Another project, all digital DDX amplifier

[soundcheck]

Originally Posted by raschaa

is kind of sad that the early adopters always turn out to be the better beta testers

Yep. You got a point. I'd also prefer an amp done right from the beginning.
Especially if the receipe (at least most of it) is known, you shouldn't leave
out half of the ingredients.

Quite nicely made full digital amps such as Sumoh or the newer Maestro-50 sell at around 250$. Why should I go for a 100$+PS+tweaks+chassis diy-module instead? And then the V2.1 would be the third one on my table.



PS: On above list of lacking features on the V2.1, I'd like to add that the
digital supply pins would work presamumble better with very low ESR
Oscon decoupling caps attached instead of FCs..
And I'd also say that they should consider an option to get the firmware
updated. One wrong firmware setting and you'd have to go for a new
amp.

[raschaa]

Originally Posted by soundcheck

Yep. You got a point. I'd also prefer an amp done right from the beginning.
Especially if the receipe (at least most of it) is known, you shouldn't leave
out half of the ingredients....
....
And I'd also say that they should consider an option to get the firmware
updated. One wrong firmware setting and you'd have to go for a new
amp.

Especially after v1.0 failed... FW flash should really be a matter of course nowadays.

I've now come to the conclusion that it's not the remote transmitter thats causeing my problems, it's more likely the reciever. Recently it has started to react to the SB Touch remote every now and then. Veeeeery disconcerting when you're listening well cranked up, just want to add a track to the Touch playlist via remote and the DDX jumps to a EQ setting with max. Bass boost.... OUCH! Then it can take up to 10 min. pressing the EQ button on the DDX remote until it finally gets back to E----, because it only reacts every 10 - 50 pushes of the button and then jumps like 5,6,7 steps ahead.

I'm wondering if I'm the only one with this phenomenon and it has something to do with my build....

[soundcheck]

Hi there.

I havn't been looking closely at the STA508 power amp chips implementation.

That's what I did now.

First thing I noticed is that the Zobel filter (R63/C52 datasheet) seems to be missing on channel 1 + 2 output on my v2 !?!?

It is recommended in the datasheet and in place on channel 3.

Is there any explanation for this?


Cheers

[raschaa]

Was busy as well... got fed up with the remote woes and waiting for end of chinese new year (20. Feb)... Had a closer look at the pcb where the display and ir-reciever are mounted. The IR-Diode is a three pin job. Middle (ground?) is connected on the rear traces of pcb and the other two have their traces on the front side. Unfortunately they are only soldered on the rear where the two outer pins actually have no corresponding trace, corrected that.

Disassembled the remote, puuuuh, chinese state of the art workmanship.... not! Ok, I really, honestly wasn't expecting much but they could have made less of a mess of it... The pcb was full of production/soldering residues, half of the soldering joints looked to be cold and the contact pad for the inner of the two batteries fell straight out after opening the remote... Gave all joints a touch of the soldering iron, resoldered both battery contacts adding more points by scratching lacquer where needed, cleaned the whole thing up.

Crossed my fingers, did a reset on the ddx and voila, the remote finally works again and much better and more reliable than to begin with.

So, back to listening enjoyment and waiting for a moment to maybe implement some mods a la "soundcheck".

[jrling]

Originally Posted by soundcheck

Yep. You got a point. I'd also prefer an amp done right from the beginning.
Especially if the receipe (at least most of it) is known, you shouldn't leave
out half of the ingredients.

Quite nicely made full digital amps such as Sumoh or the newer Maestro-50 sell at around 250$. Why should I go for a 100$+PS+tweaks+chassis diy-module instead? And then the V2.1 would be the third one on my table.

I do agree. The Maestro-50 also comes in a very nice case by the look of it.

But I cannot find what chip it uses. Do you know? No reviews either, so it would be a shot in the dark.

Anyone listened to one?

[raschaa]

they will be showing at Bristol 22-24 Feb....
Bristol Show 2013 | AVA-Media Blog

[soundcheck]

True Digital AMP is the term usually used by TI and beside that they talk about PurePath which is a trademark of TI.

There are IMO two major advantages of certain TI TAS chips.
The volume control ican be done via supply voltage. No digital control in this case. That's alsa a very nice feature for -- almost lossless -- speaker leveling and gain control.
And 2nd they use two different switching rates 352.8 (n*44.1) and 384 (n*48). BTW: Regarding switching frequency: NAD is running their famous M51 PCM/PWM DAC or M2 digital amp at 844khz!!

I also own a single chip TI TAS5706 amp. (That chip is also used in miniAMP at 60$). But that 5706 IMO can't compete with the DDX320. In my case the DDX 320 V1 replaced that amp. With my tweaked DDX V2 I'm a huge step ahead of this 5706. However. I havn't listend to the two-chip solutions of TI which would be comparable to the two-chip DDX setup.

Cheers

[robob]

Originally Posted by jrling

I do agree. The Maestro-50 also comes in a very nice case by the look of it.

But I cannot find what chip it uses. Do you know? No reviews either, so it would be a shot in the dark.

Yes, it is certainly a TI chip : if you look at Maestro-50 technologic FAQ, Ava speaks about "Pure audio", "modulator" and the pictures diagrram are the same than the Texas Instrument true digital audio power amplifiers PDF.
So it's certainly a TAS chip.

(Like the HFX RiAMP 2.1/100 : same pictures but not the same price , TAS5086 for convertor/modulator and TAS5342L for power stage)

Sorry for my english .

[Kjeldsen]

Hfx amp are made by Sumoh (small world right)

[jrling]

Originally Posted by robob

Yes, it is certainly a TI chip : if you look at Maestro-50 technologic FAQ, Ava speaks about "Pure audio", "modulator" and the pictures diagrram are the same than the Texas Instrument true digital audio power amplifiers PDF.
So it's certainly a TAS chip.

(Like the HFX RiAMP 2.1/100 : same pictures but not the same price , TAS5086 for convertor/modulator and TAS5342L for power stage)

Sorry for my english .

Very helpful and thanks also Soundcheck. I have to say the build quality of the HifimeDIY gear does put me off, as well as their treatment of you and other 'beta testers'.

I have emailed Maestro to ask what Ti chips that they are using.

Bet I don't get an answer.