SuperFuzz matching which transistors?

Started by Canucker, April 30, 2014, 11:08:41 AM

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Canucker

which would be the transistors to match on this layout? http://ustomp.com/?p=12 It would be for the sake of getting a good octave effect going correct? Thanks!

Mark Hammer

It's the two forming the mirrored pair - i.e., the ones staring at each other.  Although in this particular instance, if you use the trimpot connected to their emitters, there is perhaps less need for them to be all that well-matched.

Canucker

thanks for the info.... I was lucky enough to pull six 828 transistors out of an old stereo and its basically three rather well matched sets....I really excited to give these a go! THANKS!!!!!

digi2t

Like Mark pointed out, use a trimmer between the two, and you'll be able to really fine tune the octave. I highly recommend it.
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tjdracz

Plus, put the lowest gain in q6, really works better!

LucifersTrip

Quote from: Canucker on April 30, 2014, 11:33:20 AM
thanks for the info.... I was lucky enough to pull six 828 transistors out of an old stereo and its basically three rather well matched sets....I really excited to give these a go! THANKS!!!!!

I'm sure they'll work out great....but just curious about the gains. So far, most of the old ones I've pulled were lower hfe (80-100) than the modern ones (150+) I bought in recent years .
always think outside the box

tjdracz

Quote from: LucifersTrip on April 30, 2014, 03:28:06 PM
Quote from: Canucker on April 30, 2014, 11:33:20 AM
thanks for the info.... I was lucky enough to pull six 828 transistors out of an old stereo and its basically three rather well matched sets....I really excited to give these a go! THANKS!!!!!

I'm sure they'll work out great....but just curious about the gains. So far, most of the old ones I've pulled were lower hfe (80-100) than the modern ones (150+) I bought in recent years .

Did you get them both in the q gain range. I've only seen them in r range (2sc828r) which are higher gain bracket. Couldn't find any q variety that Superfuzz original had

armdnrdy

Looking at the data sheets:

828Q
HFE 130-260

One could sub a 2SC1815Y for the same pin out and very close HFE.
1815Y
HFE 120-240

You can still get quantities od 1815Y for a reasonable price:
http://www.ebay.com/sch/i.html?_odkw=2SC1815Y&_sop=10&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0&_nkw=2SC1815Y&_sacat=0
I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

Canucker

they are marked C828 and cus of the pin out I had to do some twisting...I only put two of them in there at the octave spot so far..... I tested it out at night so it was really just a "does it work" test rather then a "how does it sound"..... the pin out wasn't nice for this layout but I took care of that....I'm guessing they aren't the proper transistor because the HFE is rather high.... the lowest of the six being 237 and the highest being 312.

reguardless of what I end up doing with this (waiting on an order that includes some MUCH NEEDED sockets) I'll try out that lowest HFE in Q6.... that was gonna be my question today before I even logged in! Thanks guys!

tjdracz

Might be just higher gain bracket of 2sc828. Should sound good anyway. I used six 2n2222a's with hfe around 200 and the octave pair matched with the same gains and same voltages and sound killer!

armdnrdy

Quote from: Canucker on May 02, 2014, 10:18:50 AM
they are marked C828 and cus of the pin out I had to do some twisting

That's a bit odd.

C828 transistors should have the standard 2SC ECB pinout.

The layout that you posted is set up for a ECB pinout.  ???
I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

Canucker

Quote from: tjdracz on May 02, 2014, 12:27:16 PM
Might be just higher gain bracket of 2sc828. Should sound good anyway. I used six 2n2222a's with hfe around 200 and the octave pair matched with the same gains and same voltages and sound killer!

I was actually pulling out the 2N2222a's to do this...I wanted to tame the pedal...as in smooth it out some...I think it actually damaged two speakers of my 4x10 amp...one of the ones I pulled out had an hfe of about 130....maybe the are 2n2222's without the a....I'm not sure as its at home and not here with me.

Canucker

Quote from: armdnrdy on May 02, 2014, 01:12:10 PM
Quote from: Canucker on May 02, 2014, 10:18:50 AM
they are marked C828 and cus of the pin out I had to do some twisting

That's a bit odd.

C828 transistors should have the standard 2SC ECB pinout.

The layout that you posted is set up for a ECB pinout.  ???

I tested em and of course still put them in wrong on my first try....retested them and adjusted....and tested the 2n222's that I pulled out to make sure I had things correct.... my source for getting these transistors was  an old stereo head that I had heading for the trash so its really a matter of nobody made me any promises.... more the treasure hunt route of doing things! My order of parts should arrive some time next week and then I can put in sockets and really speed up my testing of things.

zombiwoof

Quote from: tjdracz on May 02, 2014, 12:27:16 PM
Might be just higher gain bracket of 2sc828. Should sound good anyway. I used six 2n2222a's with hfe around 200 and the octave pair matched with the same gains and same voltages and sound killer!

They are probably just unsorted 828's, so no suffix for gain range.  This would mean that they could measure anywhere within the min and max gain ranges for that transistor.  Transistors were often sold in either sorted for gain range or unsorted.  Having them marked for gain range just makes it easier to find ones in the range that you need.  If they have no suffix, and you need a tranny that measures within a specific range, you will have to measure them and find the ones that will work for you.

Al