20 w trainwreck based amp nearly completed

[unparalleled]

Just needs a bit more cosmetic detailing.
Produces 20W RMS @ 1Khz with NOS Russian EL84Ms.
Chassis solid heavy copper. Tonestack NOS mustard caps Mullard preamp valves.
Has more gonads than a Tiny Terror, great cleans I am told. (I am not a guitarist)
Will post sound clips as soon as I can get someone to do 'em.

[loudthud]

Looks like the first preamp tube is next to the rectifier, the input jack is just below the output transformer, the impedance selector switch is in the opposite corner from the OT... I would think a layout like this would cause lots of problems.

[unparalleled]

Originally Posted by loudthud

Looks like the first preamp tube is next to the rectifier, the input jack is just below the output transformer, the impedance selector switch is in the opposite corner from the OT... I would think a layout like this would cause lots of problems.

The layout produces no problems, no hum no unwanted oscillation, no HF parasitics, no instabilty, no undue noise. The heavy copper chassis may be a redeeming factor.
This was my first valve based amplifier build started about a year ago, The layout did not follow my original plan because I ran out of space for a tremolo bottle & components, Thus the extra blanked off pot position. Since then I have built several other guitar amps of different types.
I do understand audio layouts, I was designing SS amps for production in the late 1970s and before that I was employed servicing valve based and SS amps and equipment.

[xKennyx]

So far this head looks awesome. I hope it sounds as good as it looks. Also, since you're not a guitarist am I correct in assuming people commision you to build these?

[melvin]

I don't think I've ever seen a chassis made of copper alloy, looks cool. Will it petina after awhile?

By the way, I think Ken Fischer only made his chassis out of aluminum because it doesn't mess with magnetic field lines...

[unparalleled]

Originally Posted by xKennyx

So far this head looks awesome. I hope it sounds as good as it looks. Also, since you're not a guitarist am I correct in assuming people commision you to build these?

That is what I prefer, but I am building various amps that guitarists can try in my sound room so I am in no hurry to sell what I have.
It always helps to let a prospective buyers try different types to help them decide what they would like me to build.
I am active on:
NZGuitars.com • View active topics
As Anvil Amps Alan.
There are photos of my other builds in progress there.

[unparalleled]

Originally Posted by melvin

I don't think I've ever seen a chassis made of copper alloy, looks cool. Will it petina after awhile?

By the way, I think Ken Fischer only made his chassis out of aluminum because it doesn't mess with magnetic field lines...

It was polished to mirror finish and sprayed with 2 pack automotive clear.
It should not oxidize.
The product must have an acidic content because it turned the copper pink.
I made the chassis from a piece of sheet which was lying around because I thought it would look nice and would be easy to work with.

[revharry]

What would you compare the tone to?

[unparalleled]

Originally Posted by revharry

What would you compare the tone to?

I am not a musician so I don't speak tone.
I believe that every individuals perception of tone is completely different and I make it my job to build amps to sound like the the new owner wants.
Every guitarist who has tried it is impressed.
There are lots of clips on YouTube with "Trainwreck Express" type amps.
Similar circuit to Vox AC15.

[Steve Conner]

Someone commented on the layout earlier. I've built two amps that have the OPT next to the input jack, and it's no big deal.

What IS a big deal is the wires going from the power tube plates to the OPT, those have to be kept far from the input wiring, or separated from it by a shield. Same applies to the exposed bobbin of a drop-through OPT. I noticed that screened wire was used for the input jack, this probably helps.

As for the rectifier snuggled up against the first preamp tube, I'd have thought that would cause a bit of hum.

[loudthud]

The Trainwreck Express has an extra gain stage compared to the AC15. It is very difficult to stabilize and layouts that deviate from the original usually oscillate. It has three 12AX7s but only half of the third tube is used.