Ampeg Scrambler (DragonFly) Debug

[bryantabuteau]

Hi,  I just put together a scrambler using the dragonfly vero layout and the schematic found  at
http://www.generalguitargadgets.com/diagrams/scrambler_sc.gif

I used 2N5306 for Q1,3,4
I used 2N3904 for Q2
I used 1N4148 for the diodes.

After a quick debug, I fixed a missing jumper, and bent all my 2N5306 pins (was BCE) to a CBE configuration (the 2N5306 has two different pinouts.  One produced sound the other didn't)

So now.... I have a nice distortion/fuzz.  I hear no octave, and nothing like the sound clip at the tone frenzy site.
The Blend pot works sweet, i get a clean signal blended into my distortion.  The Texture pot at one end gives a solid distortion, and at the other end.....I get almost a compressor/ducker/sag out of it.  When I hit the strings hard the volume drops hard and then slowly comes back up distorted.  kinda cool, but I'm still not getting an octave out of it, and I don't think its supposed to do that.

+v = 8.6

Q1
C 8.6
B 2.85
E 3.2

Q2
C 3.23
B 0.9
E 0.24

Q3
C 8.56][url][/url]
B 3.9
E 3.2

Q4
C 8.42
B 3.9
E 3.2

If anyone can help, it would be greatly appreciated.

[Toney]

Q1s base voltage too low...needs to be a diode drop higher than the emmiter.

Also according to the ballpark voltages posted at GGG   http://generalguitargadgets.com/index.php?option=com_wrapper&wrap=scrambler_inst , scroll down, Q4 should be seeing ~ 8.2 at the emmitter and 3.7 at the collector.

[bryantabuteau]

thanks for that, i'll go check it out.  Last time I looked at the 'build instructions' for a project it was some generic document, so I never bothered looking again.  Handy to have voltages to check against.

[bryantabuteau]

I have to say, I think the voltages posted on that build instructions page are a bit screwy,  I think they have the Q4 voltages round the wrong way.  According to the schematic, both Q3 and Q4's Emitter are connected to the same 4k7 resistor to ground with no other connections, but the instructions page say they have an emitter voltage of 3.7 and 8.2 respectively.  I would assume they should be at the same voltage on the emitters.

[bryantabuteau]

adjusted the resistors on the base of Q1 to make it higher than the emitter, and no noticable change in output quality.  maybe a bit louder if anything.   anyone have any other thoughts?