Mid-Fi Electronics - Demo Tape Fuzz  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby Nocentelli » 23 Aug 2014, 21:42

I don't think the taper will cause/reduce any oscillation, I think it's just the design. I used a 100k log pot for treble, there's still plenty of bright on tap but it sounds about right at halfway up which is how I like it.
brownwhopping wrote:How can I learn by reading threads an making circuits, when some day I can see a lawsuit or somebody beat me in the face for that?
User avatar
Nocentelli
Tube Twister
 
Posts: 2086
Joined: 09 Apr 2009, 08:06
Location: Leeds, UK
Has thanked: 859 times
Have thanks: 837 times

Re: Mid-Fi Electronics Demo Tape Fuzz

Postby VanPorter » 06 Sep 2014, 04:17

Nocentelli wrote:
pinkjimiphoton wrote:nocentelli, is your vero verified yet?


OK, this one is now verified:

Demotape_vero_nocentelli_verified.gif


In my actual build:

I used a C100k pot instead of the 25kB for trim, giving a wider range of lower gain sounds with humbuckers which tend to overload it. I also used log 100k pots for volume and treble, putting the most useful settings closer to noon.


Hello! I'm building this pedal for second time, for a friend, and this time I'll use 1micro electrolitic caps. I can't realize the polarity, could you help me, please?
VanPorter
 
Posts: 3
Joined: 16 Aug 2014, 00:15
Has thanked: 4 times
Have thanks: 0 time

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby Nocentelli » 06 Sep 2014, 09:26

Negative to connected to guitar for the input cap, positive connected to output of the chip (pin 1) for the middle one, and negative connected to trim lugs 1+2 for the gain cap at the top.
brownwhopping wrote:How can I learn by reading threads an making circuits, when some day I can see a lawsuit or somebody beat me in the face for that?

For this message the author Nocentelli has received thanks:
VanPorter (10 Sep 2014, 20:07)
User avatar
Nocentelli
Tube Twister
 
Posts: 2086
Joined: 09 Apr 2009, 08:06
Location: Leeds, UK
Has thanked: 859 times
Have thanks: 837 times

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby lippajad » 12 Jul 2016, 08:26

is there a list of components somewhere?
lippajad
 
Posts: 1
Joined: 28 Jan 2012, 22:08
Has thanked: 0 time
Have thanks: 0 time

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby Boba7 » 18 Jul 2016, 00:29

Boba7
 
Posts: 31
Joined: 15 May 2015, 00:05
Has thanked: 0 time
Have thanks: 7 times

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby Addy Bart » 07 Nov 2016, 17:06

I built this twice (using the milk fuzz boards at OSHPark) and strange enough, the second build does not squeal like the first when the trim is fully clockwise. I measured the pots on both builds and the first one is 24.8k compared to the second: 23.1k. I tried a 100k pot in there too and it still didn't squeal. I'm wondering what other parts of the schematic I can look at... Could the diode be responsible?

I already tried increasing the 470k resistor in the op amp loop but that made no difference.
Also changed the 100uF cap for the power to 47uF, as is there in the schematic that Doug confirmed to be 100% accurate.

Any ideas on what I can do? I'm making it for a friend who adores the Jesus & Mary Chain and he nearly wet himself when he heard the first build squeal like crazy.
User avatar
Addy Bart
 
Posts: 11
Joined: 27 Jul 2016, 11:47
Has thanked: 27 times
Have thanks: 8 times

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby doug deeper » 08 Nov 2016, 02:32

So you want it to squeal?
Try some different op amps, I had a batch of 4558s at one point that squealed in this circuit (I changed to TL072s shortly after).
Shouldn't be hard to find an opamp that would be unhappy in this circuit!

For this message the author doug deeper has received thanks: 2
Addy Bart (08 Nov 2016, 23:43), Nocentelli (08 Nov 2016, 06:30)
doug deeper
Breadboard Brother
 
Posts: 93
Joined: 06 Dec 2007, 18:39
Has thanked: 0 time
Have thanks: 87 times

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby Addy Bart » 08 Nov 2016, 03:32

Right! Thanks Doug, I'll give that a try.
Been enjoying MMOSS lately too.. Good stuff!
User avatar
Addy Bart
 
Posts: 11
Joined: 27 Jul 2016, 11:47
Has thanked: 27 times
Have thanks: 8 times

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby jgriff1095 » 01 Aug 2017, 14:32

I know this is an old thread but I cant seem to figure out my problem. I can pass signal through this circuit, but the trim pot doesn't do anything. And its definitely not as loud as it should be. I can't find anything missing, or any touching solder joints. Any one have any idea what is causing this?

I'm using this layout https://effectslayouts.blogspot.com/201 ... -fuzz.html
jgriff1095
 
Posts: 1
Joined: 01 Aug 2017, 14:19
Has thanked: 0 time
Have thanks: 0 time

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby jrfox92 » 01 Aug 2017, 17:26

Bear in mind that "trim" isn't a trimpot, just in case you might've gotten that mixed up. Trim is the gain control.
I'd mess around with the values and tapers on it, but it sounds like there are probably connectivity issues there.
That or there are problems with whichever op amp you used.
jrfox92
Breadboard Brother
 
Posts: 69
Joined: 11 Jun 2014, 05:46
Location: Akron, Ohio
Has thanked: 4 times
Have thanks: 52 times

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby garyg » 13 Oct 2018, 14:34

I've just built one of these on vero and I think it's basically working (bass and treble do what you expect, trim goes from clean to very fuzzy) but there's a kind of raspy noise (not sure of the terminology of fuzz :)) on top of the guitar sound, don't remember hearing it in any demo audio/videos.

It's not a constant noise, very much signal dependent, fades out with the sound but kind of stuttery as it fades.

Any ideas where I should look? I'm guessing the biasing or something?

Thanks.
garyg
 
Posts: 2
Joined: 10 Mar 2018, 23:44
Has thanked: 1 time
Have thanks: 0 time

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby Boba7 » 13 Oct 2018, 16:07

Try some other opamp, ne5532, lf353, op275. Its very much opamp dependant. Let us know what you find!

For this message the author Boba7 has received thanks:
garyg (14 Oct 2018, 18:48)
Boba7
 
Posts: 31
Joined: 15 May 2015, 00:05
Has thanked: 0 time
Have thanks: 7 times

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby Boba7 » 13 Oct 2018, 16:11

I remember loving an opa2604 in it but its way too expensive an opamp haha!

JohnK found that the best opamp for the circuit is th MC33172 and I really trust his ears.

Otherwise I had good results with a classic ne5532 :)
Boba7
 
Posts: 31
Joined: 15 May 2015, 00:05
Has thanked: 0 time
Have thanks: 7 times

Re: Mid-Fi Electronics - Demo Tape Fuzz

Postby garyg » 13 Oct 2018, 21:53

Thanks guys.

I feel a little foolish as I tried it again tonight with a better amp (ie. a proper guitar amp not my thrown together, workbench 1 watter...) and it sounded a lot smoother straight away... lesson learned there. :) (this is the first pedal I've tried to build since... hell, the early 90s I guess...)

I had a tl072 and ne5532 in my spares box and the ne5532 did seem a little smoother (tl072 I couldn't hear a difference).

So, yeah, sounding good. I think I'll play with the treble pot as that seems pretty much on or off then box it.

Cheers.
garyg
 
Posts: 2
Joined: 10 Mar 2018, 23:44
Has thanked: 1 time
Have thanks: 0 time

Previous

Return to Boutique Stompboxes dissected...

Who is online

Users browsing this forum: abc1234, lead2203, Saruman, Suicufnoc, temol and 18 guests