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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.

Really nice job on that little board!

Yup, that's it.

You can do it with a SPDT. I created a little breakout board for that and shared it on OSHpark. You can order the PCB there. Takes about 10 days to get it, depending on how far you are from Portland, Ore. How it works: Remove the feedback capacitor from the pedal circuit and solder it to C1 on...

Doh! Fixed. Thanks for the heads-up.

I use the 2SK2145 dual JFET in a discrete opamp booster I came up with. They're not specified as matched, but all the ones I've tested have been. I believe it's a dual 2SK880, so low VP and different IDSS ranges. Again, the downside is it's SMD only. Great little package, though.

Changing gears: Chuck Roast That's the plan for mine after gaining it up a bit. Sounds awesome, but found myself wishing there was more on the gain knob. Been meaning to do some experiments to boost the distortion when I have some time.

I think the 2SK880BL would be a good fit for JFETs. Same Vp as a 201, but IDSS is 6-14mA. It's also a low-noise JFET intended for audio.

Looks like it's basically a Tubescreamer with the feedback diodes lifted and more lower frequencies added back in. It's the opamp clipping. I'd recommend using a A500K gain pot and a pair of clipping diodes across C5.

Cool idea. Dunno why I never thought of that before. I'm not familiar with DipTrace, but I use curved traces in EagleCad. It's an option called "Miter Wires."

If you look on the forum list, you'll see one called the Boneyard. Member Chuck D. Bones is an electrical engineer who volunteers his expertise on the forum and that's his space. A Boneyard edition is when Chuck comes up with fixes for pedals that need a little design help and other mods. If...

Right, you'd just do those substitutions for the tone stack and the gain control. It's not strictly necessary, though. I have a lot of A100K pots, so scaling lets me use those instead. Be interesting to build it both ways and see if one is less noisy. Never actually done that. Another Edit...

Here's a way to check it out. The SFT above uses a James stack. You go to the James stack at Tone Stack Calculator and test values. Look at the response with the default values, then scale like I suggested above (Cap values X 22 and divide resistor values by 22) and you'll see it comes out the...