Who's using digital amps?

[damonrpayne]

What brand are you using, what brads did you consider, how much did it cost?

[Arkytype]

Damon,

While my McIntosh MC502 amp was on my bench getting re-capped, I bought one of the Teac A-L700P amps with the Tripath chip.

It is amazingly good. After my McIntosh was back in service, I rigged up an A-B switch which selected either amp's outputs. When amp A was connected to the Klipschorns, amp B was terminated into an 8 ohm load. After carefully matching the gains, and having a second person set the A or B position (so I was unaware of which amp I was listening to) I couldn't tell any difference between the two amps.

What is interesting is that while my McIntosh was out of service, I could swear on a stack of "Dope From Hope" that the Teac had deeper, punchier bass. Ah, how easy it is to fool the ear with our perceptions. Once the A-B comparison was in play, I could hear no difference between the amps.

There is a great comparison of digital amplifiers at this link.

http://www.stereomojo.com/SHOOTOUT2007INTEGRATEDS.htm

Since the Teac amp has been discontinued, the best bang for the buck is the shootout winner, the Trends Audio TA-10.1 and this eBay seller has them for sale. The amp doesn't use surfqce mount parts and is a tweaker's dream.

http://cgi.ebay.com/Trends-Audio-TA-10-1-Class-T-Stereo-amp-Tripath_W0QQitemZ220157630610QQihZ012QQcategoryZ39783QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Lee

[Islander]

Class D amps are not all digital. "D" is just the next letter after "C". There are likely very few actual digital hi-fi amps on the market.

The Yamaha MX-D1 power amp that I use is marked "digital" on its front, but magazine reviewers all call it a misnomer. The amp does sound great, though. It has lots of power, runs cool and presents the music with whole new levels of detail, clarity and solidity.

Other brands of power amp I had considered were Bryston and McIntosh.

[damonrpayne]

Those digital amps were tiny! They should make them more visually appealing, like a wide "rack" form factor so I can run my system with a huge stack of them, maybe add some blinking lights [6][]. The price beats the hell out of the cost of high end solid state though.

[Jay481985]

I am going to get crown XTI amps which are true digital since the signal is converted from analog to a digital controller back to analog.

[damonrpayne]

.5% THD according to Crown's own specifications, that is much higher than the THD claimed by most hifi solid state.

http://www.crownaudio.com/amp_htm/xti.htm

[Jay481985]

i believe that .5% is rate at said power.... being that I will never use max rms power or so.... I doubt it will be that high thd.

DrWho recently listened to the xti and he said some wonderful things, some things soo wonderful i cannot say it or we will be flamed

but i believe the thd is much lower at lower power ratings

[Islander]

i believe that .5% is rate at said power.... being that I will never use max rms power or so.... I doubt it will be that high thd.

DrWho recently listened to the xti and he said some wonderful things, some things soo wonderful i cannot say it or we will be flamed

but i believe the thd is much lower at lower power ratings

I think most amps have more distortion at near max power levels. The Yamaha has its lowest distortion ratings (.003%) in the 6-10 watt range. Crown probably uses the higher rating because, as a pro amp, it's expected to be used at its higher power settings. People who have the Crown amps seem to like them.

[DrWho]

The Crown XTi amps are great if you want to do active crossovers since

it's a feature built into the amp. If you weren't going to use the DSP

section, then I would persue different amplification. The XTi is also

not a "digital" amp in the sense of this thread ("switching" amp might

be a better term to include all of the topologies).

I have heard most of the digital amps mentioned in that one article and

have heard various home brew versions of them too. We are building our

own active (digital) amplifier right now for one of my labs and have

been making all kinds of comparisons to the existing amps on the market

(and a little reverse engineering too). We have found that the Hypex

amps sound much better than all the others. The noise floor is much

lower and the sound just so much cleaner. I hate to put it this way,

but the mids have a very SET-like quality to them. It's weird hearing

this combined with very controlled thunderous bass. After our extensive

listening sessions I am absolutely sold on this kind of amplification

(self-oscillating pwm).

I don't believe you can purchase the Hypex amps in a finished form

though and the modules will be shipped from the Netherlands...

http://www.hypex.nl/

The prototype we're working on will be finished by the end of this

semester. I think we're looking at something like 800W per channel (and

costing $60 per channel, so $120 for a stereo amp or $420 for a

7-channel amp). That's raw cost though...something manufactured would

be about 10x more expensive (so just add a zero to the end of those

numbers). For what it's worth, I think we've stumbled upon better sound

than the Hypex [] - I would love some outside opinions though. We're

doing most everything by ear and then trying to find ways of measuring

and quantifying what we hear - then fixing it and moving onto the next

problem. Anyways, since the raw cost is so cheap I wouldn't mind

building a few to see what other people think.

One of the things you have to be careful about with the digital amps is

that they clip very easily. I was quite surprised how quiet 2.83V into

my Chorus II's measured. It was something like 75dB at one meter

C-weighted fast. The problem with digital amps is that they clip just

like anything else digital. If you've got transients in the music, then

you need to make sure you're not clipping. In our case we were

listening to music with about 27dB transients (Blue Man Group). It's

probably more like 20dB because there is some lag time on the SPL

meter. Anyways, the point is that you need a lot more power than you

might think. 75dB ain't loud at all - especially when you're sitting on

the other side of the room. In order to get a "full" volume at about 10

feet away we're using about 100W into the Chorus II. I haven't

measured, but I think that correlates to about 95dB on the SPL meter. And yes, my SPL meter is calibrated (just in case anyone asks).

But ya, them Hypex amps are real nice. [Y]

[Jay481985]

I would like to be the first outside opinion

[Wardsweb]

I've built one, bought one and am building a third. Here is a pic of the first two. The top one is a LM3875 chip amp (gain clone) using BrianGT PC boards. The bottom one was a kit from Winsome labs. These are suprisingly good and powerful enough that you don't need high efficiency speakers. The most revealing thing I can say is they are real clean up to distortion and then the noise ramps up quick (about 3/4 volume).

[damonrpayne]

Put me in line. If they are sweet I'll pay you to build me 3 channels of amplification.

[Deang]

The XTi is also not a "digital" amp in the sense of this thread ("switching" amp might be a better term to include all of the topologies).

The XTi series of amps do use switching power supplies though.

We have found that the Hypex amps sound much better than all the others.

I had one built using the then upscale AD modules, which have now been replaced by the newer HG modules. Though it sounded really good, I thought the high frequencies sounded a little steely compared to the VRD's and the Super-T (Tripath). I still think the Super-T is the cleanest sounding of the ones I've tried. I'd love to get the same sound with 20 watts per channel.

I don't believe you can purchase the Hypex amps in a finished form...http://www.diycable.com/main/product_info.php?cPath=140_142&products_id=616

[Jay481985]

I don't believe you can purchase the Hypex amps in a finished form...http://www.diycable.com/main/product_info.php?cPath=140_142&products_id=616

expensive devil

[seti]

I am between amps at the moment so I bought a trends 10.1 tripath amp with a whopping 10wpc. This little box sounds better than it should and was built to be modified. I may try my hand at some of these mods to see if it sounds better. It is very clean and I like it ok but there is something it is doing that I can't shake or figure out. Perhaps it has been too long since I have listened to solid state. It seems too clean too quiet.... I'll figure it out. The next amp for me is a BAT VK60 : )

[Deang]

expensive devil

Depends on how you look at it. Certainly not that much compared to the better tube amps and higher end conventional solid state -- but kind of expensive compared to some of the nicer Tripath implementations that are coming out now. Hypex does have the advantage of much higher power, which would work better for you Reference HT folks. Kind of expensive too compared to something like the Crown XTi 1000, which you can get for less than half the money -- and those sound a lot better than they ought (yes, I've hear them).

I'm still hooked on Tripath, and I'm eyeing the Kings Rex stuff pretty hard. Biamping with two of the Crowns is tempting though, so right now I suppose I'm still on the fence.

http://www.6moons.com/audioreviews/kingrex/t20.html

http://www.6moons.com/audioreviews/kingrex2/u.html

[Deang]

It is very clean and I like it ok but there is something it is doing that I can't shake or figure out.

The top end had a lot of tizz over here, sounded a lot like what I heard with the TEAC when I had it in the system. Those amps have a lot of qualities that can make you overlook that, especially for the money -- but once you notice it, it's hard to ignore it, and after a dozen CD's you notice it more than you want to. With both my modded Khorns and the Jubilees, the Super-T walks all over it.

[Jay481985]

expensive devil

Depends on how you look at it. Certainly not that much compared to the better tube amps and higher end conventional solid state -- but kind of expensive compared to some of the nicer Tripath implementations that are coming out now. Hypex does have the advantage of much higher power, which would work better for you Reference HT folks. Kind of expensive too compared to something like the Crown XTi 1000, which you can get for less than half the money -- and those sound a lot better than they ought (yes, I've hear them).

I'm still hooked on Tripath, and I'm eyeing the Kings Rex stuff pretty hard. Biamping with two of the Crowns is tempting though, so right now I suppose I'm still on the fence.

http://www.6moons.com/audioreviews/kingrex/t20.html

http://www.6moons.com/audioreviews/kingrex2/u.html

thanks and that is what I will most likely buy in the short future for the rf-83

Also its alot more expensive comparatively to the sonic t amp

[pzannucci]

I actually have three different sets of IcePower amps. They sound very good to me. Bass control is especially good in the larger units with very clean highs.

Murano Audio P-200S monoblocks - great deal at 299 each

Murano Audio P-500s Plus monoblocks - 769 each (still pretty good deal for 250watt @ 8ohms /500watts @ 4ohms)

Bel Canto Ref1000 monoblock amps - 1995 each - wonderful sound

Two Panasonic Class T xr-50 and xr-70 receivers - require good matching but good price / performance ratio.

My class A monos and tube amp are in the closet [:'(]

[cjgeraci]

While I'm fascinated with Hypex, primarily based on Dean's impressions, I still think that everyone should at least spend the $150 and try a Sonic Impact Super T amp. I've had that amp in my system and it ended up staying along with the Teac unit (which I initially discarded and then came back to). The Super T is very clean and detailed on the top end, with surprising bass. It will likely stay in my system powering my Fortes. The Teac, while clean, does not have the detail on the top end that the Super T does, and its a little lacking in the bass dept. That being said, the Teac was good enough to be reintroduced into my system as my backup amp for my modded Khorns (plus the Teac seems to do better bass-wise on the Khorns as opposed to other conventional speakers). Well at least until I start playing with active crossovers.......

Carl.