Best NOS 12AT7 tubes for Fet Valve 400R and 600R amp?

NIGHTFALL1970 · « **Reply #40 on:** 12 Apr 2013, 11:16 pm »

Kyle, Hydro and all other members,
I received my Cryo Gold Lion 12AT7 tubes today. I replaced the stock JJ tubes in my AVA 400R. I did an A/B comparison using Led Zeppelin's "Stairway to Heaven" from my CD of IV. I WANTED there to be no difference. Then I could forget about spending any more money upgrading tubes in my other AVA components. OMG! The GL blew away the JJs. It was not even close. The GLs gave the music a whole new level of REAL! Everything sounded better! EVERYTHING! I had to turn the volume down three times! It is something that one must experience to believe. Now I will be buying more to try in my preamp and dac. I had no interest in "tube rolling" at all before this and I do not care about "voodoo" audio tweaks. This upgrade is for real.
Thank you both for helping me make my system that much better!

Kwebb · « **Reply #41 on:** 13 Apr 2013, 01:37 am »

Nightfall,

Tube rolling is a good thing. The Cryo Gold Lion 12AT7 tubes are the real deal and there is no way would i pull them out of their sockets. Hydro turned me onto them. Here is what else i have done:

1) Replace the stock tubes in my FET Valve Preamp with the Gold Electro-Harmonix 6CG7 match cryo pair tube set. This produce a slight but noticeable improvement (5% to 10% sweater).

2) Replace the stock tubes in my FET Valve DAC with RCA Clear Top 6CG7 NOS (new old stock). This is a bigger improvement over the stock Electro-Harmonix 6CG7 (15% to 20% improvement). Better, deeper, clearer base, better over all resolution and liquidity.

I am really happy with these changes and i am glad to be able to share with all.

Kyle

Hydro · « **Reply #42 on:** 13 Apr 2013, 02:33 am »

Glad others are hearing the same thing I did. Don't forget tube dampers, another cheap tweek. Not on the same scale as tube rolling but worth the few $ they cost. I have found the Red Silicone o-rings are about as good as any. Put them where the mica supports touch the glass. Good listening everyone.

trackball02 · « **Reply #43 on:** 13 Apr 2013, 05:29 pm »

Kyle, I'm pretty much running the same combination as you: Cryo Gold Lion 12AT7 in my 400R and RCA Clear Tops NOS in my Avastar. Great combination and I also do not see any reason to change the tubes. I am also re-visiting my music collection.

If you get bored, buy an Ultravalve, like I did, for more tube rolling fun!

Kwebb · « **Reply #44 on:** 13 Apr 2013, 08:38 pm »

Trackball02,

Thank you for you inputs. This is a great hobby. I was kind of itching for a T8 preamp just to hear how different it is. Was also thinking of getting the source switching box and a Humdinger to polish things off. My problem is my wife, who is already on to my addiction, is making me slow down. So i will take the steady easy goes it path and spread out the purchase of new toys over a longer period of time.

Kyle

NIGHTFALL1970 · « **Reply #45 on:** 23 Apr 2013, 08:44 pm »

Kyle, Hydro and all other members,
Update: I received my cryo treated tubes today for my AVA Fet Valve Preamp (Gold Lion 12AT7s) and AVA Fet Valve Dac (EH 6CG7 gold pin). There was an improvement over the stock tubes but not as much a difference as upgrading the AVA Fet Valve 400R tubes. I think they sound clearer, quieter and more detailed. Not night and day but maybe a 10% improvement (hard to describe). There was the least change with the DAC. Very glad that I tried them. I hear things that I never noticed before. I think my system sounds better than it ever has. Anyone willing to try out the cryo treated interconnect? It makes me wonder.

Hydro · « **Reply #46 on:** 24 Apr 2013, 01:20 am »

Nightfall, Have you tried Telefunken 12AT7's in your preamp? They really make my AVA modded Dynaco Super Pas sing. You can have them cryo'd for 10$ each. If you would like to try some before buying, I have an spare pair you could try. Just pay shipping both ways.

Hydro · « **Reply #47 on:** 24 Apr 2013, 02:39 am »

Nightfall, just remembered my spare pair of Telefunkens are 12ax7's. I have quite a few different 12at7's though. The Siemens 801S's are best in my AVA Ultra DAC and Sylvania tripple mica's work well in recording preamps.

NIGHTFALL1970 · « **Reply #48 on:** 24 Apr 2013, 09:58 am »

Hydro,
thank you so much for the offer to try other tubes but I am not really interested in further "tube rolling". I only tried it this time because you guys said it made an improvement. I really don't like removing my covers for fear that I will strip the screws or screw something up inside. I think this was definitely a worthwile upgrade, but I like to leave my stuff alone and not tweak things too often. The next thing I might give a try ($ permitting) would be a Magnepan DWM. Thank you and Kyle for helping make my system sound better than it ever has. I got goosebumps listening to RUSH "Vital Signs" last night! I can believe how 3 dimensional it sounded!

martyo · « **Reply #49 on:** 24 Apr 2013, 01:50 pm »

Quote from: NIGHTFALL1970 on 24 Apr 2013, 09:58 am

Hydro,
thank you so much for the offer to try other tubes but I am not really interested in further "tube rolling". I only tried it this time because you guys said it made an improvement. I really don't like removing my covers for fear that I will strip the screws or screw something up inside. I think this was definitely a worthwile upgrade, but I like to leave my stuff alone and not tweak things too often. The next thing I might give a try ($ permitting) would be a Magnepan DWM. Thank you and Kyle for helping make my system sound better than it ever has. I got goosebumps listening to RUSH "Vital Signs" last night! I can believe how 3 dimensional it sounded!

Hey. So you would run the bass panels with your 1.7's? That should be fun.

mrlittlejeans · « **Reply #50 on:** 27 Nov 2013, 08:36 pm »

I have a 600R and Fet Valve DAC coming next week. I went ahead and ordered a pair of the Gold Lions for the amp. Is the consensus the stock tubes are best for the DAC?

jeenam · « **Reply #51 on:** 27 Feb 2018, 04:18 pm »

I know this is a very old thread, but I wanted to post my experiences regarding tube rolling.

I picked up a 350EXR off usaudiomart that came with Sylvania 12AT7WA tubes with green lettering. They are very dynamic and musical with good highs and lows, and a very nice midrange that presents the soundstage a bit more forward than I'm used to. For all previous tube gear I had been running the re-issue Genalex Gold Lion tubes. Gear that I have used the Genalex tubes with are Decware CSP2+, TAD 150 Signature and Doge 8. Since I had a spare set of Genalex I installed them into the 350EXR thinking they would better the Sylvania 12AT7WA. I think the Genalex 12AT7's that I installed into the 350EXR must be bad because the soundstage shrank and moved back a bit behind the speakers. Additionally, the bass was really lightweight compared to what I'm used to with the Genalex. The decrease in bass was as if the speakers were hooked up out of phase. Double-checking the speaker cables confirmed they were wired properly.

I'm considering ordering another pair of Genalex Gold Lion 12AT7 to see if the spare tubes have simply gone bad. Overall I'm really happy with the amp, though the heatsink fins on the back of the unit do get extremely warm. I'd estimate they're over 130° F.

Equipment = NAD M51 --> Doge 8 (4x Genalex 12AT7) --> 350EXR (2x Sylvania 12AT7WA) --> PMC OB1

avahifi · « **Reply #52 on:** 27 Feb 2018, 04:34 pm »

If the heat fins are getting too warm in normal use at idle, then the bias adjustment is set too high.

This can be just a case that the tubes in use are far different than the JJ ECC81/12AT7 we supply, or possibly someone has messed with the setting.

Bias current is measured with an ammeter replacing the internal V+ fuse for the channel under test. It should be about 100 mA. It is difficult and can be hazardous to attempt to measure or adjust bias yourself. You might want to have us do it if a new set of tubes don’t help.

Call us at 651-330-9871 for more help.

Frank

Bill O'Connell · « **Reply #53 on:** 27 Feb 2018, 05:08 pm »

Mullard gold pin 6201 is the best 12AT7 I've ever tried.Just saying

jeenam · « **Reply #54 on:** 27 Feb 2018, 05:20 pm »

Frank - Thanks for the feedback. I do have a multimeter that can be used as an ammeter so I can perform the biasing myself. I'll give you a call later this week. I'm going to install another pair of Genalex 12AT7 that I know are good (they were purchased from Cryoset last year) and see if those work better than the pair that sounded off.

avahifi · « **Reply #55 on:** 27 Feb 2018, 09:09 pm »

See if you can find an audio circuit board part number so I can dig it out of archives here to better advise you of the tricky and dangerous bias set task. Be very careful of the big vertical board in front of the audio boards. There is 330V dc on the black heat fins.

The board will be labeled PC-xxxx. Something

Frank

jeenam · « **Reply #56 on:** 28 Feb 2018, 04:45 am »

The serial number of the 350EXR is 062804a if that helps. Regarding the shock warning, I read through various threads and read the documentation that was provided with the amp so I'm well aware of the dangers of working inside the chassis and will be picking up a pair of thick rubber gloves from the store to prevent contact with the heatsinks.

avahifi · « **Reply #57 on:** 28 Feb 2018, 05:39 pm »

Assuming that your amp has our PC-704 single sided audio circuit boards, the bias adjust trim pot is located near the bottom of the circuit board, straight down from the tube socket.

Small tweets of the pot make obvious bias current changes. Don't over adjust.

Frank

jeenam · « **Reply #58 on:** 2 Mar 2018, 06:28 pm »

Thank you Frank. A pair of fresh Genalex 12AT7 are on the way from Cryoset and I'll report back after testing.

Regarding the sound of the amp, it easily betters every single amp I've ever owned. I will definitely recommend your gear to others. If I had the budget I would spring for a 400r, but I am more than satisfied at the moment. It's been a long, long time since music has been this enjoyable to listen to. Thank you thank you thank you.

jeenam · « **Reply #59 on:** 3 Mar 2018, 01:52 pm »

After installing a fresh new set of Genalex 12AT7 from Cryoset into the 350EXR.........the sound returned to what I was expecting. Compared to the Sylvania 12ATWA (green lettering), the Genalex are less lush and more solid state sounding, which is exactly how they should sound.

The bias pots are directly below the tube sockets as you had suggested Frank, and I'd hate to have to adjust the bias on the left channel because there's not much room to work on that side.

Thanks again.