Q on octavias...

[rx5]

hello guys,

does the roger mayer octavia sound similar to the tychobrahe octavia??

can someone elaborate how they sound like??


thanks... :wink:


-Ralph

[petemoore]

The build is different than the Tycho [no transformer], I never built one of those but I imagine they sound different/
 I run the Tycho into a Fuzz to good efkt, great on the high notes.
 Some octaves are known to work over a wider area of the neck than tha Tycho...but I like it..say pretty easy build
 The Fox Tone Machine gets harder octave, more range, less ring moddy stuff too severe for me after a bit.
 From what I've read on the RM, I would like to build one/

[analog kid]

http://bryant02.home.att.net/schematics/mayeroctaviaschem.gif
this link right here should work right now. Check it out for me please and see what you think.
I'd never have dreamed that small value would affect anything that much. Thing is from my view the Q2voltages that those res. are on don't look screwy , Q1 does. BUT Q2's Base does connect to Q1  collector. Well we'll see I guess?
I still haven't been told , is that a misprint.? Does it really use a PNP for Q1 even though it's a neg. ground crkt?

[brett]

Hi.
The RM octavia sounds has richer/more desirable harmonics than a tyco IMO.  RM made a good circuit there.  

And yes, there's a PNP driving an NPN.  PNPs have lots of applications in neg earth circuits, including active loads, supply regulators, etc.  The PNP here is in the same setup as in the RM axis fuzz (which is a much under-valued circuit).  What a great idea to tap the feedback, and control gain  with that 22uF cap and 10k reverse-taper pot to ground.  By the way, that pot can just as easily be linear.  Original was almost certainly a 2k2 reverse log. With a 10k you won't get much effect until the two or three o'clock position.

cheers