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?
Problem with old Randalls is that the audio from both channels travels a long path to the actual pedal, where it gets switched to ground, end easily "jump" to each other.
The real solution would be to mod the amp, adding a DPDT (also called double inverter) relay at the amp itself, so 1 set of contacts chooses between channel outputs, and the other set grounds (kills) signal on the unused one, leaving nothing to bleed.
It involves surgery wiith a certain complexity.
That really sucks. The amp is pretty much unusable right now unless cranked really loud. Any wanna buy it? ::)
Try EBay, you'll sell it in no time. If a wanna-be Dimebag buys it, he'll *never* use it clean.
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.
I don't get you very well.
If you play clean and have a fuzzy mosquito in the background, it's annoying; but the opposite, a very weak clean signal mixed with the distortion isn't heard, ot at worst enhances the sound, that's part of the "secret" of the Tube Screamer, which always lets *some* clean pass through.
If you post the schematic, I can suggest you the mod I talked about.
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.
Hi,
In that case your clean is not being switched to ground.
The likely culprit is the Foot Sw is faulty,, or whatever part does the switching.
Phil.
I know this is an old post, but as long as you turn all of the controls for the clean channel to 0 this bleed shouldn't be a problem, at least it's not for the Randall's i've owned. It's a problem with the earlier RG heads too, and almost everyone that uses these amps just use these amps as if they were single channel amplifiers and just use the lead (red) channel, so you keep the clean channels (green) gain and master at 0, as well as the EQ section if it's a Century model because of the independent EQ's.
I notice that the clean channel on one of my RG 100 ES heads has a bit of bleed from the lead channel, so i hear a bit of distortion in the signal... at least i think the distortion is from the lead channel, but the thing is... if I bypass the pre-amp by plugging direct to the loops return jack i still get that bit of distortion??...weird. Anyways, I guess this bleed issue is why these amps were discontinued?? It too bad cause these Irvine era Randall's are some of the best, if not the best solid state amplifiers ever made for distorted tones. Throw a boost in front of the lead channel and they sound like some kinda tweaked modded Marshall, but much tighter in the lows. Freakin loud as hell when running at 4 ohms too. I can run mine against any 50 - 100 watt tube amp and cut through the mix no prob. It's got that tube like drive to it that works really well in a live situation.