Aksa Lender P-MOS Hybrid Aleph (ALPHA) Amplifier

[ostripper]

Well, there are other "problem": maybe there are too many DIY class A amplifiers, and many doubt which to build, even though the ALPHA has very good measurements!

And class A need speakers with high/very high sensitivity, and better with true nominal impedance near to 8 Ohms I think.

And, no less important, fewer and fewer people appreciate good recordings, with unadulterated voices and acoustic instrumentation and high dynamic range (DR).

That is why the commercial and DIY market must be shrinking year after year.

As it happens in other fields, such as (good/true) literature. For decades the books are worse written, use less vocabulary and contain a lot of spelling mistakes, at least in Spanish. Now I read little, but years ago I got fed up and decided to read books written years ago. It is the same philosophy that I use with music. I was a regular at the Public Library of Tarragona, to which I ordered the purchase of many books to make it richer, tired of it being full of best sellers, so badly written in its vast majority. Now, the few that I read, I do it from the screen.

These are my observations exactly.



They (the builders) want gobs of power without the amp being a ship anchor.
Also , ""Gobs" must be PPM !!

They want class A harmonics and Valve overload behavior.
They still want 20th century discrete components to stay away from tweezers
and magnifying glasses.


Believe it or not , the simple first ASKA amps are a baseline in my complexity
vs. accuracy design criteria.


Many roads can lead to the same place.


OS

 

[xrk971]

Welcome back DrPro. I have been loathe to order anything from the multiple carts I have saved for fear of spending another $200 for handful of caps and transistors. I try to make my existing stash of Mouser parts useful before ordering more. I have stuff that has come in and now can’t remember what project they are for. The stuff that seems to go are the large power supply caps and red Wima film caps. Can never seem to have enough.

The JK cap Mx will drop say 2v and at 3amps per rail that’s 6w per rail or 12w total. The diode bridges drop 0.6v x 3amps x 2 x 2 bridges = 7w approximately. If you mounted both MOSFETs and both bridges to one of these cheap heatsinks (which I think are good for about 15w) it will be ok running at 19w but maybe a bit toasty at 60C about. But if you place these sinks in the exit flow from the main MOSFET CPU cooler out flow, it will run quite cool. Or you could mount one cap Mx and bridge per heatsink and it will work fine and stay relatively cool.

Look what I found on AliExpress
(Special offer) 150x60x25mm radiator Aluminum heatsink Extruded heat sink for LED Electronic heat dissipation cooling cooler-in Fans & Cooling from Computer & Office on Aliexpress.com | Alibaba Group

They are not expensive and nice to have around.

Btw, it seems diode bridges get quite hot when running Class A. I just ran across this nifty “ideal diode bridge using 4 N channel MOSFETs and an LT4320. Pretty slick.

An externally hosted image should be here but it was not working when we last tested it.

LT4320 Ideal Diode Bridge Controller Cuts Power Dissipation, Improves Efficiency | Power Electronics

Probably overkill here but thought it was interesting - and for applications needing 20amps it might actually make a lot of sense vs a huge heatsink and losses from a bridge going up as heat vs the actual workload.

 

[ostripper]

Aliexpress ?
Will they last , like my 4 day UV leds (turned white) or my 4 microwaves
that blew up after a few weeks.


I would buy the LT IC and build my own.
To trust my speakers and audio to Aliexpress would make me like walmart (traitor) ,
where I'm on my 4 'th microwave with a challenged magnetron in 6 months.


Wow , 20 amps = a nice 1kw AB/G amp.


OS

 

[xrk971]

Aliexpress ?
Will they last , like my 4 day UV leds (turned white) or my 4 microwaves
that blew up after a few weeks.

It’s an aluminum heatsink - not much to wear out.
(Maybe you were thinking that I meant the LT IC
From Aliexpress? No, that’s a different subject - just thought worth mentioning for anyone interested who might need a 20A continuous bridge without a massive heatsink.)

That LT4320 is very nice - stand-alone operation with no external parts needed except 4 MOSFETs.
https://www.mouser.com/datasheet/2/609/4320fb-1271125.pdf

Here is the $4 heatsink I was referring to on Ali:

I don’t buy transistors on Ali anymore but their CNC aluminum cases are quite amazing and can be well made.

I hope you saved the 4 microwave oven transformers from your dead microwaves. Those are like gold as far as making a SE Class A amp goes.

Recall from a few posts back that those are what enable my MOAMOFO to swing voltage higher than the rails.

 

[ostripper]

Even the heatsink , Chinese audio amp case I had was Mg/Al + other waste
heavy metals for the heatsinks. It drilled funny , I broke off taps in it.
Go buy real aluminum - Heatsink USA stock.


I used that USA stock , better thermal conductivity , better milling.


PS - I returned the microwaves , #3 is going back 2/1/19... # I might luck out on # 4.

 

[xrk971]

I won’t argue with you OS, but there are many vendors and the cases I have bought such as this one, tapped just fine. Nice thing was all the usual holes for IEC, power switch, pot, bananas and RCAs are pre-cut.

This finished case cost the same as what I bought two smallish 7in x 5in bare heatsinks for from Heatsinks USA.

Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier

 

[ostripper]

I won’t argue with you OS, but there are many vendors and the cases I have bought such as this one, tapped just fine. Nice thing was all the usual holes for IEC, power switch, pot, bananas and RCAs are pre-cut.

This finished case cost the same as what I bought two smallish 7in x 5in bare heatsinks for from Heatsinks USA.

Nothing to argue-

That IS the one I had , you got it.
It is hard Mg/Al.

Even 12" X 5" the most expensive heatsink USA item is 26$ ($5.20/ft X5)

So you got your case for under 55$ ???

That is what it cost me to replace the heatsinks on YOUR case.

My Chinese case cost more than that to ship. About $160 to receive it.
They all sit around the melting pot laughing as they throw heavy metals
into the mix.



OS

 

[thimios]

Agree, i have used, Chinese, modushop, fisher heatshink.
Nothing better than Fisher.
Easy to drill and tap, extra fine and deep anodaized, just the best.

 

[maty tinman]

Allow me this off topic:

Just now, with literature but the same with music... Culture, from CEO of Alianza Editorial, interview:

[Spanish] – Valeria Ciompi: <<Se escribe muchisimo, se publica muchisimo, pero es dificil encontrar textos que te remuevan>>

Has expresado en alguna ocasión tu preocupación por la «banalización de la escritura». ¿A qué te refieres?
La lectura nunca es banal, pero los contenidos sí pueden ser banales. Desde la última etapa de los ochenta, todos los que estábamos ahí participamos de la ilusión de que la alta cultura iba a llegar a todo el mundo.

¿Y cómo está ese sueño ahora mismo?
Pues que no es así. El sueño ya no es que la alta cultura va a llegar a todo el mundo, en absoluto. Cuando hablamos de los lectores que hay en este país y la asiduidad de la lectura, lo que vemos es que hay un núcleo de un número indeterminado que varía según los países, de lectores fieles de muchos contenidos de muchos libros. Pero no se ha extendido a toda la sociedad. Con los medios de comunicación, las redes sociales, los nuevos usos culturales, los nuevos consumos y el empleo del tiempo… todo eso ha hecho retroceder lo que pensábamos que era la alta cultura. Pero también es verdad que el número total es superior al que había antes. Tampoco hay que hacer una lectura tan pesimista.

Sobre el sueño de darle a la alta cultura una vocación universal, si habéis renunciado a él, ¿eso implica asumir que te diriges solo a una élite?
Yo me temo que hay que reconocerlo, sí. Es tremendo hablar de una élite, pero sí es verdad que hay una gran parte de los ciudadanos que le han dado la espalda a la cultura, o la han sustituido por otros contenidos que poco tienen que ver con la cultura. Ahora, entrar a analizar cuáles son los motivos y las razones es complicado, porque me temo que la respuesta está en el mismo sitio: empieza con tres años, en el colegio. El libro ha sido postergado dentro del propio sistema educativo.

to English: Google Translate

You have expressed on occasion your concern for the "banalization of writing." What do you mean?
Reading is never banal, but the contents can be banal. From the last stage of the eighties, all of us who were there participated in the illusion that high culture was going to reach the whole world.

And how is that dream right now?
Well, it is not like that. The dream is no longer that high culture will reach the whole world, not at all. When we talk about the readers in this country and the assiduity of reading, what we see is that there is a nucleus of an indeterminate number that varies according to the countries, of faithful readers of many contents of many books. But it has not spread to the whole society. With the media, social networks, new cultural uses, new consumption and the use of time ... all this has pushed back what we thought was high culture. But it is also true that the total number is higher than it was before. Nor should we make such a pessimistic reading.

About the dream of giving high culture a universal vocation, if you have renounced it, does that imply that you are addressing only an elite?
I'm afraid you have to admit it, yes. It is tremendous to speak of an elite, but it is true that there is a large part of citizens who have turned their back on culture, or have replaced it with other content that has little to do with culture. Now, going to analyze what are the reasons and the reasons is complicated, because I am afraid that the answer is in the same place: start with three years, at school. The book has been postponed within the educational system itself.

That is why they sell or build less and less good/very good equipment to play quality music, well/very well recorded, it is the same phenomenon.

Books, music, fast food.

 

[xrk971]

Nothing to argue-

That IS the one I had , you got it.
It is hard Mg/Al.

Even 12" X 5" the most expensive heatsink USA item is 26$ ($5.20/ft X5)

So you got your case for under 55$ ???

That is what it cost me to replace the heatsinks on YOUR case.

My Chinese case cost more than that to ship. About $160 to receive it.
They all sit around the melting pot laughing as they throw heavy metals
into the mix.



OS

Yes, $55 shipping included. That was pre-trade war price of course.

It’s $83 now shipping included.

HIFI audio amp Aluminum case 2412C Full Aluminum Amplifier case /Mini AMP Case/ Preamp Box/ PSU Enclosure 240*120*271mm-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

 

[xrk971]

That is why they sell or build less and less good/very good equipment to play quality music, well/very well recorded, it is the same phenomenon.

Like cooking our own food, thank goodness there is DIY available to make some very fine amps and speakers.

 

[Juntuin]

X, did you personally delivered those pcb's in my mailbox? I mean, they came pretty fast to Finland! I had forgotten how nice those B.B.'s are, never seen pcb's like those.

This build have to wait a little while though gathering parts and planning something nice for casework. One thing is for sure, fans are going to be Noctuas again. Have to find cpu heatpipe coolers that also looks good, they are going to be visible this time. Dell server coolers worked well but they don't look so pretty.

Thanks again!

 

[xrk971]

Nice to know my teleporter works!

 

[zman01]

Nice to know my teleporter works!

Teleporter or Mika Häkkinen was the Transporter for those PCBs?

 

[jwjarch]

Juntuin, check out these CPU coolers. Special Edition | Prolimatech

I have a pair of these waiting for my MoFo build. They can accommodate many different CPU's. I'm guessing they can easily dissipate 150W and look great too!

 

[Juntuin]

Juntuin, check out these CPU coolers. Special Edition | Prolimatech

I have a pair of these waiting for my MoFo build. They can accommodate many different CPU's. I'm guessing they can easily dissipate 150W and look great too!

Thanks jw, they indeed looks awesome!

 

[Mleod]

Greetings to everyone!

I would like to deepen the study on BB: I can ask where to find the complete definitive scheme, and performance and supply voltages as well as the BOM and how to find PCBs.
Thank you and greetings. Ciao

Mleod

 

[xrk971]

Greetings to everyone!

I would like to deepen the study on BB: I can ask where to find the complete definitive scheme, and performance and supply voltages as well as the BOM and how to find PCBs.
Thank you and greetings. Ciao

Mleod

It’s all in Post 1 of GB thread.

Aksa Lender P-mos Hybrid Aleph (ALPHA) Class A Amp GB

 

[Mleod]

Thanks... X

 

[anatech]

Hi folks,
Please do not quote the entire post above yours that you are responding to. You can quote a small pice of the post, just don't do the entire thing. It makes the thread a pain to scroll through. FOr the same reason, please don't copy pictures either.

-Chris