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Big MUff>>Read for info!

6/12/1997 6:00 AM
Paradiddle	Big MUff>>Read for info! I recently ripped apart a original big muff (version 2) and i have noticed a number of componate changes no parts were added but various values of Resistors and Capactors were changed I will have more info later a change that i noticed right away was the coupling caps they were oppisite of the original as RG stated in his schmatic...... Later all,..... Jeff

6/12/1997 6:39 AM
R.G. Keen	It wouldn't surprise me if a number of component values were different from the schematics. Effects were often made from the parts in stock, and if the maker ran out of 10K's, they'd use an 8.2K or an 11K for instance. I would be VERY surprised if the schematic was very different, as this would require a new board layout, which was expensive and time consuming in vintage effects days. Just speculating, you might have either a test unit that EH only built a few of for internal testing, or it may have been "improved" by an earlier owner. I'd very much like to see the schematic when you get it traced out. I have schematics for three versions of the transistor type of Big Muff, all very close to the schematic I drew up, but with slight differences. When you say "opposite of the original", do you mean "with the coupling capacitors connected to the emitters"? God, this is great - a mystery version of a vintage effect - like the old Moody Blues album, "In Search of the Lost Chord".

6/12/1997 6:39 AM

R.G. Keen

It wouldn't surprise me if a number of component values were different from the schematics. Effects were often made from the parts in stock, and if the maker ran out of 10K's, they'd use an 8.2K or an 11K for instance. I would be VERY surprised if the schematic was very different, as this would require a new board layout, which was expensive and time consuming in vintage effects days.

Just speculating, you might have either a test unit that EH only built a few of for internal testing, or it may have been "improved" by an earlier owner. I'd very much like to see the schematic when you get it traced out. I have schematics for three versions of the transistor type of Big Muff, all very close to the schematic I drew up, but with slight differences.

When you say "opposite of the original", do you mean "with the coupling capacitors connected to the emitters"?

God, this is great - a mystery version of a vintage effect - like the old Moody Blues album,
"In Search of the Lost Chord".

6/12/1997 9:32 AM
Paradiddle	Ok,.....well I almost have the whole thing transcribed. This is my first transcription so i'm working my ass off trying to make sure that its done right,......The coupling caps where you noted 1uf were changed to .1 and some 1 uf were added on the diode path i believe,......i will have to check that tonight,...i will have more info on it later today,.....as i'm on lunch at school. The transistors used are BC239 are they NPN or PNP? because like i said before the collectors are grounded with a 15k resistor totally reverse of what you transcribed in your schmatic,...RG.,. but as you said regarding the componate differences there were some dramatic changes in resistors not little changes but changes like in the 100k range,.....so i will let you know more tonight,....i will also scan the schmatic could you scan your copies for me???/,.....thanks,.... Jeff

6/12/1997 9:32 AM

Paradiddle

Ok,.....well I almost have the whole thing transcribed. This is my first transcription so i'm working my ass off trying to make sure that its done right,......The coupling caps where you noted 1uf were changed to .1 and some 1 uf were added on the diode path i believe,......i will have to check that tonight,...i will have more info on it later today,.....as i'm on lunch at school. The transistors used are BC239 are they NPN or PNP?
because like i said before the collectors are grounded with a 15k resistor totally reverse of what you transcribed in your schmatic,...RG.,.

but as you said regarding the componate differences there were some dramatic changes in resistors not little changes but changes like in the 100k range,.....so i will let you know more tonight,....i will also scan the schmatic could you scan your copies for me???/,.....thanks,....
Jeff

6/12/1997 4:35 PM
R.G. Keen	BC239 are NPN, I think. Is there a chance that the "ground" is actually +9V or that the BC239 pinout is actually different than you're thinking? In tracing circuits with known-NPN transistors, I count on the most positive lead being the collector in anything that is clearly an amplifier. If the pinout was different than expected, then it makes sense that the outputs come off the "emitter" and that the "collector" would be grounded, while leaving the circuit essentially the same. I was talking to an effects historian today. Apparently in their salad days, EH would cram what ever was at hand into pedals and diddle it a bit to get them to work. Trips to the surplus stores to round up some transistors of any kind to get some boards out were relatively common, if this guy is right.

6/12/1997 4:35 PM

R.G. Keen

BC239 are NPN, I think. Is there a chance that the "ground" is actually +9V or that the BC239 pinout is actually different than you're thinking?

In tracing circuits with known-NPN transistors, I count on the most positive lead being the collector in anything that is clearly an amplifier.

If the pinout was different than expected, then it makes sense that the outputs come off the "emitter" and that the "collector" would be grounded, while leaving the circuit essentially the same.

I was talking to an effects historian today. Apparently in their salad days, EH would cram what ever was at hand into pedals and diddle it a bit to get them to work. Trips to the surplus stores to round up some transistors of any kind to get some boards out were relatively common, if this guy is right.

6/16/1997 6:39 AM
PARADIDDLE	I was talking to my Electronics teacher today and he said that the schmatic would make sense if the BC239 transistors were PNP I have to make sure of this. I also think maybe,...like you said about the Pinout of the transistors i will also have to find out about that too,......but from talking to my teacher he seemed to think that the circuit would not work with grounded collector NPN transistors,.....can you help? Thanks,......... Jeff

6/16/1997 6:39 AM

PARADIDDLE

I was talking to my Electronics teacher today and he said that the schmatic would make sense if the BC239 transistors were PNP I have to make sure of this. I also think maybe,...like you said about the Pinout of the transistors i will also have to find out about that too,......but from talking to my teacher he seemed to think that the circuit would not work with grounded collector NPN transistors,.....can you help?
Thanks,.........

Jeff

6/16/1997 6:55 AM
R.G. Keen	If this is an approximate dupe - my replies have been being posted erratically, don't know whether the problem is on my end or at Ampage. The 239 is NPN. Which side of the battery is connected to signal ground, + or - ? This thing should have the (-) lead connected to ground. I confused + and - traces on my first tracing of the Univox SuperFuzz back in 1972, just lost track of which was which on the board. As you can imagine, that took a lot of debugging to get fixed Do you have (or can you make) the schematic in a form that can be emailed?

6/16/1997 6:55 AM

R.G. Keen

If this is an approximate dupe - my replies have been being posted erratically, don't know whether the problem is on my end or at Ampage.

The 239 is NPN. Which side of the battery is connected to signal ground, + or - ? This thing should have the (-) lead connected to ground.

I confused + and - traces on my first tracing of the Univox SuperFuzz back in 1972, just lost track of which was which on the board. As you can imagine, that took a lot of debugging to get fixed :-)

Do you have (or can you make) the schematic in a form that can be emailed?

6/16/1997 7:30 AM
Paradiddle	Hey,..... I have scanned the schmatic that i have made I will send it to you tonight All the collectors are grounded with a resistor: Q1=3.3k, Q2=150 ohm, Q3=150ohm and Q4=100ohms now i'm not sure if the transistors are right but i will do one more check over tonight to make sure the Emitter and collectors are not mixed up as was suggested by my teacher........ the battery + goes to the emitters off 3 transistors with a resistor in the path 15 k on each transistor.

6/16/1997 7:30 AM

Paradiddle

Hey,.....
I have scanned the schmatic that i have made I will send it to you tonight
All the collectors are grounded with a resistor:
Q1=3.3k, Q2=150 ohm, Q3=150ohm and Q4=100ohms
now i'm not sure if the transistors are right but i will do one more check over tonight to make sure the Emitter and collectors are not mixed up as was suggested by my teacher........
the battery + goes to the emitters off 3 transistors
with a resistor in the path 15 k on each transistor.

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