Trainwreck Express Build

[Littlewyan]

Countersunk screws! Got it

[M Fowler]

I meant to post on this last night but TAG knocked me off when I tried.

Put transformer mounting bolts from the inside out for more board clearance.

Use counter sinking bit to mount board stand-offs, you can put them under the transformers that way without any problems.

Mark

[Littlewyan]

Ah yer didn't think of that Mark thanks. Amazing how much i've learnt by buildng this from scratch and I haven't even started building yet!

[Littlewyan]

Guys when it comes to the power supply wiring will it make any difference if I twist wires together? So for instance the two wires going from the mains socket to the power switch? Or even the Secondary Winding wires from the OT? Just wondering if this would help with oscillation and interference.

[Bob S]

I'm sure some of the guys will chime in.
They are usually a fair distance from the signal wires.
I normally do it anyway - keeps things neat.

[Littlewyan]

Neatness is one thing, however in my amp the Secondary Winding Wires will be going inbetween the two 6V6s in the Output Stage and so will be next to the Primary Winding Wires. I don't think this will be an issue as Marshall used to do this in their amps anyway and I thought to make sure it won't be a problem I could just twist the pairs of wires together.

[Bob S]

Yup - usually they cross at 90 degrees which also helps.
Problems usually start in the early stages of the pre-amp.
Then get multiplied by the following stages.
I've taken liberties in the power section & gotten away with it.
Good Luck.

[Littlewyan]

Thanks Bob

Just read a thread on this forum where Glen K said that guitars with unpotted pickups can't really be played with this amp. My pickups are completely uncovered will this really be an issue?

[geetarpicker]

You will have to try it and see. If the pickups don't have covers that can actually help as sometimes pickup covers themselves can be microphonic if not installed tightly and/or dampened with a little wax, silicone, felt, or ? It also will depend how you set the amp, how close you are to the cab, and if you are attenuating the amp. That said if you really crank the amp into controlled feedback territory it may be a tricky beast without having potted pickups but it just depends on the particular pickup. Hope that helps! GK

[Littlewyan]

Thanks Glen

I did read some of your posts about potting pickups and just thought geez that doesn't sound like something you'd want to practice on your fav pickup! I have some old pickups I could practice on but don't really have the space to do it (still living with parents).

Anyway I will be attenuating the amp and I never turn to face the amp on stage so shouldn't be much of an issue.

[Littlewyan]

Here are some photos of the build so far, as I still haven't got my faceplates I've only done the Heater wiring.

[Littlewyan]

With regards to my grounding i'm going to connect the ground mains to the bolt for the mains socket itself. This shouldn't be a problem should it?

Edit: Gave it it's own solder lug in the end, best way.

[M Fowler]

Yes the earth from IEC should have it's own ground lug.

I bet your amp is going to sound great and low noise based on larger chassis layout, can caps and component layout.

Enjoy.

[Littlewyan]

Well its a good thing that I haven't had my faceplates yet as its given me time to think about the layout a bit more. Imagine if I built the amp and then tried to drill a hole for a earth lug

[Littlewyan]

Right guys I think my faceplates should either be here tomorrow or early next week so nearly ready to carry on building. Now my OT Secondary and Primaries are going to be run side by side due to the design of the chassis, I suspect Marshall must run them this way as there doesn't appear to be any other way! Anyone done this before? I know Bob S said he's gotten away with this sort of thing before but reading through a lot of the threads it can be a bad thing twisting the any signal wires together, especially the OT Secondaries. I think Marshall tend to run them parallel in their builds, just wondering what people's opinions are on this.