death by audio - germanium filter
Posted: 01 Feb 2022, 03:31
some gut shots that might be of interest! 
Another clearer pic:
freestompboxes.org
tracing pedals since 2007
https://www.freestompboxes.org/
death by audio - germanium filter
Page 1 of 1
Re: death by audio - germanium filter
Posted: 03 Feb 2022, 04:22
Re: death by audio - germanium filter
Posted: 12 Feb 2022, 02:17
Hey! .. some movement from a ‘redditor’ over at the diypedals subreddit.
Hopefully this ignites some momentum!
https://www.falstad.com/afilter/
Copy below and go to ‘insert from txt’
$ 1 0.000005 5 50 5 50
% 0 20615.097787781793
c 112 144 112 192 0 4.7000000000000004e-8 0
r 64 144 112 144 0 33000
O 144 112 256 112 0
g 112 192 112 208 0
170 64 144 32 144 3 20 1000 5 0.1
174 112 144 144 80 0 500000 0.9950000000000001 Resistance
c 112 80 64 80 0 1e-9 0
w 64 144 64 80 0
r 112 80 160 80 0 33000
c 160 80 160 32 0 2.2000000000000003e-9 0
g 160 32 192 32 0
o 4 16 0 34 5 0.00009765625 0 -1 in
o 2 16 0 34 2.5 0.00009765625 1 -1 out
Hopefully this ignites some momentum!
https://www.falstad.com/afilter/
Copy below and go to ‘insert from txt’
$ 1 0.000005 5 50 5 50
% 0 20615.097787781793
c 112 144 112 192 0 4.7000000000000004e-8 0
r 64 144 112 144 0 33000
O 144 112 256 112 0
g 112 192 112 208 0
170 64 144 32 144 3 20 1000 5 0.1
174 112 144 144 80 0 500000 0.9950000000000001 Resistance
c 112 80 64 80 0 1e-9 0
w 64 144 64 80 0
r 112 80 160 80 0 33000
c 160 80 160 32 0 2.2000000000000003e-9 0
g 160 32 192 32 0
o 4 16 0 34 5 0.00009765625 0 -1 in
o 2 16 0 34 2.5 0.00009765625 1 -1 out
Re: death by audio - germanium filter
Posted: 29 Mar 2022, 13:56
MOSFET boost (similar to SHO) > inverted PNP germ gain stage > Fuzz War II tone control (mostly) > inverted PNP germ gain stage (collector bypassed 2.2u).
Gain: B50K, Tone: A500K, Volume (trim pot): 100K
Enjoy!
Re: death by audio - germanium filter
Posted: 01 Apr 2022, 09:56
Amazing..! Ideally someone that knows more than me can whip up a layout off the back of your dissection!
Re: death by audio - germanium filter
Posted: 04 Apr 2022, 14:53
I'm pretty sure those MP10B transistors are NPN, not PNP.
Re: death by audio - germanium filter
Posted: 04 Apr 2022, 15:24
That would explain the absence of some integrated circuits.
Re: death by audio - germanium filter
Posted: 04 Apr 2022, 17:46
Re: death by audio - germanium filter
Posted: 05 Jul 2022, 13:01
Thank you so much for the teardown! Very interesting.
While a work-a-like is definitely doable, knowing DBA, it most likely is a "twisted" take on a gain stage. They call it a "drive circuitry in the style of classic recording consoles". Just like the Hudson Broadcast, I note. That one was inspired by "old RCA consoles". Perhaps the BA-71 preamps?
Perhaps someone - more of an electronics wiz than I - could make a schematic that combines an SHO (https://external-preview.redd.it/dKsAR- ... b8d928eff4) into a germanium console stage from something like a RCA ba-71 (http://www.jlmaudio.com/RCA/BA-71A%201024.jpg) into the fuzz war mk 2 filter (https://www.pedalpcb.com/docs/BellumMKII-PedalPCB.pdf) into yet another ba-71 stage...
I'm sure mr. Fuzzhead/Dirtboxlayouts.blogspot.com would be willing to do the vero.
Re: death by audio - germanium filter
Posted: 13 Aug 2022, 07:34
Any movement or interest on some of these ideas?Sesh wrote: ↑05 Jul 2022, 13:01Thank you so much for the teardown! Very interesting.
While a work-a-like is definitely doable, knowing DBA, it most likely is a "twisted" take on a gain stage. They call it a "drive circuitry in the style of classic recording consoles". Just like the Hudson Broadcast, I note. That one was inspired by "old RCA consoles". Perhaps the BA-71 preamps?
Perhaps someone - more of an electronics wiz than I - could make a schematic that combines an SHO (https://external-preview.redd.it/dKsAR- ... b8d928eff4) into a germanium console stage from something like a RCA ba-71 (http://www.jlmaudio.com/RCA/BA-71A%201024.jpg) into the fuzz war mk 2 filter (https://www.pedalpcb.com/docs/BellumMKII-PedalPCB.pdf) into yet another ba-71 stage...
I'm sure mr. Fuzzhead/Dirtboxlayouts.blogspot.com would be willing to do the vero.
Re: death by audio - germanium filter
Posted: 21 Apr 2023, 21:00
This is what I traced from screenshots taken from graybench's excellent video. Obviously I have no idea what I'm doing, in way over my head here
Re: death by audio - germanium filter
Posted: 21 Apr 2023, 22:32
Re: death by audio - germanium filter
Posted: 22 Apr 2023, 15:36
You're right!
Re: death by audio - germanium filter
Posted: 15 May 2023, 16:19
Is there a verified schematic for this one out there?
Re: death by audio - germanium filter
Posted: 17 May 2023, 18:08
don't think so. AFAIK there's only mine above, which is probably incorrect and missing the output. Someone should breadboard it and see, at the very least. Hopefully someone with access to a unit can trace it properly.