Iron diet

[PakProtector]

Hey-Hey!!!,
I started in on the bigger amp. Things got heavy fast, so I decided to build my first 4-chassis amp. Two for PS, two for the amplifier section. I am not sure how exactly to lay it out. Filament power and a final L-C stage will go on the amplifier chassis. I can't help thinking it is a ground loop waiting to hum a few bars.

The amp chassis will be fairly simple, though it isn't quite going to be light. So I took out the baby scale and see how heavy it was going to be. The plate TX came in at 33 lb. and I knew it was going to need good handles. With the first set of lower power finals, I am getting about 45 lb for the amp, and 97 lb. for the PS. The PS is a whole lot closer to being complete and ready than the amp. It shouldn't get much heavier when I go to 813's, and raise B+ from 500 to 650V.

The I am trying to make it as simple as is possible for the swap to 813 finals. Re-wire the filament TX's, swap in the bigger output TX, change primary taps on the plate Iron autoformer and then set the bias...:) nooooo problem, until it has to move. I'll go from 4 lb./Watt to 2...
cheers,
Douglas

[Kegger]

DUDE I LOVE IT!

Can't wait to see that baby in person!

[PakProtector]

Hey!!!,
I can't wait to see it either...:) There's soooo many details to work out. How is it going to be 'Racked'? Orientation is even more important when there are two independant pieces. One TX can interfere with another( as in power/filter>>output ).

How long to make the cord? goes back to the first one, how to locate it, and then should any AC interlocks be used? I don't want to fire it up when the load isn't plugged in. Where does the main switch go? on the PS? or on the amp?

Looks like the only difference between Artists and Engineers is the medium...:)
cheers,
Douglas

[jaymanaa]

I gotta get to Michigan! Any demand for worn out pipefitters up there? :D I think about multi chassis all the time. Can't wait to see what you come up with. Now that you mention it 4# per watt sounds familiar. :thmbsp: I've been doing some reading on higher voltage stuff. I've got a huge TX waiting patiently, and would love to have a need for Hg vapour. :scratch2: Jay

Edit-would there be any particular Hg rectifiers you would recommend researching? 83, 816? etc. Besides there ability to handle higher voltages and current swings, and the obvious "wow thats cool" factor, what are some other advantages of Hg vapour? I'm just very curious. :scratch2:

[Kegger]

No JAY, no need for any kinda workers in michigan, I've been out of work for over a year. :thumbsdn:

But we sure would welcome yu! I'd love to have some more tube/audio guy's around. We
do have a pretty good size group around here with some great guy's pretty local. :thmbsp:

[PakProtector]

Hey!!!,
For Hg vapour, I would suggest staying with the single diodes like 816 and 866 or if you need more than an amp the 872...:)

You must get some additional control circuitry to handle the warm up time before applying HV. And maybe more to prepare valves that have set unused for decades. My single reason for not using them is the turn-on surge. In this way, they're just like a SS diode. They do sound good, and they look very neat....it's my favourite shade of blue.

I have room and filament TX's to do 866's....have to think about that...:)
cheers,
Douglas