Transformers placement

[Sansteeth]

Hello everyone,
I'm working on building a Marshall JMP 50W copy (2204) on a 17“ x  6 ¾“ aluminum chassis. An I'm trying to figure out transformer placement relative to the preamp circuitry.
I've had great success using the headphone or oscilloscope method prior to drilling any holes to find the best spot for the OT and PT relative to one another.
But I'd like to take a different approach and have the transformers as far as possible to one another, for stability's sake when the head is being carried but also because the two ends of the chassis are the strongest spots on the chassis to support the weight of those transformers. However, according to Merlin

preamp circuitry should always be placed as far away from any transformers as possible, especially power transformers.

. Which is also the opinion of fellow forum users on this thread: https://el34world.com/Forum/index.php?topic=11386.msg105122#msg105122), on there HotBluePlates mentions the example of Hiwatt amps that have the OT on the left side but because those chassis are just so big, the distance between preamp circuitry and the OT itself makes it a non-problem.
However that is also the prefered layout for Vintage Orange OR's and Matamp. I have both amps and while it is true that modern Matamps unusually have big (read deep) chassis, my OR120 Master Volume really doesn't, it's really compact and the OT sits right above the input.
Merlin mentions that

The output transformer is not so much of a problem because it should have little to no hum current flowing in it. It does handle high primary voltages that generate strong electric fields, but it is much easier to shield against these. Nevertheless, it is usual to mount power and output transformers at the opposite end of the chassis from the input valve.

Designing Tube Preamps for Guitar and Bass, second edition, p.71
So my question is do you know how was Orange doing it? and what are the ways that Merlin mentions to shield against the high primary voltages (because those wires would indeed be traveling a lot in that chassis if both transformers are at opposite ends.

thanks a lot

[pdf64]

A 2204 has over 20dB more gain available than eg a 1959, and even the latter can be prone to instability. The last thing you need is OT wiring in close proximity to preamp circuits, especially input stages. Tracking down and quelling problematic coupling is a pain. 
I suggest to stick to a proven layout and mount the cab handle above the centre of gravity, rather than dimensionally centred on the cab top. 

[Dave]

I suggest to stick to a proven layout and mount the cab handle above the centre of gravity, rather than dimensionally centred on the cab top. 

I don't think I've ever actually seen this done in practice, but it sure sounds like good advice to me.

Dave

[66Strat]

Build an off-set head cabinet.

[Sansteeth]

A 2204 has over 20dB more gain available than eg a 1959, and even the latter can be prone to instability. The last thing you need is OT wiring in close proximity to preamp circuits, especially input stages. Tracking down and quelling problematic coupling is a pain. 

Thanks for your response, yes that's what I would imagine and I certainly don't want to track those coupling issues down, however Orange has been doing that over and over again (having the OT right above the input stage) with amps that have as much if not more gain than a 2204. My '76 Orange OR120M has more gain than my '81 JMP and has a big ol'OT right above the input stage.
Unfortunately both amps are in another country right now so I can't open them up and try to figure it out. Orange amps are hardly what you'd call oddballs so I would guess their layout is just as proven as the Marshall's and I want to know their secret!!

The carrying part of the problem is not a huge problem, it's easily solved two handles carved into the side of the amp, keeps the guitarplayer's hands busy with the whole thing rather than be tempted to haul their 50W head in one hand and their guitar in the other up to the venue, banging both against everything that comes in their way.   

Build an off-set head cabinet.

Controversial take: the lack of symmetry on those off-set Marshall heads give me cold sweat haha

[sluckey]

Sunn put the OT on the preamp end of the chassis. Not a problem the way they did it. However, the Sunns were not high gain amps either. Here's some pics that may give you some ideas...

     http://sluckeyamps.com/sunn/sunn.htm

[Sansteeth]

Sunn put the OT on the preamp end of the chassis. Not a problem the way they did it. However, the Sunns were not high gain amps either. Here's some pics that may give you some ideas...

     http://sluckeyamps.com/sunn/sunn.htm

Wow that's an interesting layout, but it's PTP in the preamp stage which seems to be keeping all these components pretty far from that OT. Made me think that I didn't look up the inside of a Sunn Model T, now that's a Sunn amp with lots of gain, and it's entirely PTP, so I guess you get more flexible with wire runs if you go down that road (which I am not remotely close to be able to take).
Food for thoughts though! thanks sluckey!

[sluckey]

Made me think that I didn't look up the inside of a Sunn Model T, now that's a Sunn amp with lots of gain

The Model T has a lot of POWER but it's not a high gain amp.

[Sansteeth]

Made me think that I didn't look up the inside of a Sunn Model T, now that's a Sunn amp with lots of gain

The Model T has a lot of POWER but it's not a high gain amp.

Oops you're right, my mind was mixing it up with the Sunn Model Reissue, which is basically a different amp, and probably PCB circuitry