25 watt stomp box amp design

[rring]

Okay I just misunderstood that some how you were saying the transfer function over the entire range of the filter would be altered.

So I just used linear pots because that's what I had - but there is so much variation regarding the other effects in the signal chain - guitar type, pickup type, the EQ weighting in my op amp stages.....

that when you are making adjustments, the lions share usable guitar tonal adjustment falls in a comfortable range on the knobs

I don't think it will matter much to guitar players.

[PRR]

> I just used linear pots because

Ah, interesting.

Open this image in a different window.

http://i.imgur.com/0hYjqQ2.gif

Three tone networks. All pots set at 50% rotation.

Top is a "High Fidelity" James stack using LOG 10% pots ("audio taper"). It is flat +/-1dB over the audio range. Loss is about 20dB. Minor errors due to 38K source and 1Meg load (should be zero and infinity).

Middle is a "James" but made with LINEAR taper pots set at 50% rotation. Loss at 400Hz is still about 20dB but lows and highs have less loss (are relatively boosted).

Bottom is a Fender, still all pots at 50% and using factory-like tapers. Referencing 400Hz again, lows and highs have less loss (are relatively boosted).

[rring]

Those graphs tell an interesting story. I did a basic circuit simulation in spice and tweaked accordingly  - I should use this tool and examine further - I suspect I am compensating with the 1uF(C3) for a scoop..etc.


someone earlier wanted some gut shots here they are:


you can see my home brew heatsink made out of 1/2 inch copper pipe I split and shaped - it is made to contact the box. You can see there is room to make the board bigger and use leaded parts - if desired

[tubegeek]

Sweet!

Nice use of leftover plumbing, too!

Did you solder the SMD's with big fat plumber's solder?!?!

[rring]

Yes I wasn't sure what to use for a heat sink at first because I didn't want to deal with trying to make something fit..etc

its pretty easy to saw copper pipe and form into any shape you want.

actually I glued everything into place and then dipped the whole board into a crucible of molten alloy.. I saw Vincent price do that to one of his victims once.

[J0K3RX]

pretty sure you were joking about the plumbers solder usually acid core.. doesn't play well with electronics.

[bool]

Old AMD athlon heatsinks are good for chipamps.

[tubegeek]

pretty sure you were joking about the plumbers solder

Yeah, it was merely a plumber's crack.