Baldwin-Burns - Buzzaround  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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MoreCowbell
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Post by MoreCowbell »

briggs wrote:Yeah, I'm wondering why a darlington pair was used when a singular silcon stage could have produced the desired results. I'm thinking this setup was chosen just due to availablity as far as silicon devices went back when the circuit was designed, the darlington arrangement was used to compensate for the low gain germaniums.

As far as I would read things the fuzz and clipping in this circuit is developed in Q3. The first stage is just hitting Q3 hard enough to coax out the clipping

Now, what I'm looking at doing is removing the darlington germanium front end and generating a new front end stage with a smaller parts count but more frequency fitering/boosting to really fine tune the sound of the fuzz. As I said before I've had the 3 knob TB circuit on my Breadboard for a while, the buzz around sounds more inspiring though..
a front end similar to the electra distortion (minus the clipping diodes of course) should work fine.

you might parallel a small cap across the collector-base resistor to soften it up a bit.

a 2n5088 or 2n5089 should have plenty of gain - if not, a mpsa18 should get you there. i doubt its necessary to use a silicon darlington (like mpsa13).

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Post by briggs »

The "Electra" style front end is one way I'm thinking of going. The other option I'm looking at is going the mosfet/jfet route... What do you recon to a JFET booster front end MCB? Possible to add a prefuzz bass control then in a runoffgroove Omega type setup. I think I'm going to convert it to run NPN as well, keep those pedal boarders happy 8)

The calculations I'm doing on the tone section - I'm getting one cut off freq at around 15Hz, the other 15000Hz, hmmmm, seems a little odd. I guess you can't beat the old Breadboard (I'm away from mine at the minute :( )

The most important factors in this little project are to keep the same feel that the pedal produces - just slightly alter the tonal landscape that it produces (And it is a landscape!).
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Post by MoreCowbell »

briggs wrote:The "Electra" style front end is one way I'm thinking of going. The other option I'm looking at is going the mosfet/jfet route... What do you recon to a JFET booster front end MCB? Possible to add a prefuzz bass control then in a runoffgroove Omega type setup. I think I'm going to convert it to run NPN as well, keep those pedal boarders happy 8)

The calculations I'm doing on the tone section - I'm getting one cut off freq at around 15Hz, the other 15000Hz, hmmmm, seems a little odd. I guess you can't beat the old Breadboard (I'm away from mine at the minute :( )

The most important factors in this little project are to keep the same feel that the pedal produces - just slightly alter the tonal landscape that it produces (And it is a landscape!).

you'll have to try it...i generally prefer a transistor in front of a fuzz, though a jfet could give an interesting "texture".

you might try a gagan blend style control on the output cap of the boost section (the 4u7 cap)....maybe a .01u and a 10u for the values, with a 500k pot

i would think that a 2n5088 boost into a npn germ should get you there though... or if you want to go pnp, a 2n5087 as q1/q2

bust out the breadboard !

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Post by briggs »

Yep, there's no sub for the old breddy! I'm liking the flexibility of the standard NPN transistor boost setup (Plus it can easily get me the required gain without any fuss), I've got a few really nice old BC108 metal cans that sound so good. I'll have to try them. Tune the EQ hitting the fuzzer Q3 and tine the output tone control and we're rolling. Think I'm going to try and tweak it to work with a few AC128's I have lying around to start with!
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Post by RnFR »

so i just got done building the npn version of this pedal and i had some mixed results. on the whole i think it sounds good, but i think that transistors that i have might be a bit too high gain. i got some splat and gatedness with certain combinations. i also found that this circuit will bias up with the transistors backwards. i think i remember from a jack orman article that it is actually the leakage that is causing the transistor to turn on. if i remember right... :scratch: it actually had a nice sound with just Q2 reversed. there was more note definition, and there was more separation of the strings.
well, i guess i need to get some sleep!
thanks to everyone that made it possible to get this circuit RE'd. i've been keeping up with the progress for a while and it was pretty awesome to see it come together.
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Post by RnFR »

just like to put it out there that once i got some proper transistors on this thing it's fantastic. really great thick fuzztone.
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Post by Alex Frias »

I think the best working trannies for this thing is the low to medium gain / low leakage ones. The leakage is worst. in my opinionn, leaving the sound more on the splaty/gated side. But don't forget that low setings at the "Balance" control tend to leave the decaying sound very gated.

Using the right Ge transistors, eventhough you build NPN or PNP project, the thing sounds amazing to my ears, better than I expected to be honest!

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Post by RiGLEY »

Can somebody please make a compact vero-layout for this circuit that fits inside a 1590B case?

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Post by Torchy »

Not yet verified.

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Post by RiGLEY »

Thanks Torchy! :D

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Post by Alex Frias »

Wow! Now it's getting really popular...

Very well done!!!

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Post by danielzink »

What's the "Rpd" resistor listed ? not in the BOM. Optional 1m input resistor ?

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Post by WhiteKeyHole »

Yup. "Rpd," Resistor pull-down.

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Post by briggs »

To eliminate switching pop 8)
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Post by danielzink »

etched and built a Buzzaround using the above schematic.......to no avail.......no sound from my Buzzaround (a new song maybe ?)

I have voltage to the board, I have eliminated the switch at this point and I have the output run from the board direct to the output lug on the jack - same for input.
Grounds go from DC jack to sleeve on input jack, then connect ring of input jack to ring of output then from output ring back to the board marked "GND" (these "grounds" are carrying +9v)

Voltages are as follow:

Q1
C=3.96
B=3.85
E=3.91


Q2
C=3.95
B=3.92
E=.07


Q3
C=.10
B=.03
E=0


There's obviously something wrong at Q3.
As per the schematic - electro's are always + to the square pad right ?

Somebody please help me make my Buzzaround buzz !!! :D


Thanks, Dan
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Post by graemey »

danielzink wrote:
etched and built a Buzzaround using the above schematic.......to no avail.......no sound from my Buzzaround (a new song maybe ?)

I have voltage to the board, I have eliminated the switch at this point and I have the output run from the board direct to the output lug on the jack - same for input.
Grounds go from DC jack to sleeve on input jack, then connect ring of input jack to ring of output then from output ring back to the board marked "GND" (these "grounds" are carrying +9v)

Voltages are as follow:

Q1
C=3.96
B=3.85
E=3.91


Q2
C=3.95
B=3.92
E=.07


Q3
C=.10
B=.03
E=0


There's obviously something wrong at Q3.
As per the schematic - electro's are always + to the square pad right ?

Somebody please help me make my Buzzaround buzz !!! :D


Thanks, Dan

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Post by Torchy »

Check your component values.
Also check for solder bridges, particularly on the -9V pad and Timbre lug 3. Also look at the small gap between C5 & R6.
Could also be a crap tranny in Q3.

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Post by danielzink »

Got it sorted - will report more later.

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