tube rectifier

[bonsai171]

Suppose you have a preamp with solid-state rectification (the Audio Electronic Supply AE-3). Dennis Had, the designer of the preamp (and also Cary Audio owner/designer) offers one particular upgrade for this preamp- tube rectification. The purpose of rectification is to correct osciliations in voltage, correct? What would be the advantage of having him upgrade the preamp to tube rectification, and would it be worth it? I have heard that tube rectification is someone less reliable, are there any other negatives? Thanks!

bonsai

[analog_sa]

The purpose of rectification is to correct osciliations in voltage, correct?

No.

I have heard that tube rectification is someone less reliable, are there any other negatives?

It is not less reliable. A rectifier tube in a preamp will give you thousands of hours of service before replacement. And much better sound. Enjoy.

[audiousername]

Originally posted by analog_sa
It is not less reliable. A rectifier tube in a preamp will give you thousands of hours of service before replacement.

Provided they are treated with respect.

I have heard that some (commercial) manufacturers use something like 1000µF behind their valve rectifiers with no apparent regard to the charging current those caps will cause.

Valve rectifiers will most certainly not be reliable when mistreated.

[baggystevo82]

1000µF behind their valve rectifiers

Ouch!! Just a thought though, you know in PSU designer it tells you when you exceed the current rating of a given rectifier, couldnt you go a little bigger on the first cap as the rectifier turns on slowly? Not instantly as it is simulated. Also are the current ratings of rectifiers absolute, or an average current rating, i.e. more like a max dissipation rating?
Cheers,
Steve

[Sherman]

Originally posted by baggystevo82

...when you exceed the current rating of a given rectifier, couldnt you go a little bigger on the first cap as the rectifier turns on slowly?...
Cheers,
Steve

No,

Most (all?, I haven't checked) rectifier tubes have info in the data sheet regarding the max size capacitor you can use immediately after the tube in a circuit. For instance the 5U4-G can have a max of 40uF in a cap input circuit.

[SY]

Originally posted by bonsai171
What would be the advantage of having him upgrade the preamp to tube rectification, and would it be worth it?

The major advantage will be Had's ability to make this month's payment on the BMW. And the enhancement of your ability to impress the fashionistas with your preamp.

Tube rectifiers have one real advantage: slow warmup. Other than that, they're costly, degrade regulation, inefficient, and hot.

[analog_sa]

I have heard that some (commercial) manufacturers use something like 1000µF behind their valve rectifiers

Heard? From whom? Doesn't sound very plausible in a commercial design.

[Sheldon]

Originally posted by Sherman


No,

Most (all?, I haven't checked) rectifier tubes have info in the data sheet regarding the max size capacitor you can use immediately after the tube in a circuit. For instance the 5U4-G can have a max of 40uF in a cap input circuit.

And with modern electrolytics, which surely must be different from those made 50 years ago, does that number change much?

Sheldon

[Sherman]

Originally posted by SY


...Tube rectifiers have one real advantage: slow warmup. Other than that, they're costly, degrade regulation, inefficient, and hot.

But they look so nice! Whenever I've gotten silicon to give that nice orange tube glow it has never lasted very long.

[SY]

That's a point well beyond argument, I'll grant you!