High Gain Fuzz vs HFe

[bmsiddall]

Greetings from Australia fuzz brethren.

I had recently been given a batch of recovered and NOS AY1113 NPN silicon transistors (measured hfe 27-200, https://sites.google.com/site/transistorhistory/australian-semiconductor-manufacturers ) from one of our service engineers.  That inspired me to finally get around to making an Ace Tone Fuzz Master FM-2.  I had previously made a superfuzz with medium gain transistors (200+) and after reading the odd comment here about lower gain transistors decided to throw some of these into the new build.  I ended up using transistors with hfe around 100 (give or take) and was really pleased with the pedal- plenty of nasty, and nice octave.  4ths and 5ths had a satisfying doomy grind to them.  It also had remarkable string definition (relatively speaking - it's an octave up pedal!), and even cleaned up quite well with guitar volume backed off. 

Tried it side-by-side with the superfuzz build, which made me think the SF was sounding too compressed, so I put some of these transistors in (hfe 95-50).  To my ears a definite improvement with less compression and more "air".  Still super nasty!

My next trick with these transistors was into a Bee Baa I had made last year with SC1000 (500+).  I'd always thought it was too fizzy and compressed and sure enough, loading it with transistors with gains 97 (Q1) 78 (Q2) and 27 (!) Q3  revealed a lot of missing character/texture.  It's still a completely unruly beast but will now get more airtime from me.

Lastly, a Foxx Tone Machine also built last year, but this time with 2N3565.  These were hfe 300-400 I believe.  I replaced them with some T0106 transistors (not sure which?) I received from small bear recently and loaded it with transistors reading hfe 106 (Q1) 97 (Q2) 130 (Q3) and 70 (Q4).  Same thing again as I preferred a much lower hfe over my initial build.  More grit, texture and clarity in non-octave mode.

Not saying this would work for every fuzz.  Indeed, after trialling 2n2222 in a Colorsound one knob I found much higher hfe (BC109C 600, 500 for Q1 Q2) worked best for me.

Cheers,
Brett

[Mark Hammer]

Sometimes, less IS more, eh?

The thing to remember about transistors, tubes, and chips is that "gain" is given by the components surrounding them. Hfe is really more the potential for gain, when set up in a given manner.  We stick transistors into circuits, expecting that the number on it will provide "the magic", irrespective of the biasing, etc.  The "wrong" transistor often can be made to do what the "right" one does, but if you're like me, one doesn't have enough electronics knowledge to be able to change those surrounding components in the appropriate manner.  If transistors were as precise and uniform as 1% resistors, then all that would be required is to get some of the indicated part number and stick them in.  Sadly, they are not quite that consistent.

But I applaud your experimentation, and letting us know of your findings.  Thanks from the "winter side" of the world, where we have about 40cm of snow recently, and temperatures averaging around -15 to -20C.

[bool]

Most of those circuits were designed back in the days ... of low hfe transistors.

[mac]

Another question,
3 similar stages of gain 10 each, or 2 stages of gain 31,62 each?

Thanks from the "winter side" of the world, where we have about 40cm of snow recently, and temperatures averaging around -15 to -20C.

I'm reading this post at the beach right now, 11:53 AM, 31ªC, blue sky, waves... what else? 

mac

[pinkjimiphoton]

yeah, i take a lot of flack for saying the same thing.

try a big muff pi with q's around 200, and its like a trip back in time to the originals.

i find some of the best sounding ge in particular are around 40-60 hfe. in the most current project, the fuzz ovation, it literally sound like poo if ya go above 100, with th sweet spot right around 40hFe

[duck_arse]

bmsiddall - a lot of people around here just like to look at piles of transistors. some people around here like to say "photos or it never happened".

I like to say show us some pics, transistors and your builds. I'd also like to say that I've never even seen one of those series australian mades. could probably dig up some magazine ads for retailers quoting prices for, but I was always more interested in the BC's prices. actually having those parts in a build, and saying 'oz trannies, mate' is one level of mojo, being able to point to the page with their history multiplies the bonus mojo thru the roof.
[/flag_wave]

[bmsiddall]

Haha, fair enough.  I'm travelling at the moment but managed to take a rough picture of the transistors.  Will try to upload the pedal innards when i get the chance.
Cheers,
Brett

[bmsiddall]

Here's the Superfuzz (Volume, variable mids pot, fuzz, footswitchable octave on/off)





Fuzz Master FM-2 with fixed fuzz (Volume,  variable mids pot).  By the way, after living with it for a while, I decided single note leads were a little thin for my taste, so changed the longtail pair to hfe 280 each (original transistors were at least hfe 250 i think).





Foxx Tone Machine (Volume, tone, fuzz, footswitchable octave on/off).





Roland Bee Baa (Volume, tone, fuzz, variable mids pot).  I added the small additional board when I was troubleshooting the fizziness.  Had initially left off the non-scooped network (10k, 33k, 47k, 4.7nF) as i was varying the notch filter and hoped adding it back might tame the fizz.  Nope, lower hfe was the key.

[duck_arse]

[/drool_drool] hmm. very nice. what are those green spot part numbers? glad to see someone else using those green perfs, too. and those boxes - are they sloped/wedged fronts? why haven't we seen those before?

[bmsiddall]

The npns are SE6022 i got from small bear in a mixed batch of TO106.  Plucked these out at random, measured the HFe and away we go. 
The enclosures are standard boxes I got from Mammoth- they are 1590BBT (FTM, FM2, SF) and 1590BBM (RBB). I get Mammoth to do the powder coating as I'm generally too lazy!  I think they look a little off in the pics from the iphone lens being in proximity