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Posted By: ratpack Digital Amplifiers - 03/05/06 02:39 PM
What does the tribe think about the new craze of digital amplifiers?

I hate to admit it but when I went to school there was no such thing as class G, H, I, J, K or whatever.

Anyone using them?

What say?????
Posted By: 2x6spds Re: Digital Amplifiers - 03/05/06 05:55 PM
I'm using a modified T-Amp in a large family room (15' ceilings, stone floor open to a large kitchen), speaker output from T-Amp > Velodyne CHT10 subwoofer, line out from sub > a pair of Michaura M55 (like the M22). Source is an upgraded Ah! Njoe Tjoeb (upsampler, Siemens tubes). The sound quality is excellent at low, or normal-to-high (for me) listening levels, but if you push it a bit too far the sound quality breaks down. Within its comfort zone it is an unbeatable value with sound quality which matches or tops amps costing 50 times as much.

I recall pmbuko posted a comparison with a receiver and found the T-Amp performed like you would expect a $20 amp to perform. He must have tested a bad one. This thing is a joke it's so good.




Posted By: AdamP88 Re: Digital Amplifiers - 03/05/06 09:32 PM
Hmm, I don't recall him saying anything of the sort. In fact I remember him saying he was surprised at the sound for $20 (as was I). However, we both preferred his receiver.
Posted By: 2x6spds Re: Digital Amplifiers - 03/06/06 12:13 AM
I saw a post recently from a fellow on this board who reported that he was driving his 95db efficient M80s with 1100 watts of amplification. I was puttering in my audio laboratory (my desk in the garage), listening to Ladysmith Mambazo through a pair of big Dahlquist DQM 905s (some of the best speakers ever made IMO), sourced by a Sony CA9ES CDP and driven by a superb Kenwood KA-9100 amp ... with 2 power meters. Now, these Dahlquist speakers are about 87db efficient, which is to say, not very. Anyway, at loud volumes I never saw spikes higher than 5 watts per channel, mostly between 1 - 3 watts.

The T-Amp is rated at 15 watts per channel, into 4 ohms. I figure the T-Amp is good for no more than 5 wpc. Anyway, I think it is a superb 2 channel amp for stereo listening.

Now, you may not want to invest $20 (and go spring for another $20 for a nice Pyramid power supply) for a 2 channel stereo music system, but if you have a 7.1 receiver with only 5 channels of amplification, and 2 unused pre-outs for your back surround channels, you might consider one of these T-Amps to handle amplification for your back surround speakers. I doubt they are ever called on for more than 5 watts.

I have to check to see how many T-Amps I have left after giving bunches away, I think I still have 5 or more. One of the projects I have never gotten around to is to make a beautiful wood cabinet and jerry rig 4 of these T-Amps to make an 8 channel Home Theater amplifier. I figure that the guts of this thing would weigh less than 2 lbs!

Tell you what ... if you get one of these T-Amps, get it out of your head that it cost you $20. Pretend that it cost you $1000. Hook them up to a quick subwoofer and a pair of M3s (I think that would be the best Axiom speaker for the T-Amp), close your eyes, listen to the music, and tell me whether you have heard any $1000 amps which sound any better.

One last thing - compared to my previous receiver - an Onkyo 797, I don't think the T-amp gives up any sound quality for most types of music (not big orchestral pieces).

Anyway, my advice? ... scrounge under the cushions of your couch, your golf bags and under the front seat of your car ... you will probably come up with enough change to buy a T-amp. Do it. Listen to it ... let me know what you think.
Posted By: BruceH Re: Digital Amplifiers - 03/06/06 03:39 PM
For those DIY'ers, another other option for a little more power and even slightly better sound quality can be found at www.41Hz.com. The concensus there seems to be that the low power SMT amps sound the best. I have bought one of these kits but I have so much on my plate right now I have not had time to construct it. Maybe this spring/summer I will get around to it...
Posted By: ratpack Re: Digital Amplifiers - 03/07/06 12:20 PM
Doesn't appear that many have any experience with the new amplifiers. That's sort of interesting.
Posted By: neb Re: Digital Amplifiers - 03/07/06 07:24 PM
Im not sure if this counts for the thread.... but I do use the H?K DPR 2005 receiver. DPR = digital path receiver.

A few notes about the receiver and my experience.

My last receiver was a 30+ year old Luxman that at one point in its lifetime was litterally top of the line. However, it still had all the failings of an oder reciever. It tended to color music in its own special way and fuses blew and it was not the cleanest amp I ever heard either.

After growing up in the digital age (no, I never have owned a record since my 5th b-day... Im now 30 for those counting) the DPR made sense to me. Why have all these nice digital inputs then switch back and forth internally inside the amp to analog then to digital then to analog etc. Too much loss and noise for no reason.

Now, I realize that the actuall amount of loss would be negligible in comparison to some other high end receivers but I bought one of these dprs of ebay reconditioned for less than $600 and at the time it was the BEST deal that was out there, imho.

So the receiver is great. Paired with epic 80-600 7.1 can you get better? Probably but not unless you can spend tons more money and then can you get clearer music that is actually discenable to the ear? Prob not!
When I compare the DPR to a Pioneer 5.1 that I have in the garage... the 80s seem brittle. I know that that is a weird word but the analog reciever sound differnet. I realize the pioneer has trouble pushing the 80s and it was only $200 three years ago but it is a very different sound with only the reciever bing the differing peicve of the acoustic puzzle. The DPR is clear. Is is not noticalbe. I feel that it has very little effect upon the recording. This is even more noticalbe when I switch it out to run 2 channel with the luxman. Don't get me wrong , I LOVE the LUX, it was inherited from my father and i grew up listening to Iron Maiden to Yo-Yo Ma on it but it colros the music. It nice warm and fuzzy. Its great but it simply is not a neutral sound as is the DPR.

As for features all Digital amps will be diffeent but the DPR has it all... Dolby I II, Neo , logic 7 etc. the only thing it does not do is handle video. No farudja here but I'm sure that is coming soon from HK. Besides msost of us would probly be buying a DVD player to handle the upconversion anyways...

Those are my thoughts and they are limited in the sense that all the DPR does is amplify the music as you direct it. I am very happy that I bought it.

Neb
Posted By: ratpack Re: Digital Amplifiers - 03/08/06 12:31 PM
neb: thanks. I was more interested in the digital amplifiers with the new classes of efficiencies. My new Onkyo "digital" receiver has more features than I will probably ever use. I guess that is a sign of the times.

I'm in the market for a seperate amp and thought that I would try to get a few opinions from some folks who actually had digital amps. But, it may be too soon for that on this board.
Posted By: Wid Re: Digital Amplifiers - 03/08/06 01:09 PM

Here is an article at Audioholics about the D class amps.
Posted By: ratpack Re: Digital Amplifiers - 03/08/06 01:11 PM
Thanks Wid.
Posted By: KC23 Re: Digital Amplifiers - 03/08/06 10:42 PM
Wonder when we are finally gonna hear about Axiom's new digital amps? Was supposed to come out early this year.

Its this year ... its early. Hey, sup Axiom?
Posted By: Ken.C Re: Digital Amplifiers - 03/08/06 11:35 PM
Where's the data that says early this year? As far as I know, there has been no official Axiom acknowledgement of the project.
Posted By: bugbitten Re: Digital Amplifiers - 03/09/06 12:15 AM
Something in here maybe!
Posted By: richeydog Re: Digital Amplifiers - 03/09/06 12:40 AM
In reply to:

Audioholics Quote:

No official product release date has been announced by Axiom, but we were told to keep a look out sometime early next year.




You are right, sir!


Posted By: JohnK Re: Digital Amplifiers - 03/09/06 01:43 AM
Bernard, what I've read and heard thus far hasn't had me reaching for my credit card, but this is developing technology which will become increasingly significant. You're probably referring to class D switching amplifiers which aren't necessarily digital(D doesn't stand for digital, it's simply the class which follows C). You may be interested in reading more from Putzeys on the topic here as well as Moreno's more detailed technology analysis .
Posted By: ratpack Re: Digital Amplifiers - 03/09/06 03:51 AM
Thanks John. I will read those articles.

The article that Wid referenced was quite interesting and timely. I know that switching power supplies have been out for several years. There have been many reports of the cheaper or poorer designed supplies being very "noisy." The better designed ones seem to work just fine. I use one to power my ham radio transceiver and I have not found any noise in the 1.8 to 30 MHz spectrum. If it is there, it is below my threshold.
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