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Premium ACA with CapMX PSU

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jean-paul

jean-paul

Disabled Account
Joined 2002
Rudi_Ratlos said:
Gentlemen, I have received the "Premium ACA PCBs" this morning (image 1).

Concerning the post of "Jean-Paul" (post #194) in this/my Premium_ACA – thread a couple of posts before:

I have appreciated the posts of "Jean-Paul" in this forum in the past and thought of him to be a „High-Ender“.
He is definitely no more – in my opinion - after his post.

I have looked through all of my „Premium-ACA“ EXCEL – buyer sheets.
"Jean-Paul" has never ordered/bought a PCB-pair of them.
So: what is he talking about?

I doubt that he has even taken a look on the schematics on this (my) „Premium – ACA“.
He would have noticed – in this case - that my ACA – layout contains a „high sophisticated“, regulated (!) CAP-Mx PSU,
which does an undoubtedly good job, not regarding „who is doing the rectification“.

There is definitely no reason to optimize anything concerning „my Premium ACA – design“.

I would be very happy, if Jean-Paul apologizes to have intruded this thread with his ears“ - Rudi_Ratlos
Click to expand...


Strange remarks, please reread the post. I do notice you did change some things after my suggestions (the 10 µF film cap, speaker relay) which you denied implementing in PM also in a strange way. Reading is an art, I never even mentioned ACA in my post nor did I criticize anything of your (YOUR) design. Please point at the in your eyes ruthless criticizing of the design. The fact that you post this publicly says more about you than about me I think and apologizing?!?! For what? Never been a high ender whatever that may be and why the "Jean-Paul" ? It IS my real name contrary to yours. I think I just suggested in general that ideal rectifiers have their merits, both technically and sonically, no more no less but "needing" is exaggerated. We need to breathe, eat and sleep. Long toes, Rudi?

For evaluation:

jean-paul said:
The information on "needing" LT4320 is incomplete IMHO. No one "needs" the amplifier in the same sense either.

The ideal rectifier has way lower Uf and resulting rectified/filtered DC voltage will be higher and losses/heat will be lower. Since the ideal rectifier starts to conduct earlier wave form looks slightly better and transformer loading is slightly more elegant. Regardless of whatever technical reasons/beliefs/preferences, in my experiments with other devices that consume way less current than 2A the difference sonically was so interesting I updated nearly all devices to LT4320 rectifiers. If it wouldn't be that I could choose lower secondary voltages of transformers when using LT4320 etc. I would do it just because it sounds better. Don't ask me why, as much as I would like to know myself I haven't figured out why the difference is there. To be honest I thought them to be overly complex compared to the good old diode bridges. I also use Saligny rectifiers and results are OK too.

All situations are with well measuring, previously already good sounding HiFi devices.
Click to expand...

BTW the thread title is :"ACA - PCB offer with LT4320 based rectifier and CapMX PSU"....which triggered my interest only to see that the LT4320 is omitted. Now who needs to apologize to who?
 
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Rudi_Ratlos

Rudi_Ratlos

Member
Joined 2009
Thank you, Mooly, and thank you, jean-paul, for your assistance.

I will open a new thread tomorrow, the day after, ... ?
Its title will be: "Audible benefits when using a LT4320 based rectifier".

So everybody, who changed his existing rectification, can publish his listening impressions and answer the question:
"Is the LT4320 worth while - from a pure audible point of view".

Best regards - Rudi_Ratlos
 
Rudi_Ratlos

Rudi_Ratlos

Member
Joined 2009
Knuds1: I have included the BoM in the ACA's Builders documentation file, that I have sent you some time ago.
Its name is: ACA_doku.zip.
Since I myself normally order from REICHELT Electronics in Germany,. I do not have the MOUSER article numbers.
I have attached the BoM to this post.

Gary s: things get complicated.
I have done some research concerning the usage of the LT4320 diode bridge controller in German forums.
Only very few posts emphasized the benefits of the LT4320 in audio applications (as replacement for the PSUs' Graetz bridge controller).
Most of the posts described its importance in low-voltage or high current applications (I did not even know, that there are applications that use 20-50A of DC current).

The advantages of the LT4320:

small heat dissipation because of very low forward voltage drop
A normal bridge rectifier - used in the ACAs PSU - will consume about 3-4W.
The heck with it - compared to the ACAs power dissipation of about 50W per channel!

higher rectified voltage (once more due to very low forward drop)
But does about 1.5V more (on the output transistors collector - compared to a standard rectifier) make an audible difference?
A 5V higher output (comparision between the original ACA powered by a 19 VDC Laptop PSU and the current 24VDC ACA) makes a difference!
Just take a look at the IRFP datasheet to see, how the internal capacitance differs! A 5V difference is something that you will be able to hear!


When somebody wrote in his post (in a German forum) that after the replacement of a "normal" bridge rectifier his music sounded much better,
the "feared audio-esoteric" discussion began: Panasonic FC capacitor on the output makes the sound smeary, take Silmic II instead, ...

I myself have quite good (though rather old) ears.
I play the piano, for example, and know to distinguish between authentic and recorded music.
I have compared an LT4320 bridge to a GBU15L05 (from Taiwan Semiconductor) in "my" Premium ACAs- PSU". I did not hear an audible difference!!

This is my humble impression / opinion.
If somebody hears a difference: he shall open the thread instead.
This thread has become a builder's thread in the meanwhile, and I politely ask you to keep it as that.

Best regards - Rudi_Ratlos
 

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cl00sed

Member
Joined 2013
I have done with populating 2 boards.
First channel came up well and working as expected.
Using 22v transformer and the vdc was set to 28mv and the bias to 14.5v

Facing issue with second board, power led was not glowing and the vdc was at 32v

Please help me out in solving the issue

Regards
Raj
 
C

cl00sed

Member
Joined 2013
70149c7c-ba7a-45f9-933a-3e72c26676a6.jpg

Only this channel is having problem

Led near cap mx module is not glowing, earlier it worked after some time stopped.
When it was on the vdc was 28v and when it was off 32v is displayed at vdc
Not sure what is the issue
 
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