User reviews of our new Fet Valve 600R & 400R amplifiers

Mike-48 · « **Reply #160 on:** 19 Jul 2017, 07:45 pm »

Yesterday, a friend came to listen who's a professional mastering engineer. His unforced comment about the sound: "I'm jealous."

Photo of the system with AVA Fet Valve 400R and Janszen Valentinas:

LarryRS · « **Reply #161 on:** 19 Nov 2019, 07:43 pm »

Hi all,

After reading through this entire thread and all of the reviews I could find, yesterday I ordered a new Fet Valve 600R. It will be used in a system where the primary source is a VPI Prime with a Hana ML cartridge feeding a Bob's Devices Sky 20 transformer to a Vision Q phono preamp. The Vision Q connects to a Rogue Audio RP-5 preamp. The speakers are Magneplanar 3.7i's that are crossed over at 35Hz to a pair of MartinLogan 1100X subwoofers. The 600R has some big shoes to fill - it will be replacing a Bryston 4B SST2 amp which I consider a fine amp, especially for Maggies. All of the information I could find about the Fet Valve 600R made it a pretty easy choice for me but, in truth, it is the reputation of AVA, and my direct dealings with Frank and others, that sealed the deal. There are few audio companies out there that offer the value that AVA does, and I can think of very, very few that have maintained a standard of excellence in the same league for such an extended period of time. I'm greatly looking forward to getting my 600R and will certainly report my impressions to this thread once I've had the opportunity to form them.

LarryRS

Brad · « **Reply #162 on:** 19 Nov 2019, 09:21 pm »

Quote from: Mike in NC on 19 Jul 2017, 07:45 pm

Yesterday, a friend came to listen who's a professional mastering engineer. His unforced comment about the sound: "I'm jealous."

Nicely treated dedicated room!

gryphongryph · « **Reply #163 on:** 2 Feb 2020, 06:34 pm »

Larry, how do you like the amp ?

LarryRS · « **Reply #164 on:** 2 Feb 2020, 07:09 pm »

Quote from: gryphongryph on 2 Feb 2020, 06:34 pm

Larry, how do you like the amp ?

Haven't really finished evaluating yet but I do have a couple of comments I can share. Right now, based on initial listening tests, the Fet Valve has supplanted the Bryston 4B SST2 in a system with Magneplanar 3.7i speakers. The Bryston then was compared in a Magneplanar 1.7i system to a Parasound A21. The result was that the Bryston replaced the Parasound. I still have much more listening to do before impressions are finalized. I heard Sheku Kanneh-Mason in concert the other night and was planning on listening to his "Inspirations" this afternoon to get a better handle on the sound.

LarryRS · « **Reply #165 on:** 12 May 2020, 09:44 pm »

Below are some updated impressions on the sound of the FET Valve 600R in my system. It is currently in a system with Magneplanar 3.7i's where, as I mentioned previously, it replaced a Bryston 4B SST2. My first impression when I substituted the AVA for the Bryston was that I had lost some high frequency detail. But as I kept listening, it seemed that what I was hearing sounded more natural than it had. I was fortunate enough to attend a live Sheku Kanneh-Mason concert right around the time that I was comparing the amps. The sense of more life-like sound (for lack of a better term) was very evident on recordings of his cello (I had bought some of his recordings at the concert). A fellow concert-goer, who also happens to play cello, agreed - pointing out to me that the 600R sounded more natural than the 4B SST2 before I made any comment about my impressions.

In a lesson in system synergy, maybe, another comparison was made by swapping between the Bryston and a Parasound A21 in a system with Magneplanar 1.7i's. Here the Bryston's high frequency balance, which had seemed a bit too much with the ribbon tweeter 3.7i's, meshed very well with the quasi-ribbon drivers of the 1.7i's.

LarryRS

LarryRS · « **Reply #166 on:** 19 Jun 2020, 11:00 pm »

A question about the 600R. I've now been listening for a few months to the 600R and my overall impressions of the sound quality have not changed - the natural tone of the amp is really very enjoyable in my system (some details of the system below). I do have a question though concerning the imaging/soundstage. A consistent difference in the presentation of the 600R vs. other amplifiers I have had in that system is the size of the image. The height of the image produced with the 600R is less than that of the Bryston 4B SST2 that it replaced or a Parasound A21 that I had in that system. This is apparent on many recordings but is striking on some. A good example is the cut "Chameleon" on the MoFi LP version of Herbie Hancock's Headhunter. On that cut the image with either the Bryston or the Parasound extends from wall-to-wall but also from floor-to-ceiling - some sounds seem to come from the upper corners of the room behind the speakers on both the left and the right. With the 600R, the sounds seem to pretty much come from wall-to-wall but they definitely do not extend as high (e.g., the sounds extend maybe 2/3's of the way up). Is the image height and width something that is likely to be affected by the tubes in the 600R? Has anyone replaced the JJ tubes that it comes with it and noticed a difference in the image? I should also mention that the image also shifted just a little bit to the right with 600R and that the image changes are apparent independent of the source. Thanks in advance for any information/opinions.

LarryRS

Preamp - Rogue Audio RP-5
Speakers - Magneplanar 3.7i/Martin-Logan 1000X subwoofers
Sources - Oppo BDP 103 disc player/Bluesound Node 2/ turntables: VPI Prime (Soundsmith Zephyr MIMC ☆); Dual 1219 (Shure V15 Type III w/JICO SAS); Technics SL1200 MkII (Grace F9 w/Soundsmith Ruby OCL)

I.Greyhound Fan · « **Reply #167 on:** 19 Jun 2020, 11:50 pm »

I reviewed the 600R for Frank. I did not notice a drop in sound stage compared to my Pass amp. Tube rolling does make a difference. I have a friend that has a 400R with Magnepan 1.7's and he rolled tubes and the sound was much better. I also have a friend that has the 3.7's with 2 600R's and they sound great with a huge soundstage. The preamps used are the AVA FET Valve in both systems.

No surprize that the Bryston sounds better than the A21. I gave my A21 to my son. It is a nice amp that was a bargain for a while. The new A21+ is much better.

LarryRS · « **Reply #168 on:** 19 Jun 2020, 11:55 pm »

I've got some vintage Tung-Sols on the way for the RP-5. We'll see what effect they have. Any idea what tubes your friend settled on?

I.Greyhound Fan · « **Reply #169 on:** 20 Jun 2020, 12:23 am »

You can PM him. Tell him Larry in Woodbury referred you. PM him at edn4x4

If he does not get back to you, I will email him.

Regards,

Larry

aln · « **Reply #170 on:** 20 Jun 2020, 12:38 am »

Be sure to share the 12at7’s used with the rest of us. Inquiring minds want to know.

LarryRS · « **Reply #171 on:** 20 Jun 2020, 10:28 am »

Quote from: I.Greyhound Fan on 20 Jun 2020, 12:23 am

You can PM him. Tell him Larry in Woodbury referred you. PM him at edn4x4

If he does not get back to you, I will email him.

Regards,

Larry

Maybe I'm not doing something correctly but, for some reason, I can't message him at that address.

I.Greyhound Fan · « **Reply #172 on:** 20 Jun 2020, 11:49 am »

Quote from: LarryRS on 20 Jun 2020, 10:28 am

Maybe I'm not doing something incorrectly but, for some reason, I can't message him at that address.

I will send him an email. It may be a few days before he answers.

LarryRS · « **Reply #173 on:** 20 Jun 2020, 12:33 pm »

Thanks.

avahifi · « **Reply #174 on:** 20 Jun 2020, 12:57 pm »

My email is frank@avahifi.com. You may be sending to an obsolete address.

I try to answer all within 24 hours, but a few may wait longer on weekends when I am not at the business computer.

For a quicker response just call me at 651-330-9871. I answer the phone 7 days a week as long as I am home.

It is a land line so not answered when I am not here. In that case leave a message.

Regarding the 600R, any good quality 12AT7/ECC81 tube will work. We have e excellent results with the JJ brand we supply in new units.

Frank

avahifi · « **Reply #175 on:** 20 Jun 2020, 02:43 pm »

If you have a channel balance issue, the first step is to swap the two tubes from channel to channel and determine if the issue follows a tube.

Frank

LarryRS · « **Reply #176 on:** 20 Jun 2020, 05:34 pm »

I planned to do that - although I'm not so sure it is an imbalance as much as a difference from my other amps.

brusson · « **Reply #177 on:** 20 Jun 2020, 07:36 pm »

I was curious about the possibilities of tube rolling my 600R and found this thread after a Google search: https://www.audiocircle.com/index.php?topic=104025.60.
After reading, I decided to try a pair of the 6201/12AT7 Sylvania GOLD BRAND. I heard a difference right away, although Brent Jessee said they'd take about 40 hours to break in. They have gotten better over time.
I like a big sound stage and have set up my room and speakers (Salk 9.5) accordingly. Although the results vary with the recording, especially with the best ones, the sound stage is wider and deeper, and individual instruments are localized within.

LarryRS · « **Reply #178 on:** 20 Jun 2020, 10:06 pm »

brusson,

Thanks very much for the information. I will take a look on the Brent Jesse site right away. Thanks again.

I.Greyhound Fan · « **Reply #179 on:** 21 Jun 2020, 01:57 am »

LarryRS, Here is the link to the tubes that my friend bought and loves-

https://www.tubemuseum.org/ProductDetails.asp?ProductCode=SH%5FECC801S+BWB

Siemens NOS ECC801S, they are pricey.

Cheers,

Larry