Quote from: LOBO on October 12, 2010, 11:49:19 AM
Hey FSX, i do pcb layouts as well, can u share the schematics? I'll send my results.

What would you charge to do a layout of the Randall RG100ES Red channel?

http://www.diystompboxes.com/smfforum/index.php?topic=79923.0

Quote from: mensur on August 18, 2010, 01:05:50 PM
Here's new version of the preamp, with some new mods , MC34063 DC converter, to get 24V from 9V battery, plus it has voicing control, exact the same as Century C170II/2000,plus it has added gain stage to compensate volume drop caused by diode clippers.

Do you have a PCB layout or Eagle files for this?

That's the thing...the clean signal is loud in the distortion channel. It's not weak by any stretch and it sounds terrible. I'll get that schematic posted.

Quote from: J M Fahey on October 24, 2010, 08:39:21 AM
Try EBay, you'll sell it in no time. If a wanna-be Dimebag buys it, he'll *never* use it clean.

That was my plan, but the clean bleeds in the distortion...not the other way around.

That really sucks. The amp is pretty much unusable right now unless cranked really loud. Any wanna buy it?   

I finally got my Randall Century 170 passing signal. I took it in to the shop and they replaced one of the jacks in the FX loop and now it miraculously passes signal, but now I have another problem. The clean channel bleeds into the distortion channel and it sounds like complete garbage. I don't know if this was an issue before getting it repaired because I bought the amp broken. I hear this is a problem with older Randall amps, but how does one fix it?

Quote from: teemuk on September 30, 2010, 08:19:58 AM
Passing signal is one thing, passing signal without significant attenuation another...

Have you tested that you get flawless signal output from preamp using the effects loop?

If preamp works correctly that only leaves the power amp. Since it passes signal it most likely works ok, which leaves the master volume control: Is it worn, have the solder joints failed?

I'll check this evening. Thank you very much for the help!

Alright guys. I finally got the amp in my possession, and it actually does pass signal.  :tu:

The problem is that you need to have the volume on 10 to get a very low signal. The preamp appears to be functioning fine because the distortion works, EQ works, reverb works....just not loud.

Here is the schematic that Randall sent me:

http://dl.dropbox.com/u/8772719/C500%2C%20C1000%2C%20C170%20-%20Schematic.pdf

I'm not sure how to troubleshoot where in the power amp things aren't right.

I'd gladly pay for the layout. I'm not really good at doing them myself.

I bought a Randall Century 170 that powers up, but has no output. I've debugged stompboxes using an audio probe located at http://www.diystompboxes.com/wiki/index.php?title=Debugging, but before I do that I wanted to see if any of you have tips on debugging something plugged in to the wall.

I've built a bunch of gear (including a tube amp) that run on mains power, but never had to debug them...luckily only stompboxes.

Your help is appreciated.

I'm new to amp building, and have successfully finished the tube Firefly project that is floating around the internet. I'd like to build a high gain amp, and I'm really a fan of amps like the Randall RG100 and Century (that Pantera sound).

Are there any projects you recommend I look at? Maybe something not too crazy to start?