AV800 rails

[Anvil]

Hi. Can I run AV800 on +- 83 V rails or +- 76 V rails without any modifications? Rails are normally +- 90 V. I don´t need all that power and lower rails mean more current from transformer of same power🙂 Current is nice😀

Anvil

 

[Mattyo5]

Sounds like a good idea to me 🙂 Someone correct me if i'm wrong, but should be no problem to run with lower rails. Probably better overall, and cheaper... those higher voltage power supply capacitors are not cheap. Good luck!

-Matthew K. Olson

 

[thylantyr]

I think Holton mentioned it was ok to run lower rails,
search the archives to verify. I think it was in reference
to bridging the AV800, he recommended lowering the rails
to maybe 75v.

Post pics and listening impressions when done.


😎

 

[Anvil]

help

I cant find that thread. Can you find that? What happened to your "terawatt" projects? Can you post some pictures of your projects, if you have any?

Anvil

 

[K-amps]

Lower rails should not be an issue as long as your set the bias current and DC offset correctly.

Also lower rails do not mean more current (unless you lower the load impedance as well, in both cases, it is a function of load not rail amplitude.)

On a personal note, I find lower rails have a softer sound with less glare. However if the motivation is to avoid blowing your speakers, then we get into the old "will clipping destroy speakers quicker than a high powered amplifier" argument.

Good luck! 🙂

 

[Anvil]

I mean more current from the transformer, because the VA:s stay the same and voltage is lowered.

Anvil

 

[TonyTecson]

rails will sag to that level anyway

no problem as far as i can see...

 

[K-amps]

I mean more current from the transformer, because the VA:s stay the same and voltage is lowered.

Anvil

Anvil,

I am not an expert, heck I am not even an Engineer, but I believe lowering voltage will decrease VA rating because maximum current that can be delivered from a given gauge of secondary coil is fixed. Meaning you cannot extract more current from the coils than rated.

The second variable is the saturation of the core, maybe thats what you were referring to.

Lastly with increased flow of current, the Toroid begins to heat up because of several variables, usually this is the limiting factor in most commercial Toroids as far as VA rating goes, This might also be what you were referring to.

Any Tranny experts might shed better light on this,

regards,

K-

 

[Anvil]

I simply mean that transformer with lower secondaries but same VA gives more current, because P = U * I.

 

[K-amps]

I simply mean that transformer with lower secondaries but same VA gives more current, because P = U * I.

😉 P might mean U * I but if I is fixed, lowering U will lower P.

 

[SkinnyBoy]

if you use the AV800 board, with all the output devices, but only use +-76 volt rails, it will happliy run into 2 ohms.. 🙂 or, you could leave a few of the devices out, and only ever run 4 ohms 🙂