The Amp Garage

I'm resurrecting this thread because while trying to find the best solution to the Hiwatt tonestack bypass switch it occurred to me that maybe my attempts last year to design a Hiwatt Hybrid preamp (the original goal was to have the 80's high gain Hiwatt sound and the early 70's Hiwatt clean sound i...

ok thank you, that makes sense.

Yes I see your point.

And I like your idea, would this be a 2nd option in the same vain?

Thanks Mark,

In light of this, would this be a way to do it?

The Hiwatt tone stack is a bit unique, so I just want to double check with you all. If someone wanted to bypass the tone stack on a Hiwatt amp you would connect the switch like so:

Ok will do! Thanks again for the help.

I went back to sluckey's on/on/on switch schematic and I just want to make sure I understand the important details. Quick note: I'll be using a Mullard Blackburn era 7247 (I've been looking for a reason to use this tube for years!) I couldn't find a datasheet for this specific tube but I did find on...

Thank you everyone, these are some really good options. I'm excited to try them out and report back.

Yes Mark I stole them from "Minimalist" schematic I believe

So more like this?

I want to put a 12DW7 in the V1 position where I can choose between the clean 12AU7 side (unbypassed) or the bypassed higher gain 12AX7 side. Would this be a good way to do it?

Thanks Phil,

This makes sense, I did miss this detail the first time. I suppose the only way to find out is to build it and go from there. Thank you again for your help!
-Ryan

Phil,

I see your point about the normal channel feeding v2b but also the anode and cathode of v2a - creating a strange kind of loop. Hmmm I'm wondering the best way around this? I could always install of 5th preamp tube so that I didn't have to share the input of v2b?

-Ryan

Thanks Phil, What you have drawn is basically the 80's Hiwatt circuit or the OL version, I've attached it. I've also attached the 4 input early 70's schematic. The phasing issue I knew would be one downside, being that one channel would have an extra gain stage. The goal of combining one channel fro...

Would it be possible to build a hybrid Hiwatt preamp where the Normal channel follows the early 70's circuit design and the Brilliant channel follows the early 80's "OL" circuit that has the extra gain stage? I've modified the attached schematic (from Mark Huss' original "early 70's" schematic) roug...