important volume loss on Fuzz Face with added tone pot

[poppyman]

Hello,
I hope this issue wasn't discussed somewhere else
I built a Si fuzz face with a musikdinbg kit (one of my 1st builds). I wanted to add a tone pot to it and I followed these instructions:

http://www.bigtonemusic.com/ffmods.html and picked the tone pot mod. It worked surprisingly well. The tone range is great and the fuzz sounds still as good. The problem is that the volume loss is very important. Unity volume is not reached until the volume pot is round 2 o'clock.

Here's the mod: (sorry for the picture, I tried several photo hosting sites and resizing but that's the best I could come up with)



Is there a way to fix this by swapping or adding parts to the circuit?

Thanks in advance.

[poppyman]

sorry, you have to click the thumbnail to see the pic 

[CodeMonk]

Passive tone control suck quite a bit of volume.
You need a "Gain Recovery Stage".
It would go between the tone control and the volume control.

Look at a Big Muff schematic. That's a typical gain stage.

[pinkjimiphoton]

or, easier, look up an electro harmonix lpb1. one transistor, a couple parts, and you're good to go.

OR, depending on the size of the volume pot..you may be able to get it louder by changing the pot. if it's 500k, try 250k, 1meg...and see if that's easier for ya.

[Seljer]

You can also a fuzz face louder by increasing the value of the 470ohm resistor above the 8.2kiloohm bias resistor (you may need to reset the bias afterwards)

[LucifersTrip]

Unity volume is not reached until the volume pot is round 2 o'clock.

I'm confused as to what the problem is...or did I misunderstand.

If unity is at  2 o'clock, then full clockwise is way above unity. What's wrong with that?

[poppyman]

Sorry, I might have not explained clearly. Most of the range of the volume pot is way below the unity and at some point it reaches an equivalent volume as the clean sound. But overall it's very far from the volume "jump" you expect of want from a fuzz when it's engaged even with the volume maxed out.

[pinkjimiphoton]

yah, some fuzzfaces are like that. +1 on increasing the resistor.

try subbing a 10-20k trimmer for the 8.2k resistor, and increasing the 470 to maybe 1k or so. the trimmer will let you find a good bias point.
most folks who want fuzz agree, 4.5 v is perfect...i like a little more dynamics, so 5-6 volts is usually where i end up.

for me, a fuzz has gotta sweep well from clean to mean to SCREAM.

listen to lucifer's trip's advice, if he offers some, the man seriously knows his fuzztones.

[pinkjimiphoton]

oh, duh...

forgot... go to RG's site, and read "the technology of the fuzzface" for the real dope on how to get the most out of this venerable circuit

http://www.geofex.com

[poppyman]

Thanks a lot, everyone.

For the volume, I forgot to mention that it's with the fuzz pot maxed too. It's just that the volume is way below what it used to be before the mod.  

I found a thread  about Recovery stage :

http://www.diystompboxes.com/smfforum/index.php?topic=68363.msg546478#msg546478

It is explained that I could add a LPB1 circuit after the tone pot, and somehow, get rid off the Fuzz Face volume pot to use the LPB1 volume pot as the actual volume pot of the pedal.
In this case (newbie content) , I just connect the IN of the LPB circuit to the OUTPUT of the added tone POT, and connects all the ground wires of the LPB1 to the ground of the FF and the +9V in to the FF DC socket.

Is that right?

I think I'll try the easier mods/value changes  first and then I'll try to add the LPB circuit.

By the way , I'd love to follow Lucifer's trip advice  

"edited for English language mistake sorry"

[pinkjimiphoton]

Thanks a lot, everyone.

For the volume, I forgot to mention that it's with the fuzz pot maxed too. It's just that the volume is way below what it used to be before the mod.  

I found a thread  about Recovery stage :

http://www.diystompboxes.com/smfforum/index.php?topic=68363.msg546478#msg546478

It is explained that I could add a LPB1 circuit after the tone pot, and somehow, get rid off the Fuzz Face volume pot to use the LPB1 volume pot as the actual volume pot of the pedal.
In this case (newbie content) , I just connect the IN of the LPB circuit to the OUTPUT of the added tone POT, and connects all the ground wires of the LPB1 to the ground of the FF and the +9V in to the FF DC socket.

Is that right?

I think I'll try the easier mods/value changes  first and then I'll try to add the LPB circuit.

By the way , I'd love to follow Lucifer's trip advice  

"edited for English language mistake sorry"

take the output where the input to the volume pot would be. connect it to the input of the lpb1. you can probably drop the input cap of the lpb1 or the output cap of the fuzzface. you don't really need both. then just wire the lpb1 circuit in. take the output of the lpb1 and connect it to the high side of a 100k pot. ground the other.
audio out is in the middle.

personally? i don't see a need for a tone control on a fuzzface...did ya try just using the knobs on your guitar? the guitar is pretty much part of the circuit, and the knobs have a great effect on the tone of the fuzz.