Grant Fidelity DAC-11 tube rolling

[blackraven]

I am currently using a Grant Fidelity DAC-11/Preamp with a Class D Audio CDA 254 amp and my MMG speakers as my second system. Today I swapped tubes. I replaced the original NOS 6N11 tube with an early 1960's Amperex 6DJ8/ECC88 tube made in Holland with the white lettering (non A Frame version). I was astounded by the difference in the sound. The sound stage sounds like it tripled in size and the sound is much more transparent and holographic for lack of a better term. The detail and resolution has dramatically improved. Treble is a little laid back and bass is tight. The midrange is smooth as can be with out any detectable grain by my ears or my 21 year old budding audiophile son's ears. Bass is just a little less prominent than the original tube but I fixed the issue by removing the sound absorbing material that I had behind the MMG's. Swapping the tubes took this system to a whole new level and proves that the Grant Fidelity DAC/Pre is a Gem at $325.

I have one more tube that I am going to roll. I bought a vintage 1970's Amperex 6DJ8/ECC88 tube with orange lettering and the orange globe logo with an A frame as a back up tube. I will give it a try in about a week.

Both tubes cost $20 each.

[Feanor]

I'm glad you're please with that upgrade.

There is no doubt that rolling tubes can significantly improve the sound. On the other hand it demonstrates that tubes do color the sound for better or worse.

[blackraven]

I'm glad you're please with that upgrade.

There is no doubt that rolling tubes can significantly improve the sound. On the other hand it demonstrates that tubes do color the sound for better or worse.

That is the thing that I like about tubes. I can tailor the sound to my liking. We all pick different speakers, amps, sources and cables that appeal to our senses. Every piece of gear has its own unique sound just as tubes do.

My only beef about the Grant Fidelity DAC is that it does not have a remote for the volume. So now I have to get my lazy rear end off the sofa.

[blackraven]

Just an update on the new tube. After about 10 hours of play time the bass has really come alive, deeper with more punch. I am really diggin the sound. I am spending more time in my basement listening to my second system.

I think that the Grant Fidelity DAC-11 with this Amperex tube is a match made in heaven for this Class D Audio amp.

[Feanor]

Just an update on the new tube. After about 10 hours of play time the bass has really come alive, deeper with more punch. I am really diggin the sound. I am spending more time in my basement listening to my second system.

I think that the Grant Fidelity DAC-11 with this Amperex tube is a match made in heaven for this Class D Audio amp.
There are some great Amperex tubes. Back when I had my Sonic Frontiers preamp, the I tried at least half a dozen different tubes. The best by far were these Amperex USA white label 'PQ' 6922's ...

9085

I did not buy they as new tubes, (true "NOS"); they were used but worked great. I paid about $85 for two. Actual new, NOS, if you can find them, retail for $190 each -- see HERE (http://www.tubedepot.com/nos-6922-amp-usa.html)

But note that not all Amperex PQ's are the same. I had orange label 6299's that were definitely not as nice. Also a pair, white label but "6922/E88CC", probably later model, that weren't quite as nice.

[blackraven]

I've done a lot of reading about the 6922/ECC88 tubes and the Amperex in particular. The 1950's and early 1960's Amperex tubes tend to sound the best. The PQ's stand for premium quality, there are others labeled SQ's for superior quality, both are supposed to be made to better specs. The 1970's A frames with the orange globe logo's are supposed to be very good as well. You have to be careful about the Bugle Boy's because there are counterfeit's.

[E-Stat]

The 1970's A frames with the orange globe logo's are supposed to be very good as well.
I prefer Amperex tubes of that family as well. I use 70s vintage gold pin JAN 7308s in my ARC preamp.

[blackraven]

I prefer Amperex tubes of that family as well. I use 70s vintage gold pin JAN 7308s in my ARC preamp.

I was thinking about giving the 7308's a try as well but the cheapest used tube in good condition sells for about $84 vs $20-40 for the ECC88's. Next week I am going to give the A Frame a listen.