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Supply voltage?

That fish is a whopper! How the drain voltages looking?

If you're going by the schematic above, use 18K for R8 and 24K for R9. That should give you about 5.3V on the drains with a 9V supply. Also, I used 2u2 for C3 ad C7 because I had those laying around. Those caps could probably drop to 100n without running into trouble.

Wow! I don't think I even have a shipping notice yet on mine. Ordered from Digikey. I'm also planning on trying a non-inverting servo bias on the JFET gates and possibly just a simple voltage divider on the gates. You can bias up a Black 65 with trimmers that way without changing the Drain or...

Overdrive. Sounds great at low and med-high gain. Highly recommend.

Agree with Chuck, but I have a bit of an out-of-the-box suggestion: Try 1N5817 you use for polarity protection. You probably have some around and they're hella leaky like a D9-Russian whatever.

Good catch. Totally whiffed on that. I've already got a few coming, so we'll see if they start up with 9V. I think there's a pretty good chance.

No sweat! I love this stuff. The TL062 won't give the best results. I tried an 072 today and it couldn't keep up. Looks like the trick is a Fet-input, rail-to-rail opamp for this.

It's a good one. I was heavily into JFET ODs for years and the Black 65 is easily in the top 3 for me in that category. If I build this out, I'm most likely going to leave off the bonus boost stage. There are a lot better boosts to hit it with, especially a good ol' Klone. Might look into...

Nope. those are pretty much the 358. Only other rail-to-rail I've got on hand is a 2272 and it works fine (mosfet-based). It's through-hole, but they're $5 each these days. OUCH! If something comes of this, I'd like to make it through-hole capable so you guys can build one if you want, and I...

Spent a little more time playing around with this today. Unfortunately, an LM358 doesn't perform well. Think I'll look around for a cheaper JFET-input rail-to-rail opamp. Also confirmed it's easy to raise or lower the value of the drain resistor to dial in the amount of gain while maintaining...

You'd reduce C1. Going to 100n, even, would make a pretty noticeable difference.

Bat46 Mouser, Newark, Digikey, etc.

Chuck's thread on the Brownout OD finally motivated me to do some breadboarding with JEFTs and opamp servos for biasing. So far, things are looking pretty neat. I put together a couple stages of the Wampler Black 65 for testing and sure enough, I'm able to swap in and out JFETs willy-nilly and...

Yuge - and it's just adding a few passives. I'm sure there's a reason more tube amp manufacturers don't do more of this, like Bugera, but I don't know what it is. So would a simpler approach like this one from Elliot Sound be better suited for a typical common-source JFET amplifier stage?

Love where this going. I've been meaning for a long time to get around to see what I can do as far as making the Wampler and other designs work with servos and gate bias voltage. Definitely adds a lot more parts than a trim pot, but I think it'd be fun to play with. Cool thing here is you've...

Very cool. I've been waiting to see the schematic for this one. My guess would have been Muamp, like Catalinbread. Source and drain resistors on those input gain stages look kinda wonky. I'd expect them to be about 20% of those values.

Sounds like a Bluesbreaker variant. The high-pass corner frequencies on the 3 coupling caps are low enough that you won't notice they're gone. With a split power supply from the charge pump, you just jumper those 3 caps. The clipping options are the feedback (OD) and hard clipping (distortion)...

Split supply so everything is referenced to ground. They write about it like they invented fire. :rolleyes:

I've dumped the alcohol into a Tupperware container and brushed the PCB while it's submerged. I've got a friend who even uses and ultrasonic cleaner, like what they advertise for cleaning jewelry.