Derailment ?

[Max Blast]

Does anyone have any personal experience with the Derailment shem posted in the files section? Looks interesting to me as I am looking to build an EL84 sounding amp in as small a package as possible. (actually 2 amps in one cabinet).

Looking for comments regarding the tone of this schem (mp3 clips ?) not so concerned with volume (1watt to 5watt is fine)

thanks a bunch,
Max Blast

[LeftyStrat]

I haven't built it, but I have read comments that deviations from the wreck topology (Gain->ToneStack->Gain->Gain->PI->Power) don't sound the same. The power section distorting first, followed by the PI is supposed to be part of the mojo.

Of course I haven't built a wreck clone yet, so all I have is hearsay.

[DutchMarco]

I haven't built one either, but I don't even recognize half the tubes in there! The 12BZ7 is completely unknown to me, maybe you can find the spec sheet at tdsl.duncanamps.com, but I don't know how ubiquitous they are. I'm not sure if they're in current manufacture.

I know about the ECL86, it's a 12A?7 (I believe 12AX7) triode and lower-power EL84 pentode in one tube. Should be good for 4-5 watts of power, but I don't think this one is in current production either.

You could get by with NOS or pulled tubes if you get enough of them, but personally I'd shop around for tubes before I started this project.

Another option would be the AX84 P1. It's not on this forum but at www.ax84.com. Hate to pull people away from this forum but there are some advantages to the P1 design, mostly in that it uses very common tubes (12AX7 and EL84). The downside is that it doesn't sound very much like a mini-Vox/TW: it has one gain stage less which may not be to your liking and the tone stack is tuned differently (more Fender/Marshall).

The P1 is good for about 6W.

Hope this helps.

[Max Blast]

Thanks for the responses.

DutchMarco, I am familiar with the AX84 stuff. I have been stufying it for a few months now. I used some of their preamp schematics to modify one of my Fender amps.

What intrigued me about the Derailment schematic is the use of the Compactron style tube. I had not seen these before. The ECL86 is out of production but the ECL82 is currently produced and both are available on ebay. The ECL82 is roughly equivalent to a 12AT7 triode and EL84 pentode in one bottle. In a single ended amp this would do the work of 2 tubes (kinda .. driver and power) but only take up the space of one tube on the chassis. I was personally hoping to use the 12AT7 triode for a "Foldback Reverb" recovery stage. That way I could use just 2 preamp tubes (12AX7) and the ECL82 to produce a Hi-gain amp with reverb but only use 3 tubes total.

I was not necessarily looking for the sound/tone of a Wreck but only posted here because the Derailment schematic was here and I was hoping to hear from someone who had actually had sone experience with it.

thanks again,
Max Blast

[DutchMarco]

Max, you're welcome. If the ECL82 is easily enough attainable then by all means go ahead. (I forgot if it was the ECL82 or ECL86 on the schem)

Still leaves the 12BZ7, but if you're not using this preamp then I guess you're in much safer territory. Although you will have to do some calcs yourself on the preamp output signal into the ECL82.

Either way, good luck with your build.

[jones]

Max, you're welcome. If the ECL82 is easily enough attainable then by all means go ahead. (I forgot if it was the ECL82 or ECL86 on the schem)

Still leaves the 12BZ7, but if you're not using this preamp then I guess you're in much safer territory. Although you will have to do some calcs yourself on the preamp output signal into the ECL82.

Either way, good luck with your build.

The 12BZ7 is like a hotter 12AX7, it has the same pinout, actually each section is electrically similar to parallel 12AX7 sections. it requires 2 times the heater current and is readily available at AES for a little over 5 bucks. However any 12AX7 pinout type can be used. Using the 12BZ7 results in a slightly more raspy sound with a bit more distortion. Current design specifies 2 12AX7s, and typical octal tubes like 6V6, EL34 etc. for the standard version, the ECL86/12BZ7 was an experiment in doing a high-gain amp with only 2 tubes, in doing the 2 tube version, if you use the ECL82, I would definitely use the 12BZ7 as the ECL82 triode is more like a 12AT7 section, and the additional gain of the 12BZ7 could help.

[Richie]

"""12BZ7"""

Yes the data says what you described..bit useing these as a swap for a 12AX7.. the 12BZ7 is most likey to be more microphonic..and have alot more noticable hum.

[slajeune]

Hi Max,

I have actually built a derailment:

http://www.sopht.ca/index.php?s=41

The two sound clips at the bottom of the page are of the ECL86 version. I recently changed it into a 2x12ax7 + 1xel84 as they are easier to obtain.

This amp has a lot of gain. I modified the design slightly. I added a switch to bypass the third design. This makes for a killer rythm 'channel'. Simply crank the gain until you have think power tube distortion. Very sweet. The 'lead channel (i.e. trainwreck express)' is just what you expect a very good lead channel to be.

The clips were created very quickly before I had time to play a lot with the amp.

Cheers,
Stephane.

[teleamp]

Your Derailment looks great Stephane. I thinking of trying a single El 34 version.

MikeY

[slajeune]

Hi MikeY,

Your Derailment looks great Stephane. I thinking of trying a single El 34 version.

MikeY

Thanks for the kind words. It is a bit messy in terms of wires and all. Actually, currently, it's a bit more messy as I switched from buss wire to star grounding. But it sounds GREAT! Keep us posted on the EL34 version, would be interested in hearing how it works out.

Cheers,
Stephane.