Anyone using a Class D amp w/ribbon tweeters?

I'm looking for some feedback about using a Class D amp 
with speakers that use ribbon tweeters. 

Anyone have any experience? How do they sound?

At least 3-4 years ago I was still believing that ribbon tweeters 
were not a good mix with Class D b/c of the sibilance it produced from the tweeters.

But now we have gone from ICE modules to NCore, Pascal, etc 
and other proprietary designs (Dig Amp Co) that may not be so bright, digital etch, etc

Anyone know about using more modern Class D amps with 
ribbon tweeters while having better control of the high frequencies?
I’m not a big fan of Class-D yet, but the best one I heard was the Belcanto M600 monoblocks, and this was driving a two way speaker that had Ravens best ribbon tweeter, and it was I believe because the Raven tweeter was a very benign 8ohm constant load, compared to when I heard that same amp with normal dynamic drivers.

Cheers George
Should sound great with any modern good quality Class D amp. Try it and see.
I’m using Class D with top-end AMTs, no problem at all, though technically not ribbons. 

If you are using a true-ribbon they tend to have transformers, I'd be curious to know how the Class D work with those. AMTs are nearly purely resistive, so I may have better luck. :) 



Thx, I’ve only heard of high marks for the bel canto Ref600 Monoblocks. And I have read that with each generational evolution with Class D, that we’re getting about a 10% jump in SQ pretty much across the boards, but particularly in improving the high end sibilance and listener fatigue. Apparently we are in the 3rd generation now (?). 
I don’t hear top end sibilance on either the NC500 or 1200as  based amps nor on the proprietary modules from Nuprime. You can try the first two types for right around $1000 new. Just like the other types all Class D implementations are not the same or equal.
but particularly in improving the high end sibilance and listener . Apparently we are in the 3rd generation now (?)

Yeah we’re getting close to me selling my hot, energy sucking, boat anchors.

When future technology allows the switching frequency of Class-D to be taken from 600-800-khz to around 2-3mhz so the output filters can do their jobs properly. This is day the day my boat anchors will become obsolete.

Technics with their $20k usd SE-R1 is on the right path with a switching frequency of 1.5mhz using the new limited gallium-nitride (GaN) semi conductors, who’s designers were the same guys who invented the Power Mosfet

Here’s what one reviewer said about the SE-R1
" Listening to tracks that we’ve heard 100s of times — and on excellent systems at that — is now a revelation of once hidden nuance and detail. Not only are we hearing things we’d never heard before, we’re hearing it in a way we’ve never heard it before. A music system that sounds like a live performance is a tough goal to attain, but Technics’ flagship nails it."

I don't know if this is real or a hoax, but there was one actually for sale on Audiogon

Cheers George
jackd135 posts08-24-2018 3:39pmGeorge

See if you can get a listen to these.

Still the same switching frequency at around 600khz, to me it’s too low for the low order output filters filters to get rid of it all without having bad phase shifts (artifacts) down low into the audio band.
That why in older tests you still see switching noise across the top of 10khz square waves. )

(Unless lately, last year or so Stereophile have been filtering it out in testing, with "Audio Precision’s auxiliary AUX-0025 passive low-pass filter". a high order "but very low power handling filter" between the tested amp and the Oscilloscope picture just so you don’t see the switching noise on the 10khz square wave, which I believe is not the right thing to do, as that filter is not there when you listen because it can’t handle any power at all.

Technics SE-R1 switching frequency is around 1.5mhz, better, because it’s phase effects are not into the audio band so much, but 2-3mhz would be best.

Cheers George

BTW: From what I’ve been able to find out, the above "Audio Precision’s auxiliary AUX-0025 passive low-pass filter" used in Class-D bench tests, is a 60db per octave passive filter.

Cheers George
I’ve heard sibilance in some recordings over the years , and I hear no top end sibilance produced by the Bel Canto ref1000m.

The BEl Canto c5i is a newer model and the top end on that is perhaps the most relaxed of any amp I have owned.

In practice, I find fears of Class D deficiencies these days are totally unfounded. i will likely only go with Class D amps moving forward as needed. At one point I considered tube amps but Class D amps put an end to that need, though I still like tube amps as well especially if well matched to rest of system, but I do not like the additional cost of ownership due to maintenance, etc. In teh end I’d rather spend as much time as possible just listening to the music and Class D enables that very well.
can I ask which Class D amp? 
Which speakers with ribbon tweeters? 

When I first got my Rogue Pharaoh, class D integrated hybrid, I used them with some Legacy towers with a form of ribbon tweeter. This pairing sounded wonderful. IMO.
Thx E. Which Class D amp are you using?

i was not familiar with the AMTs, looked them up. Look nice. 

Ive actually got a pair of Dali Helicon 400s with ribbon tweeters. I’m not sure about the the transformer with the ribbons, but these speakers were made around 2007. 

1graber2...Sure you can ask. I am using the Merrill Audio Veritas mono block amps driving the Acoustic Zen Crescendo Mark II's. A little piece of heaven...  
I listened to NuPrimes some years ago (2010), 
at that time, I wasn't too impressed, and unfortunately wrote them off.
Unfortunately b/c now apparently they have received many compliments. Will have to try them out again ....
Would be worth the effort as like all the Class D modules they have improved a great deal over the years. 

I am using ICEpower 25 ASP based mono blocks. One under each speaker. Literally. :) 

My ribbons are from Mundorf. Sound fabulous, but electrically VERY different than a ribbon.

Ribbons tend to be very low impedance, and need a matching transformer.

AMT's have no need for a transformer, and are almost purely resistors (relative to most drivers). 


interesting what you say about the Bel Canto C5i (same for the C7?), 
that has been on my list of "all in one" units to pick up 
and play with as an extra system in another room. 
I was worried that it might have some upper end grain.
Yeesh, this Merrill Class D monos are ridiculous! (aka awesome),
as described on the Merrill site, 

"Start with a 66 pound of Aircraft grade 6061 solid aluminum block. Delicately machine the chassis from this solid block isolation chambers to limit any sonic interference and minimize vibrations. Keep the walls 1 inches thick, to limit and absorb vibration. The result is a ..."
and I hear no top end sibilance
What I’ve heard is either two things in the upper/mid highs from Class-D, either sibilance as mapman mentions or an opaque whiteness.

This to me comes from "high power the low order switching noise output filters" either "set too high" which lets through too much of the switching noise (sibilant) and some audio band phase shifts, or "set too low" which hacks out most of the switching noise but also hacks into the audio frequencies upper mids ,highs (opaqueness) and creates not only attenuation but even larger phase shifts than the "too high" filter does.

The only way to fix this to me is to raise the switching frequencies much higher so the "high power low order output filter" can do it’s job properly without any effects down into the audio band. As Technics have started to do with the flagship SE-R1 with more twice the switching frequency of today, but at $30k aud and limited supply.

BTW you can see this switching frequency noise on Class-D amps in Stereophile bench tests that sits on the 10khz square waves, like a buzz saw across the top of the square wave.

But last year or so Stereophile have introduced a special filter (Audio Precision’s AUX-0025 passive low-pass filter) that goes between the the Class-D amp and the test measuring equipment that gets rid of the buzz saw, just for Class-D tests purposes, they always say they use it somewhere slightly hidden in the bench test reports. ( Belcanto with AUX-0025 filter applied Still to me a disgusting looking 10khz square wave, but better than the buzz saw with the special filter.
This is what a proper Linear Class-A/B amp square wave looks like.

Cheers George
Igraber2 the c5i is had to fault. Simply wonderful. About the size of a shoebox. 60 watts perfect for my second system. If it just had more watts I would put it in my main system and just forget all the separate components. My main system is ARC sp 16 pre to Bel Canto ref1000m Class D amps to large OHM Walsh speakers with 12" driver that love power and current.

If the c5i did not work out I was going to go tube amp.   Never happened.   I've had the c5i for a few years now.  
dsycks15 posts08-25-2018 9:18amI ran BelCanto with Magnapan 1.6s for years.

It was pure sex.
Yes, I can imagine it was, as in my first post about the Raven ribbon tweeter with the Belcanto M600’s, Maggies are also similar "usually" a nice smooth benign mainly resistive 4ohm load.

Cheers George
I have heard 3.7is as well as a pair of Vapor audios with Raals run on Jeff Rowland's 525 and the new Kinki Studio integrated. All gear was pretty well broken in. I listened to tracks I knew well. Class D (to me ) has come a long way. I had no issue with high frequency harshness. They seemed sensitive to the power cables we ran, different materials colored the music noticeably. The value is absolutely there for both these compact monsters and they like to be good and warm before they perform. 

I'm using an Aavik U300 with Raidho D3.1's. The highs IMO are spectacular.
"I ran BelCanto with Magnapan 1.6s for years.

It was pure sex."

which bel canto’s? REF 500 Monos? Ref 1000 mons?