Tube upgrades for AVA FET preamp?

0 Members and 1 Guest are viewing this topic. Read 2558 times.

LinuxMichael

  • Jr. Member
  • Posts: 3
Tube upgrades for AVA FET preamp?
« on: 7 Apr 2018, 07:09 pm »
Does anyone here have any experience tube rolling with a AVA preamp? How much of a benefit did you hear?Any recommendations of tubes to look at or to avoid?  What tubes does AVA normally ship with? Thanks,

Reid O.

charmerci

Re: Tube upgrades for AVA FET preamp?
« Reply #1 on: 8 Apr 2018, 07:23 pm »
If you go to the AVA thread and type in Tube Rolling in the Search (above right) - you get this -


http://www.audiocircle.com/index.php?action=search2

JerryM

  • Full Member
  • Posts: 4708
  • Where's The Bar?
Re: Tube upgrades for AVA FET preamp?
« Reply #2 on: 8 Apr 2018, 07:33 pm »
Does anyone here have any experience tube rolling with a AVA preamp? How much of a benefit did you hear?Any recommendations of tubes to look at or to avoid?  What tubes does AVA normally ship with? Thanks,

Reid O.

I have a fair bit of experience rolling tubes in an AVA T8.

There is a lot of benefit.

What AVA preamp are you asking about? Different preamps use different tubes, even from AVA.

The AVA website always states the tubes that compliment a unit.

What do you have in mind?

I.Greyhound Fan

Re: Tube upgrades for AVA FET preamp?
« Reply #3 on: 8 Apr 2018, 08:05 pm »
I have an AVA Ultra 2 preamp and tube rolling made a huge difference.  Unfortunately, I can't recommend any tubes for yours as mine uses 6CG7's.  Rolling tubes is trial and error.  I read a lot of forum threads on the sound of various 6CG7's and tried at least a dozen different tubes.  In my experience, the best tubes were from the 1950's and early 1960's.  I have a phono preamp that uses !2AX7's and the 1950's Raytheon
shiny long black plate tubes sound the best for me.  I also have a cheap Grant Fidelity tube pre and found that the 1960 Telefunken 6DJ8's sound great.

Here is a link to a tube store that has some descriptions of tubes which may or may not help-

http://www.audiotubes.com/12ax7.htm

WGH

Re: Tube upgrades for AVA FET preamp?
« Reply #4 on: 8 Apr 2018, 09:12 pm »
Do you have the original FET Valve Hybrid or the FET Valve CF?

The FET Valve Hybrid preamp replacement tubes currently supplied by Van Alstine are select high gain JJ Electronic 12AT7A (ECC81)

If you use your FET Valve a lot, like I do, then replacing your tubes every year will maintain the excellent sound. I have gone for as long as 4 years between replacements but the tubes do get noisy so I don't recommend waiting that long.

Any tube replacement after 2 or more years will change and probably improve the sound but that does not mean that they are necessarily better than new JJ 12AT7A tubes. To perform an accurate comparison you should order a new tube set from AVA and then the NOS tubes from your favorite vendor, make sure they are a matched pair, low noise and high gain.

A word of caution, buy reliable tubes - a tube short or catastrophic tube failure in the older FET Valve Hybrid pre-amp will result in a very loud static screech from one channel that will continue until either the amp's speaker output fuse blows or everything is turned off. AVA amps have a speaker output fuse that will protect your speakers.

LinuxMichael

  • Jr. Member
  • Posts: 3
Re: Tube upgrades for AVA FET preamp?
« Reply #5 on: 9 Apr 2018, 02:39 am »
FET Valve CFR on the way. This will be my first tube amp of any kind, so still a little new to the process.

Charmerci,
 My account is still new, and I get an error that says I can't search. I'm guessing that will go away after a bit more time, or. A few more posts, but for now, I rolled through the first couple pages of the AVA circle, and didn't see much in the subject lines.

Lefty052347

  • Jr. Member
  • Posts: 139
  • AVA Associate
Re: Tube upgrades for AVA FET preamp?
« Reply #6 on: 9 Apr 2018, 05:57 pm »
I am using NOS Mullard M8136 (12AU7) and M8162 (12AT7) in my FET Valve CF.  Before rolling I would suggest spending some time with the stock JJ's.  The pre-amp is great with either set.

Regards,
Dean