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

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Hydro

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #180 on: 21 Jun 2020, 05:20 pm »
I have rolled a lot of tubes in my 400 and 600R amps. NOS Mullard tubes have a great soundstage with more depth than any other tube, they also have a more "tube" sound as in lush. Gold Lion cryo tubes are more neutral but still have the huge soundstage. Sylvania are the brightest tubes that still have good bass, excellent imaging, about half of the Sylvania tubes I have tried are at least a little microphonic. Tung Sol are bright but thin on the bottom end. RCA are very neutral but don't open up like the Mullards and Gold Lions. GE JANS are really good tubes in all respects and could be a great choice in some systems, but I like the Mullards the best

tonyptony

Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #181 on: 22 Jun 2020, 11:44 pm »
I like the Valvo 6201 Blues the best.

Hydro

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #182 on: 23 Jun 2020, 04:13 pm »
Valvo didn't  make their tubes, just sold others under the Valvo name. Where were the 6201's you have made, tonyptony? If in West Germany they are probably Siemens, Holland would be Amperex or Great Brittan would be Mullard. Valvo tended to sell premium tubes from whatever manufacturer they bought from. 

aln

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #183 on: 24 Jun 2020, 09:10 pm »
Great stuff here-I am using the Sylvania 6201 gold pin in my 600R but want to try something different in the near future.  Thanks for the great ideas!

tonyptony

Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #184 on: 3 Dec 2020, 12:09 am »
Valvo didn't  make their tubes, just sold others under the Valvo name. Where were the 6201's you have made, tonyptony? If in West Germany they are probably Siemens, Holland would be Amperex or Great Brittan would be Mullard. Valvo tended to sell premium tubes from whatever manufacturer they bought from.

Hydro, better late than never I guess! :D I’ve been putting a new house together so I’ve been away from the sites. I’m pretty sure my Blue labels were made in Germany. They are pinched waist varieties, although I know there were a number of variations in these. Most of what I have are df1 variants. A few of other dc variants.

ckullmann1

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #185 on: 25 Nov 2022, 08:16 pm »
I have a Fet Valve 400R amp and I’m looking to try Genelex Gold Lion tubes. One of the posters mentioned that they are “Hifi” sounding. Has anyone tried these tubes that didn’t like them for this reason?  I’m looking to try one reasonably priced alternative to the stock tubes and these seemed like one of the safer bets. I definitely like a detailed top end. Any thoughts or insights would be much appreciated.

WGH

Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #186 on: 25 Nov 2022, 10:08 pm »
RCA are very neutral but don't open up like the Mullards and Gold Lions. GE JANS are really good tubes in all respects and could be a great choice in some systems, but I like the Mullards the best


I have a Fet Valve 400R amp and I’m looking to try Genelex Gold Lion tubes. One of the posters mentioned that they are “Hifi” sounding. Has anyone tried these tubes that didn’t like them for this reason?  I’m looking to try one reasonably priced alternative to the stock tubes and these seemed like one of the safer bets. I definitely like a detailed top end. Any thoughts or insights would be much appreciated.

I have a pair of Genalex Gold Lion 12AX7 and the CV4024/12AT7 Mullard NOS in my AVA Fet Valve CFR preamp and there is nothing hi-fi about the sound. The original JJ tubes certainly have a detailed top end, I got tired of it. The Genalex/Mullard combo is perfect for me. That's the thing with tube rolling, each person likes something different.

I thought I had a noisy Mullard 12AT7 so I plugged in the original JJ's. The detail was back, and not to my liking either. As it turned out the NOS Mullards have copper pins which oxidizes in a year, a quick and easy pin cleaning with CRC QD Electronic Cleaner fixed the noise problem.

Double check the tube type, it is easy to get letters mixed up.

I get my tubes from Jim McShane, he is honest and one of the good guys selling tubes.
http://www.mcshanedesign.net/tubes.htm

CV4024/12AT7 Mullard, NOS/NIB, military boxed, the pin protectors in place, no Mullard logo on
them. With double stapled plates and copper getter ring supports, these are really fine tubes, $49.50 ea., $99.50/pair.
Beware of fakes!! A number of vendors have used/washed tubes in fake boxes and are selling them for full price! In
their defense, they may not even know they have used tubes! But I guarantee my stock is 100% new!

Genalex Gold Lion B759/ECC83/12AX7 reissues! Tis is a great tube - warm, excellent (one customer described it
as "sublime!") midrange and super soundstaging. The latest production tubes are much quieter, I can now recommend it for
phono and or other noise sensitive stages with its low hum spiral wound heater. $44.50 ea., $89.50/pair.

ckullmann1

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #187 on: 26 Nov 2022, 01:23 am »
Thanks so much! I assume I would need the 12AT7 gold lion for the 400r, not the 12AX7?

WGH

Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #188 on: 26 Nov 2022, 01:35 am »
Thanks so much! I assume I would need the 12AT7 gold lion for the 400r, not the 12AX7?

Don't know, never owned the 400R. A post from 2015 says 12AT7 but AVA does running updates so pop the hood. The manual will have the tube type too.

Tubes for Fet Valve 400R
https://www.audiocircle.com/index.php?topic=132189.0

ckullmann1

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #189 on: 16 Dec 2022, 03:45 am »
So I ordered a pair of Gold Lion tubes for my Fet Valve 400R and they arrive tomorrow.  I don’t have much experience with new tubes. Do they take time to break in or do they sound good from the beginning?  Thanks!

aln

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #190 on: 16 Dec 2022, 06:35 pm »
You will hear the “character” of the tubes very soon after start up.  Let them warm up for a half hour or so before doing serious listening.  Check the rear heat sinks to see if they are very hot.  Sometimes the amp has to be re-biased depending on the tubes used.  That usually requires the amp to be sent to Frank.  Enjoy

I.Greyhound Fan

Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #191 on: 16 Dec 2022, 06:58 pm »
So I ordered a pair of Gold Lion tubes for my Fet Valve 400R and they arrive tomorrow.  I don’t have much experience with new tubes. Do they take time to break in or do they sound good from the beginning?  Thanks!

Tubes take about 30-50 hours to break in.

ckullmann1

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #192 on: 16 Dec 2022, 07:31 pm »
Thank you. Is the bias setting for the stock JJ tubes likely fine for the Gold Lions? I’m not sure I’d know how to change it, anyway.

ckullmann1

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #193 on: 16 Dec 2022, 07:32 pm »
Oops, I just saw the other post. Has anyone switched from the JJs to the Gold Lions that can comment on the bias?

danielgk

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  • AVA engineer/technicion
Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #194 on: 16 Dec 2022, 08:28 pm »
Fetvalve 400 and 600 have a self bias circuit that has no adjustments.  You might be thinking about the ultravalve - that one has bias adjustments.


Dan

SoaringBear

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #195 on: 23 Feb 2023, 03:13 am »
Hi All,

I just recently purchased a Fet valve 600R and a Vision RB preamp and thought I would share my impressions.

I was able to listen to the Class A Vision RB preamp, Fet Valve, Synergy 450 and Fet Valve 600R over the weekend. A seller was selling Totem Forests and loaned me the AVA equipment in hopes I would purchase an amp and preamp as a package.

I started my evaluation by paring the Vision RB with my Emotiva UPA-2 amp which has 125 watts/8Ohms powering Totem Forest speakers. The amp sounded OK before, but when paired with the Vision RB, the Emotiva amp came alive. It already had good low end, but now it got noticeably better lows and higher. My 27-year old son was listening too and he heard it too. Then, we swapped out the Emotiva amp for the Fet valve 600R.

Where the 600R really shined was playing at louder volumes. First, the amp never sounds strained at some point as gain is increased. This is the first amp that I have owned I can say that. It remains wonderful sounding at any volume. This is very important because with my sensitive hearing, I was constantly turning down other preamp/amp combos to avoid coloration and strain. It's a very pure sound. It is not warm, it is very precise, neutral and sweet. I would characterize it as very analog, like a very fine phono based system. That is a compliment. Voices are distinct, clear and unstrained. The harmonics are incredibly good to the point that instruments don't sound "like" the instrument, they are the instrument playing in my room. I hope that makes sense. Cellos, acoustic guitars, electric guitars, drums, voice all just shine. The 600R is a wonderful amplifier and I could readily hear its improvement. Recording after recording shines with this setup that features the RB preamp and 600R amp. It is amazing. Incredible.

I should mention my source is an Audiolab CD transport with optical connected to Denafrips Pontus II and Hermes units feeding the RB preamp.

I enjoyed reading Frank sharing on this thread how he and his engineer's designed/engineered the 600R to utilize regulated power supplies and that the output devices use the lower voltage rails. The amp runs cool. (Ha, the Class A Vision RB does not.)
 
What I am hearing is amazingly good. I would love to meet Frank in person and tell him how much joy his preamp and amp are bringing me.



tonyptony

Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #196 on: 23 Feb 2023, 04:22 pm »
Congrats, SB. How did you like the Synergy 450 by comparison?

SoaringBear

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #197 on: 24 Feb 2023, 04:58 pm »
Good question. I assumed it would be similar, but I did not find it to be. I thought it was grainy

SoaringBear

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Re: User reviews of our new Fet Valve 600R & 400R amplifiers
« Reply #198 on: 2 Mar 2023, 03:13 am »
I called AVA and spoke to Frank about the 600R running hot. He advised me that the 600R needs more breathing room and not put the Class A preamp directly on top of it. So, I put 1" blocks of wood between the two. And temps went from 135F to 105F. All components are running cool. Frank was certainly correct.