Univox - Superfuzz  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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tabbycat
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Post by tabbycat »

kaycee wrote:You could keep the original tone section, and add a tone knob. Taking the output from after the diodes and run it to a pole of a DPDT switch. On one side have the route through the normal tone stack with the two position switch intact. On the other throw you can insert the tone stack of your choice, the other pole of the switch goes to the volume pot.

You can try whatever tone stack you like, I'd suggest the Stupidly Wonderful Tone Control that Jack Orman put out, works quite well on this circuit. Does it cover the ground of the original tone selections? Kind of.
thanks kaycee.

had tentatively come to the same sort of conclusion (re keeping tone 1 and 2 as stock, and patching in an adjustable third tone option to the third position of the on-on-on) but it's good to have the reassurance of someone who has done it and it worked for. just a matter of which stack is most sympathetic to the qualities of the original. too toppy and it ends up in tinny fy2 wasp-in-a-coke-can territory, and two much bottom end and it muffles out.

have investigated the orman swtc after you mentioned it to me re poss mods to an ibanez standrard fuzz i built (which i abandoned after building it with the vero strips running vertically instead of horizontally, my best fail to date). i also read up on some extensions and varations to it by rg keen i think, or mark someone (it was either amz or geofx, i think, have got them all in a word doc somewhere). so have options to work through.
finally got some more breadboards yesterday. keep filling them up. six now with different builds on. when they are must-have they get promoted to being soldered up and boxed). so one will now become superfuzz tone stacks.

drag is i'm too ill to get out to anywhere i can use my valve amp. so reduced to a little tabletop amp with no bottom end. or headphones, which tends to overstate the bass. which is why i was wondering which 'should' keep (in 'theory') as much of the original range as possible, in pure circuit physics terms. the derringer scoop trim looks least intrusive. not sure about the wattson. i just don't know enough yet to judge.

anyway, rambling on. will def put swtc on breadboard and report back as and when.

thanks,
tabbycat.

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Post by digi2t »

Try this. Used it on mine, I like it. The clipping control is optional.

Image
No matter how many times I cut it, it`s STILL too short!

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Post by tabbycat »

digi2t wrote:Try this. Used it on mine, I like it. The clipping control is optional.
many thanks dino. i notice your scoop trim uses the original superfuzz 0.1uf wheras the derringer scoop trim replaces that with a 0.056uf . derringer's 0.056uf gives a wider scoop than the 0.1uf (a range wider than the 1khz that is the standard superfuzz scoop). but i suppose the trim lets you take up that slack to pick up the stock setting as you turn it. it's an easy one to sub in and out so will try both. but i like the idea that the scoop's parameters should stay within the orignial parameters, as i don't want it to sound too non-superfuzz.
btw, i did notice your schematic on p18 of this thread but didn't include it in the shortlist i posted on p20 as it is close enough in principle to the derringer listed one to not need to post both to pose the question. but is your choice of the scoop trimmer because you feel that is a 'better' (least intrusive) option than the 100k pot used to mix tone 1 and tone 2 as used by wattson? or is it just two means to exactly the same end?
tabbycat wrote:have investigated the orman swtc... i also read up on some extensions and varations to it by rg keen i think, or mark someone (it was either amz or geofx, i think, have got them all in a word doc somewhere). so have options to work through.
just to clarify my rambling here and give due credit where it is certainly due, the swtc was mark hammers idea http://hammer.ampage.org/ , later adapted-extended by jack orman http://www.muzique.com/lab/swtc.htm and the rg keen article i was half-remembering was this 'Simple, Easy Parametric and Graphic EQ's, Plus Peaks and Notches' found here http://www.geofex.com/article_folders/eqs/paramet.htm (which is far too brainy and over-my-head at present, but understand enough of its significance to know i should persevere with it until i get it).

tabbycat.

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tabbycat
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Post by tabbycat »

btw, has anyone tried this (i hope mark hammer won't mind me reposting one of his diysb comments here)

re superfuzz scoop mods...

"Alternatively, here's an idea. The .1uf cap sets the corner frequency where the dip in the middle starts to happen; i.e., it helps define what "the middle" is. What if you wired up a smaller-value cap in parallel, like .022 or .01uf? Both caps would be connected at one end to the junction of the 10k and 22k resistors. At the other end, each cap would be connected to an outside lug of a 10k pot. The wiper of the pot would go to ground. Rotating the pot in one direction or the other would make the series resistance for one cap higher and the other lower. This would yield two different flavours of mid-scoop and variable midlift. I think I might try that out."

https://www.diystompboxes.com/smfforum/ ... #msg809894

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Post by digi2t »

The scoop trimmer (or pot in my case) was simply an effort to get some variance in the scoop, instead of the scoop/no scoop option. I'm quite happy with the overall sound of the Superfuzz, and didn't want to mess with it that much. The scoop control simply gives me the "in between" settings that are impossible with the original switch scheme, but like you say, retains that classic Superfuzz sound.
No matter how many times I cut it, it`s STILL too short!

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Post by warioblast »

I added the Wattson scoop mod to a SuperFuzz kit. http://uk-electronic.de/onlineshop/prod ... b454b9c942
It gets the job done but I have a slight volume drop with the in-between tones. The volume fades a bit during the first half of the travel of the pot and then rises back during the 2nd half. Do other scoop mods behave the same ?

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Post by mictester »

I built two of these last week using the "Fuzz IC" - the CA3046. Each board has two 3046s (or 3086s) and two 2N3906 transistors as part of the bistable relay switching. The transistor that has to have the emitter grounded (the "substrate" pin) is used for the other transistor in the bistable relay circuit.

The transistors with the common emitters are used for the long-tailed pair - the frequency doubler stage, and because they're identical, the trimmer in that stage can be eliminated as long as the resistors are reasonably well matched. It makes for quite a small PCB, and the fairly low gain transistors in the transistor array ICs are not too different from the original 2SC828B which were quite low Hfe parts. It's one of my favourite sounding Fuzzes and with some slight tweaks to the tone stages (as suggested in other parts of this thread) it can be tweaked to work well with almost any rig.
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Post by tabbycat »

^
mictester wrote:I built two of these last week using the "Fuzz IC" - the CA3046... (edited)

... It's one of my favourite sounding Fuzzes and with some slight tweaks to the tone stages (as suggested in other parts of this thread) it can be tweaked to work well with almost any rig.
curious. it seems a logical step since the muff has an ic sort-of equivalent, but i haven't noticed many ic superfuzz derivatives. maybe i'm not recognising them when i see them. the only smd superfuzz (superfuzz-derivative) i have is the behringer s300, which uses smd trannies rather than going for ics.

https://www.freestompboxes.org/download/ ... &mode=view
behringer s300 superfuzz mod thread here https://www.freestompboxes.org/viewtopic ... 11&t=24995

how does your ic version sound in comparison with a vintage germanium diode superfuzz? does it have that extra sheet metal buzz thing that the ic muff has? i'd imagine it to sound finer grained, less blistering, but more metallic. i wonder what other ics would make good substitutes. though it's only a single opamp (so layout would be huge) my favourite ic for distortion is the LM741. the LM386 distorts in a good-bad way too when cranked. but single opamp again.

thanks for the post. i would definitely be interested in seeing a schematic if you have one already done and don't mind showing.

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Post by induction »

tabbycat wrote: curious. it seems a logical step since the muff has an ic sort-of equivalent, but i haven't noticed many ic superfuzz derivatives. maybe i'm not recognising them when i see them. the only smd superfuzz (superfuzz-derivative) i have is the behringer s300, which uses smd trannies rather than going for ics.

...

how does your ic version sound in comparison with a vintage germanium diode superfuzz? does it have that extra sheet metal buzz thing that the ic muff has? i'd imagine it to sound finer grained, less blistering, but more metallic. i wonder what other ics would make good substitutes. though it's only a single opamp (so layout would be huge) my favourite ic for distortion is the LM741. the LM386 distorts in a good-bad way too when cranked. but single opamp again.
The CA3046 and CA3086 are NPN transistor arrays. They are not op-amps, like used in the IC Big Muff, so I wouldn't expect much comparison there. The main difference between using discrete transistors and a transistor array IC is that the array transistors will be very well matched and will have fairly low hfe for modern NPN devices (which makes them good for vintage fuzzes). Beyond that, a CA3046 Superfuzz shouldn't be much different from a discrete one.

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Post by tabbycat »

induction wrote:The CA3046 and CA3086 are NPN transistor arrays. They are not op-amps, like used in the IC Big Muff, so I wouldn't expect much comparison there. The main difference between using discrete transistors and a transistor array IC is that the array transistors will be very well matched and will have fairly low hfe for modern NPN devices (which makes them good for vintage fuzzes). Beyond that, a CA3046 Superfuzz shouldn't be much different from a discrete one.
thanks induction. jumped the gun at the thought of an ic superfuzz and ended up paradingmy ignorance. have not come across a transistor array before so its superficial resemblance to an ic caught me out. have got the CA3046 datasheet on my desktop for further investigation.
btw are you familiar with any superfuzz derivatives that use opamp arrangements instead of the 6 discrete transistors?

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Post by induction »

tabbycat wrote: btw are you familiar with any superfuzz derivatives that use opamp arrangements instead of the 6 discrete transistors?
No, I'm not, but I'm not an expert on the Superfuzz circuit. My experience with transistor array chips comes from playing with the Tonebender MkII.

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Post by mictester »

The beauty of using the transistor array is that the frequency doubler pair of transistors are very accurately matched, and the HFE is quite low for silicon devices and it does a good job of emulating old fashioned transistors. The germanium diodes remain germanium diodes, but I put a 10k preset in series with them to ground. This allows an amount of resistance to be introduced which has the effect of making the germanium diodes even smoother sounding!

I used these pedals as a way of using up some fairly useless germanium transistors (used for the diodes), and with a pair of the little bistable relays, a couple of pnp silicon transistors for the relay switching and a couple of jumper-selectable filter capacitors in the tone stages, it's a reasonably compact PCB, 9V battery-powered, low noise and really fuzzy!
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Post by warioblast »

warioblast wrote:I added the Wattson scoop mod to a SuperFuzz kit. http://uk-electronic.de/onlineshop/prod ... b454b9c942
It gets the job done but I have a slight volume drop with the in-between tones. The volume fades a bit during the first half of the travel of the pot and then rises back during the 2nd half. Do other scoop mods behave the same ?
Image
So I tried this method to compare. As far as volume goes, I'd say the non scoop gets slightly louder. Like I did for with the Wattson mod I used a toggle switch to get a good comparison.

With the Wattson mod you really keep the original tones; scoop & non scoop are dead-on. With the scoop method just above, the scoop tone is true to the original but the non scoop is a bit different. As a matter of fact it sounds better to my ears. While switching the toggle, I realized the original non scoop tone has a bit of congested mids. With this mod, the congestion is gone, the sound is clearer and nastier. :thumbsup

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Post by tabbycat »

a couple of random superfuzz research things i've been looking into that i thought might be well-placed here:

related to the transistor array superfuzz discussion above.

dino's the man. https://www.diystompboxes.com/smfforum/ ... c=102477.0

and this superfuzz on a scope. interesting to superfuzz fans who don't have a scope.


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Post by Llwyt »

Hi!

I'm lost in my first project in "DIY" stompbox :scratch:
I bought the Univox Superfuzz kit of UK-electronic (http://uk-electronic.de/onlineshop/prod ... ts_id=3085, there's an access to the manual with schematics in this page) and... nothing's OK. Even the LED doesn't lit when ON (or even OFF).
I've check several times the schematic and don't see where I'm wrong.
Is there some basic things I can check to find the problem(s) ?
I've attached some piuctures, but I'm not sure it will help.

Thanks for your help.

PS : sorry for my english (doing my best) and hope I'm in the right place to ask.
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Post by Bret608 »

Hi,

Your pictures actually do help! I see a problem on your wiring for the input jack. You've reversed the ring and tip. In other words, the lug that has the purple wire should get the black lead from your battery connector, and the lug that currently has the black wire should get the purple one that goes to your footswitch. Try that out and see if it works.

Cheers,

Bret

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Post by Llwyt »

Hi!
Thanks for your help. Indeed, I reversed the purple and the black wire on the input jack.
Now, that's better but not totally solved: bypass = OK, effect on = silence.
I think I'll have to check all the wirings and their weildings [smilie=a_smartie.gif]

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Post by Llwyt »

Long time no see...
A few times after my last post (more than one year ago), i've checked and find nothing wrong comparing the schematics and the realisation, so get kind of desperate.
But I really want to finally finish that first project and superfuzzed my sound, so checked another time and again, everything seems OK.
So, when bypass, ok, but when on, nothing: can you tell me what can i look that may be the cause of my problem?
Thought the 3PDT was maybe miswired. I can't see that time of the day night, I'll checked again tomorrow (1am here), but if you have a hint... Thanks.

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Post by digi2t »

Llwyt wrote:Long time no see...
A few times after my last post (more than one year ago), i've checked and find nothing wrong comparing the schematics and the realisation, so get kind of desperate.
But I really want to finally finish that first project and superfuzzed my sound, so checked another time and again, everything seems OK.
So, when bypass, ok, but when on, nothing: can you tell me what can i look that may be the cause of my problem?
Thought the 3PDT was maybe miswired. I can't see that time of the day night, I'll checked again tomorrow (1am here), but if you have a hint... Thanks.
Search "audio probe".
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Post by Dibya »

2sc828 are rare gens , can I use something else?

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