C- is a bias supply. You did mention a bias winding. Rectify that with 100 PIV Schottky ("noiseless") diodes.
Draw up a new schematic that follows the 'AQ5 original. The conditions for good sound from the 'T7 are (each section at "idle") 200 to 220 V. on the plate and IB = 3 mA. So, the CCS gets set for 6 mA.
Oh yeah, the LENGTHY saga of "El Cheapo" can be found here. Get your hip boots on. It's a lot to wade through.
Ok, Eli if your still with me, I read through most of the posts from the link above. There wasn't any info on running the 7591s ( I have a pair of EH, I also have a quad of KT66). As far as PTs, as said before I have a couple of Edcors that might work;
EMO0726
300-0-300, 250mA
6.3V, 4.8A w/CT
5V,3A
Emo0731 same as above but
320-0-320
and a
Em0725a I really don't want to use this one unlees the need is there
325-0-325,400mA 50v tap
6.3v, 7A
5V, 3A
I am planning on ordering the Edcor OPTs you mentioned and run UL.
Also for the C-, the spec'ed Allied transformer is 6.3 filament transformer? I've got a new Hammond 166n6 6.3,4A or a pulled 6.3, 1.3A
What are your thoughts about what I have to work with?
BL
EMO0726
300-0-300, 250mA
6.3V, 4.8A w/CT
5V,3A
Emo0731 same as above but
320-0-320
and a
Em0725a I really don't want to use this one unlees the need is there
325-0-325,400mA 50v tap
6.3v, 7A
5V, 3A
I am planning on ordering the Edcor OPTs you mentioned and run UL.
Also for the C-, the spec'ed Allied transformer is 6.3 filament transformer? I've got a new Hammond 166n6 6.3,4A or a pulled 6.3, 1.3A
What are your thoughts about what I have to work with?
BL
BL,
A good reason for the competence of "El Cheapo" is the fact that the PSU has cojones. The 'AQ5 amp's supply can produce over 200 mA. So, 250 mA. is really not enough for a "Grande". Yeah, 400 mA. is a little OTT. So what! The finished product will play bass very well. Can you upload or link to the spec. sheet for the '725A power trafo?
You need to get another matched pair of EH 7591s. Being 6L6 family members, the KT66s require more drive voltage than the 'T7 based small signal circuitry can deliver.
By SS rectifying the B+, the 5 VAC winding becomes available. You will voltage multiply that winding to get the B- rail. The "beefy" 6.3 VAC winding is good. Better to have more current than needed than not having enough.
A good reason for the competence of "El Cheapo" is the fact that the PSU has cojones. The 'AQ5 amp's supply can produce over 200 mA. So, 250 mA. is really not enough for a "Grande". Yeah, 400 mA. is a little OTT. So what! The finished product will play bass very well. Can you upload or link to the spec. sheet for the '725A power trafo?
You need to get another matched pair of EH 7591s. Being 6L6 family members, the KT66s require more drive voltage than the 'T7 based small signal circuitry can deliver.
By SS rectifying the B+, the 5 VAC winding becomes available. You will voltage multiply that winding to get the B- rail. The "beefy" 6.3 VAC winding is good. Better to have more current than needed than not having enough.
Don't have the spec sheet other than what I gave you. This is a custom wound for guitar amps. I was going to use it for a bass amp.........but that can wait and I can get another. I know the guy that had them wound, if you have something else we need to know? I bet this this weighs close to 13 pounds.
So, do I use the HV CT and the full wave the first cap of the CLC, ala guitar amp?
BL
So, do I use the HV CT and the full wave the first cap of the CLC, ala guitar amp?
BL
As another member said some time ago, a HIFI amp is like a guitar amp gussied up in lipstick and nylons. 
Yes, you use a FWCT rectifier setup and a CLC filter. You might as well minimize the stress on both the power trafo and diodes by keeping the 1st filter cap. at the minimum value consistent with an appropriate B+ rail voltage. Use plenty of energy storage in the 2nd cap. position.
Speaking of the B+ diodes, high PIV Schottkys are best, as they don't produce switching noise. The down side is expense. DigiKey stock # C2D05120A-ND is what's needed and they cost $8 each. If that's too much for your budget, UF5408s and a reverse recovery spike filter (RRSF) will come darned close in the noise dept. Regardless of the diode setup you settle on, install a CL150 inrush current limiter between the diodes and the PSU filter. The thermistor will delay B+ rise a little. That small amount is all that's needed to allow the instant on C- (bias) supply to electrostatically protect the "finals" against cathode stripping.
Yes, you use a FWCT rectifier setup and a CLC filter. You might as well minimize the stress on both the power trafo and diodes by keeping the 1st filter cap. at the minimum value consistent with an appropriate B+ rail voltage. Use plenty of energy storage in the 2nd cap. position.Speaking of the B+ diodes, high PIV Schottkys are best, as they don't produce switching noise. The down side is expense. DigiKey stock # C2D05120A-ND is what's needed and they cost $8 each. If that's too much for your budget, UF5408s and a reverse recovery spike filter (RRSF) will come darned close in the noise dept. Regardless of the diode setup you settle on, install a CL150 inrush current limiter between the diodes and the PSU filter. The thermistor will delay B+ rise a little. That small amount is all that's needed to allow the instant on C- (bias) supply to electrostatically protect the "finals" against cathode stripping.
BL,
The tap gets used for C- (bias), while the 5 VAC winding gets voltage multiplied to produce B-. Look here to see what a proper multiplier looks like. Turn the diodes around, as this is a negative supply. It is possible to tap the multiplier to provide both of the necessary negative voltages. Doing so would allow the tap to be tied off and "cockeyed bridge" rectifier topology to be used. The CB is a way to get the "noiseless" performance of Schottky or vacuum diodes at reduced expense.
The tap gets used for C- (bias), while the 5 VAC winding gets voltage multiplied to produce B-. Look here to see what a proper multiplier looks like. Turn the diodes around, as this is a negative supply. It is possible to tap the multiplier to provide both of the necessary negative voltages. Doing so would allow the tap to be tied off and "cockeyed bridge" rectifier topology to be used. The CB is a way to get the "noiseless" performance of Schottky or vacuum diodes at reduced expense.
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Ok, I think I'm with you:
B+ 7591 plates
B2 12AT7 plates
B- 12at7 bias
C- 7591 fixed bias
That's the of the places I got screwed. I'm looking at the schematic thinking self biasing power tubes.
Looking at the schematic above that you drew, this transformer I have does not have a CT on the 5V winding.
The 6.3V winding is not CT'ed either, but I figured to make a suedo CT with a couple 100 Ohm resisters.
BL
B+ 7591 plates
B2 12AT7 plates
B- 12at7 bias
C- 7591 fixed bias
That's the of the places I got screwed. I'm looking at the schematic thinking self biasing power tubes.
Looking at the schematic above that you drew, this transformer I have does not have a CT on the 5V winding.
The 6.3V winding is not CT'ed either, but I figured to make a suedo CT with a couple 100 Ohm resisters.
BL
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