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I finally got around to finishing my Boogie57, and I like the sound, but a couple issues.
1) The pot takes it from no gain to much gain instantly. This may be related.
2) Most important, unless it’s related to that same resistor, it’s loud. Like, absurdly loud. Testing it through my amp, I had to set the amp so bypass was barely audible–I could head the actual guitar louder–and turning it on went LOUD. Like from volume 1 to 6 just from the footswitch.
I mean, it’s just an old Fender Champ 15, but it’s no slouch for the el cheapo.
3) It creates a loud buzz. So far I attribute it to testing with the pedal unclosed and using my only available short cord, which places it right next to the amp. Will check into this later.On the other hand, I didn’t have any trouble with biasing like I’ve seen. One trimmer is pretty much bottomed out, but all the transistors read at 5.00. I think I’m reading it right (drain should be far right, with flat side up?) and I assume I’ll have to re-bias after fixing.
Next time, I’m stocking up on 9mm pots. Offboard wiring all of these was the least fun thing I’ve done outside of work. And I do autopsies. Props to you guys that make the massive combo pedals.
Totally skipped the pictures…
Typically when overall volume has increased dramatically it is because of an incorrect resistor value.
Likewise when this happens noise is also increased.
I would check each resistor by color band one at a time.
I cannot easily distinguish colors from your photo but for starters R3 does not appear to be correct.
Sorry, flash on cheap resistors. I miss my old batch.
Should be 68k, blue grey black red brown. I’ll grab the MFT and get to work once I get home.
R3 is spot on 68k.
However, this batch either has some mislabels, bad QC, or burn extremely easily. They’re from Amazon.
R5, R6, R15, and R21 are all reading either half or twice what they should. From here on out, everything meets the tester ahead of time.
Well this is going to be a project.Unfortunately, you cannot measure a component while its installed. Judge them by their color bands and match them to a chart.
Check the content in this post. It may help give you some things to try, if in fact you don’t have a build issue. I came across this yesterday. I’m positive that a resolution has been finalized, but interesting read.
Okay, quick brief resurrection!
Life hit me like a truck for a time before I started my current batch. Finally found this again in one of my boxes while sorting tools.So, summary of needed changes:
1) Change R11 to 100k.
2) Swap gain pot to an A250k, OR an A300k/A500k with 1M resistor from legs 1&3.
3) Add an 8k2 resistor between gain pot leg 1 and board.Am I correct in those? Did I miss anything?
As far as I recall all that needs done is
- R11 to 100k
- Gain Pot A250K
I am not sure the 3rd mention is necessary but up to you. It is subjective. Try it if you like.
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