Bazz Fuzz questions

PurpleStrat · February 12, 2008, 07:04:51 PM

I just got my first Bass Fuzz build to work! I had no idea it was a "Short Decay Fuzz". Could not tell from the clips. Can I do anything to make it not "Short Decat"?

superferrite · February 12, 2008, 07:40:03 PM

Which version did you make?
Try and swap out the one diode with two in series, diodes of different values, or an LED (red works fine).
The single resistor replaced with a trim pot really helps dial it in, too.

PurpleStrat · February 12, 2008, 09:00:52 PM

Version 1.

I'll give the diodes a shot thanks!

Dragonfly · February 12, 2008, 09:04:30 PM

also....

add a small value resistor to the emitter of your transistor... 100 ohms or so...

IMO a MPSA13 sounds great, and you should also use a 100k trimmer in place of the 100k collector resistor.

PurpleStrat · February 12, 2008, 09:33:35 PM

I'l try the resistor next. I have to get another 100k pot to try that as well.

I wired another diode in series with the other but it reall made no change.

ambulancevoice · February 13, 2008, 01:33:30 AM

definitely try to 100k pot in place of the collector resistor
also, are you sure you have the diode orientated correctly? is the side with the ring around it connected to the base and the side with no ring connected to the collector?

PurpleStrat · February 13, 2008, 07:52:14 AM

Yep thats how I did have it but now I have two diodes in series.

mac · February 13, 2008, 11:12:57 AM

Do you mean poor sustain?

mac

PurpleStrat · February 13, 2008, 03:51:33 PM

Quote from: mac on February 13, 2008, 11:12:57 AM
Do you mean poor sustain?

mac

No the note decays like a gate. If you pick light on the higher strings it will not even make a sound.

Caferacernoc · February 13, 2008, 05:38:51 PM

That's a bias issue. Definitely try a 100k pot in place of the collector resistor and dial it in.

PurpleStrat · February 13, 2008, 07:46:56 PM

Well can someone tell me how to wire in the pot? I tried and I got smoke.

deschete · February 13, 2008, 10:05:39 PM

Quote from: PurpleStrat on February 13, 2008, 07:46:56 PM
Well can someone tell me how to wire in the pot? I tried and I got smoke.

I had the same problem just this week, it's because when the pot is "off" there is no resistance... and the voltage makes the LED/Diode burn up!

Someone mentioned putting a small resistor in series so that won't happen. I'm just a newbie though, so someone with more refined knowledge will probably be by shortly to answer this one!

mountainking · February 13, 2008, 10:32:26 PM

Quote from: deschete on February 13, 2008, 10:05:39 PM
Quote from: PurpleStrat on February 13, 2008, 07:46:56 PM
Well can someone tell me how to wire in the pot? I tried and I got smoke.

I had the same problem just this week, it's because when the pot is "off" there is no resistance... and the voltage makes the LED/Diode burn up!

Someone mentioned putting a small resistor in series so that won't happen. I'm just a newbie though, so someone with more refined knowledge will probably be by shortly to answer this one!

Correct. Put a small resistor, say 1k, in series with the pot so that you don't create a short if the pot/variable resistor is set to minimum resistance.

PurpleStrat · February 13, 2008, 10:36:46 PM

Thanks I'll try that. Guess I need a new pot now though.

PurpleStrat · February 13, 2008, 10:59:39 PM

Ok found a pot and tried it with no smoke.

It still sounds the same though and only sounds good when fully open.

jayp5150 · February 14, 2008, 07:52:41 AM

Did you replace that diode? You might have fried it...

deschete · February 14, 2008, 08:55:22 AM

Quote from: PurpleStrat on February 13, 2008, 10:59:39 PM
Ok found a pot and tried it with no smoke.

It still sounds the same though and only sounds good when fully open.

I found the same thing. Using the "dirt" mod on the Deluxe Bazz Fuzz made a lot more difference to me.

mac · February 14, 2008, 11:01:24 AM

Sometimes I had this gate effect when using a) low gain transistors, b) Ge diodes. I prefer the darlington version.

If the transistor is low gain you should use a +250K pot.

Try this. Add a 470k to 4.7M resistor in parallel with the diode, from base to collector. If this solves/reduces the gating fx then it is a bias problem. Expect less gain at full gas because of the negative feedback resistor.
Or add a second diode in the opposite direction. Leakage current of the diode may act, if enough, as a resistor.

Consider a darlington transistor.

http://www.diystompboxes.com/smfforum/index.php?topic=62944.0

mac

Dragonfly · February 14, 2008, 02:13:35 PM

Quote from: Dragonfly on February 12, 2008, 09:04:30 PM
IMO a MPSA13 sounds great, and you should also use a 100k trimmer in place of the 100k collector resistor.

Quote from: mac on February 14, 2008, 11:01:24 AM
Consider a darlington transistor.
http://www.diystompboxes.com/smfforum/index.php?topic=62944.0
mac

As usual, you and I are on the "same page" !

PurpleStrat · February 15, 2008, 05:14:05 AM

Thanks for the help guys! As for frying the diode I did. After my post about smoke above I built a new one from scratch that still had the same gate problem.

I figure it might help to post what parts i used. I got the layout from Dragonfly. I know it's not up any more but I have had it copied for a while. I belive it also is the same as V1 at Runoffgroove.

4.7uf Cap
1N94 Diode
2N3904 transistor
100k resistor
0.1uf Cap

Should I make any subs here? Besides trying a Darlinton (Don't have one on hand).

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