Tube Amp Archive

Finally I got it. I had to rewire the relay board to make "OD off" normally closed. It was backward because I looked at the Ceriatone layout.
Referring to different layouts drives to problems.
Sorry for these idle postings.
Best regards.

I'm going to try to explain my problem. The pic shows my switches' wiring. Pab works ok. Overdrive Toggle up: OD off. Footswitch doesn't turn it on (just switches the led on/off). Overdrive Toggle down: OD on. Footswitch turn it on/off, but the led brights when OD is off. What is wrong? Please help!...

Thanks for your answer.
Yes the switches on the back of the amp are grounded. Pab works ok.
Should the OD be engaged when the switch-on-the-back disconnect the ground?

Hello. I'm testing my diy D-preamp. I can't get the OD/PAB switch working correctly. PAB is ok, not OD. I can turn OD on/off by the manual switch (when the switch lifts the ground... is that normal?). When I hook up the pedal then the footswitch works only in "manual" position, "footswitch" position...

Hi Gil. First of all thanks for all the advices you gave me... once again (I'd never build anything without the "school" from you and other guys on Ampage and elsewhere many years ago ;-) In fact I see that D-design is rich of tone nuances. I've to play and learn to use it. Voltages are correct, the...

My preamp is still in progress but here are two pics. The schematic is #124. The layout has to be arranged (mirrored and rotated) to fit in the chassis I had at hand. I use salvaged parts as I can. I have a couple of external PS for preamps, built into PC supply boxes. Filaments run on DC. Relays at...

Update:
solved the FET issues thanks to the 2-batteries-trick found in an old thread.
BF245A asked for only 240R source resistor to get 9V at drain and 17,5V supply. Perhaps it's a weird value but seems to work.
Still puzzling with the other questions and hope in your advice.
Thanks in advance.

Hello. I almost finished my standalone D-preamp and I'm testing it connected to the power amp of my DIY Hiwatt. I've a pair of question and hope in your help. - FET input seems to be clipped by a Strat also at low trimmer setup. I understand it's intended for low-signal piezo but I'd like to get mor...

Many thanks to everybody!
Best regards

Hello. I'm checking my diy Hiwatt and I have a doubt about a mod I did. The original design use one triode for each input channel (norm-brill): http://www.drtube.com/schematics/hiwatt/hwpre1.gif My mod use just one triode and a switch to select norm-brill. In the original design the two triodes shar...

Thank you very much for your help!

Thanks for your explanation. If I understand correctly the attached pic shows the way to go. Or also here the relays supply's minus hasn't to be grounded?
Please excuse my little knowledge.

Thanks for your answers. I attached a pic. Should that work good?

Thanks. Then I've to use the same 12VAC winding (it's a 6-0-6 indeed) for filaments' supply. What about the ground reference?
And also 12VAC have to go to 2nd PT to get high voltage for B+.
Is it ok?

Yes, #124 is my aim. I read a lot about it here!
My doubts are about no-relays option.
Thanks