Does the Express get its distortion from the preamp or the poweramp?
The sound clips I've heard are incredible, but I think I'd still need to turn it down. (I'd also want to add a fx loop, so a AirBrake wouldn't help me.)
Also... do they take pedals in the front well? So let's say I had to use a tube screamer... Would it sound good? I've got both a strat and a les paul. The amp would have to be friendly to at least one of them.
Hello Mark,
An Express is supposed to be clipping the powertubes first, followed by the PI and the 3rd gainstage. So, it isn't really for a FX-loop! Ken Fischer also meant the Express to be played directly from the guitar. It needs no boosters etc. for it has enough gain for sure. What you could do is have an attenuator with line out and feed the lineout signal through FX to another (clean) amp and cab. I've done that (just delay) and it sounded great!
Greetings,
Timo
Mark,
I've built an express and have used a tube screamer in front of it - it SCREAMS! If you'd like, I have a rather "rough" clip of a Dokken tune which features a Keeley modified Tube Screamer in the front. PM me and I'll send it to you.
My Express clone works terrific with an attenuator. The attenuator has a line out and you could run a wet/dry system with it or a microphone if you preferred. It is my experience that the distortion is primarily phase inverter and pre-amp tubes but that the power tubes have to run loud to get the full effect of the Express. The compression and saturation of the power tubes is an important component of the Express sound and you can't get that with a master volume or an effects loop. I run KT88/6550s in my Express and it still sounds like an Express only with more bottom end and slightly less mids.
I haven't that much of experience, but I have tried a TS-9 (with the 808 mod) in front of my ceriatone express (sorry, I bought a clone and yes I feel bad), and it will push it into extreme metal, although very noisy. A set of EMGs will clean up in the rhythm department and make it less noisy, but you will get some noise. I know, this is not what a Trainwreck was meant for, but it will deliver more than enough gain for everything else, so that's the only use I see for a booster
Thanks for all of the replies... I'm kind of looking for an amp that can do clean to dirty, but at any volume level, so it sounds like an express isn't exactly what I'm looking for.
It's just as ODwan stated. Ken designed these beasts to distort earliest on the power tubes, then PI, then the preamp clipping stage. Close to unstable, yet gnarly tone. I'm not sure why you'd want to run a pedal with a Wreck, but whatever trips your trigger.
I've been meaning to ask, but what do most people here mean by "close to unstable"?
When studying signals and systems instability is one of the common notions present, so I just want to know if the meaning you're applying to that term is the same I am...
sure I can grasp the concept, but I also can't help but wonder how close to unstability a trainwreck is, after all there are a lot more amps out there with gobs of gain on tap... I've even seen some with very efficient/simple handwired layouts!
yes, other amps have more gain stages but, look at their schematic and you will see that they have attenuation between stages (470k / 470k voltage divider for say a Marshall). The Express has no voltage divider. This is one of many differences between a normal 'high gain' design and the express.
Does a bogner shiva, for example, which has 4 gain stages plus a cathode follower stage, have any kind of attenuation or local negative feedback to control the gain? I suppose from what I've seen in the internet schematics, that's what the 500k resistors are for...
either way thanks for enlightening me!
One last question: While I'm at it, what does the 150k resistor do on a trainwreck? The one placed between the second gain stage (coming out of the tonestack) and the third gain stage (before the pi), that connects to ground:
second gain stage -- 100k to B+ -- 0.002uf cap -- 150k to ground -- third gain stage
Does a bogner shiva, for example, which has 4 gain stages plus a cathode follower stage, have any kind of attenuation or local negative feedback to control the gain? I suppose from what I've seen in the internet schematics, that's what the 500k resistors are for...
either way thanks for enlightening me!
One last question: While I'm at it, what does the 150k resistor do on a trainwreck? The one placed between the second gain stage (coming out of the tonestack) and the third gain stage (before the pi), that connects to ground:
second gain stage -- 100k to B+ -- 0.002uf cap -- 150k to ground -- third gain stage
What's it's purpose in the circuit.
thanks
Bogner Shiva: you are correct, the 500k resistors form the voltage dividers. With a 500k series resistor followed by a 500k resistor to ground you have a 50% attentuation of the signal. This is done to avoid grid rectification and blocking distortion.
Express. the 150k to ground acts as a grid load and a bass cut.
