Noob wants to build his first Wreck. Request guidance.

[Matthews Guitars]

Greetings to the readers of this subforum.

Let me start out by introducing myself. I go under Matthews Guitars, and my first name is Chris.
I am an experienced electronics technician (with experience spanning 35+ years) with familiarity with most kinds of electronics. You name it, I've probably worked on it or at least something that is in the same category. Audio, video, RF, digital, mixed signal, test equipment repair and calibration, a bit of everything and a lot more of some of it.

I'm no stranger to working in tube guitar amps, either. I'm not the MOST experienced tube amp technician you're going to find but I'm competent.

I am an actively working amplifier technician. My specialty is in finding problems other technicians may miss. Troubleshooting is really where my passion is. I love to find the problem and defeat it. That's what gives me satisfaction at the workbench more than anything else.

In the past few months I've rebuilt three Fender amps, a '63 Tremolux, a '67 Vibrolux, and a mighty 400 PS. The 400 PS was incomplete with major parts of the circuits missing, the other two were almost gutted chassis with very little still in them. I've rebuilt and restored a few JMP era Marshalls. Some of those rebuilds were on the level of making a whole new amp from previously used parts.

But I've never built an all new amp. And certainly not a Trainwreck clone.

For tonal reasons and also for the relative simplicity of the circuit, I've decided that this is what I'll build. An Express, more or less.

Not trying for cosmetic accuracy. Not trying even to duplicate the exact original component types tha Ken Fischer would have used, which apparently could get expensive anyway.

I'm just looking to build an amp that is a good clone from a purely functional and tonal perspective.

As I gather, there was something of a mania for building TW clones, but that was a few years ago, so I kind of missed the boat.

This may make it harder for me to source unique items for the build. Transformers, correctly pre-punched chassis, etc.
If you know of sources for those items, sources that are currently stocking them, please let me know about them.

I understand that TWs tend to be picky about wire dress and routing and can be unstable or erratic if this isn't addressed during the build.
If you have any specific pointers concerning that issue, I'd love to hear them.

I'm thinking of making it using 6V6 output tubes. Good idea or bad?

In general I'll listen to any advice you care to give me and explore any resources you suggest.

I have spent some time in the Trainwreck files section and downloaded a lot of it. I'm probably going to make the Express board set as soon as tomorrow, using .062 G10 circuit board.
I have not decided if I'll do it with bifurcated 2 level turrets or do it Fender style with brass eyelets. I've got lots of both.

[martin manning]

This may make it harder for me to source unique items for the build. Transformers, correctly pre-punched chassis, etc.
If you know of sources for those items, sources that are currently stocking them, please let me know about them.

I understand that TWs tend to be picky about wire dress and routing and can be unstable or erratic if this isn't addressed during the build.
If you have any specific pointers concerning that issue, I'd love to hear them.

I'm thinking of making it using 6V6 output tubes. Good idea or bad?

The Express was advertised as being able to run either EL34 or 6V6 output tubes, so that option is "built-in."

There was some recent discussion about sourcing 'wreck transformers, but if you look they are available. Here's one source, but the Heyboer-made OT is out of stock: https://shop.amppartsdirect.com/collect ... trainwreck Mojo has it, though: https://www.mojotone.com/Mojotone-TW35- ... ransformer

The Express is a very simple circuit. As much as people have obsessed about the details, I don't think they are as critical as all that. Some builds with unconventional layouts have been done and were quite successful. Here's the one I did a decade ago: https://ampgarage.com/forum/viewtopic.php?f=1&t=17915

For the chassis, if you get a blank one you can drill it yourself with a step bit (get a good one, though). Even a bench top drill press would probably work. The originals had pretty flimsy Bud aluminum chassis, and a home-made look with Demo labels and all, so a fancy pre-made chassis would actually be off the mark.

[Matthews Guitars]

Thanks for that information.

I have ready access to a fully equipped sheet metal shop and an established customer relationship with them, as I've been making highly authentic replica front and back panels for JMP era Marshalls for some time now. So with a good chassis layout in hand I can have any chassis I want made for a reasonable cost or even have a production run made of them.

I'm not really looking to replicate the look of a homebrew amplifier. Not when it's totally within my capabilities to make it look like the product of a mature factory production process.

I don't even intend to replicate the general cosmetics. The circuit may be Trainwreck, but the presentation will probably be more Marshall-esque as that's home territory for me.

[gktamps]

Having built a bunch of Rocket-style and a couple of Express-style amps, I've come to the conclusion that within the amp (excluding speakers), transformers have the biggest influence on the character on the amp. I've experimented with a wide array of capacitors (power, coupling, tone), added middle control to one, 5881 tubes in a Rocket, fixed bias, and lots of switchable coupling cap mods, in addition to other things like a full board with distributed filter caps similar to Martin's build. If the transformer deviates too much from what is considered correct, the sound and response has been compromised from original. Not necessarily a bad thing, but not really faithful anymore.

Probably not surprisingly, I have also found that what one takes out of the circuit can have as much effect as what one puts into it. If you move the PT and OT apart, the result will still sound similar, but there will be a difference to my ear. My own tastes are for a Rocket that approaches the tonal character of the Liverpool but with less aggression and more versatility, probably because I don't use pedals that often.

[ViperDoc]

If you move the PT and OT apart, the result will still sound similar, but there will be a difference to my ear.

I've wondered why the PT and OT are so closely positioned in Wreck builds. Can you describe the difference you hear?

[RockinRocket]

If you move the PT and OT apart, the result will still sound similar, but there will be a difference to my ear.

I've wondered why the PT and OT are so closely positioned in Wreck builds. Can you describe the difference you hear?

Probably because the chassis was what was available to Ken and it is somewhat limiting. The power and output use a dowl placed between them to help support them from caving in through the super thin aluminum chassis. Also, it appears they are positioned and bolted in a certain way that 3 of the 4 bolts are still accessible from the power supply board.

[gktamps]

ViperDoc: I've built one Rocket with PT and OT separated and found it was a little easier to eliminate hum that can be a little trickier to eliminate with the PT and OT together. Regarding tone and other changes to sound, I can't really say I noticed much if any at all. My later builds were with RJ's undrilled chassis so I could use the headphone method of making subtle changes to actual placement of the transformers.

By the way, RockinRocket, the chassis on which I built the separated transformer amp was narrower than the standard rocket, and 1/2" shorter, so not optimal but quite possible to separate the transformers. There must have been particular reasons why Ken did what he did that could have been related to the chassis dimensions, because of tube socket placement I'm guessing.

[wpaulvogel]

All my express builds (6) have used the original layout for everything and the transformer location has always created magnetic coupling hum. Power on standby on (no plate voltage) the amps hum quietly. I prefer the original layout because I acquired a build that used a different layout and it suffered from stability issues and required lots of band aid stuff to stabilize. I personally like the look when they are original.

[ViperDoc]

Thanks for the info, guys.

Paul, those head cabs look super. I love the flatsawn ash/oak faceplate version.

[wpaulvogel]

Thanks for the info, guys.

Paul, those head cabs look super. I love the flatsawn ash/oak faceplate version.

The oak amp was the diamond in the rough also. It was the best sounding amp of those three.

[gktamps]

I personally like the look when they are original.

Yes, I do too, though I consider my amps tribute amps and not clones. My preference is for original design cabinets (with a few beautiful exceptions) as well as transformer layout, despite the on-off experimental build which was my development amp. Here are a few...

DSCN0933a.jpg

[wpaulvogel]

I personally like the look when they are original.

Yes, I do too, though I consider my amps tribute amps and not clones. My preference is for original design cabinets (with a few beautiful exceptions) as well as transformer layout, despite the on-off experimental build which was my development amp. Here are a few...


DSCN0933a.jpg

Very nice!

[Matthews Guitars]

You're talking about some of the very things I have questions about. Like things to avoid in the layout, so as to make the amp stable under all conditions.

I do know to orient all transformer and chokes in different planes to reduce crosstalk to a minimum. I always cringe inside when I see an amp where the PT and the OT are oriented in the same plane. That can't be good!

I made a set of the PC boards for the Express already, and have every capacitor and resistor I'll need for the preamp board. Tomorrow I'll put the turrets in the board.

What's the recommendation for the power transformer? I'll get the OT from Mojotone. It's in my shopping cart waiting for me to check out.

I'm looking for a source for chassis if anyone is currently making them...preferrably in the USA to keep shipping costs reasonable.

[martin manning]

I put a link above to Amp Parts Direct; they have the Heyboer PT.

[ViperDoc]

That curly blonde head cab! WOW!