Got Iron

[Papa Jim]

Ok. Shooter. Tomorrow I'll do some tweaking. Thanks,

[Papa Jim]

Bumped the cathode resistor up to 750 ohms to get the cathode current lower.

Plate Voltage = 327 VDC
Cathode Voltage = 21.3 VDC
Plate to Cathode Voltage = 306 VDC

21.3V/750 = .0284A or 28.4mA
327 x .0284 = 9.28W

I haven't removed the choke yet and replaced with the resistor. That will be next.
Since the amp is not over dissipating, guess what? I just had to hear it for a test. Who wouldn't    It is very very hum free, and sounds awesome.
So dissipate a little more and soon as my tubes get here go from try going from (both halves of the 12AX7)  to ( combo of 1/2 of an 12AY7 and 1/2 of a 5751) as a tone experiment. Loving the sound though already. Thanks to all who helped me. I will be sure to keep you all posted on my progress.   

One question are wirewound's suitable for cathode resistors?

[sluckey]

Absolutely.

[shooter]

I haven't removed the choke

you're there without swapping it out, leave it if you like it.  was just a suggestion to lower B+

[Papa Jim]

Ok. Gotcha. But the 750 ohm was correct wasn't it to get a proper safe dissipation percentage. Before that it was over the max.

[sluckey]

Plate Voltage = 327 VDC
Cathode Voltage = 21.3 VDC
Plate to Cathode Voltage = 306 VDC

21.3V/750 = .0284A or 28.4mA
327 x .0284 = 9.28W

You should use the plate to cathode voltage for your final calculation.

IOW, 306 x .0284 = 8.69W

[Papa Jim]

Ok. Cool. I will do that after I add the other tube socket and tweak the resistor for a little more dissipation since I am on the low side right now.
Another question is it a good idea to check any voltages on the preamp tubes. The schematic shows 1.5 cathode volts with 150 Plate Volts. Is it the ratio of those two that is important. I suppose it takes tweeking the plate resistor 100k to get this voltage? Is that important.

[SILVERGUN]

Ok. Cool. I will do that after I add the other tube socket and tweak the resistor for a little more dissipation since I am on the low side right now.
Another question is it a good idea to check any voltages on the preamp tubes. The schematic shows 1.5 cathode volts. Do I play with the plate 100k to get this voltage? Is that important.

Check these 2 videos out. They will give you some of the back story behind the answer to your question:
https://vimeo.com/28565075

https://vimeo.com/33244955

[PRR]

> idea to check any voltages on the preamp tubes.

Your supply rails are zero V and (say) 300V. The tube works with a *part* of the 300V across it and a part across the plate (or cathode) resistor. So as long as the tube plate-cathode voltage is not zero and not full supply voltage, it "is working".

A specific guide: Fender's 12AX7 with Rk=1.5k and Rp=100k, the plate sits near 70% of supply voltage. I would not be distressed about 60% or 80%, except 12AX7 are so consistent around this point that any other result suggests checking resistors and tube. Russian "similar to 12AX7" may be different. 12AU7 *will* bias-up different.

[Papa Jim]

Thanks PRR. I just never hear anything on checking them that is why I asked. 

[Papa Jim]

Ok so I got the amp done with all three tubes now and I am really loving it. Here's the final schematic. I did change up the tone stack also to the original 5F2A tonestack. The 12AY7 and 5751 worked great together.