Ampeg Scrambler weirdness

BryanRensema · Status: Offline

Ampeg Scrambler weirdness

BILLYL · Status: Offline

Bryan-

To better help what schematic are you using.

A great tool to have in your troubleshooting box is a simple AUDIO PROBE. Basically a .1uf cap tied into your output and you can basically trace the signal and find where it stops. Check this link out for more details.

http://www.diystompboxes.com/pedals/debug.html

Most likely the problem lies with the pin outs of the trannys. If they are good - one thing I also do is make sure I have no cold solder joints - best thing is to simpley hit each joint with the soldering iron.

Hope this helped

BILL

BryanRensema · Status: Offline

Thanks, Bill, I'll try what you said. By the way, I used the schematic on www.tonepad.com (http://www.tonepad.com/project.asp?id=16). I used the same parts that Phillip used on his build too. I'll try hitting all my joints today (after shopping) and maybe it'll work! Thanks again.

-Bryan

http://www.brotherlush.com

fuzzcentral · Status: Offline

Did you try it with the 2N5089 installed as CBE? I've never seen a 5089 with that BCE pinout before.

Also, since the Scrambler has so many electrolytic capacitors, go back and double check that they're all oriented in the correct direction.

There's an error in the Tonepad schematic of the Scrambler (and the original Ampeg factory schematic that it was redrawn from). The 1uF capacitor on the emitter of Q1 should be turned the other way, with the positive lead facing toward the emitter instead of the negative lead. If it's installed the way shown on the Tonepad layout, you'll get a very loud "pop" when the pedal is switched on and off.

Phillip

BryanRensema · Status: Offline

I've tried everything except for the probe idea. Will probably try that next. No luck yet!

Phillip, I was doing a visual check of my work compared to the board on your site and it seems that the links to your scrambler pics are broken!

I just had a thought, though...I did re-install the 2N5089 in the CBE configuration and experienced NO CHANGE to the sound!!! IE: it turns-on and lets signal through but barely colors the sound...maybe adds a hint of treble...not much different from the bypassed effect. Maybe this is indicative of some specific problem. Anyway, I've checked everything four times and can't find anything. I must have tunnel vision so, pretend I'm ignorant (which I essentially am with these matters) and PLEASE HELP!!!! Thanks in advance...

-Bryan

http://www.brotherlush.com

BryanRensema · Status: Offline

Haven't gotten around to doing the probe. Been working 5 straight 12's--barely time to eat much less mess with dysfunctional guitar pedals. Anyway, Philip, I see that you fixed the links to your Scrambler pics. Thank you! I'm glad you did 'cause I do see a difference--not sure if it's a problem though.

The diodes that you have installed appear to be brown with multiple colored bands around them. The 1N456's that I got from Mouser look to be smaller and black with one silver band that indicates the cathode (I guess).

Not sure if this is a problem or just a case of different manufacturers having different looks.

Thanks in advance!

-Bryan

http://www.brotherlush.com

fuzzcentral · Status: Offline

Yep, the 1N456 diodes that are installed on the board in the pictures are NOS ones from Small Bear Electronics. Those colored bands read like a resistor, but one of the bands marks the cathode...I think

On modern diodes, the band marks the cathode of the diode. The ones in the pictures on the Scrambler page are installed like the ones shown on the TonePad circuit board layout.

I've also used 1N914 and 1N4148 diodes with no difference in the sound.

Phillip