Trying to understand 6BM8 regulator (audio note clone)

[00940]

The main advantage of the ECL82\6BM8 over the other ECLs is that it can take up to 900V on it's anode should you need it. That plus it's still being produced AFAIK.

Quick (and honest) question: 900V ? The svetlana datasheet for the 6bm8 gives a va rating of 600V for the pentode and the philips datasheet for the ecl82 gives a va rating of 300V.

Are those ratings extremely conservative ? Both datasheets list 2500V as acceptable for short bursts.

 

[fdegrove]

Hi,

Quick (and honest) question: 900V ? The svetlana datasheet for the 6bm8 gives a va rating of 600V for the pentode and the philips datasheet for the ecl82 gives a va rating of 300V.

Can't remember quite where I found that info but I think it's safe to say that it's wrong going by the published specs of that valve.

Sorry 'bout that,

 

[00940]

Hi,

Can't remember quite where I found that info but I think it's safe to say that it's wrong going by the published specs of that valve.

Sorry 'bout that,

No harm done. A bit disappointed at most

 

[Ketje]

What is the problem? High voltage occures only for a short time at startup.Once stabilised the voltage must not be to high or you will disipate beyond the limit.
Mona

 

[TheGimp]

That's a good place to end the sentence.

Try running an impulse load response.

I got a 22 volt drop with a 30ma load increase.

I find that optimizing load impulse response seems to be at odds with optimizing ripple rejection.

The ECL84/6DX8 lists the cutoff plate max voltage at 550V and operation max at 300V, so I expect 600V cutoff max is reasonable for the ECL82 along with a 300V operating max.

I've operated several brands of ECL84s up to 400V and at three times the rated plate dissipation (4W) for extended periods of time without failure.

For preamp regulators I expect the ECL84 is a good choice as well.