New build starting....need suggestions

[iknowjohnny]

No doubt you'll have plenty questions to answer in the next few days. I'm basically building a spankin new version of the amp i have spent forever tweaking and i have questions. one for now at least. If you look at the pic below can you suggest a better way to layout the transformers and choke? I have a feeling the way i did it on this amp wasn't good because they are close enough that i fear some sort of emf interaction that may affect tone. how would you do it? I wondered if i should have them spaced out as far as possible, pt at one end and ot at the other with choke dead middle or what. Thoughts on the best way to go for the least chance of sonic wierdness?

[ampgeek]

Didn't see an attachment.

But....I don't think that you can go wrong by starting with a review of how Fender (and maybe Marshall?) configures their iron.

A gazillion or so good sounding amps made can't be all that bad!

Good luck,
Dave O.

[Structo]

I'm pretty sure that the placement of the choke isn't all that important within reason.

When I added a choke to my D'lite amp, I put it between the PT and OT.

There isn't much room there at all and I didn't notice any added noise.

[Jana]

Placement of iron is extremely important if you want to minimize hum.

[iknowjohnny]

Oops, sorry....heres the pic..

[img525]http://i24.photobucket.com/albums/c39/dazco/trannys.jpg[/img]

by the way, i'm not really concerned with hum because that amp has none. More about tonal changes due to emf from the trannys interacting.

[danotron]

looks good to me......I usualy put one on one side and one on the other side turned 90 deg.....BUT....I just built an express and they are jammed up beside each other at 90 deg. and theres no problem there either

[iknowjohnny]

Whats the most common thought on this, or the general consensus? Is there no right or wrong aside from the 90 degree rule?

[dreric]

I'd stick to the 90 degree rule. The way that you have them in the photo seems fine, look at all the amps that pretty much lay them out like that. Put the PT near / over the AC line in and the OT closer to the power tubes.

Spreading them out makes lead dress more unpredictable and unstable. In other words, yes the transformers are at the far ends of the chassis, but the amp has an additional 3 feet of wire in it.

[iknowjohnny]

When you say put the OT closer to the power tubes, are you suggesting i put the choke to the left and have the PT and OT next to each other, or noving the power tubes more to the input side? What is the reason?

[dreric]

Chokes usually go in the middle. Less wire is always good.

Eric

[M Fowler]

When I built my Rocket Reverb I carefully considered where the placement will go and ended up like this no noise either love it.

Great amp by the way for those considering the octal rocket with Normster reverb addon.

[Jana]

spin your transformers so they are like the picture Mark posted. That is the way I prefer them.

[iknowjohnny]

what advantage will i see if i turn then 90 degrees from where mine are?
By the way, another question....i see a lot of builds where there are other wires twisted like the heaters. What wires can i do like that? i like the look. i twisted the secondary OT wires, but i seem to see some of the PT wires twisted in some builds. Unless i'm mistaken.

[guitardude57]

AC leads get twisted.......... helps cancel out hum.

[iknowjohnny]

I haven't yet recieved the chassis, so i can still change my mind on tranny layout. so i'm looking at marshall chassis and notice at least the 800's seem to have the choke on the input side instead of in the middle like i did on the amp i posted a pic of. It gos from the power section side, PT, OT, choke. Can anyone tell me why i'd be better off doing it my way then like that? I would think marshall knows better than me ! But what do you all think?