Aksa Lender P-MOS Hybrid Aleph (ALPHA) Amplifier

[Vunce]

X,

Check out the Tang Band W4-1720, the magnet structure is monstrous for a 4” driver. No problems with woofer excursion. If I build another pair, I’d use a flared port instead of the regular port, lots of air moves through it.
I built two pairs for my kids, but they have not put them in their rooms yet because I can’t let them go, haha!

Vunce

 

[Juntuin]

You have really nice looking original HUGE Class A amps - seems folks in Finland have really nice audio setups from what I have seen on this forum.

Thank you when I built "Guardian" it was meant to be my last DIY-amplifier..seems that it definitely wasn't. Have still sooooo much to learn. Every single project, all these conversations with all of you nice people teaches so much new with every project.

There are lot of skilled builders in Finland, they just seem to be "typical" Finns, if you can say so, many of them build by themselves without social side and most of them build and design only tube amps. I don't write for example anymore on Finn-forums. You can write and ask there, but no one answer anything. So I'm glad there is forum like this where people are kind and willing to answer even stupid questions!

Hi Juntuin,

Your ALPHA case is awesome! I really like look of the angled heat sink. Form and functional

Thanks a lot Vunce!

 

[prasi]

Piece by piece, slowly it's going to get it's PSU and frame ready. Too big toroid just for modeling it's upcoming place. Tomorrow I'll try to add lower platform for trafo and rectifiers (3mm alu). First test will be as "skeleton"-frame, if I get it work right then aluminium sheets all around and dreaming about BigBoy-version

Wow! Juntuin...thats very unique! I wish was handy with metal work like you.

 

[Juntuin]

Wow! Juntuin...thats very unique! I wish was handy with metal work like you.

Thanks Prasi! It doesn't look so good when you take closer look drilling is usually way off etc, but I drill everything by hand. My girlfriend said about the frame: "Yes, you can do it yourself. But if you want it to look good, let me do it."

But thanks to you guys, without you there would be nothing to build for me.

 

[manniraj]

Thanks Prasi! It doesn't look so good when you take closer look drilling is usually way off etc, but I drill everything by hand. My girlfriend said about the frame: "Yes, you can do it yourself. But if you want it to look good, let me do it."

But thanks to you guys, without you there would be nothing to build for me.

I see that you are using bridge rectifier modules to take AC-in and then DC-out directly to the Prasi/Juma cap multiplier boards. So the output from the cap multiplier goes to the Alpha amp boards? No need for any CRC or other kind of PSUs in place for regulation of the voltage.

Thanks

 

[prasi]

I am fired up with stereo speakers!!
After messing around with the SMPS bricks some more without success, I scraped the plan.
I put together a traditional linear power supply with components on hand and fed both ALPHA boards 22vdc.
SUCCESS!! Sweet music from both channels. Even with my pieced together power supply you can get the feeling that this is a special amplifier.
Words of advice, do not skimp with heatsinking. Even at 22vdc the ALPHA gets warm/hot rapidly. I planned to use forced cooling with the cpu coolers anyway.
With the proper power supply treatment, this amplifier is going yo ROCK
I tend to agree with X, “no doubt it will be an enduring classic”.


Thank you Hugh and X for bringing the ALPHA to the DIYA forum
JPS64, your amazing layout/design and board quality is first rate!! Thanks.

Yes its the work of ....Amazing AKSA, Relentless X and Artist JP.

Must be very very special. congratulations on successful build. what are you using for PSU? CRC ?

To X,
I was wondering if this can easily drive the Tarkus to listening levels and some ...

source will be CD player attenuated via B1 buffer...

regards
Prasi

 

[prasi]

I see that you are using bridge rectifier modules to take AC-in and then DC-out directly to the Prasi/Juma cap multiplier boards. So the output from the cap multiplier goes to the Alpha amp boards? No need for any CRC or other kind of PSUs in place for regulation of the voltage.

Thanks

CMX is doing that job, albeit with some loss in headroom..

 

[Juntuin]

I see that you are using bridge rectifier modules to take AC-in and then DC-out directly to the Prasi/Juma cap multiplier boards. So the output from the cap multiplier goes to the Alpha amp boards? No need for any CRC or other kind of PSUs in place for regulation of the voltage.

Thanks

Yes, that's how I thought to do it

CMX is doing that job, albeit with some loss in headroom..

Instead of 2x18v trafo, I took 2x20v so that should compensate voltage losses? I have to say that this is one super simple PSU if it really works

 

[xrk971]

20vac trafo is the way to go with the Juma/Prasi cap Mx. 28vdc drops 4v to 24vdc. You may have some voltage sag (to say, 22.5v or so) depending on how big your trafo is. No CRC after Cap Mx is required (its function was to eliminate costly caps from equation). It was designed by Prasi, at my request to use cheap rectifier bridge blocks rather than the more expensive and complicated 8x TO220 MUR diodes route.

 

[manniraj]

CMX is doing that job, albeit with some loss in headroom..

Yes, that's how I thought to do it



Instead of 2x18v trafo, I took 2x20v so that should compensate voltage losses? I have to say that this is one super simple PSU if it really works

Thanks prasi/Juntuin

Yes if it works as per your idea then its one of the simple PSU and economical to build and just relay on the best quality transformer. I already have the 18v 7A transformer from my old SX amplifier build and thought of using that along with CRC Prasi psu but looking at your build thinking I can just use my other 0-22v 6.8A transformer with the cap multiplier.

 

[xrk971]

To X,
I was wondering if this can easily drive the Tarkus to listening levels and some ...

Not having heard the Tarkus, but see it was designed by Paul Carmody to be 85dB at 2.83v. As I have used it with 82.5dB speakers, I would say, yes. Max output is 38vpp or about 13.4vrms. That’s 22.5wrms with 25v rails - and this lets you get +13.5dB over 85dB for 98.5dB. That’s loud but not rock concert levels. For reference, dance floor loudness is usually 89dB. You have to yell for your friend next to you to hear you.

I think Alpha 52w would be a better choice as that gets you 3dB more.

 

[pinnocchio]

Got the boards yesterday. Really nice quality!

Thanks
Do

 

[Juntuin]

Forgot to ask earlier X, is there any turn on/off thumb on Alpha20 (dc peak on speaker outputs)? Just wondering that do I need to add speaker prot boards to protect compression drivers.

 

[xrk971]

Lucky for you, you use the cap multiplier, so no. It provides a soft start and soft turn off mechanism that is basically inaudible. I use the cap multiplier in my headphone amps for this reason - you can get rid of an output relay and delay timing mechanism. Without cap multiplier, there is a slow thump - you can see cone moving slowly as the Aleph feedback caps charge up. But please test with just regular cone drivers before connecting your CD.

 

[Juntuin]

Lucky for you, you use the cap multiplier, so no. It provides a soft start and soft turn off mechanism that is basically inaudible. I use the cap multiplier in my headphone amps for this reason - you can get rid of an output relay and delay timing mechanism. Without cap multiplier, there is a slow thump - you can see cone moving slowly as the Aleph feedback caps charge up. But please test with just regular cone drivers before connecting your CD.

Ok, thanks! Wow, this Juma/Prasi (and should I add X, man behind this design) cap multiplier seems to be quite clever thing, solves many problems.

 

[Vunce]

Must be very very special. congratulations on successful build. what are you using for PSU? CRC ?

regards
Prasi

Hello Prasi,

I’m going to use the Prasi/Juma capMx
Do you know of any 47000uF 35v caps that fit this board? I can find plenty of 33,000uF.

Regards,
Vunce

 

[maty tinman]

Friday I changed the caps of my DC Blocker prototype (EPCOS B41231A7159M000 - Electrolytic Capacitor, Snap-in, 15000 µF, 35 V, B41231 Series, 2000 hours @ 85°C, ± 20% ) with:

Mundorf MLytic Audio Grade (AG) MLGO 25VDC / 47000µF @ 125°C

[/COLOR][/COLOR][COLOR=green][COLOR=Black] [url]http://maty.galeon.com/WP-imagenes/hum/ATL-Hi-Fi-DC-Blocker-prototype-inside-Mundorf-47000uF.jpg[/url]

[IMG] [url]http://maty.galeon.com/WP-imagenes/hum/ATL-Hi-Fi-DC-Blocker-prototype-inside-detail-Mundorf-47000uF.jpg[/url][/COLOR][/COLOR][B][COLOR=green][COLOR=Black]

and the improvement was great!

[/COLOR][/COLOR][/B][PDF] [URL]http://www.mundorf.com/english%201.1/Broschuere%20Einzelseiten/MLGO.pdf[/URL]

[CENTER][URL="http://maty.galeon.com/WP-imagenes/hum/Mundorf-MLGO-table.png"][img]http://maty.galeon.com/WP-imagenes/hum/Mundorf-MLGO-table.png[/URL]
[/CENTER]

If you want 35 V, only 33,000 uF. Pinnocchio uses them with USSA 5 amp.

Amplificateur USSA: Dans le ventre de la bete - construction par Pinnocchio - Page 7 [pictures]

[French] Amplificateur USSA: Dans le ventre de la bete - construction par Pinnocchio - Page 7

to English with Google

I let the amplifier work for over a week and a half and listened to lots of music. I wanted to be sure of what I heard. I will also validate with Fab, but so far I “hood” on the sound of my USSA 5!

The power supply in an amp makes all the difference, a huge difference in fact. That’s why you should never be afraid to invest in it. The double bridges of ultra-fast diodes with “soft-recovery”, the Mundorf M-Lytics MLGO condos with low impedance and ripple very high and the layout of the PSU very well done, high quality processors. All that matters a lot. This makes a power supply with lower impedance and a much lower noise in the end.

Result, full of low-level micro-details that were difficult to hear or went unnoticed, improved dynamics, a super silent background (very black) and micro-details that are no longer hidden or washed (washed). It was excellent before but there, as I told Fab, I almost fell off my chair. On some recordings that had a remarkable stage depth, it’s even better, difficult to explain, must be heard. I can stick my ear directly on the tweeter and not even a slight whistling, nothing, enough that sometimes I do not know if the amp is open or closed (I have no switch illuminated forward)!

In short, I am very impressed to hear that with a high quality PSU, the USSA 5 sounds even better. Proof that the PSU is the "bottleneck". ]

J’ai acheté 8 condos Mundorf M-Lytics MLGO 33000uF 40Vdc pour mettre dans mes deux nouveaux PSU pour le USSA 3/5. Un ESR de 6mOhm et Ripple de 11.2A

 

[Vunce]

Thanks Maty Tinman,

I’ve used the Mundorf AG’s in past projects, they are very good. I was trying to keep costs down, but the more I listen to this amp, my mind is telling me otherwise.

 

[maty tinman]

HifiCollective, 2 x Mundorf MLytic Audio Grade (AG) MLGO 25VDC / 47,000µF

56,46 EUR, with taxes + cheap shipping to Spain from UK.

In my others DC Blockers: (DCB, DCBx2 and DCBx4)

EPCOS B41505A7189M000 - Electrolytic Capacitor, Long Life, 18000 µF, 35 V, 5000 hours @ 105°C, ± 20% (EUR 12, two years ago)

In my Audiocircle thread I wrote:

In other words:

DCB proto with Mundorf is better than DCB proto + DCB.

It is an expense that is worth it. Once you notice the improvement you do not want to go back.

By the way,

GRAPHS: medium life electrolytic capacitor

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

​

 

[pcgab]

Set R105 to 1050ohms. The other pots R125 and R1270 are optional. If they are used skip the resistor corresponding. Set the pots nominal value to equal resistor it replaces (100k and 1k).

1050 Ohms between pins 2 and 3?