adding a bit of volume

[mrfjones]

okay i have been working on a few pedals and so far none of them work like i would like them to.  i know what is making the sound of the fuzz pedal that i like.  i have isolated that part of the fuzz effect but i would like to boost the volume before the effect.  could someone please post the most simple volume boost that you know.  preferably the volume boost will have a neg ground.

[bwanasonic]

Not really enough information to go on. Could you provide some more info on  the circuit you are using? A better look at the big picture will make for more useful suggestions.

Kerry M

[mrfjones]

i have been working with a bazz fuzz, but i really liked the sound of the two germanium diodes i was using when i cut the transistor out of the circuit.  it then only had the guitar signal going through a 10uf cap to two germanium diodes with +9v connected to the other side of the diodes from there it went to the output cap (i forget the value of that one off hand)  so i basically want to build the most simple volume boost and experiment with it before and after the diodes to see which sounds the best.  I really just want a little volume boost, not much at all, just to get it a bit louder than the regular signal.  i thought someone might know of a really simple boost with something like a bs170 or other mosfet at the heart of it.

[NaBo]

amz mini-booster (colours sound a bit), or amz mosfet (clean) should work... both projects are available at GGG, along with others you might wanna try.  the beauty of boosters is that they're tiny and dirt cheap to make, so you should breadboard a few and see what you like best

[squidsquad]

IMHO...the easiest is the Fetzer Valve:

http://www.runoffgroove.com/fetzervalve.html

Use MPF102 & tweak the output cap (I used a .047uf to get more bass).

[mrfjones]

i was looking into that one but i was thinking about using the jfet 201.  what would the difference be?  and then also where should i put the diodes? before or after?  i am afraid i would blow something if i put them after the boost.  any opinion?

[squidsquad]

MPF102 is sparkly clean...J201 a tad darker w/more boost...the NTE458 is louder still.  Diodes come after the boost...they won't blow...they clip...add distortion & limit the signal. Silicone diodes clip more harshly...germaniams are softer...and some people prefer asymetrical clipping using one of each.

[mrfjones]

thanks, i will get both a j201 and an mpf 102 and socket them and see which works better.  thanks for the advice on placement too.

[mrfjones]

okay i had most of the parts but i had to go to radio shack to get an mpf102  now my circuit kinda works, sound comes through and it is nice sounding but it isn't adding any volume.  i did have to use a different cap value and i ound that to be one culprit.  i took it out of the circuit and it is not the same volume as the guitar signal when it is bypassed, just distorted.  i really have't figured out what all i am doing wrong with these things but it is working, sorta just getting too much signal bled off i think.

[squidsquad]

Hi again,
I'm no expert...I've simply read a lot on this & the other sites.  In the beginning...you said you wanted a small boost...so I recomended Fetzer. However, I DO know diodes need to be slammed with a strong signal.  If you had a sound you liked (before putting in the boost)...go ahead & try boosting after them diodes...it may work. Tinkering is fun & you'll learn what works & what doesn't. Also, the trimmer on the Fetzer is VERY critical...a tiny move makes the difference between getting the loudest boost.  And it takes a second for the cap to charge...so be slow & carefull there.  That's about all I can share.

[Paul Marossy]

sound comes through and it is nice sounding but it isn't adding any volume

Try adding a 10uF cap in parallel with the source resistor. That should increase the gain (loudness) substantially. Also, you might want to use a trimpot (10K?) in place of a fixed source resistor and dial it in to the place where it's loudest. The MPF102 isn't as quiet as a J201, but it should work OK.

[mrfjones]

thanks paul, i will stick that in first, then i will try the other mods i was talking about.

[bigjonny]

Looks like I'm a bit late, but Tim Escobedo also has some great boost suggestions:

http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#boostorama
http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#cmosboost
http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#duende
http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#duendejfet
http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#syrupp
http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#utilityboost

[mrfjones]

those are great links. i will be looking at those for the next pedal i build, a lofi type octave

[mrfjones]

okay i put the cap in and it made a good sound difference, more bass than before, but i am still not getting any big volume boost.  now i had to switch the source and drain lugs on the mpf102 for it to let sound through, what kind of a difference would this make.  it seems that it isn't pushing enough to really clip the diodes i added at the end and it is only slightly louder than the guitar going straight to the amp.  would just putting a j201 in make a big enough difference or am i not getting enough voltage or something to drie this thing properly

[bigjonny]

those are great links. i will be looking at those for the next pedal i build, a lofi type octave

If lo-fi is what you want, best to study Tim's Lofo Mofo, as well.  Not the only lo-fi circuit out there, but good to know about.

I did a compact stripboard layout for that one, if you're interested.

Good luck!

[mrfjones]

hey thanks for the links, but i can't look at the one you did.  for som reason my mac can't open the file.  can it be done as a jpeg or other pic type file?

[mrfjones]

has anyone used a differnt value pot with this fetzer valve?

[lovekraft0]

If I understand this correctly, you're using the booster to drive the Ge diode clipper. If that's correct, changing the amount of gain from the booster is never going to get you more output, because it will always get clipped at the GE diodes' forward voltage. For more output, you'll have to add gain after the clipping diodes.

If I missed something, and this has already been covered or isn't applicable, please feel free to ignore this post!  

[Paul Marossy]

changing the amount of gain from the booster is never going to get you more output, because it will always get clipped at the GE diodes' forward voltage. For more output, you'll have to add gain after the clipping diodes.

That's a good point. So... the bypass cap didn't quite have the affect that I thought it might.  :oops:  I don't think that a J201 would be significantly louder. If adding the gain after the clipping diodes doesn't work quite to your expectations, then maybe the thing to try next is running it on 18V.