Wampler Velvet Fuzz (with mods)

[MAO]

Wampler Velvet Fuzz (with mods)

Verified by me


I added a few mods and the potential for noise reduction mods as I found the pedal a little dark for my tastes (and sometimes noisy). All of which can be omitted, however I recommend them all.

The original H11F1 switching scheme has been omitted.  

I hand selected J201s that biased at 4.5v while using the 9v supply (I only had 5 out of 100 J201s that biased between 4.4v and 4.8v, the 15k drain resistor values may require tweaking if necessary) I also selected a 2n5089 that biased close to 4.5v.

Mods - In no particular order:

Bright Control - Original value is 25k Linear, I used 50k to extend the bright range.
Big/Tight Fuzz bypass switch - Allows bypassing both fuzz inputs leaving just the "Plexi" engine.
Gain Switch - Adds a little boost to the 1st Jfet stage for a bit more gain.
Bottom Switch - to select  different "bass" cap values. (I used a 2P4T mini rotary to select 4 cap values)
Road Rage Charge Pump & 9v/18v Switch - Allows the "Plexi" engine to run off either voltage. (The Fuzz circuits always run off 9v)
Noise Reduction - Sockets for an extra resistor and cap to reduce LM386 hiss if needed. I also socketed the 4n7* cap in case the 2n5089 added to much hiss.
Polarity protection - added series diode protection rather than the original parallel diode protection.  

For the noise reduction mods:
   I read the need to sort through jfets, LM386 and 2n5089 for best noise performance and consistency. If you don't have enough to sort through, and find to much hiss, the following should help.  
   If the Tight mode (LM386) injects to much hiss, add a 10k resistor in the ** socket and start with a 4n7 cap in the * socket. Increase the 4n7 to taste. If no problem with hiss, leave those sockets empty.
   If the Big mode (2n5089) injects to much hiss, increase the original 4n7* cap to 10n. Increase further to taste. If no problem with hiss, leave the cap at the original 4n7 value.
   NOTE - none of these noise reduction mods were needed in this particular build. But I have used them both successfully in the past.

The original H11F1 switching scheme grounds the Big fuzz input when the Tight fuzz is engaged and grounds the Tight fuzz input when the Big fuzz is engaged. If using the Fuzz Bypass mod, it's probably a good idea to ground both fuzz inputs when using just the "Plexi" engine. (A 4P3T Rotary switch or two 3PDT switches can be used to accomplish this)

To reduce the number of toggles, I opted for a 3P4T Rotary to select Big/Tight/Plexi/Boosted-Plexi modes. However, only one of the fuzz inputs is grounded in the Plexi mode, neither is grounded in the boosted Plexi mode. Although I haven't yet noticed any issues by not grounding those inputs, a 4P3T Rotary and a separate Toggle for the boost mode may have been a better choice.      

For original specs (minus the H11F1 switching), use a 25k linear for the Bright control, omit the charge pump, D2, D3, 12v Zener and the 10u caps, do not install noise reduction mods (leave those sockets empty), omit the 2P4T rotary and its 680p and 1n5 caps, replace the 470pf cap with a 2n2 cap and omit the 2n2 cap directly above the 1st J201, omit the Bottom SW1 and SW2 connections, omit the SPDT 9v/18v toggle, omit the 18v out connection, connect the 9v out connection to the 9v/18v in connection, omit the Gain Switch, Gain SW connections and the 1u* cap, increase the 47u* cap to 220u, replace D1 with a 10R resistor and add parallel protection diode between the newly added 10R and 9v supply.    

I posted a picture of the stuffed 125b over in the forums   

   

[Muadzin]

Awesome! I always dig your Wampler layouts. It shows your passion for the man's hard work. Plus I also dig Wampler pedals. He's one of the few boutique builders who I wouldn't call a bootweeker.