Super Twin Reverb 180

[LarBal]

Got one of these 6x6l6 things on the bench, sounded horrible when it came in....did full cap job(it had the original caps), and put some good 6L6s in, and the amp works and is very very loud, but there's 620VDC on the plates AND the screens, after the screen resistors.
I thought this amp was ultralinear, and had screen taps on the OT that would be much less, no?
The other issue is that the amp is making intermittent, but steady popping/cracking sounds.
Nonetheless, I thought I would check here on the Voltage thing before I proceed. Schematic show 500V at the centertap. I would assume it would be 540 or so with higher wall voltage but 620 doesn't seem right.
Thanks!
super_twin_reverb_180w_schem.pdf

EDIT: i take back what I said about it being super loud. It is not, even with 25mA per tube being drawn. It's giggable volume, but not 180W loud

[The Dude]

What is your filament voltage? That will tell us if the high voltage is a primary or secondary issue.

[Helmholtz]

..but there's 620VDC on the plates AND the screens, after the screen resistors.
I thought this amp was ultralinear, and had screen taps on the OT that would be much less, no?

With UL connection screen voltage is essentially the same as plate voltage. The screen resistors only drop maybe 2V.

What is heater voltage?

Edit: Missed post above.

[LarBal]

Yikes heaters are 7.7VAC !! So yea that's ~25% higher, which would put 500VDC at ~620VDC.

What should I do about that?

[LarBal]

Oh damn just noticed the powertubes are on different heater circuit than the 9 pins. The 6L6 heaters are at 7.98VAC!!!

[Helmholtz]

Any chance this is an export amp for the japanese market (100V mains)?
Does the amp have a mains voltage selector switch?

[The Dude]

^^^^ Yes, that.
Same question stated differently: Is the transformer labeled 012405 as the schematic says?

[Randall]

Albert Collins used that model, and the time I did sound for him he was MFing loud. No amp in the mix that night.

[LarBal]

Oh wow, check out the pic, it appears to be a 220V, which make no sense to me as to why the Voltage is high and not low.
014679 is the PT code. I saw that 3A fuse when I started, and didn't quite process it was half of what it should be

[The Dude]

Yes, very loud and very "focused" high mids (the nice way to put it). Not a fan and not one of my favorite amps by any means, but I suppose that's not relevant to the conversation.

[The Dude]

Probably the original/existing transformer has been rewired/reconfigured. That looks like a Fender part number. What do you have for primary wires? If the primary has multiple taps, it's possible that it is wired using a 100V tap and maybe there is a 120V tap.

[LarBal]

I'll did into the wiring in a bit. I did find that PT part# in another amp. Check the notes on alternate wiring

[The Dude]

If that's the transformer you have, and it seems so, there aren't multiple taps. It's just a dual primary with two yellow wires for an internal thermal fuse. One solution would be to add a bucking transformer- make a heavy amp even heavier.

[LarBal]

I don't think the PT is wired correctly. I'll need to dig in fresh in the morning, but :
the Green/Black + Black are wired together but don't go anywhere else....
the yellw/Blk + Red/Black go directly to the white line coming out of the wall,
The black line coming out of the wall goes through the normal fuse, to the switch, which also has the lone yellow wire attached to it

[LarBal]

Also, there are not 2 yellow wires(thermal fuse wires) coming out of the PT.
There is a yellow, and a White/blk (that is not connected to anything)