Differant Ge Tranny For a RM... should I change any thing?

[Phorhas]

Hey All...

I wanna build a Range master but the only Ge trannies I could find are AC127 and AC187... So, If I use them, should I change any other part(s) value?

If so, how do I know what to change and to what new value?


(P.S. is the AC187 suitable for fuzz face use?)

:?

[bwanasonic]

As long as you are getting around 6.6 to 7v at the collector, you're fine. I used a trim pot for R2 (input cap to grnd) , but you could use a trim for R4 (emitter to ground) instead or also, to dial in the right bias for different transistors.  Be sure to socket the transistor and the input cap.

Kerry M

[Phorhas]

Thanx a lot Kerry.

[Doug H]

As long as you are getting around 6.6 to 7v at the collector, you're fine. I used a trim pot for R2 (input cap to grnd) , but you could use a trim for R4 (emitter to ground) instead or also, to dial in the right bias for different transistors.  Be sure to socket the transistor and the input cap.

Kerry M

Also, be aware that there are other cool sounds you can get out of the RM that are not in the 6.6-7v collector voltage range. So you may want to make that trimmer a pot for external control of the bias. Whenever I get around to actually building a RM I will do this. Also breadboard it first, so you can sort this kind of stuff out before you are committed to the build.

Doug

[bwanasonic]

Also, be aware that there are other cool sounds you can get out of the RM that are not in the 6.6-7v collector voltage range.

I looked and I couldn't find them :wink:  I like my Fuzz Face biased outside the *normal* range (6.x v) , but I found I didn't care for the sounds of the RM with *misbiasing* . Lower voltages do yield some *different* sounds that I might describe as *softer* and *hairier*, and higher bias sounds more *transistor-y* and trebly.  But I agree with Doug's point - not to get too hung up on exact bias voltages and twiddle until you get something that sounds good to you.  

Kerry M

[Doug H]

I looked and I couldn't find them :wink:  I like my Fuzz Face biased outside the *normal* range (6.x v) , but I found I didn't care for the sounds of the RM with *misbiasing* . Lower voltages do yield some *different* sounds that I might describe as *softer* and *hairier*, and higher bias sounds more *transistor-y* and trebly.  

It probably depends on what kind of amp you are driving and how it is set up.

But I agree with Doug's point - not to get too hung up on exact bias voltages and twiddle until you get something that sounds good to you.  

Kerry M

That's the main point!

Doug