Fuzz Face build. Picking Transistors?

[karpathion]

I'm thinking I need to figure out which Transistors I'm going to use first. Then I have to do some math and figure all the resistors and capacitors I'll need.
I know germanium is the first pick, but is there a current production germanium transistor that I can use in it's place?
If there are none, what would pick, besides the NKT275, AC128,and SFT363E?

[AniML]

Re: Fuzz Face build. Picking Transistors?

The Newmarkets are scarce and big scratch.

There are some new prod germaniums that I think are OC71 or OC75 repros, but I haven't heard much good about them. Likewise I've read mixed opiions on the ACxxx

As I mentioned in the other thread Smallbear has a pretty good variety. He also has some pre-spec'ed sets for around $20. Or try out some OC75, OC71, OC81, 2SB404, or some MIJs he has etc.

Shoot Steve an email. He'll give you some ideas

[karpathion]

Re: Fuzz Face build. Picking Transistors?

Shoot Steve an email. He'll give you some ideas

I think I'll do that.

[Schappy]

Re: Fuzz Face build. Picking Transistors?

three things that made the old fuzz faces so inconsistent. The gain of the transistors, the leakage of the transistors, and the temperature instability of germanium transistors.

You want hfe(gain) of around 70 on the first transistor and about 120 on the second.
You then need transistors with low leakage.

It might take you quite some time to find a matching pair.

Smallbear has prematched pairs and while they are expensive it will ensure you have a good sounding fuzz face.

As far as the temperature instability you can replace the biasing resistor with a trimpot.

Check you diystompboxes for more info.

[Schappy]

Re: Fuzz Face build. Picking Transistors?

forgot to mention that steve at smallbear figures out the resistor values for you and includes the resistors with your transistor purchase.

[Dr.K]

Re: Fuzz Face build. Picking Transistors?

I've forgotten most of what I once knew about the Germ FF, but aren't they reverse polarity and therefore incompatible with other pedals in a pedal chain? It sucks getting old I've forgot a lot.

[the guy who invented fire]

Re: Fuzz Face build. Picking Transistors?

three things that made the old fuzz faces so inconsistent. The gain of the transistors, the leakage of the transistors, and the temperature instability of germanium transistors.
You want hfe(gain) of around 70 on the first transistor and about 120 on the second.
You then need transistors with low leakage.
It might take you quite some time to find a matching pair.
Smallbear has prematched pairs and while they are expensive it will ensure you have a good sounding fuzz face.
As far as the temperature instability you can replace the biasing resistor with a trimpot.
Check you diystompboxes for more info.

The gain was pretty consistant from unit to unit...

The biggest thing with the vintage units was lack or tight matching and temp issues

[the guy who invented fire]

Re: Fuzz Face build. Picking Transistors?

I've forgotten most of what I once knew about the Germ FF, but aren't they reverse polarity and therefore incompatible with other pedals in a pedal chain? It sucks getting old I've forgot a lot.

Original Fuzz Faces ran on a battery so they couldn't be run on a supply anyway and if oyu want to run one on a supply a few small thinsg can be changed and then you can run them on a supply.

However none of this effects if it will work withpedals in the chain, this only has to do with the power issue and while we're on that topic you should always run them with a battery anyway...better tone, less noise...

[the guy who invented fire]

Re: Fuzz Face build. Picking Transistors?

To the original poster...real Newmarket NKT275's (which is what ALL vintage Germanium Fuzz Faces used...forget the AC128, etc...NO vintage unit EVER used those) are very hard to fine, even harder to get in any kind of matched pairs that are worth talking about and when you do get ready to shell out $50 on the low end.

Just save time and trouble and get some nice Ge 2NXXX's of some kind...

I currently have 5 Fuzz Faces, 3 with NKT's, 1 with MIJ 2SB's and one with Ge 2N404's...the 404's hold their own quite well IMO...as do the 2SB's but the 2N's are currently the easiest to find...

[Dr.K]

Re: Fuzz Face build. Picking Transistors?

Original Fuzz Faces ran on a battery so they couldn't be run on a supply anyway and if oyu want to run one on a supply a few small thinsg can be changed and then you can run them on a supply.

However none of this effects if it will work withpedals in the chain, this only has to do with the power issue and while we're on that topic you should always run them with a battery anyway...better tone, less noise...

Thanks for the reminder, now I remember. I was going to build one at one time but I just went with a Swollen Pickel instead.

[Schappy]

Re: Fuzz Face build. Picking Transistors?

If your going with your own transistors and not smallbear check the geofex site.

He shows how to check leakage and gain of transistors.

[karpathion]

Re: Fuzz Face build. Picking Transistors?

To the original poster...real Newmarket NKT275's (which is what ALL vintage Germanium Fuzz Faces used...forget the AC128, etc...NO vintage unit EVER used those) are very hard to fine, even harder to get in any kind of matched pairs that are worth talking about and when you do get ready to shell out $50 on the low end.

Just save time and trouble and get some nice Ge 2NXXX's of some kind...

I currently have 5 Fuzz Faces, 3 with NKT's, 1 with MIJ 2SB's and one with Ge 2N404's...the 404's hold their own quite well IMO...as do the 2SB's but the 2N's are currently the easiest to find...

That's what I was looking for. I like the price of these alot better.
I'm looking at something like the GE 2N109.