Bellum Fuzz MkI

M

manfesto

Well-known member
@PedalPCB is the 680p on the silkscreen possibly a misprint? The tone control had a *very* wide imbalance with a 680p, replaced it with a 100n and it functioned as expected (which maybe isn’t what DBA was going for) with a relatively even sweep from bassy to trebley, instead of insanely bassy for 20% then a crazy scoop from 20-50% then just progressively more nasal?

Other than that, I built it with 2N5088s (all around hFE 270-300) and 100n caps and it fired up straight away and sounds just like the demos.

I did socket the 27K and tried with and without; with the 27K there was a noticeable volume drop but not much change in the character of the distortion, so I left it out and wouldn’t really recommend bothering unless you’ve got germanium diodes to spare.

(left the diodes in just in case though)
 

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Robert said:
Not a misprint... Yet another one of the absurd variations of the original floating around.

The board is marked 680n, but 680p is what was installed. Which one is more correct? Your guess is as good as mine. :ROFLMAO:

I'm still looking on a daily basis for an original so I can trace it myself.
Click to expand...
At this point I’d bet dollars to dimes that if you did get an original you’d find yet *another* variation lol
 
manfesto said:
@PedalPCB is the 680p on the silkscreen possibly a misprint? The tone control had a *very* wide imbalance with a 680p, replaced it with a 100n and it functioned as expected (which maybe isn’t what DBA was going for) with a relatively even sweep from bassy to trebley, instead of insanely bassy for 20% then a crazy scoop from 20-50% then just progressively more nasal?

Other than that, I built it with 2N5088s (all around hFE 270-300) and 100n caps and it fired up straight away and sounds just like the demos.

I did socket the 27K and tried with and without; with the 27K there was a noticeable volume drop but not much change in the character of the distortion, so I left it out and wouldn’t really recommend bothering unless you’ve got germanium diodes to spare.

(left the diodes in just in case though)
Click to expand...
Hey manfesto!

I just got done with my build last night. I used the values on the silkscreen so 680n and 680p and all 2n5089.... Like any DBA clone builds.... it didn't sound anything like the demo's xD. I haven't had the time to troubleshoot yet but I have looked on other forums for where to start ! Like you the 680p tone cap makes the tone knob sound way off and it looks like anything between 100n to 220n to even 680n makes it sound better.

My question to you is did you first try using 680n caps on all the other big box ones on the silkscreen and then switched to 100n ones? I have seen a Vero and trace that used those 100n value so I am curious what troubleshooting if any you had to do to make it sound good :p.

I did socket my transistors so first thing I will try is switching to 2n5088 but I get a feeling I will have to swap out all the 680n cap too xD.

Like pedalpcb said there's so many different takes on the values flooting around for this circuit :/
 
Bobbyd67 said:
Hey manfesto!

I just got done with my build last night. I used the values on the silkscreen so 680n and 680p and all 2n5089.... Like any DBA clone builds.... it didn't sound anything like the demo's xD. I haven't had the time to troubleshoot yet but I have looked on other forums for where to start ! Like you the 680p tone cap makes the tone knob sound way off and it looks like anything between 100n to 220n to even 680n makes it sound better.

My question to you is did you first try using 680n caps on all the other big box ones on the silkscreen and then switched to 100n ones? I have seen a Vero and trace that used those 100n value so I am curious what troubleshooting if any you had to do to make it sound good :p.

I did socket my transistors so first thing I will try is switching to 2n5088 but I get a feeling I will have to swap out all the 680n cap too xD.

Like pedalpcb said there's so many different takes on the values flooting around for this circuit :/
Click to expand...
Nah I went with all 100nFs (except for the tone cap) out the gate, @Mir9 in another thread posted a gut shot of a production pedal with all 100nFs in it, so I thought it’d be a good first bet
 
Where are you getting the 2n5088 with such low hfe? I haven’t seen any lower that 535hfe?I purchased 2n5088 from Tayda and stomp box parts… no luck I bought 130 of them
 
PAGOON said:
Where are you getting the 2n5088 with such low hfe? I haven’t seen any lower that 535hfe?I purchased 2n5088 from Tayda and stomp box parts… no luck I bought 130 of them
Click to expand...

I’ve been on the search for the same…
 
Coda said:
I’ve been on the search for the same…
Click to expand...
Do you think another transistor can be used I wonder if a 2n3904 can be used… I have no idea … I also think my solder is to old and expired… but I have built 11 other pedals with the same roll and haven’t had a problem.
 
PAGOON said:
Do you think another transistor can be used I wonder if a 2n3904 can be used… I have no idea … I also think my solder is to old and expired… but I have built 11 other pedals with the same roll and haven’t had a problem.
Click to expand...

Maybe? The thing with the Fuzz War is that there really is not standard…no baseline. Each one is different. If someone who knew what they were doing built the Fuzz War, it probably would have 3904’s as standard. Instead, we get weird, low spec, transistors, that are installed backwards, and only sound good in ever 5th pedal. That 5th pedal, though…
 
Someone needs to dissect it from the original and get down to the bottom of this because it looks like someone just makes a copy and then everybody else is just a copy of that copy and you know how the saying goes… I’m done with that circuit… but I had difficulties with pcb manias ash Device and that’s a beyond easy circuit to build with few parts but that also had loud static and strange noises I even picked up a radio station when I would ouch the tone knob… oh well I think I will just relax and clean up my work station till I get my head right… I think the fuzz circuits have a tendency to pick up noise and static… I never had these problems on overdrive.
 
PAGOON said:
Where are you getting the 2n5088 with such low hfe? I haven’t seen any lower that 535hfe?I purchased 2n5088 from Tayda and stomp box parts… no luck I bought 130 of them
Click to expand...
Try BC547B. 200-450 hfe . With the BC series, the A-B-C suffix denotes sequential gain ranges, so you can "dial in' a gain bucket.
 
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