Anybody running TPA series Class-D amps? (3116, 3251, etc.)

I've been running vintage-ish solid state this and that amps for 10+ years. Even an oddball amp and a tube amp or two. Mostly 70's and 80's Japanese, all the way up to a Nakamichi PA-7. But for the last year or so I've gone in an entirely different direction; I've been seduced by the siren song of Class-D, in particular the TPA series from TI. The entry level was amp boards based on the TPA3116D2 chip, which will give a respectable 30W per channel, and a disrespectable 50W. However, I've since moved up the line, to a TPA3251 based amp. This is not just a board, but a complete plug-n-play amp (Sinewave G3H). Unfortunately, there have been far fewer commercial implementations of the higher power boards, such as the TPA3245, 3250, 3251, 3255.

As far as the sound goes, I was impressed with the TPA3116, but it ran out of steam pretty quickly. My speakers, Vandersteen 2ce, are 86dB sensitive, and need a good bit of wellie to really come alive. So the 3116 setup hasn't seen a whole lot of action here. Not to mention that many of the implementations are plagued with an on/off *pop* that can be a bit unnerving.

However, when I got the 3251 based amp, the game changed. It was clean without being dry, smooth without being slow, and powerful (almost) without limit. More than any other amp I've had, it sounds like no amp at all--just gain. It puts out a very respectable 120W per channel, and up to 150Wpc with rapidly rising distortion. This adequately pushes the Vandersteens, but I feel like there could still be a bit more headroom. Realistically though, I don't listen to music loud, per se, and don't max out the headroom that I currently have. It's just missing that last bit of bass control. It's probably all in my head.

Others have said that these amps sound their best with a tube preamp, and I tend to agree. I'm running a Schiit Saga, which is basically a stepped attenuator with a 6SN7 buffer (0db gain). Because the amp imparts no flavor of its own, it lets the preamp flavor, or lack thereof, shine through.

For what it is? IMHO it's a mind-blowing good value. It cost me a hair above $200 shipped from China, but I think it's competitive (to say the least) with Class A/B amps that cost several multiples of its price. It's definitely changed the way I look at good audio value. I can't afford to play in the "big leagues", and the local used market is very slim pickings (except when @ICTWoody goes on a selling bender :D). But I don't feel that I'm missing anything that money could buy, outside of what I noted above.

For the adventurous person who's not afraid to have audio paradigms shattered, I recommend the high power TPA series highly!

Anyone else at HFH playing around with these?
 

opa1

Moderator
Staff member
I've used the TPA3116D2 for years. I haven't kept up with the new designs. Have to check it out.
 

TubeHiFiNut

Administrator
Got one of the 3116 (IIRC) boards, the RCAs, the case, the linear PS, etc. with all good intentions.

As with all things DIY in my world, there it sits.

This, however, looks very interesting. Thank you for posting the info and your listening impressions. :)
 
@inthewoods, I'm really intrigued by your setup. It looks fantastic! I'd love to hear about it, especially the class-d amp, and your open-baffle speakers.
 

inthewoods

AARP Member
Class D I'm using is a Volt +. If I'm not mistaken it's only 50w @ 4 Ohm. It drives my woofers with authority compared to what I was using. I bought this just dipping my toes into D class. It's quiet as a graveyard with no music playing. My plan is to step up to 4 woofers in an M frame and I need 300w of power for this. There's $100 Class D's out there and that's where I'm headed in the near future. All this will take place after my conical horn build if it's successful. The open baffles you see is a Nelson Pass design and sounds wonderful. I'm on a speaker mission these days.OB SPKR (1).gif 16.jpg Conical horn.jpg 5 compression driver mount.jpg
 

mhardy6647

Señor Member
1) Re: ^^^ Wow.

2) Re: the subject line of this thread: umm, I have one of these, FWIW :o


DSC_2459 by Mark Hardy, on Flickr

I hope it goes without saying* that the smiley-faced EQ was meant to be a little joke. :confused:
___________________
* but I am saying it anyway.
 

rogerfederer

Junior Member
i am way down this rabbit hole. tried early TPA 3116 boards and built enclosures for them. tried modding them based on AC and DiyAudio threads. used laptop power bricks, then ham radio linear power supplies. i have the volt+ at work behind a pass B1 and running some small full-rangers (gr research little giant killers with fostex drivers). the volt+ sounds very very good. super detailed and balanced. i also have the TI evaluation board for the TPA3250, which has a lot more power. i have been running that on a battery setup, so totally quiet and drives speakers well.
i have an icepower amp (in a ghent audio case) that sounds very nice, though it doesn't quite have the detail the TI chip amps do.
finally i have this class D audio amp i picked up on AC: http://www.audiocircle.com/index.php?topic=149049.0 lots of power and sounds very balanced. not quite the detail of the TI amps but very nice.
i was on a tubes jag for a long time but the TPA3116 adventure has turned me towards the SS side. i have a Pass F5 clone in my best rig, so now my reference amps are all SS.
 
@inthewoods, thanks for the info on your system. I've heard that the Volt+ is the best implementation of the lower-powered TPA amps. But if you want to move up in power without sacrificing the sq, I can highly recommend the TPA3250, 3251, and 3255, depending on how much power you need. However, there is a "new and improved" Volt+ in the works. It looks very exciting, and will have about double the power of the original. However I've heard that the price will be significantly higher than the current version.

And thanks for the picture of the OB speaker plans, I have a lot of interest in OB designs (even though I'm not running one currently).

Those wood horns are wild!
 

opa1

Moderator
Staff member
They are listed at the bay also, 3255 2x260 and a 3251 2x140. Antec makes a simple rectifier setup. I used this with the ACA build. They also have the toroid PT for a good price. This board and the linear Antec supply would work great. Might have to try one out.

http://www.antekinc.com/dc-50-rectfier-module/
http://www.antekinc.com/200va/
https://www.ebay.com/itm/TPA3255-2x260-Watt-1-THD-N-Class-D-Audio-Amplifier/332371651072?ssPageName=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649
https://www.ebay.com/itm/TPA3251-2x140-Watt-1-THD-N-Class-D-Audio-Amplifier/332371653319?ssPageName=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649
 
I dig the Antek rectifier! However, the 200VA transformers are underpowered. I would recommend, for the TPA3255, the AN-5434. 500VA, which is much more suitable. (Although for most practical purposes, the amp would only be drawing a small fraction of that at a time.)
 

opa1

Moderator
Staff member
I would recommend, for the TPA3255, the AN-5434. 500VA, which is much more suitable. (Although for most practical purposes, the amp would only be drawing a small fraction of that at a time.)
@34v and 5.8a it should be enough. :)
 
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