ClassD

Hi Guys,

After getting some nice results with the low powered Amp3 from 41HZ I'm now thinking about the UCD180 modules frome here http://www.hypex.nl/
Has anybody tried these yet? I wondered how they compare against other kits regarding sound quality.
Obviously they have a higher output than the Tripath TA2021b which is used in the Amp3 but I wonder if the sound quality is as good or better
Any idea's much appreciated, theres a lot of posts on diyaudio but it seems not many people have actually finished building them yet or posted their results

Cheers

 

Leo,

I'm surprised you asked that question?, there's a fundimental difference between the tripath chipset of that family and other similar switching units.
This imho sets them apart from all others (ie the sound quality).
In the link you posted, it can be plainly seen on that amp module.
THink basic function of the i/c's from both families and see if you can work the difference out. Wm

 

I've not read much into classD to be honest until now I didn't realise it was a different technology to classT, it seems the nearest thing they share are power efficiency.
The Amp3 is the only classT amp using Tripaths TA2021 chip I ever heard, it was originally brought to be used with the PC but after trying it with my main speakers I was actually very surprised how good it sounded so thought its worth seeing what other options are available, if only it gave out a bit more power

BTW I modded one of ALW's Sr's to try out with the amp3 but it doesn't like the higher capacitance on the supply pins of the chip, even reducing them ruined the bass.
Believe it or not I've had the best results using a SMPS with 10k caps on the the output and a snubber.
Multicap Rtx's was used for the coupling, the sound was starting to be extremely good.
Unfortunately I switched the amp on the other day but it looks like its failed, I get no output and the the 5vgen pin of the chip measures low its not much fun trying to fault find on a pcb half size of a credit card with smd components

So what else is available you recommend or have heard, I can buy another TA2021 kit and probably change my speakers
My main amp is a highly modded WAD kit88

Cheers,

Leo

 

Leo - despite what Tripath and it's supporters (like wadia-miester here ) like to have you believe there's no fundamental difference between Tripath's "Class T" and any other Class D implementation. "Class T" is just a marketing gimmick, it's all the same class D really.

The "huge" difference that Tripath keep going on about is that they use a variable switching frequency instead of a constant one.

Whether one sounds better than the other is a matter for subjective evaluation . I'm very happy with my amp based on LC Audio's Zap Pulse modules. Others on DIYAudio.com are also very happy with the UCD modules.

Michael.

 

Cheers Michael

I would say though that using a constant frequency would be better in theory but I admit I've never heard two of these amps side by side so cannot say one IS better than the other regarding actual sound quality, its the main reason I posted
Thing is my Amp3 cost peanuts and started to sound very good indeed after some tweaks, I basically didn't want to spend more on another amp that wouldn't sound as good but just offered much more power.
This is a new technology to me, I basically wanted something as good as my Amp3 with a bit more output

 

Well Mike, There is something very different about this family of tripath chips compared to the others and Class 'd'.
Making sweeping statements without investigation is not worthy of you sir Wm

 

There are valid audio engineering reasons for moving a carrier frequency about. see 'dithering' 'spread spectrum' 'pipe resonance' etc.

 

Well the chips definately gone
There seems to be a few companys now selling kits using the Tripath chips, the thing I like about these things is that they don't use any external active input stages like op-amps etc and the lower powered ones only need a single rail supply.
I think I'll try another kit using the TA2020 or the SMD TA2021.
Is there any kit you guys recommend or have experience with? I could order another Amp3 from 41HZ but trying to mod the SMD pcb is a bit of a pain, I'm also a bit limited to try out my favourite resistors and caps

Cheers

 

Leo,

If you wish to sell what remains of your Amp 3 including the fitted bg's please pm me.

 

Thanks for the offer but I've just replaced the TA2021 chip (which was a real pain in the arse)
Its now working fine again.

 

I'm pleased your Amp 3 is up and running again

I made the offer because I thought the cost of the 2021b and shipping would have made it an uneconomical repair and then there's the small matter of removing and resoldering the chip


.

 

Thank you
Your correct although somebody kindly sent me a spare one, it was a real pain to swap but it takes a fair bit before I give