bazz fuss - gain pot addition

[jhicken]

Hi all,

I made a bazz fuss a couple of days and boxed it up based on the 1st version on this page: http://www.home-wrecker.com/bazz.html. It sounds great but since I put it in a 1590B, I figured why not add a gain pot since there is a lot of free real estate..

Today I drilled another hole in the enclosure and added a B5k pot from emitter to ground to control gain and it worked out ok, but I'm wondering if I used a different value pot if I could get more range between min and max gain? With the b5k fully CCW it does clean up, but ideally I'd prefer if I could get it a little cleaner. any thoughts?

thanks,
james

[chptunes]

I'm surprised that you don't think 5k is enough resistance.  I'm using a 1k Pot, and I never turn it below 50%.  Mine is semi-clean with about 500 Ohms on the Emitter.

..just my experience.  If you really need more resistance, try a 10k Pot.

A 100k Master Volume at the end of the circuit might help you clean it up, if you haven't installed one yet.

-Corey

[chptunes]

..also, I just realized that yours is version 1 and mine version 2.  I couldn't get version 1 to bias right with my pieces, so I built version 2 and am happy with it.

[jhicken]

thanks corey, I'll try and post a little sound clip later today.... maybe I'll breadboard the v2 and see how it compares.
cheers,
james

[jhicken]

here is a brief sound sample (strat into ss vox pathfinder and recorded on an ipod)

https://soundcloud.com/james-hicken/jh-bazz-fuss-gain-range[url]

[jhicken]

clean signal -- bf with gain fully CCW -- bf with gain fully CW -- clean signal

[chptunes]

clean signal -- bf with gain fully CCW -- bf with gain fully CW -- clean signal

Wow!  It hardly sounds any cleaner with 5k on the Emitter.. Mine cleans up a lot with 500 Ohms.

Something seems very fishy here.. Are you sure that the 5k Pot is not accidentally bypassed some way?

[jhicken]

how do you have yours wired? I put the pot in after the fact and have lug 3 on emitter and lug 2+1 wired to ground on the board.

one other thing that is a little odd, as I adjust the gain pot signal cuts out momentarily and then once I stop adjusting then the updated gain setting comes back after a brief pause.. you can hear it in the recording above.... kinda weird.

btw, I'm using a 2n5089, a 22uf (I didn't have anything lower on hand) input cap and .1uf out cap, 1n914 diode, and 100k resistor.

[nocentelli]

I've done a Bazz Fuss with the gain pot exactly as you describe, and also found it didn't clean up that much with the gain reduced, though it does have an effect, very similar to what is audible in your demo. I used a 1k pot: I tried other higher values to see if it would go any cleaner, but  there seemed to be little difference between 1k/2k/5k/10k - Above 1k, it just doesn't seem to get much cleaner. Maybe this is what you are experiencing.

By adjusting the emitter resistor using a variable resistor, you will find the transistor takes a split second to "settle" at the new bias: If you want uninterupted gain adjustment, you can wire the emitter direct to ground (or via a small, e.g. 100r resistor), wire the gain pot lug 3 also to emitter, then connect lug 1+2 to the positive leg of a large (47/100uF?) electrolytic cap, with the negative leg to ground. It doesn't make it any more or less gainy, but it only adjusts the AC resistance to ground so doesn't mess with the bias.

[chptunes]

I've done a Bazz Fuss with the gain pot exactly as you describe, and also found it didn't clean up that much with the gain reduced, though it does have an effect, very similar to what is audible in your demo. I used a 1k pot: I tried other higher values to see if it would go any cleaner, but  there seemed to be little difference between 1k/2k/5k/10k - Above 1k, it just doesn't seem to get much cleaner. Maybe this is what you are experiencing.

Hmm.. maybe Version 1 doesn't clean-up as well, for some reason.  I guess there's plenty of other variables to consider too; guitar pickups (single/humbucker), picking dynamics, other in-line devices, etc...

Here is a link my Bazz Fuss thread in the Pictures area.. it list specific details and pictures of my unit:  http://www.diystompboxes.com/smfforum/index.php?topic=99557.0

Happy tinkering,

-Corey

[jhicken]

thanks guys, I'll probably just leave this one as is and breadboard the other versions to see which I like the most...