Green Big Muff

[Nocturno]

Hello,

i opened up my green Russian made Big Muff and noticed that burned part on the lower right side of the PCB . It is obviously burned to death  . Now the pedal is still working fine with no problems . 
What was this part  ?? Should i replace it ?? 

[Meanderthal]

 That might be the remains of a protection diode, coulda burnt up if someone reversed power supply polarity. 1n4001- 1n4007 should work fine, if you want that protection.

What are those clipping diodes? 1n34a? That's pretty significant... I've never been inside a GREEN russian BMP, but they are reported to sound way different. That would do it... I've found I like the BMP with 1 Ge diode in the first clipping stage... kinda does a subtle octave then...

[Nocturno]

Thanks!!   

I'm sorry but  the diodes are nameless , so are the transistors . 

[Bernardduur]

Cool!

In mine there is a cap in that position....... Just a filter cap btw

[Nocturno]

    

Thats interesting!  Whats the value of that cap ? 

[Meanderthal]

 Anywhere from 22uf - 100uf will work. That's actually not a bad idea, could be used for a bit of protection like the diode, but also as filter. would work in the same place on the schematic (come to think of it, there is a 100uf on some schematics). Yours dosen't look like a cap though...

[Barcode80]

that doesn't look like a diode to me at all! that, IMHO, looks like a charred electro. which would make most sense of all.

[Meanderthal]

 Hmmm... a can with brown goo under it or a black stump... I see a black stump(and a wire sticking up beside it), however, there does seem to be something black on the pcb there that may be cap oozings. I agree that a cap makes more sense!

[Nocturno]

currently i have a 1n4001 in there  and everything works fine . Tomorrow i will try the cap .

thanks

[Nocturno]

A 22uF Cap works fine , a 1n4001 works fine but nothing in that place also  works fine 

Whats the purpose of the filter cap ?

[Nocturno]

I found another pic on the net .

[finkfloyd]

Hi, one my black re-issue which is basically the same board, that is indeed a capacitor 25v 22uF electrolytic

I was wondering if you would do me a favour, could you please tell me what values it says on the transistors (should be all the same type) and the ceramic caps? as mine are all minature mylar caps. would be very much appreciated!


An idea would be to edit the pic in paint and repost.
Thanks
Chris

[finkfloyd]

Thats strange, looks like a non polar capacitor, the filter capacitor, is supposed to help eliminate power supply hum.

[Nocturno]

Hi, one my black re-issue which is basically the same board, that is indeed a capacitor 25v 22uF electrolytic

I was wondering if you would do me a favour, could you please tell me what values it says on the transistors (should be all the same type) and the ceramic caps? as mine are all minature mylar caps. would be very much appreciated!


An idea would be to edit the pic in paint and repost.
Thanks
Chris

Hi, .... so I opened it up again, but i have to dissapoint you . There is NOTHING written on the transistors . The yellow capacitors are blank too.  The big red round caps say 47nf . The small square one on the bottom middle says 10nf, the big red squares have the lettering H51C M750.  And thats all the info i can give you on this mystery muff .

maybe this link will help you :

http://www.voxblues.com/guitar/muff/

[finkfloyd]

Hi, thanks for taking the time to look!

Yeah, on the black re-issue, the 2 round ceramics are small mylars of the same value the rest of the square caps should be 3x470pF and 1x 0.01uF (bottom middle)

It seems these are never exactly the same, and components are mixed and matched, when switching mine to the green russian tonestack, i didnt hear any noticible difference really, but everyone raves on how the green ones sound over the black ones, do they have super sub sonic hearing?? as the board and most of the vaues are the same!

seems a lot of muffs also have the transistor values wiped too.. mine uses c47c's

[Meanderthal]

 I'll say it again- those look like Germanium clipping doides on that green bmp board, and that's going to sound different than the usual Silicon! That might be the real reason they have a reputation for sounding different, and yet I've never seen this mentioned. That's why I said that's pretty significant.
The transistors don't really make THAT much difference, not as much difference as cap values and clipping diode type!

[Barcode80]

meanderthal, those are Si 4148's (1N1914) diodes. not sure which pic you are looking at, but both the ones posted here look like Si to me!

[Meanderthal]

 Jeeze, what is it with that pic? I'm seeing stuff no one else sees...?

Yeah, you're right , it's pretty obviously Si in the second pic(oops), but the first one they look just like the red&green 1n34a's I have, even in size, jeeze, in every detail! They're right beside resistors for a size comparison! Wouldn't Si look smaller? They do in the second pic, and they're copper with a black band, just like they're supposed to be.

Maybe it's something with my monitor(I'm on a laptop).  Sorry bout that...

[birt]

nah they are red/green in the first pic

[Meanderthal]

 Heh, to add to the confusion, the USA reissues have wierd blue clippers... at least the ones I've seen(in person!).