Aleph J - Transformer choice confusion (18 or 20 V)

It looks like there are several options still available from Antek with 20V secondaries. I would recommend a pair of AS-3220 over a single AS-5220. Dual mono not only gets you better power supply filtering per channel, but the improved channel isolation does great things for the imaging and overall soundstage presentation.
 
for a standard AlepJ, total of 4-500VA and120.000-180.000uF cap bank for 2 channels.
A 3U 400mm modushop chassis is enough.
Anything above this will just be waist of money.

A huge cap bank needs bigger transformer. Bigger transformer generates more noise. So your gain goes straight out the window. Huge chassis will keep your output devices cool. Wich you really do not want.
 
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Hello,
I' d be absolutely happy, if anyone could help:

Which secondary tranny voltage would you prefer 18 or 20v when going the standard psu route?

Many thanks

Rents

Get the 20V / 400VA one, this will give you 24V DC under the load.
18V version will give you around 21 - 22V DC under the load.

With 300VA, you may start to hear the buzz from the transformer after a while... this will also depend on the transformer of course.
 
for a standard AlepJ, total of 4-500VA and120.000-180.000uF cap bank for 2 channels.
A 3U 400mm modushop chassis is enough.
Anything above this will just be waist of money.

A huge cap bank needs bigger transformer. Bigger transformer generates more noise. So your gain goes straight out the window. Huge chassis will keep your output devices cool. Wich you really do not want.

This is so much BS.
I don't know where to start.
This is propaganda rubbish.

A big chassis is never a waste of money.
What if he wants to bias to 3A etc.
500mm is going to give him a lot more space to fit 2 x 500VA transformers along with 2 psu boards etc.

I've used both 400mm and 500mm chassis. A 500mm chassis is much better for many reasons. I will never use a 400mm chassis again.
I do agree 5U is not necessary but they don't make a 4U 500mm or a 3U 500mm chassis. It's worth having the extra depth.
 
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This is how it was done in Aleph 2
See (TH2)
 

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This is so much BS.
I don't know where to start.
This is propaganda rubbish.

A big chassis is never a waste of money.
What if he wants to bias to 3A etc.
500mm is going to give him a lot more space to fit 2 x 500VA transformers along with 2 psu boards etc.

I've used both 400mm and 500mm chassis. A 500mm chassis is much better for many reasons. I will never use a 400mm chassis again.
I do agree 5U is not necessary but they don't make a 4U 500mm or a 3U 500mm chassis. It's worth having the extra depth.

Read one more time. a STANDARD AlephJ. as far as i know a standard AlephJ do NOT run 3A bias. If a 3U 400mm chassis has enough colling capasity, then everyting bigger is waist of money. Overdoing PSU (at a point) is also waist of money. since do don't gain a ting, but do spend a lot more money.
When it comes to depth, bare in mind that efficient colling is only a radius of 10x the thicknes of the base of the heatsink. In this case, 7mmX10=70mm. the outher outputs is around 240ish mm apart. that leaves you 130mm from outher outputs to the edge of the sinks whith those 500mm depth chassis. Thats a lot of heatsink you won't thake advantage of. Also. when the outputs run cool, they have a higher internal resistance.
And when it comes to heatsink hights (lenght of the profile) you must dobble the hight to gain 25% cooling. Thats an expensive gain.
 
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I agree that 5U is not an effective way to improve cooling efficiency.
However 5U is the only chassis that comes with a 500mm depth, the benefit of the extra depth is absolutely worth it, for the specific reason of being able to easily fit everything in the case, and the 500mm length absolutely improves cooling efficiency in a proportional manner.
It make the chassis far more future proof. I don't know anyone personally that stops at building one amp, if there are, they are very low in numbers.

The guy wants to buy transformers, he says they only have 500VA, waiting for smaller ones to come in could be possibly weeks (who knows), I wouldn't throw my life away waiting to buy a smaller transformer when he can buy one now. If he buys the dual 500VA transformers he will definitely appreciate the extra depth.

I've used a single 400VA in an F6 build and F4 build, and I've used dual 500VA transformer the dual 500VA was an improvement over a single 400VA.
I now have those transformers for life, so the price difference over a life time is small.

Everyone can decide where the point of diminishing returns are for themselves, but these differences can absolutely be measured with fairly basic equipment. It's not opinion based.
Powersupply ripple and it's harmonics well and truly causes IMD products with the audio signal. For me I am not personally happy till it's around -100dB relative to a 1 Watt signal. That takes a certain investment level and I am happy to make it.

What would be Ideal is a 4U case, but with a 500mm depth but they don't make it at modushop. That is why I built my own, and is basically what I have.
 
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Here is what my Aleph J looks like, using a pair of Antek AS-3220 transformers and CRCRC PSU boards made by Prasi. All the bulk PSU caps are 27,000 uF, but I used different types for different positions. This is still my favorite amp in my arsenal, but the F6 is a close second after some serious modifications, some of which were suggested my Mr picoD.
The chassis is essentially a 3.5U x 400mm deep, and slightly narrower than the Modushop. This is the smallest chassis that I would recommend for building an Aleph J, or an F6 for that matter. Everything fits, but needed a lot of attention to detail. My F6 uses the same size, but with a different face plate. These two amps are both biased at 1.85 Amps per rail and run warm, but not hot to the touch. Both have ~26V rails, but by different means.

I happen to prefer this style of chassis for its construction over the equivalent by Modushop. I don't care for the way the Modushop chassis connect the heatsinks to the rest of the plates, nor for the limitation in their ability to transfer heat to the other parts of the chassis. When my amps are at thermal equilibrium, both the face plate and rear plate are fairly warm as well. The bottom plate also gets warm, due to my addition of aluminum L brackets between the main heatsinks and the base. These amps are still reasonable for me to pick up and move around, which I like to do when going for a different sound. Honestly, though, the Aleph J spends most of its time in my system, running 24/7 because that's how it sounds its best.
 

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I agree that 5U is not an effective way to improve cooling efficiency.
However 5U is the only chassis that comes with a 500mm depth, the benefit of the extra depth is absolutely worth it, for the specific reason of being able to easily fit everything in the case, and the 500mm length absolutely improves cooling efficiency in a proportional manner.
It make the chassis far more future proof. I don't know anyone personally that stops at building one amp, if there are, they are very low in numbers.

The guy wants to buy transformers, he says they only have 500VA, waiting for smaller ones to come in could be possibly weeks (who knows), I wouldn't throw my life away waiting to buy a smaller transformer when he can buy one now. If he buys the dual 500VA transformers he will definitely appreciate the extra depth.

I've used a single 400VA in an F6 build and F4 build, and I've used dual 500VA transformer the dual 500VA was an improvement over a single 400VA.
I now have those transformers for life, so the price difference over a life time is small.

Everyone can decide where the point of diminishing returns are for themselves, but these differences can absolutely be measured with fairly basic equipment. It's not opinion based.
Powersupply ripple and it's harmonics well and truly causes IMD products with the audio signal. For me I am not personally happy till it's around -100dB relative to a 1 Watt signal. That takes a certain investment level and I am happy to make it.

What would be Ideal is a 4U case, but with a 500mm depth but they don't make it at modushop. That is why I built my own, and is basically what I have.

There realy is no problem getting a 4U 500mm or 3U 500mm.
2pc 300mm sinks. 2pc 200mm sinks. 4pc of braces for the sinks (that need some mods). And maybe 2 heatspreaders. 500mm top and botom. Back and front panel in wanted sice
And yes. Ofcorse the 5U 500mm can be used for a lot more amps then a 3U400mm. But now we were talking about a AlephJ. I for one, get's a new chassis for every build. I dont reuse one chassis for all my amp. If you're gonna use 500mm depth chassis. you must spread out the outputs to match the depth to get the most out of the sinks. But there realy is no point in overdoing the sinks to much in a class A amp. Then you realy need to pump up the bias to get it to sing.
 
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