Class D Audio, Who are these guys?

[HiroPro]

I guess it's a IRAudAmp7 IRS2092 ?

Considering SMPS from Roberto P (AP2 from audiopower.com Italy) model DPS-500-S with classdaudio.com SDS-258. I hear great things regarding SDS series amps!!!

Has anyone here used AP2 SMPS with SDS-258?

About to do a DIY 2 chan rig with the latest and greatest "Cheap and Cheerful"

Current list is:

Jed Kunz Dynamic 4T SE DIY towers
Emotiva XDA-1 DAC (also used as pre)
SDS-258 amp with DPS-500-S SMPS

Comments, hints and suggestions?

[OlavHaal]

Hi there all!
This is my first go in the amp-building appartment! A SDS254Kit. It is just running its first go with some music this week - and 1 impression is - that it is just as good as my 2 year old HK980 - if not even more revealing. A little weak in the bass, but will change the electrolytic caps to some better/bigger later - in a box that is more accepting for this! A very good soundstage with my Alpair10.2 when I use the pre-amp in the Harman. Even straight from the Touch with some 24/96 music from BowersWilkins Music Club is very good(need some better DA-converter than my old DagMagic to fully unlock this possibility.
Next step - build a Nelson B1 Passive Buffer(some additional tricks from some of you guy out there as help for this build?).

And after that a F4-F5 amp - maybe? And maybe an Alpair12.2 MAOP? If time and Spirit allows!!

Building has never been so fun since I build an Hafler Pre-amp and a Sentec Power-amp in the 80s!

Best to all

Olav

[Mark Allen]

Yes I am around poping in and out once in a while in this or that thread... I am guilty of starting other threads as well and then just letting them run themselves... KSA-100 thread for instance. I am still very busy converting the world over to Digital Cinema and that is consuming 95% of my time the last couple years... Keep the thread going... Class-D makes great products and I love that it is made in the USA!

[HiroPro]

Originally Posted by Mark Allen

Yes I am around poping in and out once in a while in this or that thread... I am guilty of starting other threads as well and then just letting them run themselves... KSA-100 thread for instance. I am still very busy converting the world over to Digital Cinema and that is consuming 95% of my time the last couple years... Keep the thread going... Class-D makes great products and I love that it is made in the USA!

LOL thanks for starting the threads! I would not know about classDaudio.com then!

Very interesting work Mark!

Perhaps you have a blog of your theater modernization adventures?

[esreuter]

Hello all,

new to the forum here and working on my first DIY amp.

I have chosen to go with a module build first so i can better understand the power source and internal rigging.

I am seriously considering the TI-600 board. Actually 2 of them, one power source recapped to 60k capacitance and a 50v/1k transformer.

If i may run some ideas and methods across you members who have built several amps.

Here is what i will power now,
Polk monitors, rated 90db efficient.
from research I have learned i would need roughly an amp of ~120watts to get my speakers to play at 90db and then 20db head room for the peaks.
I will not often play them this loud as i cant stand reference 85db for to long but i like to have the power.

In the future i will be powering polk lsi line
4ohm and 88db efficient.
using the same logic i would need ~200watts. for 110peaks and 90db

i am wondering if the math formula i learned in a earlier post is a accurate representation of the output of the classd boards.

max output rms= rail voltage - 10/1.41=X. X^2/impedance
for my idea:
50-10=40
40/1.41=28
28^2=804
804/8=101watts per channel clean power.
804/4=201 watts clean per channel.

did i understand the formula correctly? I wonder if its pretty close because i do not have a sine wave generator and the other cool equipment to see when the wave distorts.
here comes the questions! Please hang in there with me.
1. is it correct to say 101 watts PER CHANNEL? or is that 101 TOTAL watts and then /2 for the channels?

2. I want to know your thoughts about my logic in choosing a transformer.

first off i want to maximize my amps potential, so I want to have 50v.
second, i simply added up the amps potential output and turned that into the VA rating.
I concluded that running 2 amp boards at 300wx4, I should have 1200va to cover the power needed by the amp.
1000va is rated at 50hz, living in America i have 60hz so my transformer would be 1250va. is that a proper logic for choosing a power source?

I will state this, I know ill never drive the amp at its max, as stated above at 8R i need about 120watts to get to 90-110db. but again i would like to have the power there especially when i get into the 4R speakers.

I have a transformer wiring question, I read the hook up schematic for the power source from class d audio, as i understand it you take the 2 50v secondaries and wire them in series and connect them to the board.
does this mean i have 100v rails?

and my output of clean power would be: 509watts at8R, 1018w at 4R?

Then finally the capacitance on the power source. I understand what a cap does for filtering and its charge holding ability.
I would like to know is 60k enough for smooth power operation of my idea?
i have read some other sources and they support a 4 channel amp to have 80k, or 20kcap for each channel.

I think that is enough for now.
oh and since i named the post about bench tests, well has anyone put the classd on the bench to see what it puts out?

Thank you all for your wisdom and time,

ESR

[esreuter]

This is just a reply to negate my question about the secondaries on the transformer.

I have just learned about what using the center tap with a transformer does when your secondaries are in series.

Still looking forward to all other advice.

thank you for your time.
esr