Axiom Home Page Forums General Discussion Stereo Class D amplifier

Parasound sent me their new Class D amplifier to evaluate against the A51 Class a/ab amp I have with the Bryston Model T's. This thing only weighs 15 pounds with the switching power supply in it. It's putting out 600 watts per channel vs. 400 watts in the A51.

Interesting piece I must say. Very powerful low and mid range, a little bright on the upper end. But they did tell me it needs 200 hours burn in and I only have about 8 hours on it thus far. I see that it has two channels each with right/left speaker outputs. I might try bi-amping the speakers tomorrow for the hell of it as that is how I ran the A51.

The sound stage is a little limited vs. the A51, but to be fair I'll give it more time to break in. But for a list price of $1300 US, it's a nice amp vs. the A51 at nearly $5K

ADA for me...

A D Amp for you?

Interesting, i would like to have that opportunity , i often wonder if i can truly hear the difference between 2 amps. I am getting a new amp with a SPS vs the one i have with Torroidial so i will see if i can tell any differnce though i highly doubt it. I can see 2 recievers sounding different but amps i am not sure . It stands to reason that they possibly could given different circuit designs and part quality. I mean a capacitor or inductor changes the sound of a speaker when configured in a crossover only stands to reason those same components play a role in a amplifier? Keep us posted as it breaks in ? not sure how that works either. I am a mechanic and breaking in an engine with mechanical parts make sense but electronics idk . If electronics break in then the computer in a car would change how it controls an engine as the computer ages which it most certainly does not. Ah technology so many questions so few answers.

Electronic components do change with temperature and also capacitors 'form' with use. In fact if an electronic device isn't used for a period of time, the capacitors will lose their internal 'shape' and become out of spec; they need to be reformed by bringing the device up on a variac from low voltage over a time frame of days sometimes to avoid damage.

So, with that being said, I can see where they speak of 'breaking in" an amplifier. I think it's probably more a factor of burning in the components inside.

I definitely hear differences between the amplifiers; they each have a specific sound which of course would be defined by what the design is internally and the quality of the components used. Some use very high quality high tolerance devices, others do not . I guess price dictates what you get to large degree.

but but i can show you break in on and engine can the same be done for a speaker or an amplifier. I have a amp thats 35yrs old and has not suffered any apparent problems with capacitors audible or visual. Once upon a time japanese products were second rate now they are the gold standard how times change.

Axioms amp.
I'd like to find a matching amp to the one I have.
Maybe a 1500 in the future to.

The switching in my AVR seems to be giving me trouble.

From what I understand, Axiom uses a toroidal inductive transformer vs. a switching type power supply and as such has a lot more dynamic headroom "power" available. They combine this with a Class D amplifier section which is very efficient and doesn't generate a lot of heat.

This new Parasound Class D amp which was sent to me to test out I am told has some new design features which make it play more like a conventional Class A/AB amplifier. That seems to be the case thus far as it has really full Low and Mid range, but the Highs seem to be a little on the bright side to me. I cannot recall what I have read in reviews of other newer Class D amps like the Anthem units, but I will have to go back to see what they had to say about the tonal characteristics so that I can determine if this seems to be common to Class D designs or if it's just that this amp needs break in time.

I also plan on swapping back over to my Class A/Ab amp perhaps later today just to hear the differences after two days of use with the D amp.

What I find interesting is that the amp with it's switching power supply seems to be holding up well to large amounts of high dynamic input without running out of gas and it runs cool. I also like the 600 watts of power at 4 ohms, it seems to drive the Model T's nicely.

If the highs are on the bright side, that could be a sign of distortion. Our human ears are more sensitive to distortion in the higher frequencies compared to the lower.

If it is distortion, there could be many reasons for this. The most common reason is lack of negative feedback from the output back to the input. Negative feedback corrects for the non-linear behavior of the output filters and if done properly, also improves the signal-to-noise-ratio. Ultimately stability and distortion are improved.

It's actually very challenging to build a high power Class D amplifier for a frequency-dependent load like a loudspeaker. Although I've never seen a magnitude and phase plot for the Model T, I would expect the impedance to vary from 2 Ohms to maybe over 30 Ohms and from an inductive load at lower frequencies to a capacitive load at higher frequencies.

If you ever find a plot, I'd like to see it.

I do have one; Ian sent it to me.....

I used a Sonic Impact $29 T-Amp for a garage system driving some M3Tis. Sounded good.

Sounds similarly good to an A1500, eh?

OK, the Parasound amp was sent back after using it for a week; I'll say that it's a really nice piece for the money, a great entry level amp for a guy who cannot afford to spend too much, but who would like a very powerful amplifier. Or a person like a college kid who is moving frequently and cannot deal with heavy, expensive gear.

My impression with it is that although very good on the low and mid range, it's just slightly harsh to my ears in the upper frequencies and definitely lacks in the imaging/sound-stage department vs. the A51. But otherwise, a very nice piece and not expensive at all.

I was so intrigued by the class D amp that I just brought in a pair of the Anthem M1 mono blocks and they arrived yesterday. Thus far having set them up quickly with two 120 volt 15 amp input lines vs. the recommended 240 volt mains, they are pretty damn good, in fact really good. Much improved sound stage and details than the Parasound A51 and far more low end power, not to mention the bass detail is exquisite. I am hearing things I have not heard before in all ranges. But to be fair, these amps are almost twice the cost of the A51.

The other major point of interest to me is how cool they run! My A51 under heavy loading got very hot, like up in the 140 degree F range. The M1's average around 80 to 90 degrees F. And I have them stacked on top of each other! Very impressed with these overall.

Give me more time with them and also will report on using 240 volt input shortly.

Slim

Besides the room, soundstage and imaging is all about the dynamic range of your gear. There is no comparison between the Parasound and the Anthem M1 when it comes to dynamic range.

Agreed, huge difference. Plus the Parasound is using the off the shelf ICE class D module; the Anthem is a ground up proprietary design.

They spent 5 years on developing this amp, I have to imagine it has some very nice elements to it.... I love the liquid cooling; very cool.

ICEpower bites the big, fat one for high fidelity audio.

Not being an EE, but having just enough electrical experience to be dangerous to myself (did take an 800 volt direct hit to my finger once from the plate of an RF transmitter tube), I cannot comment on the ICE module, I don't know what exactly they designed. But I can tell you easily that the D module implemented by Anthem is very high fidelity. I would love to listen to other Class D amps as they are very intriguing.... The M1's in standby, as in ON all the time, consume 1 watt in 120v. mode and 2 watts at 240v.

And liquid cooling to the side by side reduced size heat sinks, love it.

I plan on machining heavy duty 7075 billet aluminum rack handles for the front and holding the two amps stacked but with a rack space between for cooling and a matching spacer support block for the rear so that the two become a single unit.
And Black Anodized of course

OH yes, one very important observation which I neglected to report on with the M1's....... My Gin gut busting EP800 and little brother EP500 which were always very "present" in the room have suddenly moved to the back wall and now blend in perfect harmony with the Model T's. I mean the whole room is liquid, there is no apparent 'speaker' anywhere. Adding the massive increase in power to the T's and bringing the huge lower end performance of these speakers into the forefront suddenly made the thundering output of the subs just mesh perfectly. I don't "hear" the subs any longer, I just feel them.

Honestly, I can truly say that my chest was being slammed like in a heavy club.... I could feel the impact of the dynamics of the music (vinyl input).

I'm envious.

Stop by for a listen Mojo, I'll show you my Variac

Congrats Slimpi.

Class Ds are awesome.
I've been running an Axiom ADA1250 my self for the last year and never once has it even got warm to the touch, that's running it all day at moderate to loud volumes as well. I'd suspect the Anthem to be much the same. Plus its compatibility with your pre output is probably a large plus as well.

Plus the best part they run silent with out those pesky fans making way to much noise, my previous power was a Pro amp with an extreme fan hum

Is there any chance this is just a function of subwoofer phase relative to mains, and that one amplifier inverted the inputs while the other did not ?

Either way it's an interesting (and significant) change. Good to hear.

Apparently the Anthem M1s, when fed by 240VAC and coupled with a pair of Model Ts, vapourized Slim's EP500v4 and EP800v4. I suppose Slim will show up here and tell you. I wonder at what level the Ts will melt. He's already pumping 2,000W into each one and the soundstage is twice the size it was when the Anthems were fed by 120VAC.

It's not that the subs have any new and sudden issues; not at all, they are still doing a wonderful job. What I meant to say is that with all of this new found power, the three woofers in each T have a huge increase in output and as such, they are really quite 'present' vs. when they were being fed by an amp with significantly less output. As such, the front two mains are really rounding out the lower range and making the two subs blend more evenly. I guess its like adding in two more subs to the room which would increase total low end output and make it far more even.

The 240 volt input to the M1's just elevated this to a whole new game. It's not even close to the 120 volt set up. It was well worth the effort to make the installation.

Whew! I thought you blew yourself up over there.

I want what you have.

Have not yet heard the mighty A 1500 amp, I'm sure the $29 Sonic Impact T Amps are not in the same league.

Nevertheless, these 15 wpc battery or AC powered wee gems sound pretty darn good!