An interesting couple of days. These boards are are put together with spit and warm wind. You can mod them once if your lucky, going in for a second or third time is really chancing your arm. 4.7uf for the input gave too much bass, despite the caps being far superior to anything else I had. 2.2 ICW polyprops (dubious heritage having been in and out of other stuff) resulted in the signal dropping out (nothing to do with poor continuity on the board). Lastly some 2.2uf Wimas (275v) went in and bingo! sound very nice, although bass is still a little full. I have  Tripath TA2024, 2020 amps 2 IRS2092 amps (one dual mono 50wpc, one stereo 125wpc and this sounds really good in comparison.

Your response made me smile regarding bass control. You will probably not remember but I (think) I documented my journey with a pair of EAR Primary Drive OB's that were gifted to me. They were said to be a prototype of the design although looked to all intents and purposes like the finished article. The bass unit has it's cone surround removed and the cone is bonded to a planar panel that is attached to the OB frame. The panel was originally fixed at the 4 corners presumably allowing it to flex. I think this is called Correx sheet which is pretty stiff and doesn't flex but vibrates I suppose. It took me about a year on and off to firstly centre one of the bass units as it was rubbing and to stop any buzzing caused by the unruly panels. I cut loads of small wedges and inserted these around the correx panel and it was a matter of trial and error as to whether they were in the right place and if they were doing what I wanted them to do. 

I got to the point where I thought that they were good enough and left it like that. I have ideas as to how I could tame them hopefully once and for all but on 99% of the music played they behave themselves. I have made Fostex Back Loaded Horns (Lowther PM6c's fitted as well) Lampizator OB's used many commercial infinite baffle and reflex speakers, but these seem to do a lot of what I like to hear very well. They can however be a bit bass full and moving them about only gets me to the point where I am not sure where they sound best!

The track that had me up and down yesterday like a jumping bean was Jennifer Warnes - Way Down Deep from The Hunter. If you know this track then you will know that the bass drum (or is it a Surdo or Tar or something) is cleary at the wrong frequency for my speakers.....now who do I complain to about it

Sorry for jumping in at the end, just joined sooo, anyway the whole class D thing is very interesting, i actually work in the pro audio sector and class D is pretty much 100% all we install as far as amps are concerned, brands like Crown, Apart and Extron tend to be the ones we use most, for pro installs they are hard to beat, they tend to be much smaller lighter and run way cooler than other classes so perfect for rack mounting into a cabinet where heat is always on the high side, on top of that they are mega efficient and can kick out masses of power.

Would i use one in my setup? probably not or if i did it would only be to power a sub or a set of low frequency units in a pair of open baffles running dual amp, the reason for this which has already been said is they lack in the finer elements that makes an amp great and gives the music that sparkle, so for power hungry bass they tick all the boxes but for mid and HF they lack the finesse of a good valve amp or class A or B even.

I had some £30K class D Rowland 301 monos driving my first pair of Apogee Duettas at a bake off. Not too bad but not overly impressed especially considering the price. Those same amps where better driving Wilsons.

Had some Hypex 700 Merrill monos at £12K driving my second pair of Apogees. Bloody dreadful. Just dire. Hated them.

Actually Jerry's Crown 1500 (can't remember the prefix letters) was better than the Merrills at about £150 odd. Still while OK value the Crown wasn't great either.

Heard loads at shows etc.

Best so far was Hypex 400 modules fed with a linear power supply made by the chap who built my Apogees.

Luxman class A M-800A whallops the lot IMHO.

Yes they work well with my speakers with 92db sensitivity so not a difficult load. The Superchargers help a lot with this design.

I doubt enough power for your speakers

I hope you like them Jerry

I tried it too, against my Belles SA-100 that Tony had supplied me with.  It wasn't quite for me, or rather my speakers.  Then again, they're 4 ohm and pretty current hungry requiring lots of control.

Hi pukka2go, That's a nice panoramic vision about the classD in the audiophile context, and to me very realistic. As a diyer, I would like very much if you could give us an example of a great tripath board, for us to make a musical amplifier that would have a reasonable cost and would not make us feel frustated, because the memory of good old school analogic amps in our minds make us ceptical and not satisfied when we ear classDs. Something that at least could be on pair with good classical middle range analogue amplifiers. I will buy that board. Thanks!