Fuzz Face

[Shamharoth]

Hello,
I'm planning to build a Fuzz Face according to the first schematic here : Fuzz Central -- Arbiter Fuzz Face

I have multiple questions that may sound dumb, but I'm totally new to DIY :

- There are multiple versions of the AC128 transistor on Banzai Music :
these : Fuzz Face high gain transistor set :: Transistors (matched / selected) :: Semiconductors :: Electronic Parts :: Banzai Music (there's also a selection of diverse version of the AC128 for different gain settings)
or these : AC128 :: Germanium Transistors :: Transistors :: Semiconductors :: Electronic Parts :: Banzai Music

Why such a price difference ? Which is better ?

- I also want to ditch the battery and operate it only on a 9V adapter, I just have to remove the battery connector and put a 9V connector instead, right ?

[tubelab.com]

This is the same circuit used in the two transistor version of the Vox Tone Bender. I made a lot of them in the late 60's and early 70's. The circuit is very sensitive to the transistor used.

I built a board with transistor sockets and just tried lots of parts. Most PNP transistors will work and create some sound. A few will not. Everything that I tried had a different sound. The unit that I kept for myself for all these years has transistors out of an old Sony radio, 2SB383 I think. If you have any PNP germanium transistors, try them. Anything out of a 60's vintage Japanese transistor radio should work. Most silicon transistors work but don't sound so good.

You can experiment with the resistor values in search of the right sound. I wouldn't go beyond 1/2 to 2X the values shown in the diagram.

The AC128 went extinct a long time ago. There are some "new reproduction" parts but they are likely another type that has been relabled AC128. I don't know anything about the parts you linked to since I have never tried them.

[Shamharoth]

Thank you for your answers ! I will try first with the cheap ones and I'll change if the sound doesn't satisfy me.

[Bone]

If you can get them the NKT275s are the best. There's a guy in Germany on ebay called minifux who normally stocks them. Be prepared to pay.

[Shamharoth]

Originally Posted by Bone

If you can get them the NKT275s are the best. There's a guy in Germany on ebay called minifux who normally stocks them. Be prepared to pay.

"minifux" has nothing to sell right now, but I found these : 4x ASX12D Germanium MATCHED Transistors / NKT275 J FUZZ | eBay

Would they be suited for the job ?

[poynton]

Originally Posted by tubelab.com

............. I made a lot of them in the late 60's and early 70's................


...........I built a board with transistor sockets and just tried lots of parts. ..................

..........Most silicon transistors work but don't sound so good..........

Me too...... (showing my age..)

A socket is a good idea. The sound you are after may not be found without some experimenting.
Silicon transistors will work but, as said, the sound willnot be right. Stick with germanium.

OC71/72 OC81/82, even OC44/45 ( Mullard types) as well as the AC127, AC128 mentioned.

http://www.ebay.co.uk/itm/7-x-oc-71-...item1c21691c1f

Old '60s transistor radios are also a possible source - thrift stores.

Andy.

.

[tmblack]

I never got around to finding good germanium transistors for the Fuzz Face.
But you might want to try a Big Muff circuit as well. Uses diodes for clipping and smoother results with Si transistors.

[Jarno]

You will need to make sure the transistors are properly biased, there's an elaborate article on geofex.com which describes the FF circuit. It's called "technology of the fuzz face".

[Shamharoth]

Thank you for all your answers !
I'll try the OC71 as well as the others.

@Jarno : that article is really great, thank you

[tmblack]

What enclosure will you use?
I think a diecast aluminum enclosure would work well for peddles, and provide some shielding.