HMP Layout Confirmed!

[RDV]

EDIT - Problem has been solved and layout is now confirmed! It rocks! Again the red line is a jumper.

Thanks to All.



RickyDonVance

[RDV]

:wink:

[Darren N]

Solder bridge between D1 and R23? I'd also check around D6 and D8.

[puretube]

is the schem absolutely correct - I mean have you breadboarded that exact circuit and it actually worked?

[RDV]

First pedal(LPB-2)

[RDV]

Solder bridge between D1 and R23? I'd also check around D6 and D8.

Thanks for responding Darren. That was my thought also. I'll check again(& let you know if that's it), but I've spent hours using the continuity checker on the DMM looking for shorts around the diodes, and haven't found any.

Thanks

RDV

[spongebob]

There's an error in the schematic  

If you compare the first one you posted and the last one, you will notice that the feedback loop resistors to ground are on the "wrong" side in the first schematic. They are supposed to be on the inverting input side, not on the output...

[RDV]

There's an error in the schematic  

If you compare the first one you posted and the last one, you will notice that the feedback loop resistors to ground are on the "wrong" side in the first schematic. They are supposed to be on the inverting input side, not on the output...

I noticed that also, but would that make a difference? It does seem to be the only real difference. You know, I ran the reference voltage to the other side of the diodes and got that raspy distortion I mentioned in my first post in the thread that way. I suppose this means the PCB layout will have to be redone.

Thanks

RDV

[Gringo]

Thanks spongebob!! After Rick first told me about this, i checked the schem and layout several times, and found nothing. Even after reading your post, it took me a while to find it...

Sorry for all the trouble, Rick  :oops:  I'll send you the fixed file asap.

[RDV]

Hey Gringo: it's not like you've charged me anything for the layout, I've just been obsessed with trying to make it work. I think there is another problem though. I ran a jumper to make the first clipping section work, and it does, but if you remove the 1st gain pot from the circuit, then the 2nd clipping section works, but with no control over the amount of distortion, because the trimpot(gain 2) does nothing, and if you hook up the gain1 pot(500k), then the 2nd clipping stage doesn't seem to work. I believe I'll have to cut the trace from the 1uF to ground that feeds the 1st FB loop, as it is connected to the #2-3 pins of the trimpot(gain 2), and jumper the 1uF to Vr, so perhaps, both clipping sections will work together with control over both.

Boy, was that a mouthful, I hope it made sense.

RDV

[RDV]

Hey Gringo:

The Feedback loop of the 1st feedback section can be fixed by taking R5 to Pin 2 instead of 1.

The feedback loop of the 2nd clipping stage has the same problem as the first, in other words, no loop. I think it's an easy fix. R10 just needs to go down to pin 6 instead of 7.

Boy oh boy this has been educational for me, my brain hurts.

Thanks again Spongebob!

RDV

[RDV]

Yes it's me again!

I fixed up the PCB I had made with some jumpers and stuff. It sounds better than the prototype now IMO. The EQ seems to work better and I used a 2N5089 in the volume recovery stage for a nice hot output.

Thanks to Pablo & Spongebob!

RDV

[Gringo]

Great!  

Nice to know you could fix the board's mistakes (without etching another one)

[RDV]

I'd like to give out some setup info in case anyone ever decides to build this one. The trimpots are the keys to tweaking this thing. The 100k trim for Drive 2 should be opened(CW) until the sound comes into focus(start with Drive 1 all the way up), if you keep going up from there it will get very compressed and fuzzy. The 1k trim for Saturation sounds best to me full on(CW). It gives a nice fat sound that way, if you turn it down, the tone will get somewhat thinner. The 1k trim for Resonance sounds best to me just barely cracked open(CW) to widen the peaks and notches just a bit, though some might like the peaks to be sharp with the resistance @ 0.

RDV

[bwanasonic]

I'd like to give out some setup info in case anyone ever decides to build this one

I'm sure I'll smack my head and say DOH at the obviousness of it, but what is an HMP?

Kerry M

[puretube]

go `n` smack: "Heavy Metal Pedal"  :wink:

but, err, what is "DOH" ?

[petemoore]

HMP=Heavy Metal Pedal
 [I'm pretty sure]

[crawler486]

I would love to hear any sound clip of that baby of yours.

[Fret Wire]

go `n` smack: "Heavy Metal Pedal"  :wink:

but, err, what is "DOH" ?

Pronounced like "doe", has the same meaning as saying "duh?".

[RDV]

I'll borrow the band's 4-track and make some clips. My problem is hosting them. Any suggestions?

Another thing is the nice low-end sound that it gets will be lost on computer speakers. Oh well.

RDV