[Eeyore]

Another spin off from the recent discussion about power supply capacitance.

Aside from various ppls' ideas of what makes a PSU 'fast' or 'slow' which I
shall intentionally ignore for now since I reckon most of it is related to
driving an amplifier close to its maximum output anyway, the following occured
to me.

Because of the relatively low gain of tubes, the final load is almost invariably
placed in the anode / plate circuit.

A consequence of this is that the load is in series with the PSU capacitance.
Not something that's normally an issue for solid state designers.

I can indeed believe that poor performing ( read old technology ) caps might
introduce some non-linearities as a consequence, although data on the AC
performance of DC biased electrolytics semms to be non-existent !

In any event see my link to those nice Panasonic parts.

Graham

[tubegarden]

Eeyore wrote:
Another spin off from the recent discussion about power supply capacitance.

Aside from various ppls' ideas of what makes a PSU 'fast' or 'slow' which I
shall intentionally ignore for now since I reckon most of it is related to
driving an amplifier close to its maximum output anyway, the following occured
to me.

Because of the relatively low gain of tubes, the final load is almost invariably
placed in the anode / plate circuit.

A consequence of this is that the load is in series with the PSU capacitance.
Not something that's normally an issue for solid state designers.

I can indeed believe that poor performing ( read old technology ) caps might
introduce some non-linearities as a consequence, although data on the AC
performance of DC biased electrolytics semms to be non-existent !

In any event see my link to those nice Panasonic parts.

Graham

Hi RATs!

Here in AZ I get those nice Panasonic caps from Digi-Key, in Minnesota.
They have never disappointed me

Graham, if you build a tube amp and listen, you may find there is a bit
more to life than the large bits we can measure. You may not, it could
very well all be a lovely dream I'm having ...

Happy Ears!
Al

[Eeyore]

tubegarden wrote:

Eeyore wrote:
Another spin off from the recent discussion about power supply capacitance.

Aside from various ppls' ideas of what makes a PSU 'fast' or 'slow' which I
shall intentionally ignore for now since I reckon most of it is related to
driving an amplifier close to its maximum output anyway, the following occured
to me.

Because of the relatively low gain of tubes, the final load is almost invariably
placed in the anode / plate circuit.

A consequence of this is that the load is in series with the PSU capacitance.
Not something that's normally an issue for solid state designers.

I can indeed believe that poor performing ( read old technology ) caps might
introduce some non-linearities as a consequence, although data on the AC
performance of DC biased electrolytics semms to be non-existent !

In any event see my link to those nice Panasonic parts.

Graham

Hi RATs!

Here in AZ I get those nice Panasonic caps from Digi-Key, in Minnesota.
They have never disappointed me

Graham, if you build a tube amp and listen, you may find there is a bit
more to life than the large bits we can measure. You may not, it could
very well all be a lovely dream I'm having ...

If there's something audible, I have no doubt whatever it can be measured.

It's just a case of measuring the right thing.

Graham

[Sander deWaal]

Eeyore said:


Because of the relatively low gain of tubes, the final load is almost invariably
placed in the anode / plate circuit.

A consequence of this is that the load is in series with the PSU capacitance.
Not something that's normally an issue for solid state designers.


That, and the mostly single ended circuitry, with a PSRR of near zero.


In any event see my link to those nice Panasonic parts.


Panasonic FC is OK, indeed. One of the caps I use most in high
performance analog circuits.


--
- Ever seen someone with 5.1 ears? So, what does that tell you? -