Superfuzz with Russian trannies / diodes

[tabbycat]

Frank_NH wrote

I made a superfuzz vero layout using the CA3046 transistor array.  Haven't built it yet, but it should work...

hey frank, if it doesn't pay off as expected i know dino (digi2t) at diysb did a similar thing.

http://www.diystompboxes.com/smfforum/index.php?topic=102477.0
and he may have posted a vero at fsb as he often does with his experiements.

also, thinking back (seems a long time ago), mictester explained the workings of his superfuzz tranny array build using the ca3046 to me in the last page of the univox superfuzz thread at fsb
http://freestompboxes.org/viewtopic.php?f=19&t=3354&sid=36c372e7b4330067e6eab68c357c087e&start=400

i believe they are supposed to be better for the octave effect (near-perfect matching of long-tailed pair) but not so good for the fuzz, perhaps for the reason that the mismatching adds something to the fuzz quality.

but i would be interested to build and hear one for myself. best of luck with your adventure.

perhaps a tranny ic hybrid is long overdue, with a small ic handling the octave pair and the rest as usual with separate transistors?

[Travis]

Tabbycat - if you just want the matched pair, check out the 2N2223. I have some but haven't tried them in a Superfuzz yet. They should be perfect for the pair

[traktop]

I´ve just got my socketed board ready to try some  transistors on it when I found this thread, so I wanted to ask something before It falls into oblivion.
Talking about volume balance: Is it worth to put the toogle switch on a stompswitch?
Cheers, Gilberto.

[tabbycat]

Travis wrote

Tabbycat - if you just want the matched pair, check out the 2N2223. I have some but haven't tried them in a Superfuzz yet. They should be perfect for the pair

transistors with six legs? now i'm scared. do it.

[Travis]

I like the toggle on the stomp Gilberto. HUGE difference between the two sounds

[Frank_NH]

Thanks, Tabbycat.  Yeah, I saw that thread, but wanted to make my own layout for the fun of it.  I have already built a Superfuzz with discrete transistors and was wondering how this would compare.  I'll post something when I get around to building it.

[traktop]

I finally built mine with BC337s, 2N2222s, 2N3904s, (gains between 260-190), and 1n270 diodes.
There´s something wrong, cause I barely hear it even when all pots crancked. The sound is there in the backround, and the pots and tone switch work.
I checked the transistors, (flipped the bc337s), and the whole circuit and it seems ok, but something is wrong with q2 with those crazy voltages:

                          C        B        E
Q1 (bc337):       6.81   0,86    0,29
 
Q2 (bc337):     14,90 ?¿6,80    6,23

Q3 (2n2222a):   9,92    5,45    4,97

Q4 (2n2222a):    2,41   2,91    2,31

Q5 (2n2222a):    2,41    2,91   2,30

Q6 (2N3904):      1,50    2,10   1,45

I´m trying to find a low gain transistor of around 50hfe for Q6. Any suggestion?

[tabbycat]

^
hey tracktop, here are a set of reliable voltages for the classic univox sf original from brad at diysb.

Battery voltage 9 volts dead on...
        C        B        E
Q1  6.01    .66      .117
Q2  8.88   6.01     5.41
Q3  6.23   3.27     2.72
Q4  3.1     1.7      1.11
Q5  3.1     1.67     1.11
Q6  5.75   .98       .361

http://www.diystompboxes.com/smfforum/index.php?topic=64068.0

more useful info re desirable voltages and how to get there from jimi photon et al

http://www.diystompboxes.com/smfforum/index.php?topic=98249.0

as well as the collector votages on q2 and q3 being considerably over (q2 looks mad), your q6 looks starved, which may also be killing your output.

have you got too big a resistor to ground somewhere which is backing everythng up? maybe worth running all q to ground resistors through the meter just to double check they are as should be?

[traktop]

Thanks.
I´ve already checked those threads, hence my interest on a very low gain transistor for Q6, (it seemed to remove some shrill).
There was a bad solder on the center electrolitic of the upper row. After I fixed that the volume came up a little bit, but still so quiet.
I found a strange thing that worked. The moment I flipped the 2n3904 on Q6 180 degrees, it finally became alive, (much higher, but not so much higher than the bypass signal when I crank all pots).
I say strange cause as far as I know, 2N3904s have a pin out configuration that matches the layout, (flat side looking to the left).

The voltage readings became more reasonable as well.
I used one of those black/red boss power supplies, (8.6v).

        C        B        E
Q1  5.24     .66     .11
Q2  8.71   5.26    4.68
Q3  6.03   3.23    2.67
Q4  2        1.80    1.21
Q5  2        1.80    1.21
Q6  6.25     .92      .30

I only could test it on a little honeytone amp, but it seems to sound quite good. The octave thing is there, but it seemed to do it on a much more elegant way that other octave fuzzes I tried, (not so overwhelming), getting a nice vocal texture when bending higher strings past twelve fret.
One thing I didn´t expect, was that the volume was a little higher when the tone switch was on, (notch hollow sound), than when it´s disengaged. Taking a look at the schematics, maybe tweaking the  47/10k resistors before the tone switch would balance both configurations.

I also used a 10k pot after the junction of the 10k/22k tone resistors, then I put the 100n tone cap to ground after the pot to make a "scoop depht" control.
I will check it tomorrow on my allmighty hiwatt dr103 to see what I get.
Cheers, Gilberto.

[traktop]

I´ve been testing it this afternoon.
It sounds very nice; nasty and metallic in good way. The only thing disturbing is that I get unity gain only with both pots cranked and the tone engaged, (with tone switch off it remains a little lower), and that´s running my amp clean. If I crank it, you really feel that is not pushing it as it should.
I realized that I finally used 1n914s instead of 1n270s, so I think that It would even sound lower in volume with germanium diodes.
The pedal is usable, but I´d like to know if that´s how it´s suposse to behave, or if it should have far more  volume on tap.
Cheers, Gilberto.

[Travis]

That's pretty normal, Gilberto. I have one of the orange and blue Univox Superfuzz's and it isn't much louder than unity gain. Would probably be louder after a cap change but I haven't gotten around to that.

The output and fuzz character are both affected by transistor selection. So if you haven't already, try some other transistors and see if that helps with the output. Usually the lower gain Si trannies sound best

[traktop]

I´ve tried transistors between 180-370 hfe. The one with higher gain sounded louder but harsher, (specially Q6).
After a google search, I found a thread where there was a superfuzz with mylar 0,47uf caps instead of 10uf.
Other thing would be placing a 22/10uf cap parallel to the Q6 1k emiter resistor. This seemed to produce a big bump in volume and let more bass in as well.
Anyway, knowing that the original isn´t  much louder than unity gain will make my mind rest for a while...
I´m about removing the 47k+10k to ground of the "no tone" path, since it sounds lower than the "tone" path. Or putting the tone switch apart and keeping the tone circuit tweaking it a bit, maybe lowering, (or just bypassing), the 1n parallel to 22k/10k resistors to tame some highs.
Cheers, Gilberto.
 

[Travis]

This is a pretty harsh sounding pedal  If you swap the 1n914 for some Ge it might become less harsh

The two tone switch positions seem to be the same output on mine. All it does is one setting is super mid scooped and the other is super mid focused (not a lot of lows or highs). Both settings are intense and over the top sounding

[traktop]

I finally replaced 47k/10k voltage divider with 39k/22k and now both tone flavours sound perfectly balanced.
1n914s/1n34s on a switch and a 10k pot from diodes to ground, so I can get get more volume from there.
 It sounds really awesome, just to realize that I missed the 15k from Q6 base to ground... I was thinking on adding it to the layout, but wouldn´t this lower the output even more...?

[Travis]

The 15K is helping to bias the transistor. You should probably include it although I haven't tried it without so who knows maybe you discovered the secret mod

[traktop]

Definitely, hahaha!
I will do it tomorrow, and will do what I hope is gonna be the last superfuzz build report
Cheers, Gilberto.

[traktop]

Added that 15k resistor from Q6 base to ground and now this is crazy loud  as hell, (edit: finally not so much, but the 10k pot from diodes to ground helps here, so no complaint)
There we go:









That plastic bag inside the enclosure contains 2 sets of transistors, (2n2222a, 2n3904 and bc337 in there). Both sound very nice, but must do extensive testing. I´ve ordered lower gain transistors to try in Q6.
Added 3 position toogle for diodes, (1n4848/1n34a), 25k pot between diodes and ground and a scoop depht control.
I think that I may put a trimmer inside for diode clipping as set and forget and use the pot for a a "no-tone" volume control, cause this will definitely will go inside a bb enclosure with a tone stomp switch and maybe another one for the octave...
This is an evil killer machine. It turned my hiwatt into a seriously strange freaky scary creature. Is like the sound seemed to come from the guts of the amp itself and not from a pedal so I could say:" Hey! My amp can do that..." Amazing, but strange at the same time...

Now I just need to build  another one for my girlfriend and put together a cheesy pop band. As long as this is on all the time, I will be happy...