electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
Live streaming at radio.electro-music.com

  host / artist show at your time
  Antimon Antimon Waves

poster

Please visit the chat
 Forum index » Instruments and Equipment » Strings and things
Stereo Fuzz Circuit
Post new topic   Reply to topic Moderators: BobTheDog
Page 2 of 3 [52 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Goto page: Previous 1, 2, 3 Next
Author Message
BobTheDog



Joined: Feb 28, 2005
Posts: 4004
Location: England
Audio files: 32
G2 patch files: 15

PostPosted: Tue Oct 14, 2008 2:20 pm    Post subject: Reply with quote  Mark this post and the followings unread

And I think they are called Optical Compressors, I always wondered how they worked, you learn something new everyday!
Back to top
View user's profile Send private message
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Tue Oct 14, 2008 3:25 pm    Post subject: Reply with quote  Mark this post and the followings unread

Neato!
_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Tue Oct 14, 2008 3:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

BobTheDog wrote:
I have a sneaky feeling Unkle Krunkus has placed it in the other thread as some kind of moderator initiation test.


Not conciously, I rarely think that far ahead! Laughing
But I do agree that it's a good thing to let ideas evolve and drag threads in different directions (most of the time) and it's good for moderators to know when they have deviated far enough to warrant their own thread.
I've only ever split two threads, and they have been in the last 6 months I think, so don't imagine that I know what's going on! Embarassed Laughing

I imagine the stereo fuzz as being two parallel channels derived from a mono input. AGC could be interesting, but I think a manual gain would be the most important control. Something which lets you control the gain of the first stage would allow you to set how much clipping occurs. This could be even more crucial if what I'm proposing changes the gain of the clipping stage and/or what gets clipped (high/low freqs). There's no need for a wet/dry type control as you get the dry signal unchanged by simply pulling the gain back.

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Tue Oct 14, 2008 5:34 pm    Post subject: Reply with quote  Mark this post and the followings unread

You could make the two different channels clip at different levels by using different color LEDs.
_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Tue Oct 14, 2008 5:54 pm    Post subject: Reply with quote  Mark this post and the followings unread

Inventor wrote:
You could make the two different channels clip at different levels by using different color LEDs.


Yeah, I'm planning on trying a few different diode options, including Si, Ge, LEDs of various types etc. Even two of the "same" type should have slightly different drops shouldn't they? That's why you can "match" diodes for a diode ladder filter. It's the slight difference in drops which I hope will make the interaction work. You can also bump up the gain even further and have two diodes in each direction. Then their unmatched drops could make things even more interesting. More choices about what to put the transformer across too.

I've finished my PSU (for now) and cleared the bench. Even though I'd like to do some Chaos and BBD experiments soon, I might breadboard up a couple of clippers and see if this idea holds any water first.

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Tue Oct 14, 2008 6:10 pm    Post subject: Reply with quote  Mark this post and the followings unread

Yes, in fact I was shopping for LEDs on the DigiKey search function (which is really cool BTW) and one of the selection parameters was the voltage of a red LED. it varied from like 1.6V to 1.9V or more, if I recall correctly.
_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Wed Oct 15, 2008 2:05 pm    Post subject: Reply with quote  Mark this post and the followings unread

Well, I found a nice candidate fuzz design, and modified it to breadboard up one channel. It's just two op-amps at this stage (1/2 an 074) this could mean fitting it all on one chip! Shocked Cool
It's got nicely rounded knees, which I only just managed to square up by using 1N4148s. Ge's are much nicer. The wave just snakes along between two unspoken boundaries, bouncing and rolling like a slinky. Smile LEDs seem similar to the Ge's. (BTW difference in drop is very obvious for LEDs)
This is the kind of fuzz I wanted to start with, as it's not too harsh, but easy to roughen up if need be.
I'll get the second channel up and running today, then I'll get out the coils! Wink

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Fri Oct 17, 2008 6:44 am    Post subject: Reply with quote  Mark this post and the followings unread

Well,
Interesting progress.
Scratch the transformer, I've found a better way.
I hooked up the X input on my CRO to the second channel so I could see just how much the two channels differed from each other.
Putting the transformer across the diodes didn't do much at all really, and putting it in series with one of the diodes on each side, had varying success, but didn't really create an effect very different from simple fuzz. In fact I found a few ways of locking the whole thing up into high frequency oscillations.
But,......
In the process of connecting and disconnecting diodes etc. I struck upon the most pure, obvious, simple way of creating stereo fuzz.
Clip the positive going signal off one channel, and clip the negative going signal off the other channel. This not only preserves the classic fuzz sound, it also creates this phase shift effect between the channels. It sounds absolutely beautiful!
I also found a number of optional configurations which include not just substituting different diodes, but bypassing them with various caps (to cut top end) and simply bypassing with a large(ish) resistor. (This just dulls the overdrive effect)
The next stage I'd like to try would be to subtract the original signal from the AC coupled fuzz channels. This should widen the stereo effect even more by reducing the common signal.

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
BobTheDog



Joined: Feb 28, 2005
Posts: 4004
Location: England
Audio files: 32
G2 patch files: 15

PostPosted: Fri Oct 17, 2008 1:02 pm    Post subject: Reply with quote  Mark this post and the followings unread

Well I wish I could understand a word of it but it sounds interesting.

Would this be a simple circuit for other people to build?

Andy
Back to top
View user's profile Send private message
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Fri Oct 17, 2008 2:43 pm    Post subject: Reply with quote  Mark this post and the followings unread

Yes, it's a simple circuit. Very Happy
The options would require some extra switches and pots, and the associated wiring, but it would be fairly straightforward.
I think the best thing will be to keep it simple. How much feature creep could there be on a fuzz box? Laughing
Only 2 chips as far as I can see.

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
BobTheDog



Joined: Feb 28, 2005
Posts: 4004
Location: England
Audio files: 32
G2 patch files: 15

PostPosted: Fri Oct 17, 2008 3:36 pm    Post subject: Reply with quote  Mark this post and the followings unread

Could be our first "strings and things" project.
Back to top
View user's profile Send private message
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Fri Oct 17, 2008 3:57 pm    Post subject: Reply with quote  Mark this post and the followings unread

I understand what he's saying and it sounds kewl! Audio samples, schematics, etc!
_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Sat Oct 18, 2008 12:19 am    Post subject: Reply with quote  Mark this post and the followings unread

I'll try and knock up a schem tonight or tomorrow. I need to try the difference amps out and see if that works. If it does, I reckon it'll sound brilliant (literally!) Laughing
_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Sat Oct 18, 2008 12:29 am    Post subject: Reply with quote  Mark this post and the followings unread

What's it called? Anti-proton fuzz? fuzzy navel? spin fuzz?

Post a crude schematic of it and I'll do an Eagle CAD version for ya.

This circuit sounds promising in its simplistic elegance.

_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Oskar



Joined: Jul 29, 2004
Posts: 1750
Location: Norway

PostPosted: Sat Oct 18, 2008 3:07 am    Post subject: Reply with quote  Mark this post and the followings unread

BobTheDog wrote:
Could be our first "strings and things" project.


I'd even go so far as to say that it is- inasmuch as it's helped one of our members to "think aloud" and get feedback on various aspects from other members. Well done folks, and I'm looking forward to hearing the end result! cheers cheers cheers

_________________
Where there are too many policemen, there is no liberty. Where there are too many soldiers, there is no peace. Where there are too many lawyers, there is no justice.
Lin Yutang (1895-1976)
Back to top
View user's profile Send private message
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Sat Oct 18, 2008 4:30 pm    Post subject: Reply with quote  Mark this post and the followings unread

Here's a basic sample.
I'm no guitarist, but you should get the idea.
If you have a look under Soundforge etc. you'll see the spikyness (?) on the upper parts of one side, lower parts of the other.
This is with quite conservative options, ie; I'm using the smooth Ge diodes, part of the signal which could be clipped is going around a bypass resistor, and part is going around a bypass cap. These will be adjustable in the final version. As would switchable diode types.
Add to that I haven't added the difference amplifiers to subtract the original wave, this will "widen" the sound considerably, as the common part of the signal will be attenuated.


Fuzz Field 19-10-08.mp3
 Description:

Download
 Filename:  Fuzz Field 19-10-08.mp3
 Filesize:  962.25 KB
 Downloaded:  640 Time(s)


_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Sat Oct 18, 2008 9:09 pm    Post subject: Reply with quote  Mark this post and the followings unread

I listened to it with my new fancy Sennheiser headphones, and it was amazing! The stereo effect makes the sound seem to travel left and right inside my head... or was that just an echo in my empty skull? No, it was the funky diode action.

The creative, exploratory, experimental approach that you seem to take on your projects appears to have really paid off this time. I wonder if it is possible to enhance the stereo travel effect.

Anyway, well done!

_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Sun Oct 19, 2008 1:23 am    Post subject: Reply with quote  Mark this post and the followings unread

Inventor wrote:
The creative, exploratory, experimental approach that you seem to take on your projects appears to have really paid off this time.


Well, something had to work out sooner or later. Laughing I feel like I've been playing around with weird ideas and having the real world slap them down for too long. Rolling Eyes
I added the difference amps this arvo, and I must admit that, yet again, what I thought was going to happen only sort of did. I'll draw the schem and see if anyone has some feedback on that before I do anything else.
It must seem to some that this is a very "stab in the dark" approach which I have to strange inspirations, and it probably is, and yet I feel like every time I try to realise a theory and then have it do otherwise, I learn heaps about what to expect next time. Does that make sense?
I think part of what keeps this circuit beyond a sure thing is the large number of options/variables. The hardest part will be deciding just where the ends of the pots should lie. Confused Laughing

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Sun Oct 19, 2008 3:09 am    Post subject: Reply with quote  Mark this post and the followings unread

Uncle Krunkus wrote:
Inventor wrote:
The creative, exploratory, experimental approach that you seem to take on your projects appears to have really paid off this time.


Well, something had to work out sooner or later. Laughing I feel like I've been playing around with weird ideas and having the real world slap them down for too long. Rolling Eyes


Yeah, tell me about it. I probably like your approach because it's similar to my own, and looking back at 42 years of it I can count a lot more failures than successes. Yet the good ideas tend to be outstanding in some way. Inventing is a frustrating process and I wouldn't recommend it unless you are prepared for failure after failure before you get a small success. Plus, career-wise I'm still waiting for the first big success. Oh well...

_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Sun Oct 19, 2008 3:42 am    Post subject: Reply with quote  Mark this post and the followings unread

The reason my difference amp idea didn't have great success, was that I'd forgotten that the clipping op-amp has a gain of about 10 for the side which is not clipped (unadjusted), so I had to put the original through a similar X10 inverter for the difference to make a difference. Laughing
It's not a great clip, it's actually hard to see, but if you look carefully, you can see just how different the two channels are.
I've put one through the X input, and one through the Y. If they were the same (or had a linear relationship (ie; gain change only)) there would be a straight line at an angle on the CRO, a bit like a "/", but as you can (almost) see, we have a very much more complex set of twisting interactions going on.
Schem coming up soon.


Fuzz Field Movie 007.mov
 Description:

Download
 Filename:  Fuzz Field Movie 007.mov
 Filesize:  1.5 MB
 Downloaded:  644 Time(s)


_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Sun Oct 19, 2008 5:09 am    Post subject: Reply with quote  Mark this post and the followings unread

Here's the schem,
Updated 20-10-08
Can those of you who have more theory background than me check it over for any obvious problems or questionable practices?
Thanks heaps. Smile

For example, I don't think I really need C2/C5. I've tried bypassing them, and can see no real difference in the response. Would they change the way the clippers work? or act merely to de-couple DC?

By comparison, I know I want C4/C7 as I wanted to remove some of the DC offset from the clipped version before feeding it to the difference amps. I think this makes for more interesting crossover points. Any thoughts? I think maybe they need to be bigger though, as the clip has a bit of a ramp on it, (ie; they're discharging too quickly?)

I'm thinking of replacing R9/R15 with a dual gang pot to control how much of the original is subtracted from the clipped versions. I'm wondering if I should just replace R9/10 and R15/16 with dual pot based dividers (500K?) with the inverting inputs on the wipers? Any thoughts?


Fuzz-Field-20-10-08.gif
 Description:
 Filesize:  47.91 KB
 Viewed:  135 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Fuzz-Field-20-10-08.gif



_________________
What makes a space ours, is what we put there, and what we do there.

Last edited by Uncle Krunkus on Mon Oct 20, 2008 5:46 am; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Sun Oct 19, 2008 8:22 pm    Post subject: Reply with quote  Mark this post and the followings unread

Yes, thoughts. In the movie I did not detect the stereo shifting effect, I presume the movie is mono?

Those 100nF caps are 15 kOhm at 100 Hz, which is the region of your bass signal fundamentals, and lower obviously at the harmonic region. So they are comparable in impedance to the 10 kOhm resistors they are in series with, and they will shape the waveform. If I recall correctly, a cap on the input side of an inverting opamp has a high-pass effect. So you should hear some difference when you bypass them.

Similarly, the DC blocking caps of 100nF are too small, if they are for DC blocking only. I'd make them bigger.

Instead of using a dual ganged pot on the diffamp inputs, I'd just use a single pot on the prior inverting amp feedback path. That would be cheaper, easier, etc. - always avoid dual ganged pots when designing for cost, as I'm sure you know. Also, putting the pot there just "feels right", as in "I've seen that a lot" and in the other positions it doesn't "feel right".

Just my 2 cents, nice circuit. I may have more comments later once I have a little time to think about it, but I wanted to address your questions right away. Fuzz On!

_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Mon Oct 20, 2008 4:00 am    Post subject: Reply with quote  Mark this post and the followings unread

Inventor wrote:
Yes, thoughts. In the movie I did not detect the stereo shifting effect, I presume the movie is mono?

Yes, I think it may as well be, just an ambient pickup into the mic of the (normally still) camera.
Quote:
Those 100nF caps are 15 kOhm at 100 Hz, which is the region of your bass signal fundamentals, and lower obviously at the harmonic region. So they are comparable in impedance to the 10 kOhm resistors they are in series with, and they will shape the waveform. If I recall correctly, a cap on the input side of an inverting opamp has a high-pass effect. So you should hear some difference when you bypass them.

So bypassing them is only going to improve bass response. That's actually a good thing as I'm a bass player really and I quite like a bit of fuzz on a bass sometimes.
Quote:
Similarly, the DC blocking caps of 100nF are too small, if they are for DC blocking only. I'd make them bigger.

Cool, my intuition was right on that one. I'll probably go with 1uF BPs.
Quote:
Instead of using a dual ganged pot on the diffamp inputs, I'd just use a single pot on the prior inverting amp feedback path. That would be cheaper, easier, etc. - always avoid dual ganged pots when designing for cost, as I'm sure you know. Also, putting the pot there just "feels right", as in "I've seen that a lot" and in the other positions it doesn't "feel right".

Yeah, good call on that one, even though I don't think I'd ever "design for cost" alone, it's alot more elegant to use a single gang in that way. That high gain stage should have a small cap around it too I s'pose.

Thanks for taking the time to give me that feedback Les. Very Happy

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Mon Oct 20, 2008 5:51 am    Post subject: Reply with quote  Mark this post and the followings unread

I just updated that schematic a couple of posts back with some enhancements,
Got rid of the caps on the inputs to the clippers,
Added pots to vary clipped levels and invert levels,
Tweaked gains for each,
Changed the de-coupling caps to 1uF BP

And I must say it's really starting to sing now. It's got great control and variation.

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
Inventor
Stream Operator


Joined: Oct 13, 2007
Posts: 6166
Location: San Antonio, Tx, USA
Audio files: 267

PostPosted: Mon Oct 20, 2008 9:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

What about C1? Shouldn't that also be 1uF since it looks like a DC blocking cap?

I must say, Uncle, it is a really elegant little circuit. Do you mind if I add it to the EChucK collection? Do you know about EChucK?

_________________
"Let's make noise for peace." - Kijjaz
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic Moderators: BobTheDog
Page 2 of 3 [52 Posts]
View unread posts
View new posts in the last week
Goto page: Previous 1, 2, 3 Next
Mark the topic unread :: View previous topic :: View next topic
 Forum index » Instruments and Equipment » Strings and things
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use