Stand-up or Laydown Power Transformer Mounting

[NickC]

Is there any advantage/preference to mounting a PT in stand-up or Laydown position? I'm starting a JTM45 build and have the option to go either way. I've got a stand-up Mercury Magnetics JTM Radio-Spares version PT, but can change it to laydown. Is one orientation better than the other as far as EMF goes?

Thanks for any advice

[Alexo]

Nope. As long as the two transformers don't interfere, it doesn't matter which is standing or laying down - with a stand-up xfromer, you don't have to cut that friggin giant square hole, which is a relief. OTOH, lay-down transformers put the center of balance lower, which is a good thing in a head.

[Alexo]

PS, howdy neighbor!

[husky]

Is there any advantage/preference to mounting a PT in stand-up or Laydown position? I'm starting a JTM45 build and have the option to go either way. I've got a stand-up Mercury Magnetics JTM Radio-Spares version PT, but can change it to laydown. Is one orientation better than the other as far as EMF goes?

Thanks for any advice

I have experienced laydowns with high gain being a little noisier. I think making sure there is an internal end bell would help or cure that.

[Cliff Schecht]

I prefer stand up because I tend to build in cramped quarters and they give me a bit more room in the chassis.

John I'm not sure if the end-bell makes a difference for a laydown transformer. I would think the higher noise has to do with more stray flux physically being closer to the circuit components.

[rsi]

I always preferred lay down PTs until I built a 2204 with mods on a JTM45 chassis with a laydown PT. If I could do it over, I would use a stand up PT for the extra chassis space. That build is really cramped.

[Phil_S]

I cast my lot with Cliff and rsi. The stand up transformers don't require much real estate inside the chassis. It add (subtracts?) a good 3" square and makes life a bit easier when building. I am unclear as to why you'd want anything else unless you need to fit your product into a low profile cabinet. Maybe for a really big PT, putting the laydown halfway through the chassis improves balance, but you can address that by simple adding a counter weight to the cab.

[LOUDthud]

In some vintage amps I've seen the standup transformer bend the mounting tabs and occasionally rip lose. Mostly in cases where the amp was shipped wrong side up by gorillas. Never seen it happen to a Marshall however.

[M Fowler]

Splawn amps is going to start using laydown transformers due to shipping problems with bent Heyboer transformer mounting.

Also, they are going to start using MC iron.

I prefer the standup myself freeing up all that space

Mark

[NickC]

Thanks Everyone!

I'm going to go with stand-up orientation. I can use the extra real estate inside to mount can caps.

I also found this interesting:

http://www.mercurymagnetics.com/pages/c ... /index.htm

I bought the MM PT before this new mount-reinforcement offering, but may be able fabricate something along the same lines.

[Phil_S]

Hey Nick, if you are going to use multisection can caps, the biggest advantage you get is by mounting them on the outside with the transformers, as that reduces the footprint considerably.

[NickC]

Hey Nick, if you are going to use multisection can caps, the biggest advantage you get is by mounting them on the outside with the transformers, as that reduces the footprint considerably.

Greetings Phil,

I bought an aluminum chassis prepunched and milled for three nine-pin tubes, a pair of KT-66s (plenty of space between them), and rectifier tube. It's not milled for top-mounting the can cap like I've seen in some builds.

There are predrilled holes for two can-cap brackets inside near the PT area. I've seen some JTM45s with one cap up top, between the rectifier tube and KT66, and the other inside near the PT. But I'll have plenty of space inside by placing the PT up top.

I've had to mill the chassis a little from stock; I Greenlee punched a bigger hole for the Marshall style impedance switch (a 1 3/16" Greenlee punch was just the ticket). I'm going to make a support plate to attach the PT in standup orientation. The chassis was milled for a laydown style PT, the MM PT mounting brackets don't line up, so I'll reinforce with an aluminum plate and drill new mounting holes. It'll be solid.

I'm planning to install a PPIMV, and a few other component value changes ..... 32uF PS caps for instance.

Best Wishes,
Nick

[NickC]

PS, howdy neighbor!

Hey Neighbor!

I'm just a bit north of Syracuse, right in the notorious Lake Effect Snow Belt. I've travelled through the Hudson Valley area, it's beautiful there! A buddy of mine, fantastic bassist, and all-around-great guy lives out your way .... maybe you know him ..... Lenny Ackley? He used to play around NYC and the Hudson Valley neck-of-the-woods with a group called Fast'n'Loose?