BillFitzmaurice.info

TacT Audio has these interesting amps that are perfectly clear at 95% effieciency. They use some fancy, high-frequency IC's and power supply voltage variation to amplify the raw digital signal, push it through a filter and voila' ! The amp disappears. They've been out for sometime and the tech is based on patents that came out in (you guessed it..) the 40's.

If digital technology utilizes so few components and has been around forever, then why the heck is this stuff so expensive? So far the Behringer product seems to be the only one on the ball concerning price. My laptop cost $3000 and there's a heck of a lot more stuff in there than some CNC'd digital amp. Panasonic had the XR series of receivers for ~$500 and they disappeared in two years. What gives? Everything I own is digital...why not my amps? (I'm talking about like above, not the current D,F,G, and H, topologies that still use ADC on the front side) Are we getting milked? My speakers are ultra efficient and now I'd like my electronics to be as well.

Rant over...

Radian wrote:TacT Audio has these interesting amps that are perfectly clear at 95% effieciency. They use some fancy, high-frequency IC's and power supply voltage variation to amplify the raw digital signal, push it through a filter and voila' ! The amp disappears. They've been out for sometime and the tech is based on patents that came out in (you guessed it..) the 40's.

If digital technology utilizes so few components and has been around forever, then why the heck is this stuff so expensive? So far the Behringer product seems to be the only one on the ball concerning price. My laptop cost $3000 and there's a heck of a lot more stuff in there than some CNC'd digital amp. Panasonic had the XR series of receivers for ~$500 and they disappeared in two years. What gives? Everything I own is digital...why not my amps? (I'm talking about like above, not the current D,F,G, and H, topologies that still use ADC on the front side) Are we getting milked? My speakers are ultra efficient and now I'd like my electronics to be as well.

Rant over...

Hmmm, 650VA toroid . Where's the SPS ?

Digital technology DEFINATELY doesn't use less components! The simplest analog amp consists of 3 components. That's impossible for a digital amp...

A propos 'digital' amp. It's only called digital because it's output FET's switch very fast between the two internal powerlines. The FET's are completely on OR completely off ('1' or '0'). Most digital amps use PWM, which is internally generated from the analog input. It is not very hard to generate PWM from S/P-DIF or the like, but there is not much demand for this (yet?)...

I hear you . It would be VERY nice to stay completely digital from mic to speaker (that's also possible, but not yet at high power, only to 50 watts or so I believe; take a look at the Texas Instruments site for more info on this and/or search for 'filterless class-d'). No more noise problems or interference . I already stay digital from mixer + fx & compressors (Behringer DDX3216) to speaker processor output (Behringer DCX2496), with a DEQ2496 in between, all digital and I'm not complaining .

I don't know whether they are all digital or not but I am stocking up on the new peavey IPR amps when they finally start shipping

I'll still stand by the overly expensive but highly efficient Crown iTechs.

Especially since with a SAC or other digital console you can run a full digital signal path from the A/D converters on the side of the stage all the way through to the amplifier's final output stage.

The tell-tale of a True Digital Audio Amplifier is the complete lack of any analog inputs. It process only the raw PCM-PWM signal from either AES/ EBU or TOSLINK. It has no DAC on the front side nor does it have any use for a ADC prior to the output stage. There's only a low-pass filter there.

Les, those IPR amps hint that they may be just what I'm talking about with the addition of a ADC/DSP on the front side (lacking any digital inputs). At 7 pounds and >90% efficiency it makes it a contender. The Panasonic XR series HT receivers could almost be lifted with one hand. Pop one open when you take delivery and look for the Texas Instruments TAS5xxx series chips. I'd certainly like to know.

I did some snooping around this afternoon. Panasonic's SA-BX500 still has the same guts as their discontinued XR line, although they're no longer hyping-up the TDAA topology. Is it no longer "the future...."?

thijs666 wrote:I already stay digital from mixer + fx & compressors (Behringer DDX3216) to speaker processor output (Behringer DCX2496), with a DEQ2496 in between, all digital and I'm not complaining .

That's what got me thinking about them in the first place. I've been himming-hawing between the DEQ&DCX vs. DBX4800 for sometime now. I like the DEQ&DCX because of price, features, and would be a great match-up to my current amp config. ~But, the DBX$$$$ is all-in-one with AES output which I could eventually connect digitally to a light-weight TDA amplifier. My amps sound great right now, but between the two I'm lugging 80 pounds.

Radian wrote:My amps sound great right now, but between the two I'm lugging 80 pounds.

You're just using the wrong amps. Mine aren't as light as the 7lb Peavey's but I've got less than 80lbs in 4 amps for mains and 4 monitor channels. The PLX2-XX04 series are only 13lbs each and the 1804 puts out a decent amount of voltage into an 8ohm load.

Crown K2 & DC300A-II = 80 pounds, a couple of lead-sleds.

Yeah, but at least the K2 is worth the weight. Man, the DC300 seems a very inefficient use of rack space, besides the weight. Testament to Crown and how their amps hold up for the long haul.

I finally got a chance to pop open a Panasonic SC-BT300. It has the TDAA (TI) chip set in there. It's RF shielded to damn near mil-spec. This thing is crazy. 8 channels @ 65W RMS, and the PCB for the whole mess fits in the palm of my hand. Overall, very well constructed. Best part...it actually delivers. It sounds very nice. The only catch is the connectors on backside for plugging in the speakers are proprietary .

Although not exactly how the board looks in the SC-BT300, a solid representation of the form factor I'm talking about can be found on Page 24 of this document.

*edit* updated the first link

Finally found out what happened...Other manufacturers WERE making fully digital amps right under my nose. In particular Panasonic. Unfortunately, I was holding tight for Outlaw Audio to debut their 997 Pre/Pro. Yeah, two years later (and a few irate phone calls inbetween) their website still says "Coming soon"....My @$$!! Are they reconstructing the pyramids over there? Audyssey comes along and knocks Trinnov right-out-of the consumer market. Outlaw is caught with their pants down and has to redirect customers to the latest Onkyo that does everything their proposed 977 would have done. Thank you Outlaw USA for F*&%#*@ing up my life. Thank you Panasonic for behaving like General Motors and pulling the plug on THE coolest trump-card you ever had. Great marketing too. Now I know what people holding out for the latest GN or Fiero felt like.

Like B.O.B. said, "I feel so stupid."

some snot-nose engineer probably holds a patent.........therefore no digital amps until they ante up....

Not PA and not cheap but fully digital as far as I can work out. http://www.lyngdorf.com/index.php?optio ... &Itemid=33

Sure thing. Boz and Peter must have been in cahoots because the Lyngdorf product is strikingly similar to the Tact right down to the molded plastic parts of the chassis.

The newest TI chips (higher power, lower driven THD) can be found in the new NAD M2 for those with the coin. If Panasonic ever put these new chips in an amp at their price point, whoa mama!

I wonder if Yamaha will ever get on the ball with this? I see they're still holding onto their cards with TopArt, even though they made an honest attempt with the MX-D1. They're almost there, they just need to scrap their output DACs.

I got my paws on a couple SA-XR57's so I can stop griping for now. One is featured in this video

For those sitting on the fence about getting one of these units "used" because of it's lack of on-board DTS-HD / Dolby-HD decoding, its coaxial DVD input does indeed support 192kHz PCM audio. That way, you still get to enjoy the HD audio goodness if your player outputs PCM. I was holding my breath for a used SA-BX500 (good luck finding those) but once I found this out about the XR57, it was game on. Here's some eye candy showcasing this unit's construction and the TI TDAA chip sets.

Notice the lack of huge transformer(s) and the minimalist heat sinking. I can pick up this receiver one-handed.


Cheers!
Radian

Those look like solid polymer caps in the field. Good stuff.
They could also be the phony electrolytics dressed up to look like polys.
Check the tops for any venting lines "K" type or otherwise.
If the top is completely smooth, it is a solid poly.

My problem with consumer digital gear is the accountant-playing-engineer.
These guys force engineering to cost-cut and use lesser quality clocks, supplies, op-amps, etc.
The Behringer is the poster child for this.
For $1400 you can upgrade your Behringer DCX to premium circuitry...

At NAMM last year, I saw the Radian line of gear with the guts exposed.
They were riddled with CCS caps. A real shame.
For a few pennies more, they could have installed Rubycons, etc, for a lifetime of trouble free service.
But no... they had to go cheap.

I'll skip the digital amps as long as I have a choice for quality analog.