I thought it was time we had a pro- Class D thread. There's plenty of threads about comparisons, or detractors of Class D.
That's fine, you don't have to like Class D amps, and if you don't please go participate on one of those threads.
For those of us who are very happy and excited about having musical, capable amps that we can afford to keep on 24/7 and don't require large spaces to put them in, this thread is for you.
Just to keep the thread active: Please refer to my post of 5/20. I am a little disappointed in you folks, or maybe you were just trying to spare me the embarrassment of so obvious an oversight. First, The TP30 II is not class D; it's class T. More importantly there certainly is a way to turn the speakers off on the I32. It's called a MUTE button. Sometimes I can be so obtuse! Any way, I am glad I got everything well sorted out and can now easily select speakers, standard headphones and electrostatics as the mood strikes me.
So, a lovely resolution and a mystery have presented themselves..
My amp, after barely functioning the morning after my screw up, works perfectly now. I put it back in, just to triple check that it is the amp, not the pre, and it's back to normal. I did disconnect the input connector and reseat it, as well as remove the fuse, check it and reinstall it. At any rate, yay! As for the mystery, I bought these from an Audiogon seller who said they were Ghent audio monos. When I opened the case, though, these amps each have one ICEpower 500 asp module, not the 2 ICEpower 200 ASP modules per amp that Ghent uses. So these are not Ghent monoblocks.. I guess someone built these themselves using Ghent cases. Interesting..
Todd - sorry to read about the mishap. If you are in the market for replacement mono blocks, consider contacting Merrill at Merrill Audio. He makes a range of highly regarded Class D amps, including mono blocks. Good luck getting up and running soon.
I opened the case up... It's crowded in there. Ain't no way I'm fixing anything on that board. And they changed the design of the monos, so I can't seem to buy just one.. ugh. New amps, I guess. Anyone need a subwoofer amp?
@confuse_upgradeitis - I used a crown xls1500 for about two years. This past winter I bought a used pair of Ghent audio class D monoblocks here on Audiogon. I was sceptical, since their power ratings were the same, but I was getting too curious about what, if anything, would sound different from my crown.
What I’ve heard is an improvement in clarity, sound source separation, a reduction in harshness and an increase in bass clarity and smoothness. In addition, the sound stage is deeper and wider.
Now, all of these differences took a few days, maybe a week, to discern. So, while it was a significant improvement, it wasn’t a quantum leap and I still greatly respect what the crown brought to my system for $325 brand stinking new.
I did, however, go from a stereo amp to monos, so I can’t speak as to what improvements were due to a better amp and what were due to moving to monos.
Great thread! Thanks to all for sharing :) I have to say something now...................
I use Crown XLS amp with my pair of Magnepan 1.7i. I read online about Crown amps and maggies, and took the plunge. I am really happy with the sound. It has been little bit over a year I have this system primarily for 2.1 channel music listening. So far I have resisted the urge to switch my amp to something else - tube or ss, class A or A/B. One time almost bought a McIntosh MC452. But that was mostly for the sexy blue vumeter and to have some bragging rights as a McIntosh owner :)
Occasionally I wonder though about switching to any of the other class Ds mentioned here like Bel Canto or W4S or NuPrime or Red Dragon.
Will that improve the sound like what I constantly read in any amp or preamp discussion / review, like larger sound-stage or better separation of instruments or more air or faster micro-dynamics etc.? I don't know!
I must say, AA makes some of the very best looking gear. :) Also, there are a number of new (< 5years) dacs which sound outstanding at any resolution, and make Hi-Res and SACD less important to me.
Thanks @mdeblanc glad you found a good resource. Let us know what you listen to and what you end up buying.
Just one (okay, two) listens to the ELAC Adante speakers backed by the Audio Alchemy electronics and I'm sold on class D. I went to the LAX Audio Show just for the ELAC speakers but now I'm sold on class D as well. Hell, I might even start streaming and dump my SACD player.
I came back from the LAX Audio Show and all I can say is that I went to hear the ELAC Adante speakers (which I will get) and also fell for the Audio Alchemy (class D) electronics.
@erik_squires Great thread, a godsend because I am in the market for another amp. This thread has given me a list of brands to consider.
@kdude66 Good to hear your comments. I have a J2 and was considering an XA-30.8. So as you can see, your thoughts on your move to Class D was most helpful. If I take the plunge, I'll chime in with what I bought and my thoughts. Questions for me re my set-up, let me know.
rhale64, I'm a 2-channel person that found a way to incorporate surround sound without degrading my 2-channel. I use a Jeff Rowland 625 S2 amplifier for my front speakers. Even if the ATI sounds as good as the 625 S2, I would degrade the sound going from a dedicated 2-channel preamp to a AV preamp.
I have to say that going to Class D did not improve imaging. I found the A23’s in my set up to be great imaging amps. Maybe because I ran them as dual mono? I used them in a 4.1 channel setup, so one amp was L /LS and the other R/RS.
I have always gotten that sense of music coming out of nowhere with these speakers, whether it was class A/AB or D. As I recall, the one technical area where the Parasound stereo amps are a little weak are in the crosstalk spec.
I am very happy you are having such a great experience with a multi-channel amp though, I need to run 5 channels, and having a single unit would make things easier. :)
I have owned three class D amps. I now own a ATI 523 and a 528. These will be used in a dedicated Atmos system. They are now being used in a dedicated theater. That has been well treated. Over the last 4 years I have owned Parsound Halo a23 and A5 2nd, Krell Chorus a Theta Dreadnaught D and these two. I can say without reservation that the class D amps are different sounding. I will add class D is simply incredible.
To me the class D amps seem to float the sounds out of my speakers. The music never seems to come from the speakers themselves. But comes from out of thin air.
I think they are incredible sounding. The Theta Dreadnaught D does use nc1200 modules on all channels. The ATI uses nc 500 and each different channel figuration has different size power supplies, all linear supplies.
To the person above with the three channel 523, have you tried this to run your front three channels as I am doing? If not give it a try. It really is an awesome sounding amp. You might be pleased. I know I am
I don't know if you were addressing your comments to me or not. I have a AT523NC 3-channel Amplifier (200W RMS per channel). I only use it to power my center and rear channels in a 5.1 surround sound system. I simply love it. It's so much better than the Marantz SR5011 and the Marantz MM7055. It's provides more than enough power to all channels. It's very detailed and a relatively small amplifier.
Don't even need a working amplifier to try this, just hook up two tubes
and have them switch back and forth as you suggest. Please post the pics
of the results. By pics, I mean of the smoke. :)
Class D was first proposed in the 1940s. The problem isn't the switching, its finding tubes that could manage the current :)
On my journey to find a class D integrated, someone suggested I try using a power ampalong with a passive preamp, such as the Schiit Sys. some of the amps Im currently investigating are the Class D Audio, D-Sonic, red Dragon and Nuprime models. I recall at least a couple of these have been previously mentioned in this thread,but can readers share their thoughts on any of the power amps from these companies? Thanks for the input as I meander along the path to purchasing a new amp!
I have over 500 hrs on my S-500 and thought I might comment a little about it.I think it's a step up in Sound vs nc400 and ref600m,these are the 3 class d amps that I own and I have access to more through a local audio club where we lend and or borrow equipment or occasionally listen to each other's systems.
I have been using a bel canto pre3 with all the diff. amps just to make a even playing field,the pre 3 is a pure water no coloration preamp.
The S-500 is the best class d amp I have had in my system and it has the warmest most engaging midrange with very sweet nicely extended top end that has more air and separation with the individual instruments making the entire frequency range very coherent.The bass is equally as good maybe better than my other class d amps listed.
I borrowed a Nuprime st10 to try out and found it too be a very close match to the S-500,with the nod to the S-500 for the best overall sound especially the midrange.
Offcourse this is in my system with my ears and judging the musical presentation that I prefer.
The next test will be comparison with a modwright kwa100se that I have owned for a few years but I haven't used it in about 3 years,I have loaned it out to club members though.I know it's a very good amp but can it equal or beat the S-500,only time will tell.
in excess of 100MHz- and likely with no need for dead time circuitry
This would be a spectacular improvement upon the state of the art. I can't wait to see it in real life.
Don't even need a working amplifier to try this, just hook up two tubes and have them switch back and forth as you suggest. Please post the pics of the results. By pics, I mean of the smoke. :)
You can use a Tube stage to slow down the signal or other circuit designs in solid stage to do that as well.
Agreed- **and** FWIW, there does not have to be anything slow about tubes. Keep in mind that in order for color TV to have existed, tubes had to be able to operate with bandwidth over a range of multiple MHz.
Tubes are only slow because of the design of the circuit, not because of tubes in general. In fact you can build a class D amp using tubes as the output switching devices, and switch them at some really crazy high frequencies- in excess of 100MHz- and likely with no need for dead time circuitry. That's pretty fast! I'm pretty sure solid state isn't there yet (but that's off the top of my head; haven't checked).
One thing I do not agree with Putzeys on is that reality is logical. Reality IS. We can understand it logically, emotionally, sexually, spiritually, intuitively.. or, hopefully, all of the above and more.
However as with all transistors, there is a lag between the command to switch and the actual full switch. This is call the dead time. This has been reduced over the years with faster transistors and also limited with feedback. But it is fast. Hence the apparent speed of Class D also.
Sorry, could you be mistaking "switching time" with "dead time?"
Dead time is the consequence of switching time - i.e. time from the garage door switch is pressed (switch) to time you can actually move out of the garage - takes a while for the door to open.
@lalitk "Class D tends to be fast, unless slowed intentionally or with a tube" - Are you referring to mating Class D with a tube preamp/Linestage?
You can use a Tube stage to slow down the signal or other circuit designs in solid stage to do that as well.
In reference to above comment, the end user should be able to reduce "Coherency Distortion" issues with a tube pre as pointed out in your Synergy 2 paragraph, right?
Coherency is very tough and you don't hear it until you hear something coherent. So the short answer is - it is really difficult to get it exact.
S&V: Generally speaking, what are the key benefits of Class D versus the traditional Class AB and Class A designs that have long been favored by audiophiles? BP: Efficiency and therefore the ability to construct amps that are powerful for their size. Only that. Modern Class D amps, in particular mine—ahem—sound good not because they’re Class D, but in spite of it. I can’t repeat that often enough. Left to its own devices, a switching power stage tries to do just about anything except amplify audio. You choose Class D to save energy but it’s all elbow grease after that. People don’t realize how much more challenging Class D is compared to Class AB. It’s truly an order of magnitude. Read more at https://www.soundandvision.com/content/bruno-putzeys-head-class-d#S70SckY6kyOPIC2d.99
Can’t really argue with that. :) The separates craze creates it’s own list of extra problems to solve.
At the same time, I really really like selecting my own parts. I find it a real difficult thing to want to give control to some one else as to what makes my system.
If I could, a two box system with a 5 channel amp and HT processor would have been here long ago. :)
I received my ATI Class D 3-channel amp. Right out the box it's a definite improvement over the Marantz SR5011 and Marantz MM7055 I had. I'm using it to drive my center and rear channel. The power and clarity is just what I wanted. Now if I could figure out how to reduce the white noise between my Marantz AV 7702 and Corus preamp when in HT bypass. I thought I had it reduced with a power cord with the SR5011, but with the current 7702 it's bad. I'll start a new post or revive my old post.
In the professional world, "bi-amping" a single speaker system is always active, meaning it uses an active crossover before the amps. Multi-way active speakers also use this type of crossover.
Only in the consumer world is there a question of whether or not to use a crossover when bi-amping, hence the confusion.
Far too many types of crossovers further confuse this, because while most line-level crossovers are "active" or powered, a rare few are passive.
@toddverrone, You may be confusing 'Active' bi-amping with bi-amping.
Bi-Amp - 2 amps wired to the speakers LF and MF/HF binding posts using the internal passive crossover.
Active Bi-Amp - Putting an active crossover in between the amps and the preamp. In this case, it's highly recommended to remove the crossover in the speaker and wire the drivers directly to the binding posts. This adds a level of complexity you may or may not like because you have to know crossover point of the MF/HF and LF drivers.
Fortunately, my VT-80 outputs equal watts in 4 and 8 ohms load with 26dB gain which made it bit easy to coordinate. I tried few Class D amps that had very high damping factor or high gain settings (obviously they didn't quite gel as they over-powered the tube amp). While it's only been couple of days with THOR mono's in my system, I am throughly enjoying their more than adequate bass slam. In my system, the key was to attain just the right amount of low end without overwhelming the mid's and high's. So far I have not notice any coherence or speed mis-match issues.
PS: I am glad to hear that you're enjoying your setup.
Welcome. I'd like to ask you a few questions about what you pointed out.
However as with all transistors, there is a lag between the command to
switch and the actual full switch. This is call the dead time. This has
been reduced over the years with faster transistors and also limited
with feedback. But it is fast. Hence the apparent speed of Class D
also.
Sorry, could you be mistaking "switching time" with "dead time?"
As I understand, you are talking about switching time. How long to go fron on to off, or vice-versa.
I think "dead-time" is a little different. As I understood, the problem with bi-polar PWM amplifiers (uses + and - V at the transistors) is that you must NOT have the positive and negative sides on at the same time. This affects both efficiency and distortion. I link Wikipedia and a B&O brochure discussing it. (The PDF is a little easier to get).
By the way, this issue with multiple transistors being on at the same time plagued Carver for many years. :) but in his case, he was switching among multiple voltages of the same polarity. Eventually it was solved by reducing the switching speed.
Just about a month after getting my first class D, I now have two. I love the Primare I32; but it has no acceptable option for headphones. So I got a little Topping TP30 Mk2 which accepts input from the I32's Pre-out and has headphone and speaker outs. I can connect conventional headphones in the conventional way and my Stax electrets to the speaker terminals. It works and sounds quite nice, except the I32 does not have a speakers on/off switch, since it only has one set of outputs. I need a quick, convenient way to disconnect the main speakers, which are bi-wired and a PITA to connect via bare wire, without compromising the 12G speaker wire. As much as I wanted to avoid bananas, I ordered some stackable ones yesterday.
@lalitk I've a tube pre used in conjunction with my class D monoblocks. I absolutely love this combo. Beautiful, lush detail with loads of power and control.
If you don't mind me asking, how the heck are you going to bi amp without a crossover? I do hope you get there..
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