Wampler Velvet Fuzz  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
stagolee
Information
Posts: 3
Joined: 09 Oct 2013, 00:34
Has thanked: 1 time

Post by stagolee »

Yes that's right. Although I noticed in another schematic there is a 1k resistor between the fuzz and plexi sections. So I added that at the input lug of the plexi switch (just after the fuzz master volume) and this helped some. I think it's just a loud circuit, lord knows the crunch box is. There is more balance now, but I'm wondering if log pots on all the levels might also help. Note that the master volume is a linear on the referenced schematic.

... And as I review my own post it seems I am way off base. The added 1k resistor can't be doing much when there is already a pot to the input of the plexi side right? So the issue might just be the difference in "clean" levels of the crunch box and plexi drive circuits.

... And to answer your question more directly, yes the fuzz section sounds too loud when nothing is stacked after it.

crw414tele
Information
Posts: 44
Joined: 31 Jul 2013, 00:47
Has thanked: 5 times
Been thanked: 12 times

Post by crw414tele »

When I built mine , I found the fuzz side to be louder also but I use it only as a boost so it's overall volume is limited by the pedal it goes into.My understanding [ only guessing ] that this volume is part of the way the fuzz is created as the circuit isn't very fuzzy on it's own and it was originally wired straight into another circuit, not separate as we have it now.
I also only run my volumes at about 50% and adjust from there , but i prefer a smoother/lighter fuzz sound :thumbsup

stagolee
Information
Posts: 3
Joined: 09 Oct 2013, 00:34
Has thanked: 1 time

Post by stagolee »

That makes sense. I just need to play with it some more. I am definitely happy with the stacked tones. Will play it side by side with a Wampler version soon. Thanks again for all the guidance.

User avatar
jalmonsalmon
Solder Soldier
Information
Posts: 209
Joined: 14 Sep 2012, 22:49
Has thanked: 82 times
Been thanked: 26 times

Post by jalmonsalmon »

Hey all...
I made a schematic in diptrace that is based off of Intripped's schematic way back over here https://www.freestompboxes.org/viewtopic ... 40#p229930
Only reason I did it was so I can use diptrace to make a board and if anyone can check my work, would be great! :thumbsup
I checked and double checked everything and the only issue I see could be the DPDT connections and I am thinking about maybe trying a 3PDT instead and having it on a footswitch to change up things.
I am a noob at doing schematics and any pointers is welcomed!
EDIT: the V+ from R24 is on the same net as the R21/C1 junction so the power is good :) I forgot to flag that part with another V+
THANKS!
Attachments
WVF2.jpg

User avatar
jalmonsalmon
Solder Soldier
Information
Posts: 209
Joined: 14 Sep 2012, 22:49
Has thanked: 82 times
Been thanked: 26 times

Post by jalmonsalmon »

Oh also forgot to connect C12 to R13...
woops! LOL... Hate being a noob haha

User avatar
jalmonsalmon
Solder Soldier
Information
Posts: 209
Joined: 14 Sep 2012, 22:49
Has thanked: 82 times
Been thanked: 26 times

Post by jalmonsalmon »

I redid another layout and will build this as soon as I get everything and keep everyone posted...
I settled for the 3PDT board mounted toggle switch and will cram this thing inside a 1590b
I am only interested in one setting but nice to have both on the toggle. 8)
I think with my layout I can actually cram it all inside a 1590b laying horizontally with 2 stompers... :hmmm:
or at least a 125b

gght
Solder Soldier
Information
Posts: 186
Joined: 18 Nov 2007, 05:32
Location: Houston, Texas USA
Has thanked: 22 times
Been thanked: 7 times

Post by gght »

I am wondering if the "booster" section would work in front of a BSIABv2.

Anyone willing to guess??
Thanks!

indyguitarist
Resistor Ronker
Information
Posts: 379
Joined: 11 Jul 2007, 02:25
Been thanked: 142 times

Post by indyguitarist »

gght wrote:I am wondering if the "booster" section would work in front of a BSIABv2.

Anyone willing to guess??
Thanks!
It will, but it may get noisier -

maoriente
Information
Posts: 27
Joined: 20 Jun 2013, 18:02
Been thanked: 4 times

Post by maoriente »

I have built this with the plexi/fuzz switch option.

The Plexi by itself sounds killer, but when either fuzz is engaged there is a noticeable amount of hiss induced. The tight fuzz is the worse of the two.

Is this added noise "normal"?

I've tried 3 LM386N-1, all about the same amount of noise.

I'm getting added hiss from the Big fuzz as well, but not as much. I'm using a MPSA18 biased at 5v. I tried a bunch of those and a few Bc550Cs. Again, not much difference in noise levels.

So my conclusion is either the noise is "normal", or I need a larger lot of transistors and LM386s to try.

Anybody else experience the same hiss?

indyguitarist
Resistor Ronker
Information
Posts: 379
Joined: 11 Jul 2007, 02:25
Been thanked: 142 times

Post by indyguitarist »

maoriente wrote:I have built this with the plexi/fuzz switch option.

The Plexi by itself sounds killer, but when either fuzz is engaged there is a noticeable amount of hiss induced. The tight fuzz is the worse of the two.

Is this added noise "normal"?

I've tried 3 LM386N-1, all about the same amount of noise.

I'm getting added hiss from the Big fuzz as well, but not as much. I'm using a MPSA18 biased at 5v. I tried a bunch of those and a few Bc550Cs. Again, not much difference in noise levels.

So my conclusion is either the noise is "normal", or I need a larger lot of transistors and LM386s to try.

Anybody else experience the same hiss?
You're going to have to sort through jfets. Also, layout is critical for noise.

maoriente
Information
Posts: 27
Joined: 20 Jun 2013, 18:02
Been thanked: 4 times

Post by maoriente »

Thanks Indy!

What though me was with the fuzz inputs bypassed, the "plexi" engine sounds great...and quiet, so I had assumed the jfets were fine as is.

I ended up increasing the big fuzz C10 from 4n7 to 10n, which tamed the hiss a bit without killing the fuzz.

I also added a LM386 noise reduction trick I read about by adding a 10k and 4n7 in series from pin 5 of the LM386 to pin 1, again this seemed a good compromise of hiss reduction without weakening the fuzz to much.

I will try a few more jfets to see if I can reduce the hiss without the other modifications.

jhergonz
Breadboard Brother
Information
Posts: 55
Joined: 29 Mar 2018, 06:28
my favorite amplifier: Mesa Boogie and Soldano SLO100
Location: Philippines
Has thanked: 82 times
Been thanked: 1 time
Contact:

Post by jhergonz »

indyguitarist wrote:
maoriente wrote:I have built this with the plexi/fuzz switch option.

The Plexi by itself sounds killer, but when either fuzz is engaged there is a noticeable amount of hiss induced. The tight fuzz is the worse of the two.

Is this added noise "normal"?

I've tried 3 LM386N-1, all about the same amount of noise.

I'm getting added hiss from the Big fuzz as well, but not as much. I'm using a MPSA18 biased at 5v. I tried a bunch of those and a few Bc550Cs. Again, not much difference in noise levels.

So my conclusion is either the noise is "normal", or I need a larger lot of transistors and LM386s to try.

Anybody else experience the same hiss?
You're going to have to sort through jfets. Also, layout is critical for noise.
Hi! Iknow this thread is years ago ... but I'm really curious about this one. I'am electronics literate so please help me out. when you say "Sort" the JFETs, how exactly do I need to sort the Jfets? I really want to learn, please guide me. Thank you in advance.

User avatar
Nocentelli
Tube Twister
Information
Posts: 2171
Joined: 09 Apr 2009, 07:06
Location: Leeds, UK
Has thanked: 894 times
Been thanked: 805 times

Post by Nocentelli »

jhergonz wrote:
indyguitarist wrote:
You're going to have to sort through jfets. Also, layout is critical for noise.
Hi! Iknow this thread is years ago ... but I'm really curious about this one. I'am electronics literate so please help me out. when you say "Sort" the JFETs, how exactly do I need to sort the Jfets? I really want to learn, please guide me. Thank you in advance.
As I understand it: The J201 (and 2N5457s and similar JFETs) tend to have widely varying specs, so each JFET might/will require different bias resistors (specifically the drain in this case) to get the 5v or whatever voltage is required for the pedal to sound good/how Brian intended it. In the Velvet fuzz, the JFET drain resistor is 15k but using a random J201 will probably not give 5v (or whatever) and may also sound terrible. You could use a trimmer (e.g. 20-50k) to get the required voltage out of most parts straight out of the bag, but if it's a good distance away from 15k it may not sound too much like the og pedal. What it boils down to is either:

a) Use a trimmer on each JFET
b) buy a large quantity of JFETs, then plug them into the circuit and until you find three close to 4.5-5v with a 15k resistor
c) same as b), but find three that will bias with a standard value resistor close to 15k, (8k2/10k/12/15/18) <- what i did.

Since through-hole JFETs are going obsolete (J201, 2N5457 at least) and becoming increasingly expensive, if not actually particularly rare, for option b) and c) you may need to look into using surface mount (smd) jfets and adaptor boards, although I see that tayda are still selling through-hole for cheap enough to buy a handful to try out (though the smd are way cheaper):

https://www.taydaelectronics.com/catalo ... lt/?q=j201

Whatever you end up doing, if you haven't already bought a small breadboard, a pair of jack sockets and a bypass switch to try it out circuits, get it now.

There's a thread about the plexi drive and biasing here, and diystompboxes is generally a good source of information, if a little tricky to search (i find google searches for pedal related stuff often directs there anyway):

https://www.diystompboxes.com/smfforum/ ... c=115814.0
Steven_M wrote: 21 Jan 2011, 17:52
biffa wrote: Sorry,but u r not the only member here

I'm not? Well fuck this site then. I only want meaningful conversations with myself.

User avatar
Nocentelli
Tube Twister
Information
Posts: 2171
Joined: 09 Apr 2009, 07:06
Location: Leeds, UK
Has thanked: 894 times
Been thanked: 805 times

Post by Nocentelli »

Quick update - I recently decided to buy four SMD J201s and appropriate sot23 adaptor boards from www.bitsbox.co.uk, really just to find out how tricky it would be for my aging eyes and clumsy hands (answer - pretty tricky BTW) but i was surprised and delighted to discover the first three JFETs I managed to solder up all gave between 4.5-5.0v with the Velvet fuzz 1k source/1M gate/15k drain resistor. Ymmv, of course.
Steven_M wrote: 21 Jan 2011, 17:52
biffa wrote: Sorry,but u r not the only member here

I'm not? Well fuck this site then. I only want meaningful conversations with myself.

smurfberry
Information
Posts: 11
Joined: 19 Sep 2013, 15:13
Has thanked: 18 times
Been thanked: 5 times

Post by smurfberry »

Nocentelli wrote:Quick update - I recently decided to buy four SMD J201s and appropriate sot23 adaptor boards from http://www.bitsbox.co.uk, really just to find out how tricky it would be for my aging eyes and clumsy hands (answer - pretty tricky BTW) but i was surprised and delighted to discover the first three JFETs I managed to solder up all gave between 4.5-5.0v with the Velvet fuzz 1k source/1M gate/15k drain resistor. Ymmv, of course.
Once you've soldered a 5-10 more you'll probably no longer think it's even that tricky.

One technique I like is swiping the pads with a tinned solder tip so they have a thin layer of solder on them before placing the transistor.

Post Reply