CHUNKA-CHUNKA

[notneb]

Looking for a good metal tone, ala early Metallica, something that gives you that spongy attack when you scoop the mids and dig in hard. Tried this from RunOffGroove, http://www.runoffgroove.com/grace.html , actually the Bog Daddy version. No dice. I ended up scrapping it as the volume was just so over the top I couldn't use it. Amp turned all the way down til just before cut off and with the pedal volume just nudged it was crushing the amp. Speaker flapping like it was split in half. On to the Tufnel. (yeah I know, talk about loud!!) http://www.beavisaudio.com/projects/tufnel/Tufnel_Schematic_V1_1.gif (as if you guys don't already know this one) So far I built the first stage, left off everything from U2 over,  swapped in a couple diodes and took the output right after C7 and it sounds pretty freakin sweet. Used 1N751 Zener, good sound but getting some slight phasing sounds when note decays. Don't light the 1N4148, 49's much here. Tried leds, not bad but I like the compression I'm getting with the zeners. However, can't quite get that chunka-chunka <technical terminology> spongy attack, almost there but not quite. I'm not looking for gobs of volume, I've got plenty to work with as the amp gets turned up.

I'm not sure about adding the second 386 as Dano seems a bit leary of the shear power and awesomeness... awesomity... awesomitude?!? of his creation. (I know, armadillos in are trousers) Using the LM380N1 btw.

[samhay]

^the volume was just so over the top I couldn't use it.

You should have been able to turn the volume all the way down to 0. Did this not work?

[notneb]

Turned volume all the way down then back just enough to get some sound and it was just out of control.  Took apart and did it again to make sure i didn't foul it up the first time and same result.  Should have hooked up my scope too see the actual voltage but didn't.  Might try again later.

[PBE6]

Have you tried a BSIAB from General Guitar Gadgets? You could also try adding a Big Muff tone control to any high gain pedal, that control provides a built-in mid scoop and the compression from high gain should sponge things out nicely.

[psychedelicfish]

Deadastronaut's Spitfire. It's a really great sounding, versatile metal pedal. You can find schematics and layouts here.

[vigilante397]

Deadastronaut's Spitfire. It's a really great sounding, versatile metal pedal. You can find schematics and layouts here.

+1

[samhay]

Turned volume all the way down then back just enough to get some sound and it was just out of control.  Took apart and did it again to make sure i didn't foul it up the first time and same result.  Should have hooked up my scope too see the actual voltage but didn't.  Might try again later.

That sounds like you were using a linear (B) vs log (A) pot. You want a log pot for your volume control.
If that doesn't work, you can add a resistor between the output cap and lug 3 of the volume pot - the larger the resistor, the lower the max volume.

[notneb]

That sounds like you were using a linear (B) vs log (A) pot. You want a log pot for your volume control.
If that doesn't work, you can add a resistor between the output cap and lug 3 of the volume pot - the larger the resistor, the lower the max volume.

Sam, yes I'm using linear pot, need to pick up some logs as I'm seeing them used a lot. However, even with a different taper, it seems I'd never need anything near the volume this thing is capable of generating. I'm gonna try it again later because I'm guessing I still had something hooked up wrong.

Have you tried a BSIAB from General Guitar Gadgets? You could also try adding a Big Muff tone control to any high gain pedal, that control provides a built-in mid scoop and the compression from high gain should sponge things out nicely.

Just listened to it. Very sweet. Got it bookmarked. Thanx. Oh, and on the Big Muff, I had some not so good luck with it on a DOD250 clone and it was suggested that there simply wasn't enough gain for it to work on that design without a buffer stage... plenty of gain here so that could be the ticket.

Deadastronaut's Spitfire. It's a really great sounding, versatile metal pedal. You can find schematics and layouts here.

First time hearing it. Me likee. Gonna give this one a try. Sounds great.

[notneb]

The first Spitfire clip works but these two are dead, is there another link to these clips?

http://dl.dropbox.com/u/7464107/funkycapmod.mp3
http://dl.dropbox.com/u/7464107/hillagefuzz1.mp3

[samhay]

Sam, yes I'm using linear pot, need to pick up some logs as I'm seeing them used a lot. However, even with a different taper, it seems I'd never need anything near the volume this thing is capable of generating. I'm gonna try it again later because I'm guessing I still had something hooked up wrong.

There is a reason why volume pots are almost exclusively log taper. Don't give up on your project, as using a log taper pot will make a big difference. For reference, you may want to read this - http://www.geofex.com/article_folders/potsecrets/potscret.htm

I don't think you have a wiring problem. The 386-based pedals are LOUD. However, they have a unique distortion, and have their uses - you never know when you may want to hit the front end of a tube amp with a really big hammer signal.

One other way to drop the volume, and increase the distortion, is to add diodes to ground after the input can (these can be on a switch)...

[notneb]

When turning the the gain control between pins 1 and 8, it doesn't seem to have much effect. It gets just a slight fuzz on the edge but that's it. Interestingly, that's exactly what it looks like on the scope when I turn the pot. Not really any increase in gain, only the leading edges of the clipped wave get a little blurry, no real difference in shape.

I looked at the data sheet for the 386 and it sez to use a capacitor (no size specified) in series with the gain pot. I notice Dano doesn't include one. I tried a few different values and no difference. Soooo... what the heck. Does it sound like I've got something grounded out somewhere? It's not a complicated circuit and I've traced it backwards and forward. I need to take pictures of my scope.

With pins 1 and 8 not connected, I have a slightly jagged sine wave. Peaks slightly dropping off toward the trailing edge. With 1 and 8 connected i have a very digital looking waveform. sides almost vertical, peaks slashed toward trailing edge. Turning gain pot only seems to affect the rise and fall times of the "digital" wave. The sides get a bit more vertical.

With the cap in series, it's like the gain pot is disconnected. Is this normal? If not does it shed some light on the problem?

[samhay]

Sounds like you are overdriving the input - what signal are you feeding it, and can you turn it down?

[notneb]

My test signal is about 500mV sign wave. Right now it's on about 400Hz. The pickup on my guitar is actually putting out more signal than my test wave and I'm seeing pretty much the same effect, at least as much as you can discern watching guitar strings on a scope.