Few New & Old Dr Boogey Questions... Old Schematic VS New etc...

[Scruffie]

Hey all...

Sorry to continue the ongoing saga that is the Dr Boogey... but it is a sweet pedal anyway...

Built this on Veroboard about 5 months ago, had a quick problem but it was an error with Torchys old layout so that was sorted, it worked fine out the box (no this isn't gunna be a, it broke once I put it in) But once I put it in the box the pots I had used had been salvaged before hand and gave up after I resoldered them in as they were old so it was very intermitent and I put it away...

Now 5 months ahead, I got some replacement pots, I had to put parallel resistors accross the Mid & Treble pots (Treble pot was 1MA with 250k Parallel to take it too 200kA & Mid was 47kL Pot with a 47k Parralel Resistor to take it too 23.5k instead of 22kL)

Now... I'l admit that I am having oscillation problems and the mid control is seemingly useless and I'm getting a lot of hiss (although I didn't for the first test session of use... it cropped up later) but this I shall error check later after my next question...

My main question is, what is the difference between the original Electritab schematic and the new Gaussmarkov Schematic, I see the pots are all new values and that there are a few changes and component value differences, What are the main differences? What makes the most difference? Does it sound any different now, I assume alot of the value changes are the tone stack, is it more responsive now? (My treble is all cropped up to the end of the pot, is this the Parallel resistor making it Rev Log or just the old tone stack compared to the new one)

I just wanna know before I take this all out and re solder it back in and check all my voltages again to see what improvements have been made over time and what flaws the old schematic had and if someone has it but hasn't posted it an vero layout with the new build could be nice, but obviously not essential.

I've tried searching for this but there is already so much Dr Boogey stuff, it didn't come up at all, sorry if my question is a bit vague...

Cheers for any answers,
Scruffie.

[budjb]

With regards to the tone pots, the tonestack was scaled by a factor of 10.  For the pot values, they're all / 10, so your 25k pot went to 2.5, for example.

There's a big thread about all the changes that were made somewhere, and the point of all the changes was to tame the noise and whining, from what I can recall.

Beyond that, couldn't tell you

[Scruffie]

Damn it, I knew there'd be a big thread somewhere lol, I looked through 10 pages of stuff and still didn't see anything about it... oh well... back to the search function.

Aha! Found it via Gaussmarkovs PDF, Cheers man, any other comments from anyone though will still be interesting.

[ayayay!]

IIRC, (And don't quote/flame me on this everyone) it was mostly the tonestack being scaled down to 1/10th, Miller caps added in, and perhaps the addition of the output buffer.

I had tremendous success with the original electrictabs version, after t-shooting and a lot of help from John Lyons.  Mostly I had oscillation issues.  I used the Miller caps at John's suggestion, all original values for all the pots except for gain (500kReverse,) and used the simple JFET output buffer.   It sounded great w/o the buffer too, but was behaving well, like a bufferless pedal when in series with buffered pedals (duh.)

My treble knob also makes the bass start to cut out when it's between 2:30-5:00 o'clock.  Gets funky/interactive.  The other 80% it's fine.  But I never have it up anywhere above Noon so it's fine for me. 

I think there's also the tiny power filtering cap in addition to the large one.  Leave it in.  Won't hurt. 

Use the shielded cabling for your ins & outs.

[Bucksears]

I still have my old Dr. Boogey boxed up, still playing that while I build the Gaussmarkov version. For the most part, it's pretty quiet. No SERIOUS noise issues, but I'm still using an MPF102 for Q1.
I knew the Gaussmarkov version has less noise and a scaled-down tonestack, but didn't realize it had a buffer.

[ayayay!]

It doesn't have a buffer on most of the ones floating around, including the original.  One of the schems in that Looooooonnnng thread in here somewhere had/has a buffer at one point, so I decided to snag it and give it a whirl.  I liked it.  

I'll see if I can find it, but IIRC the tonestack was already changed on that particular schem.  Mine was off of the original, except for a 500k gain pot and the output buffer.  It's hard to say which one was the original anymore, but I'm pretty sure I had the first unadulterated electrictabs version that was adapted for JFETs but not tweaked. 

Let's see...

[ayayay!]

Oh wow here it is.  First hit!  My own thread even.  I forgot already.  Anyway, I didn't use Vb anywhere.  The whole thing is running 9.6v. 

http://www.diystompboxes.com/smfforum/index.php?topic=74313.0

Edit:  In looking at my comments, I doubled the size of that output cap after the buffer.  Worked great! 

[Scruffie]

Actually I just got rid of the noise, had to put Q2 (or was it Q3 ?) up to 9V mind but, on the plus hand no noise, negative the decays not quite as nice and it's not quite as gainy but hey, you loose some you win some... strange that it was biased correctly before and that just a change of pots put everything up by 2V but oh well and the Mid still has little to no effect though... unless I have like no treble or no bass which is pretty useless, i'l build another one (this was a while ago now, my builds have improved) and see what happens but this shall do for now, just wondered what the variations were, this wasn't the best of builds (although remarkably short wires and all shielded) I'l check out that thread you linked and the other info after I get back later,

Cheers for the comments guys.