dr boogie woes

makaze808 · August 20, 2010, 03:05:40 PM

Hi.

I am having trouble building a Dr Boogie from the schematic and pnp at gausmarkov. I have just finished try 3 and same results

I get a signal slightly louder than the input and that is consistent all over the borad as I probe with an audio probe. No gain and a mile from the distortion tones I hear on samples of the pedal.

where the power enters there appears to be some text on the layout which looks like "-3v" is this -3v a part of the build I'm missing?

The layout shows the Q's as a semi circle with flat back, is that the right orientation for j201's?

I have read on here somewhere that the j201's will have to be found from a selection and that much trial and error is needed, is that right? I bought my batch several years ago from ebay....

Any pointers appreciated,.

studiostud · August 20, 2010, 03:14:53 PM

Quote from: makaze808 on August 20, 2010, 03:05:40 PM

where the power enters there appears to be some text on the layout which looks like "-3v" is this -3v a part of the build I'm missing?

No. since the text is small, it probably didn't transfer completely when you did the PCB. It is probably supposed to say +9v which is where your power is connected from the battery/power jack.

Quote from: makaze808 on August 20, 2010, 03:05:40 PM

The layout shows the Q's as a semi circle with flat back, is that the right orientation for j201's?

http://experimentalistsanonymous.com/diy/Datasheets/J201.pdf here is a data sheet for J201s. Just compare the orientation with the layout and then check your voltages. I would probably be a good idea to measure the voltages of any transistors and ICs in the circuit and then post them here. I'm not familiar enough with this circuit to tell you if they are close enough, but I'm sure someone here does.

Schappy · August 20, 2010, 04:38:14 PM

The orientation is correct for j201s.
The -3V is actually 9V. From the bottom of the board its ground, 9V, R16.

Did you bias the transistors?

makaze808 · August 20, 2010, 05:08:39 PM

Thanks so far.

Yes I ball parked the bias at at 4.9v

I'm gonna buy some new j201's.

Thanks.

Galego · August 20, 2010, 05:28:57 PM

I don't want to be rude, but if you're asking these questions, maybe you shouldn't be doing a Dr. Boogie just yet... Have you successfully built other effects? Like simple boosts?

ViolenceOnTheRadio · August 20, 2010, 08:03:34 PM

I have no valuable contribution here but having a Dr Boogie I must recommend ditching the OEM tone stack and replacing it with something like that used in a Fender/Marshall amp.

The stock design's influence over the tone of the circuit can almost, almost be said to be negligible.

Galego · August 21, 2010, 04:20:10 AM

Quote from: ViolenceOnTheRadio on August 20, 2010, 08:03:34 PM
I have no valuable contribution here but having a Dr Boogie I must recommend ditching the OEM tone stack and replacing it with something like that used in a Fender/Marshall amp.

The stock design's influence over the tone of the circuit can almost, almost be said to be negligible.

I'll have to disagree. The only control that has a more subtle effect is the Bass control. It depends a lot on what the Mid is set to.

makaze808 · August 21, 2010, 01:45:16 PM

Galego your post wasn't welcomed.

Well I installed all new j201's and bang.......mega distortion heaven. Last time I buy a batch from ebayers, I also swapped the new ones out and all from my new batch have worked although some re-biasing was needed.

I was disappointed with the tone stack I must say, I was expecting a really big bottom end and although the interaction with the other tones pots is usable I'm a little dis-appointed. haven't had chance to play it through my bigger amps but on my superfly it was great, marshall 5 watter great, Selmer 50 watter superb.

anyway, thanks for the help.

deadastronaut · August 21, 2010, 01:52:19 PM

i had issues with the tonestack on it..until i plugged it in to a proper amp and cab.....

i run a graphic after it too..amazing..pulling the mids etc.........

great to see you got it going....great pedal ..

ghostsauce · August 22, 2010, 02:39:16 AM

QuoteI was disappointed with the tone stack I must say, I was expecting a really big bottom end and although the interaction with the other tones pots is usable I'm a little dis-appointed

When I built mine, it didn't have anywhere near the bottom end that I wanted either, so I put some bigger caps in C11 and C12. I used a 500nF in C12 and a 1uF in C11. I ride the bass around 9 and it sounds MASSIVELY awesome.

makaze808 · August 22, 2010, 09:23:06 AM

Thanks again. Will try the cap swaps once ghostsauce once I do try it on a larger rig, my gut feeling is I will need to swap the caps.

Is there a pedal that is in a similar balpark to this one (apart from the diefet)

Many thanks.

bacanador · August 22, 2010, 04:46:49 PM

When I build this one, I had a bunch of issues, I etched the board myself and that ended up being the issue. I had a small short between 2 traces. It was very hard to detect because the biasing was all OK, I set the trim pots to get roughly 5V on each drain, and it was killing me. I got an sinewave generator and inputted the signal to the circuit and started looking at every point on the signal path and I found a short.

I would start by cheking the bias voltages on each drain, then if not a scope and a sinewave generator would help.

MohiZ · August 23, 2010, 03:23:41 PM

Quote from: Galego on August 20, 2010, 05:28:57 PM
I don't want to be rude, but if you're asking these questions, maybe you shouldn't be doing a Dr. Boogie just yet... Have you successfully built other effects? Like simple boosts?

If you don't want to be rude, then don't be rude. Dr. Boogie was my first build as well, and I managed to get it right just fine.

makaze808 · August 24, 2010, 06:31:25 PM

I changed the caps as suggested and won't be changing them back.

I have had a great time on my boogie......I had been putting it into a bright channel (by accident) and now it's in a normal channel it is killing me, a really refreshing sound for me...I think I have had to much muff music. i really like the sound of the fets and many covers I play are sound much more authentic.

ghostsauce · August 24, 2010, 09:36:02 PM

Awesome!

Just so we know what you tried, which caps did you put where?

Zapp Brannigan · August 25, 2010, 01:09:03 AM

Sorry, wrong thead.

ccc · November 10, 2010, 06:39:24 AM

Hiii!!!.....I want to build a Mr. Boogie....does anyone have the schematics please?

deadastronaut · November 10, 2010, 07:04:16 AM

Quote from: ccc on November 10, 2010, 06:39:24 AM
Hiii!!!.....I want to build a Mr. Boogie....does anyone have the schematics please?

here ya go!..dr boogie...its can be a bit tricky as a first build though!..i presume!..

gaussmarkov.net...

MartyMart · November 10, 2010, 08:13:37 AM

Wasn't there some talk a while ago ( IIRC ) that the tone stack needed to have it's values
divided by 10 to get a better response in pedal format ?
So a 250k pot would become 25k .... 1 meg would be 100k etc ...

MM

ayayay! · November 10, 2010, 09:29:01 AM

Hey Ghostsauce:

QuoteWhen I built mine, it didn't have anywhere near the bottom end that I wanted either, so I put some bigger caps in C11 and C12. I used a 500nF in C12 and a 1uF in C11. I ride the bass around 9 and it sounds MASSIVELY awesome.

What did that do to the taper of the treble, since c11 is connected to the treble control? Curious.

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dr boogie woes