big muff volume problem. weird tone stuff. NEW VERO INSIDE!

nokaster · May 13, 2008, 02:14:35 PM

so after reading about big muffs and their clones for a few hours, i decided i wanted to understand what each component does and layout my own vero.

after the vero layout was done i started building my muff with it.
i was done building an hour ago and i started testing it.

i love how it sounds, especially with the tone all the way bassy with max gain and some more treble with less gain.

BUT! i can't get a decent volume out of it. it never gets to unity...
AND! tone fully bass is louder than when I turn the pot treble-wise...

all seems to work, but volume and tone control aren't A-OK...
i tried some 300hfe-ish BC549's and then some 680hfe-ish 2N5088's.
more hfe gain doesn't equal more volume... another lesson learned.
i liked the BC549's better by the way.

so here is the layout and the BOM.
maybe some big muff lover(s) are willing to take a look at it and can tell me where I went wrong...?

i'm hoping for some reactions on this one.
and when the layout should need debugging and is debugged, i'm glad to share it with everyone here.
there aren't to many vero's out there for the big muff i think.

board = 19 strips x 19 holes
17 cuts
5 bridges
4 transistor sockets

Capacitors C10, C12, C11 470pF 3
Capacitors C2, C3, C1, C4 100nF 4
Capacitors C6, C5, C7, C13 220nF 4
Capacitors C8 10nF 1
Capacitors C9 4.7nF 1
Capacitors CX 47pF 1
Capacitors Ca 100uF 1
Capacitors Crfi 100pF 1

Diodes D1, D2, D3, D4 1n914 4
Diodes Da 1N4001 1

Resistors R1 820R 1
Resistors R13, R11 18k 2
Resistors R16, R22, R10 120R 3
Resistors R17, R9, R15 470k 3
Resistors R18 10k 1
Resistors R20 56k 1
Resistors R3, R14, R21 100k 3
Resistors R5, R8, R2 33k 3
Resistors R6, R19, R12 8k2 3
Resistors R7 390k 1
Resistors RLED 1k 1
Resistors RX, R4 2k7 2
Resistors Ra 1M5 1

4 NPN transistors

nokaster · May 13, 2008, 02:16:40 PM

forgot to mention the pots...

Sustain = 100kA
Volume = 100kA
Tone = 100kB

nokaster · May 14, 2008, 03:20:09 AM

no reactions yet, so i thought i'd post my voltages with the 2N5088's

supply = 8.98V

Q1
C = 3.68
B = 0.59
E = 0.03

Q2
C = 5.94
B = 0.59
E = 0.03

Q3
C = 3.7
B = 0.59
E = 0.03

Q4
C = 2.23
B = 2.23
E = 1.65

nokaster · May 14, 2008, 03:44:04 AM

just found a tiny bit of solder bridging 2 strips that shouldn't be bridged... (Q4 B&E)
removed that bit of solder and now the voltages on Q4 are these:
C 4.17
B 1.63
E 1.18

with the BC549's these are the voltages:

supply = 8.98V

Q1
C = 4.08
B = 0.61
E = 0.03

Q2
C = 6.36
B = 0.61
E = 0.03

Q3
C = 4.07
B = 0.61
E = 0.03

Q4
C = 4.57
B = 1.57
E = 1.07

in an hour or so i'll be able to test drive again!

Gila_Crisis · May 14, 2008, 07:02:04 AM

cool vero layout.
if you have the chance try some BC239 in it! i thry 'em in mine and i think they sound a lot better than BC549

nokaster · May 14, 2008, 03:33:57 PM

Quote from: Gila_Crisis on May 14, 2008, 07:02:04 AM
cool vero layout.
if you have the chance try some BC239 in it! i thry 'em in mine and i think they sound a lot better than BC549

thx for the compliment!
the layout is now fully verified and working.
and i will try some bc239. i even have some at hand!

nokaster · July 31, 2008, 05:04:06 PM

i was browsing through the recent part of the picture thread and saw a few big muffs build with my layout!
made me proud that people are using it, but i'd love to hear some comments and results!

i love the "spaghetti muff" in the picture thread, which was i think build with my layout.
it's the one that switches between ram and triangle. lovely!

nokaster · July 31, 2008, 05:06:25 PM

since we can't edit messages nor titles, i will repeat once more...

THIS LAYOUT IS FULLY VERIFIED AND WORKING BY/FOR SEVERAL BUILDERS!

thx

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big muff volume problem. weird tone stuff. NEW VERO INSIDE!