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Dr. Boogey Build report

Started by RDV, May 12, 2006, 03:14:20 AM

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RDV

I put the Dr. Boogey together tonight in a marathon 5 hour session. It was a bit tedious wiring 6 pots but boy was it worth it. This is the best sounding high-gain DIY distortion yet. I'm not sure you could make it better unless a footswitchable cleaner sound could be made available. With that, you'd never need anything else. It really sounds good through my chipamps and I suspect a clean amp is where this will shine brightest. I always have trouble with super high gain circuits through my Marshall. The timbre of the distortion reminds me of my Fab-Metal but with less fizz and more meat!

A heartfelt DIY thanks to Electrotabs!

RDV

joecool85

Hey, sounds great!  Let's get some clips up here!  And pics..
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

RDV

When I get it boxed up(hopefully today) I'll start with the samples & stuff.

The DB would make an excellent high-gain channel for a DIY SS amp. You'd have a lot of knobs between the 2 channels(My clean preamp I built has 5 knobs and a switch) so it'd be an 11 knob job + a switch. I'd need a huge chassis. I'm wondering(out loud) if a higher voltage would give a bigger output? I suppose it would have to. I run my Thomas/Vox pre at about 15v.

RDV

joecool85

I don't know about you, but I would love to have an 11 knob head.  That just sounds sweet.  8|
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

teemuk

My first feeling is that I prefer simple setups but in the end I always find myself being a control freak: If it has a tonestack I prefer options to bypass it and have controls at least for mids, highs and bass. Same goes with everything: Gain has to have a control, so does the master volume. Switchable distortion/clean channel, as well as reverb/FX loop is a must. Everything preferably with tone/blend controls. In the end my ideal amplifier would have numerous knobs and switches but the good thing is that I wouldn´t have to use all of them. Sometimes i just love the easy front-end of digital pedals equipped with patches of tone. I guess the next amplifier I will build will have knobs mounted so that they will not turn by accident.

By the way, that Dr. Boogey design looks somewhat familiar, is it a design from the Runoffgroove.com? Higher supply voltage? I think there should be no major problems. It should be fairly easy - at least if you used those trimmer resistors at drains. However, raising the supply voltage will probably raise the headroom too and as a result the circuit would need a higher input amplitude to be driven into clipping.

RDV

Here's a crappy sample. http://fatboy.ssguitar.com/index.php?dir=Samples/&file=Artist%20-%20red2.mp3
With Epi Les Paul. I'll do a better one soon.
Straight to computer through a PT-80 delay. There is some fluttery digital distortion there.

RDV

joecool85

By crappy sample did you mean it kicks ass?  Because it did!  That sounded great!  Make sure to post it on the wiki.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

joecool85

I was wondering, have you tried hooking this straight to the lm3886 power amp yet?  If this is juicy enough for a preamp maybe we could use it's powerstages tweaked a little along with a simple 3 band EQ to have a decent preamp.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

RDV

I actually tried my Les Paul Jr. Special(w/P-100 pickups) with it last night and got the midrange pot oscillation that I've read about.

Bummer.

The circuit only seems to work right with full sized humbuckers. I also got a lot of noise with it that I couldn't identify.
I think this circuit is a little too high gain to be reliable as a preamp. I also doubt that there's enough voltage gain running at 9volts to run an amp to it's full potential unless you use a higher FB resistor.

I'm gigging this weekend too, which will limit the time I'll have available to fool with the circuit.

RDV

joecool85

Thats fine, I was just curious.  So it looks like without some pretty good modification it won't cut it as a preamp.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

Bob N

I just found this board and quite glad I did!

I've built both the DR Boogey and the JCM800 emus about a year or so ago. Both are outstanding as far as tone, but like what RDV discusses, the DR has quite a bit of noise in the circuit that I really can't tame much. What I did find, however, is that using (20 turn) multi-turn  trimmers for adjusting bias voltage to the jfets makes it a helluva lot easier to tame these high gain circuits when it comes to oscillations (JCM800 included). There's a "sweet spot" in both of these circuits that is very hard to get to by using standard trimmers. Yet another tip, once the fet biasing is done, use nail polish to hold the trimmer in it's position. That way standard handling won't change the biasing. These super high gain circuits are pretty touchy.

I saw on another board that you used MPF102s in your build... That would have been my only other possible suggestion to tone the noise down. I have to say though, even commercial boogeys are quite noisy when the gain is cranked. Maybe not this much, but noisy nonetheless.

Either way, I love this circuit and it's the only thing that kept my Krate MX-15R from meeting an untimely death by being "accidently" dropped from my roof. I can't stand the way the gain channel sounds in it. Clean channel isn't too bad, but I don't play clean very often.

RDV

I can't get mine to stop whistling to save my life. It had me down last night, but I'm gonna get after it tonight again and try to tame the beast. It sounded great with everyting spread out, but boxed up there's almost no output at all but squealing. I'm about to rename it Dr. Piggy.

I'm gonna take it out of the box(1590BB) and twist the wires together for each pot tightly and try to route them better and see what happens. I may eventually end up putting the thing in an amp chassis where I can spread it out rather than try to box it up.

I'm also going to play with the bias a bunch. I'll try setting it real high, like around 6v each. I've got them all at 5v right now and it hardly works at all.

RDV

Bob N

Ya know what... Mine did exactly the same thing.... I reboxed mine into a 1U rack, spread it out a bit and it went away.... Mine are biased to 4.51v

RDV

I worked on my DB all night last night and figured out the diagram I followed had a lot of incorrect values.  :grr

I replaced them all with correct values, and re-biased. I then had the classic sounds this circuit can make and much less noise, but the mid pot still squeals as soon as I go above 25%. I don't know why this happens. It calls for a 20k pot but I used a 25k. Would that make that huge of a difference? Where do you get 20k pots?

It's fun to play through though, but I'm scared to box it back up.

RDV

joecool85

Try some putting in a socket and try some various resistors between 200 ohm and 20k.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com