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Medium Aleph 3 8ohm@20w.
Medium Aleph 3 8ohm@20w.
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Old 26th February 2018, 08:19 AM   #11
Zen Mod is offline Zen Mod  Serbia
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Medium Aleph 3 8ohm@20w.
as long it isn't fake , it is good
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Old 26th February 2018, 03:57 PM   #12
Nag is offline Nag  India
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Thank you for clarification I will order parts and build.
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Old 10th March 2018, 12:01 PM   #13
Nag is offline Nag  India
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Hi All,

I ordered toroidal transformer. But I got huge 400VA E-I transformer. Input 240V out put two secondaries 0-18V,0-18V. If I use EI transformer any drawbacks.I it require any Faraday cage or can I return ?.
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Old 10th March 2018, 12:05 PM   #14
Zen Mod is offline Zen Mod  Serbia
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Medium Aleph 3 8ohm@20w.
just don't make Liliput-sized case , move xformer to front and you'll be good

of course, there is a issue, not related to technical side of project - if you order one thing and you got another ..... did you got what you paid for ?
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Old 10th March 2018, 12:34 PM   #15
Nag is offline Nag  India
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Paid around 50$.
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Old 10th March 2018, 12:49 PM   #16
Zen Mod is offline Zen Mod  Serbia
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Medium Aleph 3 8ohm@20w.
that's not a question;

question is - are you satisfied with service you paid for

as I said , not technical issue , xformer is adequate
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Old 10th March 2018, 12:58 PM   #17
Nag is offline Nag  India
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The quality is good. I expected a small size. But it is a big size. If technical point of view is ok then I will use. Next time when I give order I will give strict instruction it should be toroidal.
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Old 23rd April 2018, 08:08 PM   #18
tonimxp is offline tonimxp  Italy
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Default Some tips to optimize this variant of Aleph 3

Hi Guys ...Please what do you think about this Chinese variant of Aleph 3?
Some advice for optimizer it?

This are the Mister NP advices:

"No surprises. Varying the gain of the current source has a substantial effect
on the sound. As you increase the gain, the open loop gain of the amplifier
increases, so distortion goes down and becomes more 3rd harmonic in
character. As you decrease the gain of the current source toward having
constant DC current, the open loop goes down, there is less feedback,
the distortion goes up and is mostly negative phase 2nd harmonic.

Playing with the current source gain (either Aleph or mu-follower circuits)
also impacts the efficiency. If you are simply looking to maximize efficiency,
then the 50% gain figure is close to what you want - the current source is
seen to contribute 50% of the AC output current. With this the actual
efficiency of the amplifier will be 40% at best for real circuits.

When you deviate from 50% you will find that you need to increase the
bias current to have symmetric clipping, but you pick up some interesting
performance aspects:

If you double the current and the gain of the current source, what used to
be the gain transistor has very little work to do, and actually becomes more
like a driver transistor for the current source. The distortion gets much
lower, but higher order harmonic content.

If you double the current and set the current source as constant (0 gain)
then the distortion becomes more purely 2nd and continues to get lower.
This setting tends to sound quite good.

Of course in both cases the efficiency drops by half, so you're getting down
to 15% to 20% instead of 30% to 40%"

Thanks Mister Pass!

I need to optimizer this amp for good load capability but with a second harmonic thd predominant .
It is possible playng with Bias setting and AC gain?
I will use 2sj313 instead Q5 and Q6 , mpsa18 instead Q4 and Q9.
Thanks.
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Old 23rd April 2018, 10:32 PM   #19
Zen Mod is offline Zen Mod  Serbia
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why dont'ya ask Chinese vendor for advices ?

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Old 24th April 2018, 05:47 AM   #20
tonimxp is offline tonimxp  Italy
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Quote:
Originally Posted by Zen Mod View Post
why dont'ya ask Chinese vendor for advices ?

Just done... He not reply.
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