Testing with no tubes

[trem]

Having trouble with the new Photobucket webpage...but suffice it to say I am using a very narrow chassis. Not much room from the faceplate to the back-plate.
So I have had to mount some things (dual bias pots for one) under the board. I would hate to spend a lot of time wiring up the tag board, and then find I have a problem that requires removing the board.
So finally.....is there any "problem" with putting power to my build without the tubes and board.?
Tube sockets are in.
The heaters are wired.
OT CT is wired, and so are the OT Primary.
The negative bias circuit is wired, but not to the grids.
Thank You

http://s111.photobucket.com/user/zzm...ry/proto%206k6

[g1]

There is only one problem I'm aware of, that is if the unloaded DC voltage rises higher than what the filter caps can handle.
If the B+ does not rise to more than what the filter caps are rated for, no problem.

[trem]

Good point.
At the moment I only have 2 caps on line. Plates and Screens. They are rated for 450V.
My Power Supply is 300V into a 6X5 rectifier tube. I would have that one tube installed I guess.

[bob p]

I'm going to hijack for a minute to ask some questions about your build. I see that you're using a tag board, which looks a lot like the tag board that's being sold by AES/CED. I'd like to ask about the dimensions of your chassis, and if those are the typical fender tweed dimensions, or if the chassis is a different size. I ask because the tagboard looks really tight in there. thx.

[trem]

Hey Bob -
1. Yes I got the TB from CE.
2. Did you want the actual dimensions, or are you just curious,?
Would be happy to get them for you. The chassis is from an old Gibson that I salvaged.
3. It IS pretty tight, but I think I have it figured out OK. In the pic, I just have the borad sitting in there to show the lack of room I have. It will be straighter, and a bit higher when it is set.
Chip

[bob p]

yes, the chassis does look like it has some miles on it.

i was asking because i'm thinking about using that old-style tagboard from CE, and i'm just not sure how well it will fit into a narrow chassis, like the hammond that's around 13.5 x 5 x 2". I'm guessing that your Gibson chassis looks a bit tighter than that, but in the same ballpark.

http://www.hammondmfg.com/pdf/1444-18.pdf

if i knew the approximate dimensions of chassis, that might help.

thx

[trem]

OK.....
Long is 17"
Front to Back is 4".
Depth (if you stuck your finger down into the chassis) is 2.25"

Hope that helps
best

[bob p]

yes, that helps. thanks.

[überfuzz]

Oh, a seasoned veteran. Nice with a bit of patina .

[trem]

Yeah it is -
I should have showed (shown.?) the front of the chassis.
I am much closer to "done" now.
Will post more pics in a few days, after it is all wired.
If I have made any mistakes on this one, it might be a real, labor intensive fix. That is one reason it is taking me so long. I am trying to get it right the first time.
Thanks

[trobbins]

Some circuits have the B+ also across coupling capacitors, so those capacitors also need to have a suitably high DCV rating.

You may need to include a self-discharge path for the B+ power supply capacitors if resistors aren't part of the circuit.

I use this technique when initially powering up a circuit, but I have the luxury of a variac to also reduce any consequences of a circuit problem - although most use a 'light-bulb' technique to limit consequences. This power up technique also allows coupling capacitors to be checked for leakage, by using the meters resistance to provide a leakage path to 0V if the capacitor is connected to B+. You should also check that none of the cathode circuits have any voltages on them, as a cross check for wiring problems.