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Class D Switching Power Amplifiers and Power D/A conversion

Arjen Helder's 2050 boards
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Old 12th September 2011, 05:38 AM   #181
Homl is offline Homl  Canada
diyAudio Member
Join Date: Nov 2003
There is no common output ground with these amps. Both output connections of each amp must be completely isolated.

I would isolate and test each amp and power supply individually to make sure each one is operating properly; and make sure the outputs and grounds are not interconnected in any way.

Hope that helps.

Last edited by Homl; 12th September 2011 at 05:43 AM.
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Old 23rd November 2011, 06:12 PM   #182
Quba123 is offline Quba123
diyAudio Member
Join Date: Feb 2011
Hi, im new to building my own amps but im very excited to build one using Helders monoblocks, i need some help with the choice of power supply.

Should i use a toroidal transformer with a capacitor bank or a Mean Well 27V DC13A 351W.

If i use the Mean Well, do i have to use a capacitorbank aswell?
And could someone link a picture of the wire schematics for power and audio input?

And is it neccesary to use a pre-amplifier to the chip amps or could i directly connect my DAC to the signal input?

i hope im not completely irrelevant and i understand if i have to do some more information gathering before i start my build.

Sorry for my poor english but its not my native language // Reguards Quba!
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Old 19th December 2011, 07:45 PM   #183
pixy is offline pixy  Canada
diyAudio Member
Join Date: Mar 2008
Default Advise on Amps

Originally Posted by Jack Caldwell View Post
Hi, about the playing time using batteries.. have not yet tried the 24V/20A SLA on the Helders as I've been running the RedWine LFP pack to get the best comparison basis. the redWine seems to play at least 10 to 12 hours before needing recharge, maybe longer. I usually just recharge at the end of the day, when I don't keep it attached to the charger.

The playing time on the 24V/20A batteries might be similar but those do NOT fare well when deep discharged. For many, this in itself would be reason enough to get 8 good quality 20Amp LiFePo4 cells, wire em in series and outfit the whole with a good single /multiple charger. Not cheap, not cheap at all...probably in excess of $400 without a box....and probably worth every penny !!
RedWine charges $800 or more for theirs...it's supposed to be a 10amp unit...half of my SLA pack.... but it really is much better and proves the old saying about the PS making the most difference in the quality.
Sadly, many here will rule out trying it based on cost alone... I know, I know, I was once one of those who thought DC is the same from any battery... then when Vinnie lent me the LFP pack I was forced to admit it sounded waay better... my pocketbook still has a hole where that money once resided!

Now, about the sound while using the RedWine LFP supply to drive the Helder:
Well... it IS good... but not as good as any of the Virtues. It's bold and gutsy and powerful with good definition, but it is not yet special or magical like the Virtues. I suspect changing the input cap will help. Modding parts are on their way, will report more soon. Also, will compare against a stock Sure board at about the same time.

Hey, there IS another mod I'm VERY pleased with, on a Behringer DEQ2496, completely bypassed the entire output section and took the AKM 4393 DAC outputs directly through a 1:1 custom nickel transformer from EDCOR. I found that the rumors of it being very good were indeed correct. It's a fantastic sounding DAC...easily in a class that competes with the $2K and above goodies. Very analog-like, smooth detailed sound with enormous soundstage and really good PRAT. Made my daughter just jump up and start dancing! Yep, it's that good.
with built-in 24bit/ 96KHz capability, great EQ and spectrum analyzer with built-in pink noise, there's a lot to like about this box... and you can use it for LOTS of other things. But you wouldn't like the sound of its analog circuitry, it's built to drive 100ft cables... and it sounds like...well, it needs a good mod.

I may very well offer this as a standalone mod or as an option mod with my HolisticAudio.com speaker systems

OK, more later. Happy Trails!
I am debating between sensation 901 and Helder's STA508 modules. I have Helder's 2020 MKIII running with 12v SLA and excellent comination (better than Trends with SLA and Kingrex with Kingrex's own regulated power).

Helder's may not have the smooth as trends or Kignrex but I love it's openness and immediacy for vocals and instruments.

Now I need bit more power to drive my new set of speakers. So I am thining of getting M901 and plan to drive with 24V SLA. Then I heard about Helder's new STA508 MKII.

Does anyone has tried STA508 MKII and how does it compare with Virtue M901 or M451.

When it comes to listening, system doesn't get me engage or involve shouldn't be on my list. I have good results with 2020 MKIII with SLA.

Any comparison between sensation with Battery and RWA 30.2 Sig?

Jack Caldwell, can you able to give your thoughts on virtue sensation.

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Old 2nd February 2012, 01:04 PM   #184
audionootje is offline audionootje  Netherlands
diyAudio Member
Join Date: Dec 2011
Smile Sorry, newby questions

Hi, here my first post on this forum. This is also my first DIY project and still have some questions.

After lurking around on this forum, I ordered the Arjen Helders
PAIR OF MKII STA508 Tripath 100W monoblock amplifier and the MKIV Universal Pre-amp.

Separatly I ordered the meanwell SMPS
100W 24 Volt powersupply, to come to the conclusion that I will need 2 of them. Since those supplies are rather large, I ordered the Connexelectronics SMPS300R from HifiMediy to keep sizing under control. This powersupply should provide enough power for both monoblocks and maybe even the preamp.

From HifiMediy I also ordered: Hifimediy "direct out" DAC: cs4398, w/upsampling
192/24 cs8421, TCX0 and TE7022 USB, MUNDORF MCAP with a powersupply for the dac.

I've tried the monoblocks with the 1 meanwell powersupply and it sounded
promising .

I now have to make the decision to

1. Put everything in 1 box or
2. Create a poweramplifier and put the preamp with
the dac in one box or
3. Skip the preamplifier and put the DAC in the same
enclosure as the monoblocks or
4. Put Monoblocks and preamp and dac in a
seperate box

My preference at the moment is option 1 or 2 to keep things tidy (waf involved

This leaves me with a couple of questions regarding the common ground and
possible voltage difference problems I might run into when I go for option 2,3
or 4.

A. Common ground and loops
The connexelectronics powersupply need GND from the case you ( the spacers must
have firm connection to GND due to the small design). The monoblocks have
spacers attached to that seem to have connection with the minus of the
- Should I now put the amps on isolated spacers (monoblocks and preamp)to prevent ground loops?
- Should I create a star ground configuration?

B. The gnd of the source input seems to be the same as the minus of the powersupply. Will this cause a problem if I connect an other source to it that has a different operating voltage?

Thanks for you help in advance.

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