Jen - Jumbo Fuzz

sinner · Post by **sinner** » 12 Oct 2012, 06:16

Few weeks ago by email I was asked to do the vero layout for this thing

Kind of Big Muff architecture, but with some weird fuckarounds

Starting on the input section and sustain pot two things are really odd to me:

Schematic: http://generaledefoutre.files.wordpress ... shema1.jpg

Website it was taken from https://generaledefoutre.wordpress.com/ ... umbo_fuzz/

Picture of internals is attached, as there was some fucked ups with file extension

First of all there is no sustain pot limiting resistor to ground, and the sustain pot is wired other way around (probably schematic error)

There is no base to ground resistor on the Q1 as well, and AFAIK should be to, as it's a part of bias network/divider for input section

Could this be an error? Anyone have it to compare actual unit to schematic posted at ATELIER MUSIQUES LOURDES website

More fun is at tonestack

Check it out, Si, and Ge transistor combo, additional clipping stage - looks like fun

Vero coming soon, as soon as somebody justify schematic provided

sinner · Post by **sinner** » 12 Oct 2012, 06:57

Another oddity - tonestack is quite the same as in BMP, but the cap values are strange. 10nF looks right but the 47n doesn't. Should be 10 times less - 4n7 or around...

sinner · Post by **sinner** » 12 Oct 2012, 07:12

...me again - Q4 is marked as PNP, but is NPN germanium in fact

allesz · Post by **allesz** » 12 Oct 2012, 07:41

Hey Sinner, always messing with old dusty obscure fuzz eh?

I am not such a big muff kind of guy, but this schemo looks really strange to me: what q4 and q5 are supposed to do? They are connected in such a strange way....

Can in be an error wile reversing, or am I going to learn something new?

sinner · Post by **sinner** » 12 Oct 2012, 08:28

allesz wrote:Hey Sinner, always messing with old dusty obscure fuzz eh?

I am not such a big muff kind of guy, but this schemo looks really strange to me: what q4 and q5 are supposed to do? They are connected in such a strange way....

Can in be an error wile reversing, or am I going to learn something new?

Yep, fuzzes are fun

Back in the 60's and 70's are more fascinating and unusual designs than newdays

Q4, and Q5 is a part of gate circuit bro

I did an schemo with couple of mods, like Gate control, AMZ presence and missing BMP parts on the input. IMO that resistor to ground at sustain pot is must have. Without it - there would be no signal when sustain pot turned all the way down

Bernardduur · Post by **Bernardduur** » 12 Oct 2012, 10:07

The sustain pot would work like that; it'll behave like a variable resistor and not like a voltage divider. So by turning down the sustain the value of the resistor would get bigger thus cutting more volume. I'd guess the least setting would give enough gain to make it sound!

sinner · Post by **sinner** » 12 Oct 2012, 10:11

Yeah, you're right, my bad - it has no connection to ground after all

allesz · Post by **allesz** » 12 Oct 2012, 11:20

sinner wrote:Yep, fuzzes are fun Back in the 60's and 70's are more fascinating and unusual designs than newdays

+1

I gave a listen to a clip on youtube and it is a nice sounding cicuit. Better than a muff for my taste.

I don't know anything about gates actually

so to me it seems a strange piece of circuit I wonder how it would sound without it. The connection on one of the clipping diodes is really curious by me but, well forgive me, even a fuzzrite or a percolator looks strange when compare to a standard fuzz face or big muff, or similar and common devices.

Bernardduur wrote:The sustain pot would work like that; it'll behave like a variable resistor and not like a voltage divider.

Since I am in for noobish questions.... it reminds me of the filter pot on a rat, am I completely wrong?

sinner · Post by **sinner** » 12 Oct 2012, 11:28

sinner wrote:Yep, fuzzes are fun Back in the 60's and 70's are more fascinating and unusual designs than newdays
+1

I gave a listen to a clip on youtube and it is a nice sounding cicuit. Better than a muff for my taste.

I don't know anything about gates actually so to me it seems a strange piece of circuit I wonder how it would sound without it. The connection on one of the clipping diodes is really curious by me but, well forgive me, even a fuzzrite or a percolator looks strange when compare to a standard fuzz face or big muff, or similar and common devices.

Muff is an noisy motherfucker - I guess that's why gate circuity is here. Some other mods are - the lack of emiter to ground resistors in two clipping stages - kind of Creamy Dreamer mod 40 years before it was commercialized by bootwick biz

Bernardduur wrote:The sustain pot would work like that; it'll behave like a variable resistor and not like a voltage divider.
Since I am in for noobish questions.... it reminds me of the filter pot on a rat, am I completely wrong?

@Bernardduur - voltage divider I was referring to is on Q1 base to ground resistor not on sustain pot. It shares the voltage by R2/R4 resistor network on my schematic

agoldoor · Post by **agoldoor** » 12 Oct 2012, 18:17

Yay! I'm so happy to see this thread!

Now... to figure out its mysteriousnesses....

Kitrae · Post by **Kitrae** » 18 Oct 2012, 13:57

The version Jen made for Sam Ash has some parts removed.

Same pcb with parts removed used in the Sam Ash Zuzzola II.

Kitrae · Post by **Kitrae** » 18 Oct 2012, 14:22

Another Jen Jumbo missing a 68k resistor.

Kitrae · Post by **Kitrae** » 18 Oct 2012, 15:27

Forgot the period.
6.8k

jrod · Post by **jrod** » 19 Oct 2012, 16:40

Looks like the Sam Fuzzola has the gate circuit removed.

Also, it looks like that resistor that is missing form the other Jumbo Fuzz is actually 68K. At least that what it looks like in the first pic posted. Looks like orange/gray/blue.

sinner · Post by **sinner** » 19 Oct 2012, 16:46

What 6k8 (or 68k) resistor you guys talking about?

jrod · Post by **jrod** » 19 Oct 2012, 17:03

sinner wrote:What 6k8 (or 68k) resistor you guys talking about?

If you look on the first schematic that you posted there is a 6K8 resistor in the gate circuit to ground between the 4u7 cap and 220 ohm resistor.

jrod · Post by **jrod** » 20 Oct 2012, 05:07

Hey sinner. I think in your schematic R22 should be 82K, R3 - 82R, & C13 - 4n7.

sinner · Post by **sinner** » 20 Oct 2012, 06:28

jrod wrote:Hey sinner. I think in your schematic R22 should be 82K, R3 - 82R, & C13 - 4n7.

Why do you think so?

R22 is not present in original schemo, and i make it optional. In all BMP's and clones i seen values differ from 47k to 100k and I said that in schematic.

C3 as low as 82r? How come?

C13 as a 4n7 is logical, and i said that in this tread - schematic i was based on shows 47n. It might be schematic error, i don't know. What i know is i seen 100n cap in this position in at least big muff clone and that was confirmed

jrod · Post by **jrod** » 20 Oct 2012, 08:06

I've seen a schematic from a traced unit and those values were on there. Though we can't see the trace side in any pics on the net, there is an 82R resistor on the PCB. Also, there are 3-82K resistors on the PCB. The schematic I saw has the 82R from Q1 emitter to ground, and 82K resistors from base to ground on Q1-Q3.

The 4n7 cap was also in the schem I saw, but that cap is not visible in any pics I have seen, so who knows.

Another thing is there was a 12K resistor from the last transistor's collector to +9V. Again, without being able see the trace side we can't be sure, but a 12K resistor does exist on the PCB.

One thing I can't find though is the all the 22K resistors. There are 5 in the original schem. One of which I believe is actually 12K. So, that leaves 4. I only see 3 on the PCB.

jrod · Post by **jrod** » 20 Oct 2012, 08:19

Here's the schematic I copied from the one that was traced. The only difference is they had a 6K8 in the gate circuit but it looks like 68K to me.

Jen - Jumbo Fuzz [schematic]