Aleph4 vs Aleph5

[supernet]

After the very successful project with my P 1,7 preamp, I decided to build one of the pass amplifiers. Based on my money and no so much place in my room for those heat generators, I decided to go for Aleph 5 with increased bias or Aleph4 with "standard" bias. What would you choose?

Is there really so big difference between those two amps?

[jam]

The Aleph 2 sounds the best. Even Mr.Pass thinks so..........

Jam

[wuffwaff]

Hi,

it depends a bit on your speakers. If they are nearer 4 ohms I would go for a 5 with higher bias (3A would be nice).

It is very difficult to say what will sound better as we all build something more or less different from the original Alephs (parts, layout, power supply). You can choose the supply voltage and bias to suit your speakers. You can use "special caps, resistors etc. Generally speaking the more bias the better and don´t go below ca. 25V power supply voltage.

William

[supernet]

Thanks,

I know that both are good, but I got small room 22 m2 and it is quite difficult to put a large amount of heatsinks into. My current speakers are Proac 2.5 clone and most listening I do at moderate volume.

Aleph 2 with 300 watts heat for mono would be a overkill for my room, so I think about Aleph4 or Aleph5. Aleph4 has a little bit more power than Aleph5, if I use the same heatsinks for both I could pull the bias of A5 a bit higher. If I do the same on A4 I have to use bigger heatsinks what I really don´t want

So I think that A4 has a marginal increase of power than A5, so there would be a much better difference if I crank a bias of A5 a bit higher, right?

[JC Fardo]

Supernet

What is your current power amp?

Do you recall 2.5 clone sensibility SPL?

JC

[wuffwaff]

right,

an Aleph4 has 48V and 2,6A of bias giving 2x48x2.6=250W dissipation.
You could make an Aleph with 30-35Volts and around 3.5 A of bias current. Power into 8 ohms would be less but power into 4 ohms would be higher than the Aleph4.
250 watts of dissipation would like to see 8 fets per channel instead of 6 as per Aleph5 but this should be no problem.

Personally I think 30-35volts and 3A of bias would be enough. This´ll give 2x30x3=180 watts of dissipation and can be done with 6 fets.

William

[supernet]

Thanks, I would probably go for A5 with 3A bias.

Andre

[Coulomb]

Could I ask what the answer to the question posed in this thread would be if we threw an Aelph-X into the equation?

I myself have a pair of A5 boards completed, A2 boards 50% complete and a pair of Z4 boards compete and on Heatsinks.

I have powered nothing up yet as I am still to cowardly to destroy what looks like excellent work!

I have been hearing so much about the -X versions I have been thinking of throwing in the towel on my current projects and starting a new with some Aelph-X boards. I really do not need so many Class A amps around, so I am reticent to finish what I have started. As it is I recently just finished my SOBOZ preamp only to find out the -X version is so much better. Grrrrr

Regards

Anthony

[wuffwaff]

Anthony,


if you wait a few weeks I can tell you more about Aleph-X versus Aleph. I´m still very happy with my 5 and I think it is the best amp I had in my system so far (except for very high volume where power just isn´t big enough).
I´m still not fully convinced that my Aleph X is/will be better than an Aleph with just a much power but I will see.........

William

P.S. you can change your BOSOZ to X-BOSOZ very easy. You only have to add 4 resistors and remove another!

[Coulomb]

Originally posted by wuffwaff
Anthony,


if you wait a few weeks I can tell you more about Aleph-X versus Aleph. I´m still very happy with my 5 and I think it is the best amp I had in my system so far (except for very high volume where power just isn´t big enough).
I´m still not fully convinced that my Aleph X is/will be better than an Aleph with just a much power but I will see.........

William

P.S. you can change your BOSOZ to X-BOSOZ very easy. You only have to add 4 resistors and remove another!

Thanks for the reply William, could you email me the steps to convert my SOBOZ?

Regards

Anthony