Layout critique needed

Redboy

Redboy

a few good watts
Here's Option A:

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And here's Option B:

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(Please tell me if there should be an "Option C")

I'm mostly concerned about what the choke might do in this setup. Should it be rotated 90 degrees from how it sits now to avoid hum or will it be okay? My understanding is that I should be more concerned about the PT inducing hum than the choke, but I've been wrong before...
 

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I like option B, if for no other reason than I hate carrying around amps that have all the weight shifted to one side. Which would wire up easier underneath? What output tubes ya' gonna' run there ?
 
The more AC the choke sheds, the more magnetic field it will have. If it's an input choke (and it looks big enough that it might be), treat it like a smaller PT. I'd align the choke and the PT, and keep the OPTs orthogonal to them.

Should the rectifier be in front of the choke for your layout? I dunno. I'd put the rectifier up front for cosmetic reasons, but maybe the shorter heater run to the rectifier counts for something. Both present a less than ideal proximity to what I consider the signal path, but I'm paranoid. (But that doesn't mean they're not out to get me. Or you.)
 
Squidward said:
The more AC the choke sheds, the more magnetic field it will have. If it's an input choke (and it looks big enough that it might be), treat it like a smaller PT. I'd align the choke and the PT, and keep the OPTs orthogonal to them.
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It's an R-C-L-C deal, so the choke may not be carrying that much AC. The power supply schematic is here.

This is your Option C suggestion, right?

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I think you need a bigger plate to pack that iron on.
It could make for some cramped wiring underneath.

You plan on putting PSU caps underneath as well?

I remember PakProtector always saying go with a large a chassis as you can, because you'll always run out of room.
Sumthin' like that.....
 
Mike Stehr said:
I remember PakProtector always saying go with a large a chassis as you can, because you'll always run out of room.
Sumthin' like that.....
Click to expand...

Mike, I take it you've never seen Pakkie's amps in the flesh :D

Trust me, he's a man of his word :yes:

But I think it looks a bit tight too.
 
A looks dang near exactly like my 6CA7 job. I like it best, and doubt very seriously if the choke will give any hum trouble.:no:


Please excuse the dust and dirt, she got put up without a cover.:sigh:
 
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I gott nuthin to offer accept you guys are makin some fine lookin amps! :thmbsp:
 
Mike Stehr said:
I think you need a bigger plate to pack that iron on.
It could make for some cramped wiring underneath.

You plan on putting PSU caps underneath as well?
Click to expand...
Yeah, caps and some little filament transformers, too - I kinda like a wiring challenge... :rolleyes:

I remember PakProtector always saying go with a large a chassis as you can, because you'll always run out of room.
Sumthin' like that.....
Click to expand...
From a thread of mine. I remember that now!
 
jaymanaa said:
A looks dang near exactly like my 6CA7 job. I like it best, and doubt very seriously if the choke will give any hum trouble.:no:
Click to expand...
I'm leaning toward "A," too, but I'm not sure how much I like the long run forward for the rectifier tube. Might have to be "B."

Actually Jay, I was looking at your 2A3 layout earlier for ideas.
 
Redboy said:
long run forward for the rectifier tube. .
Click to expand...

I don't think so Nate, and here's why. Do a star ground toward the rear of the amp (where are the filter caps gonna be?), then tightly twist the two "tails" of the HV. They should cancel nicely, plus all your tiny signals are up front. Twist tigtly, keep snug up to the chassis metal, and if there are any turns, make them sharp 90's. You'll be fine. I've even started mounting power switches up front where they are more convinient. When dressing leads as described, I've yet to have any problems.
 
I know we like to be picky and exacting, but I'm sure you've seen commercial amps (esp. integrateds) with AC running all over the place not even twisted, yet they are dead silent. Maybe sometimes we worry a little too much about certain practices.:scratch2:
 
BTW, How I noticed that some things aren't as critical as we think maybe, was by breadboarding circuits on the bench. I'd have a gawd awfull mess of cords and jumpers, but the circuits would still be quiet.:yes:
 
Cool.

Filter caps will be at the rear, under the PT. Filament transformers flanking them. It'll be tight, but the parts count is low, otherwise.
 
I like B or a variation of B, the transformers look a bit crowded in A. It looks like it will have that spartan utilitarian look, clean and simple. Form follows function-to a point. Some day I will put my spare Mac MA230 output and power transformers to use in this way and copy the 230's circuit.
 
Layout nightmare here Nate. No less than 12 pieces of iron on (and under) a single chassis.:drool: She's quiet though, (even with tubes in her).:D
 
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I'll start out by saying I don't know much, but I think I'd cut a couple of square holes in the chassis and lay the power transformer and chock down. Bring the caps up in the middle between them, OPT's one on each side and keep the tubes up front, rectifier in the middle.
 
The one and only amp i've toyed around with showed me that getting the power transformers away from the output transformers is advantageous. Granted on the amp I was messing around with they were all in the same plane.

For the sake of discussion whats the pros and cons about building the power supply on a separate chassis and using an umbilical?

Steve
 
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