Thinking about building a PP 805 amp and have questions

[djn]

This idea has popped up at the strangest times and won't go away. So I think I should build it. I'm wondering is there is any sound difference between a tube power supply and a SS power supply for B+¿

Is there a good design I should be looking at for a starting point?

It will every large and heavy is I don't go monobloc but I have to weigh that against cost.

 

[vinylkid58]

You're ok working with high voltages?

jeff

 

[astouffer]

What voltages are you thinking? You would probably need to use tubes like the 3b28. Going that route requires choke input filters and smaller filter caps. Choke input supplies waste a lot of voltage so you’d probably need a 2kv transformer.

Silicon would be much easier and give a stiffer supply for tubes running in class B.

 

[djn]

Yes, Jeff. My GM70 SET is 900VDC. Yes I'm comfortable.

 

[djn]

What voltages are you thinking? You would probably need to use tubes like the 3b28. Going that route requires choke input filters and smaller filter caps. Choke input supplies waste a lot of voltage so you’d probably need a 2kv transformer.

Silicon would be much easier and give a stiffer supply for tubes running in class B.

Did you mean class B or class AB? Class B has to much distortion at the wave form crossover for my taste. I have a couple 3b28 rec tubes somewhere in my pile. Why do they need choke input vs cap input?

 

[astouffer]

Can the 805 run in class AB? Gas rectifier tubes can’t deal with much capacitance before the choke. The RCA transmitting tube manual has a nice section on using the 866. A lot of that is relevant to the 3b28.