Derailment Build

[Riffmonster]

Hey guys,

my first post here. So first a big thanks for all the info available here, really great work!
I just build the Derailment with two 12AX7 and one EL84. I added a MV and the power supply is a kit.
The amp sounds awesome! I could only play it on bedroom level until now, but it has a nice warm distortion and really a kind of Trainwreck flavor.
My voltages are (if anyone is interested):

EL84

Pin 7: 245V
Pin 9: 202V
Pin 3: 5.7 V

V1 12AX7

Pin 6: 125V
Pin 1: 150V
Pin 3: 1.5 V
Pin 8: 1.2V

V2 12AX7

Pin 6: 184V
Pin 8: 2V

I attach a quick phone recording on bedroom level. Just for an impression.
Thanks and cheers!

[Mark]

I wonder if this circuit would be the same as the Dirty Little Monster.

[Riffmonster]

Hi Mark,

I have not seen a (verified) schematic of the DLM yet, so I am wondering about that too. As far as I am concerned the DLM uses a El34 though and valve rectification.

Cheers

[M Fowler]

FS The Trainwreck "Dirty Little Monster" proto-type built by the late Ken Fischer. Single ended EL34 driven power section which puts out 12 watts. Built on the standard Trainwreck chassis, the tubes also consist of a Mullard GZ34 rectifier and a pair of ECC83/12AX7s. Comes with the Trainwreck manual (standard issue) with a personal note to myself. A copy of the original schematic for the DLM. And a signed letter of authenticity, with a little Kenny type joke at the end Also included will be an assortment of vintage EL34s (Mullard xf2, Mullard metal base, GE 6CA7, Seimans, and Amperex D getters ) and vintage 12AX7/ECC83 (Amperex Bugle Boy, Mullard, euro Philips, Mazda, Yugo, and various Amperican variants . The original knobs will be included, which were Sovtek amp knobs, I think the brown F type knobs look cool with this amp because of the bare faceplate. Only repair was the power switch failed, Ken gave me the part number and told me to take it to a reputable tech and have him replace it....believe me when I say that I begged him to change it for me, but he said it would be ridiculous to send an the DLM 6 thousand miles from Hawaii to New Jersey and back just to repair a power switch. Tone? Ken described the DLM as being the best Plexi type Marshall tone but with the signature Trainwreck clarity and definition. Great clean to mean tones from you guitar volume. Everything except metal type tones.

[Riffmonster]

FS The Trainwreck "Dirty Little Monster" proto-type built by the late Ken Fischer. Single ended EL34 driven power section which puts out 12 watts. Built on the standard Trainwreck chassis, the tubes also consist of a Mullard GZ34 rectifier and a pair of ECC83/12AX7s. Comes with the Trainwreck manual (standard issue) with a personal note to myself. A copy of the original schematic for the DLM. And a signed letter of authenticity, with a little Kenny type joke at the end Also included will be an assortment of vintage EL34s (Mullard xf2, Mullard metal base, GE 6CA7, Seimans, and Amperex D getters ) and vintage 12AX7/ECC83 (Amperex Bugle Boy, Mullard, euro Philips, Mazda, Yugo, and various Amperican variants . The original knobs will be included, which were Sovtek amp knobs, I think the brown F type knobs look cool with this amp because of the bare faceplate. Only repair was the power switch failed, Ken gave me the part number and told me to take it to a reputable tech and have him replace it....believe me when I say that I begged him to change it for me, but he said it would be ridiculous to send an the DLM 6 thousand miles from Hawaii to New Jersey and back just to repair a power switch. Tone? Ken described the DLM as being the best Plexi type Marshall tone but with the signature Trainwreck clarity and definition. Great clean to mean tones from you guitar volume. Everything except metal type tones.

Nice description. That kinda wants me to try the Derailment with a EL34.

[M Fowler]

More info: see the jpg below and open the pdf great info from the owner.

DLM.jpg

WRECK BOY DLM.pdf

[Mark]

That is a good picture of the Dirty Little Monster, however the article only wets one's appetite and provides no technical information.

I wonder if the Derailment is close to the mark, as there isn't a lot of difference in the basic circuits of his various amps. The exception being the Songwriter.

[Riffmonster]

It is hard to say how close the two amps are. Seems like the DLM works with NFB as well and the Derailment does not. Still the Derailment has the described Marshall character with clarity.
Here is another sound clip with the volume turned up. Still just a phone recording, but I think shows the dynamics and character of the amp quite well.

[Colossal]

Sounds great! What transformers, speaker, and guitar are you using? Did you add NFB?

[Mark]

The slope and presence controls are the tricky ones, the presence control implies a negative feedback loop provided Ken Fischer is using the circuit associated with a presence control. Slope could be a pot in line with the feedback loop.

[Riffmonster]

Sounds great! What transformers, speaker, and guitar are you using? Did you add NFB?

Thanks! It is a Hammond 125BSE output transformer and a 200v toroidal PT. Coupling caps are Roedersteins, which I like best.
I played this through 90s Celestion G12T-75 in a mid 70s Marshall cab with a mid 70s Framus S370 (SG copy with P90). It does not have negative feedback, do you guys think it would be worth trying?

[Colossal]

Sounds great! What transformers, speaker, and guitar are you using? Did you add NFB?

Thanks! It is a Hammond 125BSE output transformer and a 200v toroidal PT. Coupling caps are Roedersteins, which I like best.
I played this through 90s Celestion G12T-75 in a mid 70s Marshall cab with a mid 70s Framus S370 (SG copy with P90). It does not have negative feedback, do you guys think it would be worth trying?

Well, I think regarding adding NFB, the answer is 'it depends'. The original had it (100k on the 8R tap). But I think it would depend on the stability of your amp, how well behaved your speaker and cab are, and the sound you are going for. For me, I might be tempted to try it to see if a little NFB would add additional smoothness, take some of the "face" off the open loop sound, and add a little more apparent depth. That said, an Express in any shape or form has never been about civility!

[Riffmonster]

I understand your point! Maybe I can implement it with a switch, just a simple on-off switch. That should not be so much work and if I don’t like it I just leave the switch off. Would you stick with the 100k?

I really like the sound as it is, even though you have to play it loud. A friend of mine preferred it over a JTM45 build which is very complimenting. I missed a bit depth indeed but I played it in comparison to a 100 Watt Super Lead, which is obviously not a fair comparison.
Thanks

[Mark]

Wouldn't you use the negative feedback loop to minimise distortion and tighten bass response.

[Riffmonster]

Wouldn't you use the negative feedback loop to minimise distortion and tighten bass response.

Yes you might be right. Although I never really understood what a tighter bass response really means when you play.