18W EF86 XXL Recording Amp

[JMPGuitars]

Well, I decided to try something crazy. I designed an 18W circuit with an EF86 into a cascaded 12AX7 into a parallel 12AX7 into the PI. It's got a TMB tone stack, and this one won't be getting any reverb.

This should be interesting.

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[Bieworm]

Really high gain!
What’s the recording amp aspect?

[JMPGuitars]

Really high gain!
What’s the recording amp aspect?

No reverb, no fx loop, and attempting to design for good SNR with excellent range of dirt.

The intention is to swap out my Xtra TMB that's located on this amp wall in my friend's studio:

[Bieworm]

That’s a very interesting build! Can’t wait to see the clips when it’s finished

[yello]

Well, I decided to try something crazy. This should be interesting.

Looking forward to seeing the schematic and layout!

[JMPGuitars]

I don't know how long it's going to take for me to build and tweak this. I have a bunch of higher priority stuff I need to do. This will mostly get done while procrastinating other things.

I am looking forward to it though.

[TriodeLuvr]

The EF86 is one of my favorite tubes. Nevertheless, the search for lowest SNR and super-high gain eliminate it as a preamp candidate. What's really needed to accomplish that in the first stage is a cascode FET under a high gm tube like the 6DJ8. Allen Wright (RIP) of Vacuum State wrote a number of papers on this subject, including at least one that was published in Sound Practices. If the goal is really to create a studio quality input stage using tubes, this is the ticket. Allen claimed the FET is sonically invisible, and I believe him. He was a talented designer. The basic configuration looks like this:

[JMPGuitars]

The design I made for the EF86 Lite 2P variant is actually excellent without needing a FET. I'm not trying to get HiFi SNR, so it should be fine.

If I hate how it sounds in this cuckoo amp, maybe I'll try that out tho.

Thanks,
Josh