OTL, continued...

[Joel]

Well, after some suggestions, this is what I've got so far. How is this looking?

 

[dhaen]

You cannot be serious

 

[Joel]

What do you mean John?

 

[fdegrove]

OTL CONTINUED.

Hi,

The other OTL thread full than?

Cheers,

 

[dhaen]

1) You have a constant voltage load in the cathode of your driver. Where's the signal going to go?
2) The idea of the cathode choke was to get rid of the very lossy resistor in the cathode. You've still got one! No wonder our banter about cathode chokes made no sense..

 

[fdegrove]

PIECE DE RESISTANCE

Hi John,

Since no value is specified it could a 0 Ohm jumper?

Cheers,

 

[dhaen]

Well it wouldn't be a:

PIECE DE RESISTANCE

then, would it?

 

[Joel]

1)You have a constant voltage load in the cathode of your driver. Where's the signal going to go?

Explain further. Do I need a resistive load above the gas tube?

2) The idea of the cathode choke was to get rid of the very lossy resistor in the cathode. You've still got one!

I need to bias the output tubes, and the point of the choke is to replace RL, not Rk... and in that capacity it's keeping another 30 watts out of the chassis.

3) Lose the attitude.

 

[fdegrove]

GLOWDISCHARGE

Hi,

Joel,I don't think that OD3 is going to put out 150V all by it self.

Cheers,

 

[dhaen]

Explain further. Do I need a resistive load above the gas tube?

Joel,
The constant voltage of the gass tube is exactly the opposite of what you want. If you want to be "smart", add a constant current source.
Gas tubes are good in common cathode. Not in cathode follower mode.

 

[dhaen]

I need to bias the output tubes

Yes, that's true. But you're wasting power, both mains and speaker power with this scheme. Also, the choke won't work properly with a resistor in series.

 

[Joel]

Also, the choke won't work properly with a resistor in series.

Why is that?

 

[Joel]

all fixed?

With the additional changes. Although I still want to know why you cannot use the choke as the load in series with a resistor as Rk. John, care to comment?

 

[SY]

I probably missed something the first time around, so pardon me for coming in in the middle and asking a naive question: why not use a Circlotron? Much more efficient.

 

[Joel]

Circlotron uses an output transformer, and also if you read the first OTL thread, we were discussing single-ended OTL designs.
Yeah, it is inefficient. But so is a SET.

 

[SY]

I was referring to an OTL Circlotron.

And it's still beyond me why anyone would go SE in the forst place, but chaque un a son gout.

 

[fdegrove]

NUANCE

Hi.

For info the Circlotron AKA the Wiggins is also used to make OTL amps.

The best known so far is made by Ralf Karsten from Atmasphere.

Cheers,

 

[Joel]

And it's still beyond me why anyone would go SE...

Because it can produce some really enjoyable listening.

 

[dhaen]

And it's still beyond me why anyone would go SE in the forst place

Sy, have a look at the end of this thread, it gives a hint...
Push Pull DHT triode:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=9606

Cheers,

 

[dhaen]

Although I still want to know why you cannot use the choke as the load in series with a resistor as Rk. John, care to comment?

The resistor was in series with the energy being recovered from the choke; low efficiency.