Class D or Hybrid Amp for Fritz Rev 7 speakers


I am a long-time member but very seldom post. However, I value the expertise here as I have not bought a lot of audio equipment in my day. My goal in 2014 is to upgrade my power amp to hopefully get more detail, a better midrange, and better soundstage. After upgrading the amp, my plan is to upgrade the pre-amp in 2015.

I had some great recommendations on potential tube amps but when I started reading the manuals, I realized that I don’t have the rack space to suit a higher powered tube amp. It seems like there is a lot of discussion here on Class D so I thought I would ask for comments/help.

My current system consists of MacMini/Rega DAC/Acurus RL11 preamp/Acurus A250 power amp/Fritz Rev 7 speakers. The Rev 7s are 4 ohm, 89 db sensitivity. I plan to keep these for a long time so want an amp to match. The Acurus equipment was modded a couple years ago.

My budget is approximately $2K used or new. As of now, my plan is to try a hybrid tube amp (Rogue or Audio by Van Alstine) or Class D amp. If I don’t get one of the hybrids, I would be intrigued by Class D amps such as Channel Islands, W4S, and Bel Canto.

One criteria is that they would have to be compatible with a tube pre-amp as I wan tto try tubes somewhere in my system. In 2015, I plan to upgrade the pre-amp. I have not heard Class D or tubes extensively so I don’t have a strong inclination. However, it seems that I could put together a nice combination using a class D or hybrid with a tube preamp.

Given my budget and system, are there any obvious combinations that you would recommend? Thanks in advance for any comments.
sruffle
You could've continued to mod the Acurus amp instead of buying a new amp. I learned from experience how much the sound may change or improve from swapping out a few OEM parts for high quality parts. I never used a solder iron before I got into this hobby that has now turned into an addiction. You've been warned!

Start with decoupling power supply electrolytics with V-Caps rated at .47uf or higher capacitance. You'll hear a very impressive improvement to the soundstage. This is where my inspiration comes from - http://jimmyauw.com/tag/vcap/
After doing some research, I narrowed it down to the nCore 400 or the Rogue hybrid amps (Medusa/Hydra). I really wanted to hear the nCore 400 but I found a very nice deal on the Medusa and went with that.

I am very happy with the choice. It seems to work great with my speakers and is a significant upgrade over the Acurus. There is definitely an increase in detail but that is not the most significant benefit. The soundstage is greatly improved and there is a smoothness in the mid-range that I did not have before. Additionally, I don’t get a glare/hardness on high notes like I did with the Acurus.

Of course, after getting this improvement, I am busy thinking of the next upgrade. The big one is going to be a tube pre-amp to go with the Medusa. That will probably wait until late this year or 2014. In the meantime, I am going to:

1. Upgrade from my Blue Jeans speaker cable
2. Upgrade from the stock Medusa powercord, and
3. Consider trying new AU7 tubes from the Phillips JAN 5814 tubes currently In it ( I will wait a few months before trying this)

Thanks again to all for the comments on this thread. It was very helpful to get opinions from a group of people with this much knowledge.
Excuse my ignorance for the double post. I am fairly computer literate but cannot figure out how to send a PM. Per Strateahed's post, I am interested in exploring a 3rd party assembly on a nCore400. Can you please point me to a reputable assembly outfit. For $155, that could save a lot of headaches. Thanks.
Thanks again for the comments. Great recommendations. The Ncore 400 idea is very intriguing. I have read a bit about them but will have to do more research.
Bakalovb
I also had Virtue Sensation M901 with upgraded power supply and tube buffer. Sound wise the sound stage was rendered kind of small and imaging was not spot on, but the singer's voice was warm and upfront...which was great for vocal music. I actually thought the amp sounded better with Focus 110's. The Fritz 7 is a great speaker and I don't think I ever did it justice with the amps I paired it with at the time. I talked to Fritz on the phone and from what I gather the Rev 7 is more resolving in the highs, more tight in the lows, and a little more detailed in the mid-range. I think that basically would be the Focus 110's with a better crossover, lower bottom and, and more detail...but smooth.
Djverne, how did you like Carbon 7 with virtue audio sensation?
I have 7's and use sensation with upgraded power supply and grant fidelity tube buffer/upgraded tubes. Very happy with result.
Now contemplating to upgrade to Rev 7, but never heard any comparison between them and Carbons or if Rev's are good match with Sensation.
Hands down, go for the new Wyred 4 Sound mAMPs. I have them, $1800, and absolutely love them! Listen all night to them. Easy to drive so virtually any preamp will work w/ them. Fritz speakers and Wyred stuff seem to work real well w/ each other.
Sruffle, I don't have any direct experience with Rogue; but I've had the following in my system: Nuforce, Bel Canto, Wyred4sound, Channel Island, and Class D Audio. IMHO Nuforce was the best and slightly better than Channel Island, but cost twice as much. The CI D-200's are still in service in my system.

That said, given your current situation, you could get Channel Island D-100 at your budget ($1,800 new) or try to find some used D-200's. BTW, CI Audio amps are Hypex UcD based, versus Ncore 400 amplifier modules. The Ncores are said to be superior. I have spoken with CI Audio owner Dusty Vawter, who may come out with Ncore based amps at some point. They will likely start at $12K plus ... in the same class as the Merrill Veritas and other OEM products based on Hypex higher end modules.

If you're not inclined to take the Ncore 400 DIY route (don't blame you there), there is an outfit that will do the build for you at cost of $155. You purchase the amp modules and power supplies direct from Hypex Netherlands. Cost should be about $1,500 USD - depending on FX rate. Amp enclosures, including all connectors, can be sourced from China ($175 total). So you could have a set of mono's for under $2,000 ... out the door. FWIW, I have already started that process. If interested send me a PM and I'll give you all the details.

Finally, you could contact Fritz and asked what he thinks. I met him a couple of times at audio shows. Very friendly and approachable guy. Good luck and Happy Listening!
Thanks for the comments on your experience with W4S and the Carbon 7s. This is very helpful. I am sure that the W4S stuff is very good but I have heard the same comments in many different places about the ICE modules.

Right now, I am leaning strongly to the Channel Islands amps or the Rogue hybrids - they are both using Hypex modules.
This past fall I owned a pair of Fritz Carbon 7's. Great speaker with large sound stage and smooth sound, but too big for my living room. I paired them with a few different amps,the Nad 356 BEE, Virtue Sensation, and the W4S mINT from Wyred for Sound. Even though Fritz has demoed his speakers with the W4S I did not think the amp paired well. The midrange sounded hard and the highs had a weird metallic distortion. I think the Hypex Ncore modules would be a better option.
Thanks for the comments. On paper, a Class D power amp and tube preamp makes a lot of sense. I love the idea of building one but am not sure about the time commitment and would also be learning to solder on YouTube!
If you have an interest in building an amp, I was able to build the Ncore 400's with zero prior experience-had to learn how to solder on YouTube. Out went the B&K mono blocs, the Aragon 8008BB, and the Classe blocs. Not even close right out of the gate. Planned on long term comparisons but have never wanted to take the Ncore's out.
If you look to demo a class D; please check out the NewClear digital amp; it is very well built, a bargain and sounds fantastic. This is one of the very few Class D amps I'd ever consider and it does mate with tubes. Here's a link: http://www.newclearaudio.com/Site/NC1000L_Amp.html
I am using a class d amp with a tube pre and it is by far the best combination I have owned so far. Previous amps from Marsh, Odyssey, Adcom, B&K, Qucksilver, and a few others were easily bested by the class d amp. My speakers are Speaker Art Super Clef and Proac Response 2.5's.