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Trace through your grounds and ensure your PNP style Tonebender has blocking caps on the input and output, as well as from circuit ground to chassis ground (which includes raw 1/4" jacks).

I am not familiar with the Hydra and there isn't a published schematic.

TY for the typo correction. IDK why I typed 15. At least I got the right resistor number!

Congrats! I was concerned as EPROMS are sensitive and do not standup to deviations. Since it is tied to the FV-1, I thought there was a good chance that would need to be replaced. If you want to expand your pedal to include the 7 effects inherent in the FV-1 chip, I believe I posted a...

If you look at the schematic there is a circuit which connects Q1's base to Q2's emitter and to its own collector. That is a negative (out of phase) feedback loop from Q1 to Q1 and a positive (in-phase) feedback loop from Q2 to Q1. If feedback is in-phase to the base, it adds to the original...

Lol. I think can answer a few of your questions: The potentiometer is a component of a resistance-capacitance high pass circuit. It is in parallel with a 470K resistor that both passes and blocks full frequency. The circuit with the pot allows there to be less resistance for higher...

I suggest keeping it simple and focus on 'Q' for more vowel, to which the Clyde McCoy circuit delivers. IMHO, that is the gold standard for a musical effect. Set the potentiometer gear so that the frequencies are more centered on the crossover point where the mids seem to 'jump' from low mids...

Ensure your clipping diodes are oriented correctly. It is hard to tell from the pictures. Ensure C3 is no more than 220pF. From the picture, it looks like one of those mini 1Uf poly types. If all else is the proper component, an A1M potentiometer will pinch out a bit more gain to drive the...

I've been repairing amps since 1977 and when I was doing it to make a little side money, I'd also quickly replace and charge the customer, for any suspicious part - just for time sake. I'd primarily do what you suggest for my own gear, given the plethora of good replacements (with some...

Tektronics 453A oscilloscope, Tenma 70-1055 DMM (hFE, continuity, diode, ohms, capacitance, etc.), Fluke 87DMM, Micronita 10-185. Simpson 260 and an EICO 666 Tube and Transistor tester.

Correct. The 'trim' has pretty much the function of balancing the symmetry using bias (think of the bias balance in a silverface Fender from the early 70's). I am trying to avoid driving the cost up for the client by throwing parts at it. Most people get upset when you tell them you had to...

Thanks. I am reading no shorts, proper forward voltage from E to B and C to B, plus proper reverse voltage readings. The reason I am interested in the gain measurement (hFE) is this and its PNP counterpart are responsible for initiating the push-pull of the larger transistors in the output...

I am battling a client's science project amp repair (1970's Sunn Beta Lead solid state), where I get proper signal right up to the inverter circuit, which is clipping on both half's of the push-pull and phase cancelling the output. Thus the amp output to the speaker is almost nonexistent and...

You want to measure the Vsd (voltage drop of the source referenced to the drain). I did that then adjusted to my ear and use, which is more like a limiter with gentile compression and some transients mixed in using the Blend function. If you have it squishing, that means there is enough...

A little lemon juice from a dropper will dissolve super glue. I'd continuity test the header before disassembling it. The common fail items on those inexpensive Amazon pedals are: - Jacks and stomp switches from casual use - Pots from getting dropped and the shaft breaking the internal...

Congrats on getting it well. I have one of these and it is a great pedal. Also cool to let your daughter contribute!

Just a public service announcement that I discovered while building an Angry Andy: Page 1 shows the electrolytic capacitors C101, C7 and C100 with the plus side facing the bottom (switch side), which is incorrect. The PCB has the polarity correct. Go with that.

More of a question for the @Robert 's of the forum, who have the patience to reverse engineer double-sided SMD pedals. I was traded a Jetter Grissom Overdrive pedal for some repair work. It is one of the most useful OD's for those who get their sound from putting a tube amp on '7' and...

Yes. If the effect is working, that means it is getting 9V feed from the DC jack, but your LED indicator is not. A quick test would be adding a jumper from the DC jack to the anode pad or LED anode leg.

Just to be clear, the anode pad is square and the cathode is a standard soldering pad. Check voltage at the anode pad with the black probe to a ground source other than the cathode pad (should be +9VDC). If this checks, then check the resistance between the cathode pad and the same common...