Aleph 1.2 Trafo question - diyAudio
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Old 5th October 2013, 05:34 AM   #1
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Default Aleph 1.2 Trafo question

Hello folks, i am a complete noob, with big dream!

I would like to build aleph 1.2s someday. rest assured i will start with smaller amps, and work my way up. past projects include chip and ice projects, and some crossover modifications.

Although this project is far in the future, it's never too early to assemble parts!

Would a transformer with

Primary:
120V 60Hz

Secondaries:
2 x 60V 18A
2 x 24V 1.8A

And 2246 VA be suitable for an aleph 1.2 build?

I have seen aleph 1.2 boards that call for 50v and 1200va per monoblock. Would this Trafo be unsuitable? Is there a way to step it down or adjust it?

How would the capacitor bank need to be adjusted to accommodate the larger size?

Thanks in advance for the help, I wish I could repay you for it!

Someday I may be able to pass (so to speak!) the knowledge onto others.

I will make another DIY donation when this pipe dream sees fruition.

Last edited by theduker; 5th October 2013 at 06:39 AM.
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Old 5th October 2013, 09:47 AM   #2
Zen Mod is offline Zen Mod  Serbia
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if you add one 24V secondary in series with 120V primary , you'll have exactly 50V at secondaries

be careful - you need to connect it (24V) in phase
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Old 5th October 2013, 08:02 PM   #3
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Quote:
Originally Posted by Zen Mod View Post
if you add one 24V secondary in series with 120V primary , you'll have exactly 50V at secondaries

be careful - you need to connect it (24V) in phase
Zen,

I usually "drink" your words (almost) without thinking, but could you kindly develop your thoughts ?

Max

Last edited by coolnose; 5th October 2013 at 08:09 PM. Reason: *(almost)
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Old 5th October 2013, 08:14 PM   #4
Zen Mod is offline Zen Mod  Serbia
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connecting 24V winding in series with 120V winding will give new primary , while un-altered secondaries will ,then, have lower resulting voltage ( n/V ratio in primary is altered , so also for secondary) , ...... so decreased voltage

calc is simple :

for U= ( 60 x 120) / (120+24) = 50

fact that 24V winding is having greater dia wire than primary can't harm .....
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Old 5th October 2013, 09:47 PM   #5
WalterW is offline WalterW  Netherlands
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Wow, that's a smart idea.... never thought you could do that, putting a secondary in series with a primary...

But what the heck is an Aleph 1.2 ??? 1,2KWatt amplifier?
How many Aleph's variations are out there ?

Found some info, they are huge....24 output devices.. out of my league...
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Last edited by WalterW; 5th October 2013 at 09:56 PM.
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Old 6th October 2013, 01:52 AM   #6
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The 1.2 is a 200w class a beast!! I've always wanted to build one. It dissipates 500watts at idle, so it's really more of an exercise in chassis building, two in this case. You could always could put large value heatsink mounted resistors in the power supply to drop voltage, or use a variac before the transformer.

found some pics of someones 1.2......looks like a wallet eater

DIY Aleph 1.2 - a set on Flickr

another

http://www.diyrealaudio.com/user_rep...ru_12ap_en.htm


build it!!!

I believe there are officially 7 versions: 1.2, 2, 3, 4, 5, 30, 60
I think also the aleph 0, and maybe 1, but they are 3 stage amps vs the above 2 stage.


The cool thing about the alephs is that you can build it any way you like; different voltages/bias/output trannies. The topology between versions are the same, with some resistor value changes and bigger/smaller output stages between versions. I started with the 5, but increased the bias to 5amps, it sounded great, but died a firey death. When I told people that it was 'only' a 60w amp, their jaws dropped.

Last edited by MEGA_amp; 6th October 2013 at 02:20 AM.
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