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DIY Stompboxes => Building your own stompbox => Topic started by: bluefireamps on December 05, 2009, 09:24:25 PM

Title: Buzzaround Transistors?
Post by: bluefireamps on December 05, 2009, 09:24:25 PM
Since the NKT213's are hard to come by, what would be a good substitute? I have some OC84's. Would those sound OK in that circuit? What gain numbers should I be looking for? Thanks!
Dave
Title: Re: Buzzaround Transistors?
Post by: smallbearelec on December 06, 2009, 05:22:35 AM
In a previous post on this subject, a European seller was offering a tested set with gains of 56/100/115. That is a good typical lineup for a Tone Bender Professional Mk II. So I would say that Q2 and Q3 should falll somewhere in the Fuzz Face gain buckets, and Q1 lower. I don't have a test fixture set up specifically for the Buzzaround, but any of my sets for the TB Pro Mk II should work. Build with sockets, and you have my warranty that they can be returned or exchanged.

SD
Title: Re: Buzzaround Transistors?
Post by: Electric Warrior on December 06, 2009, 09:08:32 AM
the circuit is closely related to the 3-knob tone bender. maybe your 3-knob set would work better?
Title: Re: Buzzaround Transistors?
Post by: DougH on December 06, 2009, 09:34:12 AM
I just breadboarded it the other night with 3 ac128's hfe ~100. Sounds great.
Title: Re: Buzzaround Transistors?
Post by: bluefireamps on December 06, 2009, 11:02:21 AM
Thanks guys, that helps. Small Bear, I've purchased from you several times before and have been very happy. I'd like to use the OC84's I have if possible. I'll have to sort through them and see what gains I have. I apprecate the help.
Dave
Title: Re: Buzzaround Transistors?
Post by: Nitefly182 on December 06, 2009, 08:51:57 PM
The circuit is extremely forgiving of different measurements. Steve's 3 knob tonebender set is ideal IMO.
Title: Re: Buzzaround Transistors?
Post by: DougH on December 07, 2009, 08:16:14 AM
As a general rule- try not to get too hung up on part #'s for Ge transistors.

#1- If they are available, chances are they are bottom-of-the-barrel pieces that have already been picked over. Better to have an "off part number" that is stable than "the real thing" that won't bias if you look at it cross-eyed.

#2- Most, not all, but most of these fuzz circuits are pretty forgiving. A good stable xsistor with a reasonable hfe will usually do very well, and there won't be a dramatic difference in sound between that and the "real thing" esp in a multi-stage circuit like this.
Title: Re: Buzzaround Transistors?
Post by: bluefireamps on December 07, 2009, 09:50:51 AM
Cool! Thanks, Doug. That helps. I'll use the OC84's when I get to building this thing. I appreciate the input.
Dave