Rails voltages for A30

[same]

Hi,
for the A30 PSU I can only find transformer with 18+18V or 22+22V secondaries.
With 18+18V i have 23-24V DC rail, this seems to me a bit low.
With the 22+22V transformer, must use a CRC filter with 1,5-2 ohm resistance, for +25V/-25V standard DC rails (for monoblocks).
What's the best solution? The standard 25V/-25V DC rails are critical?

[Zen Mod]

Originally posted by same
Hi,
for the A30 PSU I can only find transformer with 18+18V or 22+22V secondaries.
With 18+18V i have 23-24V DC rail, this seems to me a bit low.
With the 22+22V transformer, must use a CRC filter with 1,5-2 ohm resistance, for +25V/-25V standard DC rails (for monoblocks).
What's the best solution? The standard 25V/-25V DC rails are critical?

it's not critical, few volts up and down

[Peter Daniel]

Originally posted by same
What's the best solution? The standard 25V/-25V DC rails are critical?

They are not critical at all, heatsinks capability to dissipate heat is more critical. So if your heatsinks are a bit shy, go with lower supply voltage, if they are large you may consider higher voltage rails.

[wuffwaff]

Hi,

you could also have a look at the speakers you want to use. For lower impedance (4 Ohms) use the lower voltage and a bit more bias. For higher impedances and better efficiency (>90dB) use the higher voltage with a bit lower bias.

William

[EsE]

What?
I though one of Nelson's own top mods for Alephs was full bias, regardless of the speakers.

[h_a]

Bias+Voltage values give different power into different loads.

So if your speakers have 4 Ohm you obviously want full power into 4 Ohm, and if they are 8 Ohm...you know the game.

Higher bias gives more power into lower loads.
Higher voltage gives more power into higher loads.

There's no such thing as an optimum that fits all.

Cheers, Hannes

[Babowana]

Originally posted by EsE


What?
I though one of Nelson's own top mods for Alephs was full bias, regardless of the speakers.

So did I.
Papa and many people here confirm that more bias current gives us better sound regardless of the speakers.

In addition, I think William is just advising on how we could use the voltages and currents in efficient way for the different speakers . . . in case we want it . . .

[wuffwaff]

True,

but most of the time we can´t dissipate as much power as we want because somehow the heatsinks are always too small

I´m also building a pair of Aleph 30´s for a friend and will use a 2x18V transformer for around 24V power supply voltage. This way I can set the bias to 3A (with 6fets per amp) and have enough power for his 4 Ohm speakers.

William

[linjunan]

I have the similar question: how many ampere of the transformer should we use for Aleph 30?

Does anyone try to use switch power?

Very thanks,

[linjunan]

Is one set of DC 24v 6.3a, DC -24v 6.3a enough for A 30?

Thanks,