The lucky break was trying out the 12AX7 on the PI before I put the MV control in. The 12 AX7 brought gain up and was saturating earlier, gave me a feel for how it would sound cranked up.I had planned on putting the MV as a trial anyways , but with the 12AX7 in there it became almost a necessity. Without the MV I think I could trash the speaker, literally bottom it out the coil at peak transitions. I have a Fender Blues Junior with the volume and master volume, and I liked that layout.
Master Vol & Attenuator
OK, SimonB I submit this: what has been done for the MV etc, and planning for the attenuator. I want a simple control of the overall amp volume, and with the attenuator I hope to get a bit more drive from the power amp circuit whilst not blowing out any speakers
IS THIS NSFW??
OK, SimonB I submit this: what has been done for the MV etc, and planning for the attenuator. I want a simple control of the overall amp volume, and with the attenuator I hope to get a bit more drive from the power amp circuit whilst not blowing out any speakers
IS THIS NSFW??
Attachments
Have fun tonight!
I am going to order up the power resistors for the attenuator, and still have to decide on whether to try a circuit scaling the plate volts and readjust bias.This amp does not have the adjustment pot for the biasing, just fixed resistors. So I need to address this anyways.
The attenuator should allow me to adjust the MV into an upper range that drives the 50W or so output, but at 12W out to the speaker. But I reckon that if I scale back the plate volts and rebias, at least there is less risk of smoking the tubes and possibly frying the OT.
I am going to order up the power resistors for the attenuator, and still have to decide on whether to try a circuit scaling the plate volts and readjust bias.This amp does not have the adjustment pot for the biasing, just fixed resistors. So I need to address this anyways.
The attenuator should allow me to adjust the MV into an upper range that drives the 50W or so output, but at 12W out to the speaker. But I reckon that if I scale back the plate volts and rebias, at least there is less risk of smoking the tubes and possibly frying the OT.
With a lot of other projects on the run, it has been a while since I posted on this ongoing rebuild.
There was a big renovation to do in my home workshop, still in finishing stage and as usual took way longer than planned. Did manage to steal some time to work on a pine cabinet converting this rather heavy combo unit to an amp head. I was going to mount the reverb tank in the head, but had the idea to leave it out for now. This frees up 2 more preamp tube sockets to play with!
Thanks Simon B and Razorrick, for encouraging me to explore some ''high gain'' options. I have the attenuator resistors now, so I need to get those wired up for some trials. More on that soon, I hope.
There was a big renovation to do in my home workshop, still in finishing stage and as usual took way longer than planned. Did manage to steal some time to work on a pine cabinet converting this rather heavy combo unit to an amp head. I was going to mount the reverb tank in the head, but had the idea to leave it out for now. This frees up 2 more preamp tube sockets to play with!
Thanks Simon B and Razorrick, for encouraging me to explore some ''high gain'' options. I have the attenuator resistors now, so I need to get those wired up for some trials. More on that soon, I hope.
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