Tube choice for 600R output transformer

[Tubenstein]

EL509 would work. As far as your driver I'm not sure. Someone else hopefully will weigh in, however, here's the driver I use, personally.

Cheers.
Koda

Hello!
So you have this driver for 4 x EL509 (wired in triode) in push pull configuration load to 600 ohm plate to plate output transformer?

Do you have the output section circuit to share with me??

Thanks!

 

[kodabmx]

I'm using it for 2X6P45S wired as triode in push pull with a 1k3 load. I don't see why it wouldn't drive two sets in parallel with 600R load...

Here's the circuit I'm using.

 

[Tubenstein]

I'm using it for 2X6P45S wired as triode in push pull with a 1k3 load. I don't see why it wouldn't drive two sets in parallel with 600R load...

Here's the circuit I'm using.

Don't you think 600 ohm plate to plate still too low for 4 x EL509 push pull in triode configuration??

 

[kodabmx]

Nope, but I wouldn't go any lower. At 600R you'll have current peaks of ~1.5A per side, 750ma per tube, but idle will be (in my example) 120ma. Also, music is dynamic with peaks. I don't play 80W of sine so I can't tell you if they'll like that, but I'm using a set of used tubes and they work fine. Also the heater current is higher on the 6P45S that I use. I've build this exact circuit dropping in 6LW6 tubes, too. Works well.

 

[Tubenstein]

]

What about 8 x KT77 in triode load to 600 ohm plate to plate? What do you think??

 

[kodabmx]

You could, but you'll be right on the edge of the max current spec (180ma per tube for KT77 vs >800ma for 6P45S)

 

[Tubenstein]

Hmmm.....What about 8 x JJ EL509S in triode load to 600 ohm plate to plate? Would it be more secure??

 

[Wavebourn]

One more option is a flock of 6P41S, they are as cheap as a dirt.

 

[FullRangeMan]

For good results, you'd need at least 8 per channel. Otherwise you could use 4 6KG6 sweep tubes per channel, connected as triodes, idle at 120ma per tube, B+ 300V. This will make about 15W class A limit, 140W total. 6C33C could also work, but they aren't very linear, hard to drive, and power hungry.

This trafo in question needs only one 6C33 which is much more affordable than eight KT150 or four 6KG6, I never heard about the 6C33 was unlinear, Iam surprised. Any more info about it welcome, thanks.

 

[kodabmx]

It would need at least two 6C33 unless you want a class B amplifier. I've built a PPP 6AS7G amp into 600R. It made 6W and sounded like marde.

 

[davorin]

6FE5 or 50FE5, and 7695 or 7754 are also a very good choice.
For 600 Ohms Push-Pull transformer You need 3 pairs of tubes per channel!

 

[Lingwendil]

How about four or five pairs of 6P43P-E or 6CW5 per channel? 25 watts a pair isn't unusual when set up correctly.

 

[PRR]

6FE5 or 50FE5... 3 pairs of tubes per channel!

10W per pair, 3 pair, is 30 Watts.

OP's transformer is 'capable >200W power'. I do not know how much of that is needed, but 30W in a 200W lump seems a waste of iron.