Warm Class D for horns?

I'm panning to build a 3 way loudspeakers, radial horn, super horn tweeter, and woofer, at first I was considering just use Class D for the 12" woofer, but what about Class D amp for the horns and super tweeter, anyone using?

efficient speakers take full advantage of the linearity and musical truth provided by modern tube amps, especially single ended designs.

Wolf makes a good point here. Horns are usually very tube friendly and since tube power is often more expensive, horns are doubly tube-friendly.

Another thing to consider is that horns often don't behave according to the Voltage rules that govern most loudspeakers. (see http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php for more information.) The voltage rules really are about a driver in a box, and controlling resonance where it occurs as a result. A driver playing through a horn doesn't have that same type of impedance curve and thus often works just fine with amplifiers with a fairly high output impedance (often zero feedback) and low power. So heat often isn't an issue since power isn't either.

I realize I spoke of non class D amplifiers. But if warmth is what you are looking for, with horns, I stick with my recommendations, and agree with wolf. 

If "valve-like" character is what any audio freak is looking for, a tube amp is out there waiting for you to find it. Is there anything more "tube like" than tubes? The inefficient speaker world obviously benefits from class d technology (as well as transistor or tube based a/b), but efficient speakers take full advantage of the linearity and musical truth provided by modern tube amps, especially single ended designs.

@cosmicjazz, they all sound different even those using the same modules because the implementation is different.

Hypex 1200 modules, designed by Bruno Putzey, as used in the Mola Mola Kaluga’s are amongst the best class D amps currently available after listening to quite a few of the top designs. If it’s a softer more valve like character then something from Spec might be worth looking at.

I have used 100’s of ss amps on my horns, and the warmer of these amps, have been the designs using mosfets, specifically, those using the original Hitachi devices. They sound nice on my horns. Hafler, Soundcraftsmen and some others available, used, and all can be sent out to Musical Concepts, or Jensen Stereo Shop, to further the designs with better everything, leaving those mosfets in place.

Cool, thanks for the advice.. 

cosmicjazz,

     The overriding characteristic of good class D amps is their neutrality, nothing is added or subtracted from the inputted signals.  I've heard many class D amps and currently own 2 stereo and a pair of mono amps, they're all neutral to the extreme.  
     In your case of wanting a warmer sound, the best solution I'm aware of is using a tube preamp that you like the sound of and pairing it with a good class D amp of your choice. The overall sound will be determined by the sound of your tube preamp and source components since the class D amp virtually has no sound of its own.  

   I used a VTL 2.5L tube preamp with and replaced the standard Russian or Chinese tubes with NOS (new old stock) Mullard tubes for a warmer, more dimensional sound.  I paired this with first a Class D Audio SDS-440-CS stereo amp and later an Emerald Physics EP-100.2-SE stereo class D amp and it provided overall the sound of a very good tube amp with very good bass, a rare combination that sounds like something you'd really enjoy.


Tim

I have a pair of Jeff Rowland 535 class D amps, bridged to mono, driving a pair of Totem Forest Signatures. Voicing is virtually identical to the 25 year old, class A/B Rowland Model 2 that they replaced. I would call them neutral, neither warm nor bright, but rich and detailed. The scale of imaging is astounding. Enormous and specific. There are times when it wraps almost completely around me. 

wondering till this days horn speakers enthusiasts do not use class d, just for the woofers, but not with the horns...

Merrill Audio , comes to mind , how much is your budget ?

I have Bruno Putzey's Mola Mola Kaluga and Makua for sale on US Audio Mart.  Class D at its finest.  They are brand new and never used.  I just listed them.  You may want to read about them. 

I also have two Bel Canto Class D amps that use more recent and prior generation Icepower modules.    I've used them with various speakers.   I love them to death.  I would not call them inherently warm.   Maybe a tad with some speakers like the Dynaudios I had for awhile but not at all with others and not as much as most other amps I have tried. 

I have never heard one but read that the Bel Canto amps are on the warmer side. Maybe a pair of Hypex NCore NC500 based Bel Canto REF600M would work for you.

"Of three recent amps of my experience, the REF600M was the warmest (...)"
https://www.stereophile.com/content/bel-canto-eone-ref600m-power-amplifier

"In timbral neutrality I’d place the REF600M on the darker, richer side of the razor’s edge, primarily due to its more nuanced lower midrange."
https://www.theabsolutesound.com/articles/bel-canto-ref600m-power-amplifier/

Let's talk about this, would like to know more how Class D evolved over the years and who are the manufacturers that are on the vanguard fo design of this amplification topology...

Oh.. Class D analog, Class D digital... never found a consensus, if Class D can be analog to..

@cosmicjazz  Class D is an analog process. People confuse it with digital because of the D, but class D was first proposed in the vacuum tube era (late 50s IIRC).

The sound of any amp is governed by distortion and all amps make audible distortion. Solid state makes low amounts but its all higher ordered stuff to which the ear is keenly sensitive. That is what causes them to be bright and harsh. Tubes tend to make lower orders to which the ear is far more tolerant- this is why they sound 'warmer'. Class D can be either- a lot depends on the design. I favor circuits that use Pulse Width Modulation and zero feedback- they tend to favor lower ordered harmonics- more like tubes. There are a number of such products on the market right now- Merrill and Technics come to mind. We're working on a class D which is built around those concepts as well.

Only some of Audio Research's early class D amplifiers are not still serviceable, to correct something stated above.  At least according to ARC's site list of unserviceable models.

I own Audio Research class D DSI200 integrated and I love it and find it to be quite warm and tube-like sounding.  That's how they voiced it, to sound like their tube amps.  And interviews with their lead designer as ell as reviews (to extend you put any stock in those) at time of release 2010-ish make clear they considered it very successful in meeting that goal.

There've been a lot of developments in last 10 yrs, but I don't think I'd trade my ARC for another class D today.  But that's just me.

I have never heard a warm class D amp. Cold and sterile comes to mind. 

I recommend the ICEPower module based amps.

I found them quite warm, comparable to the Parasound A21/A23
Best,
E

I have a Wyred 4 Sound ST-1000 MKII (460 wpc, ICE power) driving Klipsch KLF-30 speakers and it's a nice match. The mids and highs are detailed, but not shouty or bright like they can be when paired with the wrong amps and bass control is excellent. 

I have a Fosi bluetooth Class D amp I use in a small A/V system that cost $85.  It's outright amazing within its limits.   Its the size of a pack of cigarettes and ~ 40w/ch.  My  Boston  A40s never sounded better.  Is the sound a touch "warm"? Perhaps.  It uses a Texas Instruments Class D module.

I recently picked up a pair of Vanatoo powered speakers.   Each has two Class D amps built it, one for woof and one for tweet.   Don't know much about the company that makes the amp circuit.  I heard them at Capital Audio Fest last couple years, was impressed and finally picked up a pair.

I have heard a few class d and some were not bad at all... Bel Canto for one and Audio Research.... my only issue with this technology is the reliabilty and lack of support from some manufactures due to parts inability...  Audio Research's early class d aee no longer supported among others .....