Univox - Superfuzz

DiscoVlad · Post by **DiscoVlad** » 19 Feb 2012, 00:22

LucifersTrip wrote:
Rolbista wrote: i would like to have more gain available, something like this: ,

there is no better place to start than from the actual Superfuzz that was used!

https://www.diystompboxes.com/smfforum/ ... ic=64068.0

I haven't tried this yet, but in spice simulation at least, BC547B transistors seem to have the right amount of gain to bias up like this.

marshmellow · Post by **marshmellow** » 21 Feb 2012, 13:37

And now for something completely similar:

I wanted to use a dual transistor for the octave generator due to the better matching, and all of the affordable ones are SMD nowadays. It's that really small thing in the middle of the board next to the diodes. It sounds absolutely great and the octave is very pronounced. More than in any other octave fuzz I've ever played. That's why I still included the trimmer in the layout so I can dial in the degree I want. It's bridged for now, but I'll put it in eventually I think. All the other transistors are BC850B, the SMD equivalent of the BC550B.

I have some more pcbs, so if anybody is interested in a first SMD project feel free to send me a PM.

jwhtn · Post by **jwhtn** » 22 Feb 2012, 19:08

Hi again, guys.

I'm interested in putting together yet another SuperFuzz for myself, but this time in super-overbuilt mode, on eyelet or maybe even turret board. I've tried to adapt the schematic, the uStomp PCB layout, and Mike's stripboard layout (which I've built per the instructions, and which sounds awesome), but man, is it hard for me to get my head around.

Any hints on how to go about adapting something for turrets? Anybody have experience doing an eyelet or turret build of a SuperFuzz? If so, maybe you could share a layout or gut shot?

You are all awesome. Thanks!

jwhtn · Post by **jwhtn** » 22 Feb 2012, 19:11

jwhtn wrote:Hi again, guys.

I'm interested in putting together yet another SuperFuzz for myself, but this time in super-overbuilt mode, on eyelet or maybe even turret board. I've tried to adapt the schematic, the uStomp PCB layout, and Mike's stripboard layout (which I've built per the instructions, and which sounds awesome), but man, is it hard for me to get my head around.

Any hints on how to go about adapting something for turrets? Anybody have experience doing an eyelet or turret build of a SuperFuzz? If so, maybe you could share a layout or gut shot?

You are all awesome. Thanks!

PS: Yes, I know it's kinda goofy to do a turret board build of a pedal, but humor me... I've really been wanting to take a crack at it.

LucifersTrip · Post by **LucifersTrip** » 23 Feb 2012, 11:22

jwhtn wrote:Hi again, guys.

Any hints on how to go about adapting something for turrets? Anybody have experience doing an eyelet or turret build of a SuperFuzz? If so, maybe you could share a layout or gut shot?

sadly, I think that'll be a long shot, but I'd love to see it. I think it'd get kind of complicated (Is there a turret layout program you could use?)

look how many turrets are used for this 4 transistor fuzz (2 rows of 14):
http://2.bp.blogspot.com/_eZHjVPgzFx0/S ... er_tag.jpg

what would you need for a 6 transistor fuzz...

I think it's be easier to do it on perf...which I will soon.

good luck

jwhtn · Post by **jwhtn** » 23 Feb 2012, 14:20

LucifersTrip wrote:
jwhtn wrote:Hi again, guys.

Any hints on how to go about adapting something for turrets? Anybody have experience doing an eyelet or turret build of a SuperFuzz? If so, maybe you could share a layout or gut shot?

sadly, I think that'll be a long shot, but I'd love to see it. I think it'd get kind of complicated (Is there a turret layout program you could use?)

look how many turrets are used for this 4 transistor fuzz (2 rows of 14):
http://2.bp.blogspot.com/_eZHjVPgzFx0/S ... er_tag.jpg

what would you need for a 6 transistor fuzz...

I think it's be easier to do it on perf...which I will soon.

good luck

Wow, that's impressive. Is that the final layout for a Scrambler? Did you use diyLC?

I'm thinking I might do a hybrid perf/turret thing, with the transistors and trim pot on a "breakout" bit of vero, and everything else on turrets. I think I could make it elegant that way, if only I could figure out the rest of the layout...

LucifersTrip · Post by **LucifersTrip** » 24 Feb 2012, 06:57

jwhtn wrote:
Wow, that's impressive. Is that the final layout for a Scrambler? Did you use diyLC?

I didn't do it...it was from a random blog I found...just as an example of how a 4 tran fuzz could get a bit complicated on turret
http://circuitrealise.blogspot.com/2009 ... ayout.html

I'm thinking I might do a hybrid perf/turret thing, with the transistors and trim pot on a "breakout" bit of vero, and everything else on turrets. I think I could make it elegant that way, if only I could figure out the rest of the layout...

i guess that could be a blast...

LucifersTrip · Post by **LucifersTrip** » 28 Feb 2012, 10:09

I finally breadboarded this and screwed around for a while....and excuse me if this was covered, but after scanning all 15 pages of this thread, there seemed to be a lack of reported voltages, and even more surprisingly, a lack of Q6 discussion.

Firstly, I'd like to thank solidhex again for reporting the voltages of an original:
https://www.diystompboxes.com/smfforum/ ... ic=64068.0

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

There is nothing more beautiful than starting with info from an original, excellent sounding box.

I started with BC1708's with hfe ~ 150-185 and just for the fun of it, after I breadboarded the first 2 transistors, I plugged it in at the 10uF right before the expander. It turned out that it sounded (like an overdrive) far better with a higher Q1 (a 2N2222 with hfe 235). If I used a 2N2222 for both Q1 & Q2 , it sounded worse, so I stuck with a higher Q1 and lower Q2.

I finished the breadboard off with 4 BC1708's and measured the voltages. I got so close to solidhex's above I was amazed...except for Q6, where I got 3.85v on the collector. I checked all over the place and it seems many have reported voltages in that range. Here's the one set of voltages in this thread:
viewtopic.php?f=19&t=3354&start=40#p54726
Q6: 3.71 1.21 0.59

I tried about 20 different transistors in the 125 - 700 range and the highest collector voltage I got was 4.6v. A 2N5088 with around 600+ gave me around 3.5v and a 2SC1815 with 125 gave me the 4.7v. So, I dropped an old Heathkit transistor in there with a gian of 55 and hit the mark almost right on the money, 5.8v. Big difference...it's less sharp, with a little less pronounced octave, but smoother, richer and seemingly fuzzier. The 5088 was the worst...much more harsh and not as smooth.

...but, of course, you can also adjust the resistors around Q6 to change the voltage ....my favorite is the 15K from base to ground. This is really an easy fuzz to get to sound good since you are able to adjust the collector voltage all the way from 2.1v up to 7.2v and still get a killer fuzz throughout with no gating or poor decay. The big difference is the tone. Down at 2.1v it's fatter and richer and 7.2v thinner. The volume also increases as you head towards 2.1v. If you go a little below 2.1v or above 7.2v, it drops volume quickly then sharply cuts off.

Results with base to ground resistor (15K) altered.

Q6 (hfe 55)
23K (2.1v)
12K (7.2v)

Q6 (hfe 235)
17K (2.1v)
10K (7.2v)

A big note: The 235 hfe transistor at 2.1v sounds different than the hfe 55 transistor at 2.1v and the same for 7.2v
The hfe 55 was still smoother, a bit fatter & fuzzier with a little less octave effect.

So, this is a really, really hard decision. It's a no brainer for me to sub an external pot for the 15K, but do I go with the 235 or 55? I might actually put a switch on Q6, but then I have the problem of different ranges for the pot. If I throw that pot in there with a range that covers both transistors, it'll cut completely at full clockwise & counterclockwise. Yes, I could also switch in different cutoff resistors, but that starts to become a pain...

LucifersTrip · Post by **LucifersTrip** » 28 Feb 2012, 22:45

ps:

just realized I forgot one important note...the above post regarding the fuzz tones with low & high gain Q6's was for the scooped tone. for my taste, the non-scooped tone needs more sharpness, so the higher gain (200 - 250 hfe) Q6 sounded better for that....but I like the lower gain ones (that put the collector voltage in the 5v-6v range) better for the scooped tone...which makes the Q6 decision very difficult.

mictester · Post by **mictester** » 28 Feb 2012, 23:12

My most recent builds have got two different output stages - one for the direct and one for the scooped feed. It's easy then to match the levels to feed a common output pot after the last transistor. Q1 really needs low hfe (I use around 80) and Q2 is around 250. The phase splitter doesn't need much gain, so I use a CA3046 for the phase splitter and the long-tailed pair. I get plenty of octave!

LucifersTrip · Post by **LucifersTrip** » 29 Feb 2012, 01:22

mictester wrote:My most recent builds have got two different output stages - one for the direct and one for the scooped feed. It's easy then to match the levels to feed a common output pot after the last transistor.

that's cool, but not the problem I'd be running into switching between 2 different transistors. Each transistor has a different sweep/range on the bias pot....vol level is not a problem.

mictester · Post by **mictester** » 29 Feb 2012, 06:09

LucifersTrip wrote:
mictester wrote:My most recent builds have got two different output stages - one for the direct and one for the scooped feed. It's easy then to match the levels to feed a common output pot after the last transistor.
that's cool, but not the problem I'd be running into switching between 2 different transistors. Each transistor has a different sweep/range on the bias pot....vol level is not a problem.

The two output transistors I use are biased quite differently, and I switch the whole stage. This emphasises the "scoop" setting in particular.

LucifersTrip · Post by **LucifersTrip** » 29 Feb 2012, 20:40

mictester wrote:
LucifersTrip wrote:
mictester wrote:My most recent builds have got two different output stages - one for the direct and one for the scooped feed. It's easy then to match the levels to feed a common output pot after the last transistor.
that's cool, but not the problem I'd be running into switching between 2 different transistors. Each transistor has a different sweep/range on the bias pot....vol level is not a problem.
The two output transistors I use are biased quite differently, and I switch the whole stage.

...but you don't have an external bias control on the transistor in either of those stages? if so, that would be the same scenario.

btw, out of curiosity, where did you start the last change....right after Q5? what did you set the collector voltage to for Q6 in each of the stages?

LucifersTrip · Post by **LucifersTrip** » 01 Mar 2012, 06:02

in last post, I meant "stage", not "change"

btw, out of curiosity, where did you start the last stage....right after Q5?

mictester · Post by **mictester** » 01 Mar 2012, 06:27

LucifersTrip wrote:in last post, I meant "stage", not "change"

btw, out of curiosity, where did you start the last stage....right after Q5?

No - after the diode clippers. The two tone paths (the potential divider and the filter) each go to a separate output stage. The potential divider is replaced with a 50k "balance" pot for that mode. There is another "balance" control after the filter. Then there is a further changeover switch after each output stage. The "balance" controls on one series of builds were "dual-concentric" types to save panel space.

LucifersTrip · Post by **LucifersTrip** » 02 Mar 2012, 12:19

mictester wrote:
LucifersTrip wrote:in last post, I meant "stage", not "change"

btw, out of curiosity, where did you start the last stage....right after Q5?
No - after the diode clippers. The two tone paths (the potential divider and the filter) each go to a separate output stage. The potential divider is replaced with a 50k "balance" pot for that mode. There is another "balance" control after the filter. Then there is a further changeover switch after each output stage. The "balance" controls on one series of builds were "dual-concentric" types to save panel space.

seems like a lot, but worth it for the Super-Fuzz....makes my transistor-switching-with-different-cutoffs-for-each idea seem simple.

do you by chance remember what your Q6 voltages were?

LucifersTrip · Post by **LucifersTrip** » 10 Mar 2012, 07:38

LucifersTrip wrote:ps:

for my taste, the non-scooped tone needs more sharpness, so the higher gain (200 - 250 hfe) Q6 sounded better for that....but I like the lower gain (< 100hfe) ones (that put the collector voltage in the 5v-6v range) better for the scooped tone...which makes the Q6 decision very difficult.

I compromised with a a mid gain Q6 (hfe 185) and with a bias pot I was able to get the full range where it sounded good, from ~ 1.5v to 8v

Q1 2N2222 (246)
Q2 BC170B (178)
Q3 BC170B (181)
Q4 BC170B (183)
Q5 BC170B (183)
Q6 BC170B (185)

all voltages were extremely close (+/- .2v) to what solidhex reported from his bandmate's original

Diamat · Post by **Diamat** » 08 Apr 2012, 18:46

Hi to all,
this is my first post here, so as you guess i have almost nothing knowledge about diy stompboxes, but i would like to start to do some things.

i would like to ask for some help to known if i can resuscitate a diy univox superfuzz that a guy who i don´t known did about 5 years ago.
it appeared with the pcb with the cables cut out the box... i don´t known wich style of the univox superfuzz or schematic was used. had two knobs, two positions switch no led.
Also due to my lack of knowledge i don´t known if the transistors are ok or are a piece of shit.
here i drop a couple of photos for if you known how to repair it, i don´t known wich cable correspond with jack´s and the same with the pots...

So if anyone can help me in someway will be very apreciated.
thanks so much in advance

LucifersTrip · Post by **LucifersTrip** » 09 Apr 2012, 04:41

One of the first steps in troubleshooting is getting the transistor voltages (EBC). If you report those, someone may be able to help.

good luck

Thaxt · Post by **Thaxt** » 23 May 2012, 11:33

I think the 1N34A diodes - or the OA-90s - weaken this pedal's sound when they are direct to ground; the AMZ warp mod - placing a 10 K pot between diodes & ground - seems a key to getting both better volume & fuzz texture.

I've tried the stock configuration, & it does come off as way too weak...hissy & fuzzy, but (IMO) not a strong fuzz.

LED's as subs do tend to hit pretty hard, but the usual other diode subs can do wonders, & bring out the UVSF's innate, characteristic sounds.

Modding the midscoop is key too. Modding those 2 things can get you a whole 'nuther Superfuzz, meaning: in a good way.

The (overly?) scooped, meek & fizzy can become: WOW! The scoop is great for bass tho.

Univox - Superfuzz [schematic]