Fuzzy questions

[Kipper4]

I've been fooling with cozy builders Axis Face and Axis fuzz (the germanium version sounds awesome)
While doing some research I came across the miss piggy v3.
What's the deal with the piggyback transistors?
I also came across Fred Briggs vintage which has a similar deal but I must have made a mistake in the breadboard because it isn't fuzzing yet.
What's the deal fellas and are there any other piggyback designs worth fooling with.
If the piggy back is just using the body diode then why not just use a diode?.


Link here

http://www.diystompboxes.com/smfforum/index.php?topic=54128.msg1019594#msg1019594

[samhay]

As far as piggybacking goes, did you see these threads?

http://www.diystompboxes.com/smfforum/index.php?topic=17513.0
http://www.diystompboxes.com/smfforum/index.php?topic=21801.0

It essentially lets you set the hfe of the transistor by adjusting the value of the emitter-emitter resistor (10k in the thread you linked).
I would replace this with a trimmer and measure the hfe with a DMM - you can then adjust to whichever magic number you want: 80, 120, ...

There are a few designs floating around that use this including a Rangemaster. There is quite a lot of old chatter about this on the other forum too.

Ultimately, it is a reasonable way to tweak the hfe of a transistor, which is nice when it is to be used without feedback (e.g grounded emitter or capacitor-bypassed emiiter resistor). The transistor will still clip like Si though, so there is no real magic to be had.

[Kipper4]

Cheers Sam I'll just drop it like a hot buscuit then and move on.

[Kipper4]

My Axis fuzz is ticking. it gets worse when i roll back the guitar volume.
its much more pronounced when everything is balls to the wall.
tried a 220R before the drive pot it helped a bit.
i have the usual 100uf, 100nf  smoothing caps between the power rails plus a 100r in series with V+.
its a very clean wallwart too.
i tried a temorary 4.7nf across the dc jack. not a sausage....
its all boxed up which is annoying.
any help is appreciated
edit
forgot to say it improves when the vol is less than maxed too.
maybe some series resistance there will help but i doubt it since the tick is still there. grrrrr

[Kipper4]

I think it is fair to say that the transistor both have a healthy hfe too

[Cozybuilder]

Rich- My Axis Face is quiet, a little 60-cycle shows up with my strat at max attack, but thats it. Roll off the attack and the 60 cycle disappears, no matter what setting on the thick control or guitar volume.

[Kipper4]

I know I referenced the power filter caps and such but its more of a tick like it's oscillating.
I hate to be a nuisance.

[Cozybuilder]

Can you post photos and the schematic you used? I hope we can help you get rid of that tick, what kind of frequency is it? (i.e. 5 hz, 30 hz, higher lower?)

[Kipper4]

Goddam it.
Turns out it was a pesky longer than usual groundwire end on the input jack making contact with the tip. As soon as i've sniped the little begger off. its dead quite.
hip hip hooray.
Thanks guys.

[Cozybuilder]

Sausages all around 

How does it sound though?

[Kipper4]

I'll let you know tommorow bud its way too late to test it properly tonight.
Unless I want to wake my good lady Bam Margera style.
Laters