"Special Edition" - WARNING graphic turret content

[Robert]

Yep, it seems like most higher current DC supplies are center positive. That's a good solution. =)

 

[andare]

I've seen your stuff all over TB for years now, didn't know that was you here. Very rad stuff, thanks for sharing.

Yes, people on Talkbass rave about these pedals.

 

[Stickman393]

Man. I wanna build pedals like you when I grow up.

 

[vigilante398]

Man. I wanna build pedals like you when I grow up.

As flattering as that is, I have to confess that nothing I did here was really hard, machines do most of the work. Anytime I find something I'm not good at I find a machine to do it for me, so I have a ton of fancy machines, and that makes everything easy.

Yes, people on Talkbass rave about these pedals.

Oddly enough I've been on here longer than I have on Talkbass, but people there think I'm pretty neat so I spend a lot of time there I still consider myself a DIY builder (though I've been told I don't really count anymore), DIY people will always be my people.

 

[giovanni]

Mmkay, here's the schematics. This is the simplest preamp pedal I make, there really isn't much to it. A quick note, the tube pin numbers will look weird to anyone familiar with tubes as I use a daughter board for the tube, so the pin numbers correspond to the daughter board pinout, not the tube itself.

View attachment 20570
And this is the schematic of the power supply. The resistor marked 560R* is the one I adjust to change the B+ voltage, 560R gives you right around 235V, for the full 360V you need to drop it to about 360R. The part names here are the SMD versions I get pick-and-placed, it's more common to use IRF740 for the power MOSFET and UF4007 for the rectifier.

View attachment 20567
The tube mounts to a daughter board I designed that also holds the LED. I used to mount it under the tube socket, but it's way harder to service if an LED goes bad so I eventually moved the LED behind the tube. I feed the tube heater in series right off the 9V input; the tube expects 12V in series, but 9V is plenty to get it warmed up enough to pass current. Also saves you a few mA of current on the heater draw. For polarity protection I like to use a schottkey bridge rectifier on the input, so no matter what polarity the input is it will work. I use the schottkeys over standard rectifiers so the voltage drop is negligible.

View attachment 20568

I think that's pretty much it, happy to answer any other questions

Thank you for sharing! I’ve been wanting to learn about tube circuits for a while, any good reference (book, website)?

 

[jeffwhitfield]

Oddly enough I've been on here longer than I have on Talkbass, but people there think I'm pretty neat so I spend a lot of time there I still consider myself a DIY builder (though I've been told I don't really count anymore), DIY people will always be my people.

 

[vigilante398]

Thank you for sharing! I’ve been wanting to learn about tube circuits for a while, any good reference (book, website)?

I'm a big fan of http://www.valvewizard.co.uk/ he has excellent info on his website as well as his book "Designing Tube Preamps for Guitar and Bass". Not a thrilling read, but an excellent reference book. Lately I also started getting into https://www.ampbooks.com/mobile/vacuum-tubes/ He has some incredibly useful calculators on the website for designing tube circuits, and I picked up his books but admittedly haven't used them much.

 

[Blooze]

Been following your stuff for years now. Glad to see you here as well!