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Common to circuit ground is correct, but is there continuity between common and the ground terminal of the DC jack? If there isn't, maybe the converter references the wrong voltage which causes the offset of the +/- outputs in relation to chassis ground. A fix would be to run a wire from the...

Can you share your vero layout and wiring from/to the DC jack? Kind of peculiar that the converter output is offset by 9V.

Power transistors in general seem to be lower gain, just mind the pinout and the package size. I found some of them also have higher parasitic capacitances than regular transistors, which may or may not matter and may or may not be a good thing as it can lead to high-end roll-off due to the...

Cool idea. I'd like to check out that schematic. Currently planning to build it stock with a DC-DC converter for +/-15V, then see what I do and don't like about the circuit and go on from there. Simulations in LTSpice seem to suggest a bit of a lack in bass content, but it's hard to hear with...

I suspected as much. Some of those older Randalls look intriguing for sure, but I'm adapting the boost channel of the Marshall Valvestate 8100 with (probably) FETs for tubes. Uses TL072 and obsolete M5201 switching op amps throughout, which seem to be very similar in specs to plain old 4558s...

I'm working on pedal recreation of the preamp section of a solid state guitar amp. I want to stay true to the original and use the same or similarly spec'd op amps throughout. Due to the circuit design, I could either use two separate single op amps for the input and output sections, or use one...

Double check where the pins are connected on your pots. Your mids and presence pots for example seem to be reversed, so they're going to function backwards. C107/C106/D2 aren't connected to ground, so they won't do anything. Q4 is not going to work as intended. This is a source follower stage...

It's worth experimenting at least. I currently have a silicon treble booster on the breadboard and transistor choice has a pretty big effect on how compressed the signal sounds, even when biased to the same voltages. High frequency response is also affected quite a bit depending on the...

We'll see :D Wiring this up was a real turn-off. Need to get more into DipTrace so I can create a PCB with board-mounted pots and switches. Yeah, it works really well here. Overall, I prefer the sound of this DIY buffer/boost over my PedalPCB Transcendence Boost with an OPA2134. That...

I'm located in Germany. The handful of JLCPCB orders I've placed so far were with the "HASL (with lead)" option and I haven't had any issues. I use "Global Standard Direct Line" shipping with duties pre-paid to JLCPCB. Packages have been delivered directly to my door without further actions...

Maybe I should share some of the actual circuitry. This is the buffer/boost stage: C1 = 470n film C4 = 100n X7R C7 = 10u electrolytic R12 = 100K R13 = 51R "Boost" is an A10K pot with pins 1 and 2 bridged. A 1.1K resistor (R7) goes from pin 2 to 0V. The impedance selector switch simply has a...

I nicknamed this build the BSMSB – Buffer-Splitter-Mixer-Switcher-Boost. It does pretty much what the name suggests, although the splitter-mixer part doesn't really work particularly well. More on that later. A simple non-inverting op amp circuit provides adjustable gain from unity to +20 dB...

Getting slightly off-topic, but couldn't you just reference the transistor to the negative voltage instead of ground in a common emitter amplifier for example? If not, why not? I don't think this case was covered in your BJT biasing series, Chuck.

Same experience here. Tested a batch of MMBFJ201 from Mouser recently. VP of most was around -0.5V but there were groups of outliers at around -0.35V and -0.8V.

You naughty, naughty boy.

https://audiosurpluseffects.bigcartel.com/product/ok-doomer-pre-order Ok Doomer is a result of multiple cascading gain stages collapsing in on themselves running into an artisanal, organically sourced tonestack producing a high-gain fuzz/distortion designed to make you play the same riff for...

I'm just thankful for being able to add varna sankar to my list of questionable slurs I probably shouldn't be using. It sounds awesome. Muddafukkin varna sankars!

Those bias voltages seem off to me. Where did you source your JFETS? Anyway, the guitar signal can potentially swing from 0V to 22V, minus some losses. The drain voltage just defines the midpoint of this output swing.

You can also try a single 100K across the outside lugs. Using a 25K pot will affect the transistor bias slightly since the presence pot also acts as the collector resistor, and so will using two taper resistors for any settings other than 100% or 0%. The taper is going to change either way, and...

Interesting circuit. If you want to maximize clean headroom, biasing an op amp to the mid-point of the positive and negative rails is the way to go, but there's no rule that says you have to do that. Maybe they wanted to increase even order harmonics through asymmetrical clipping for more amp...