Any help with this 6sn7 circuit biasing

[Steptoe6sn7]

Hey guys just wondering if someone can help me with this kit amp it's a 6sn7 quad pp preamplifier biased hot in class A
It's got a 300v CCS power supply
And was shipped with the specified parts for 300v operation

I only have a 250v transformer so my bias will be off a little and not hot enough

Which resistor (s) do I change in the diagram and to which value would get my tubes in proper range I know I have to experiment a bit and I am learning and this will be my first time setting a bias I've attached the circuit diagrams with the post

It has been running like this with cheep Russian tubes to get it going but I just got my really good tubes arrive today

 

[Steptoe6sn7]

I'm sorry here is a much better diagram

 

[Steptoe6sn7]

I am fairly familiar with the procedure from research and a ton of reading but this will be my first time

 

[gadget73]

250 volts what? AC? Full wave rectified that should come out to easily over 300 DC. Typically you get about 1.4x the AC voltage input. If thats a full wave center tap, its 1.4x center to end voltage, for a bridge its 1.4x end to end voltage. Less any rectifier losses at least, tubes will drop more than silcion diodes will.

Looks like the whole circuit is running at very little current if those voltage numbers are accurate. 2v / 1000 = 2ma. The whole thing is essentially in series, so its 2 milliamps total for everything, or 1ma per triode section. Based on the 6sn7 datasheets thats considerably below typical conditions.

 

[Steptoe6sn7]

250 volts what? AC? Full wave rectified that should come out to easily over 300 DC. Typically you get about 1.4x the AC voltage input. If thats a full wave center tap, its 1.4x center to end voltage, for a bridge its 1.4x end to end voltage. Less any rectifier losses at least, tubes will drop more than silcion diodes will.

Looks like the whole circuit is running at very little current if those voltage numbers are accurate. 2v / 1000 = 2ma. The whole thing is essentially in series, so its 2 milliamps total for everything, or 1ma per triode section. Based on the 6sn7 datasheets thats considerably below typical conditions.

No it's a regulated power supply hence the fixed bias when I say CCS I mean constant current supply so you can dial in your tubes and there's no fluctuations or PSU sag. Perfect for hifi

 

[kyle]

No it's a regulated power supply hence the fixed bias when I say CCS I mean constant current supply so you can dial in your tubes and there's no fluctuations or PSU sag. Perfect for hifi

Generally, a CCS is used in place of a plate resistor. The resistor is not required if you use a current source (which isn't shown). The input section is cathode biased, not fixed.
What does the power supply look like?