think the changes you mentioned would cure i...

OK. So I changed to the screen tap and added the extra filtering no joy :( Tried the 1n cap trick and it has most effect on the plate resistor of the recovery stage. checked all my wiring cant see anything obviously wrong or too close. tried rerouting NFB wire nope! jumpering out the return stage ki...

Thanks Guys
I'll try changing the tap to the screens, They are at about 550V since the KT88's are running up at 560V or so but I can work out the resistor values.
Cheers
Shane

Hi Guys Thanks for the replies. I will try and post some pics tommorrow if I can. I have configured it like fischermans in that what is normally the master in the non HRM is labelled preamp out put and the return level is called master turning either of thes down reduced the osc. With a scope i can ...

Hi Folks I'm Building a 100W 4x KT88 non HRM with the Dumbelator loop built in. I've kinda followed the schematic Heisthl posted (the PV conversion one). The problem I have is I have a major oscillation problem even on the clean channel the osc is about 10khz with everything full up and falls to abo...

You do have a point and I am certainly very reluctant to mess with a circuit thats so critically well developed. To be honest if I lost a pot I think it would be the send level! I may well just build in the Dumbelator and make the loop switchable then leave it to the customer to choose wether he swi...

Thanks Fischerman, good advice. I was thinking, looking at the Dumble Master placement, that I could use the Dumbelator circuit but either lose the master(and call the return level in the Dumbelator, the master) Or keep the normal Dumble master where it is and use it to control the send level and lo...

Hi Folks Can anyone recommend a good non-switchable active series effects loop for a D'lite type amp? I have someone who wants a D'lite type amp (albeit a 100W 4x KT88 type!) and he wants a non switchable series effects loop ie it will be in all the time. I looked at the Dumbelator circuit which is ...

Thats kinda got me puzzled! if V in the calculation is 380V surely your saying the resistor is dropping the entire B+!
Its only dropping 15V, sure it'll drop more flat out but surely not the entire supply!