[ric]

For quite a while I have been using and enjoying Sophia Electric EL34's, BUT, the reliability has been a problem. More recently I tried some Old Stock Amperex type Japan made EL34's as a pair and like them as well, then bought two Mullard type fx2 tubes.
     Running a comparison between the Sophia's and the Old Stock tubes, found them more similar than different, with the Sophia's being a bit more open/airy, but with less bass definition, however, I could live with either of the quad sets.
   Because I can individually bias the tubes, I am now running the Sophia's on one side and the fx2's on the other side, and to my ears this is a great sound, so much better than either quad.
Has anyone else had this experience of mixing two and two, and having the whole being better than the sum of it's parts?

[mick wolfe]

No, have always used a quad of one particular tube. That said, I think you're somewhat valid in your approach by keeping the same tube on each channel. IOW, not mixing a Mullard/Sophia cocktail on the same channel. If it sounds good to you, continue the experiment and then maybe go back to a full quad of either to see if the mix is all you thought it to be.

[rotarius]

So the left channel sounds slightly different than the right and you like it?  Ultimately, it's what your brain perceives as better.  My brain wouldn't allow such radical behavior

[musicdre]

cool story.  go with what your ears prefer, not what is supposed to sound better.  thanks for the share!

[jjss49]

if each tube can be individually biased, then i suppose one can mix tubes - there have been ads by amps like primaluna's where they say in the ad because each other tube is biased on its own, they even put in different tube types (kt88, 6l6, el34, etc) into the amp -- well maybe it runs and makes music that way, but why do that? 

for me, all these years, i have never wanted to 'mix' tubes in that way - the thinking is, i want consistency between left and right channels, so leaving aside how even the same make of a particular tube type wears over time, i would prefer that the tonal balance stays the same left and right

[Early B.]

Ric -- mix the two brands on the same channel and compare it to how you've got them set up now. Should be interesting.

[ric]

In the past I did have a mix on one channel but the amp didn't like it, so I am keeping the tubes on their same sides. Also a while back, I had talked to VAC Audio (the maker of my Avatar amp) and he said it would be OK to have different tubes on each channel.
   Also, for record (pardon the pun) I HAVE A/B'd the sound of the tubes vs quads and this is what I prefer.
VAC said I would not perceive any negatives at my listening position and, if I were blindfolded, doubt I would be able to hear some sort of imbalance caused by tubes per side.
Thanks for your comments!

[Tyson]

The other option would be to have 1 new tube and 1 NOS tube on each side.  That would give you more of a true blend of their sounds.  I've done this in the past, just for kicks.  It's cool but I ultimately decided matched quads sounded better in my setup.

[mick wolfe]

if each tube can be individually biased, then i suppose one can mix tubes - there have been ads by amps like primaluna's where they say in the ad because each other tube is biased on its own, they even put in different tube types (kt88, 6l6, el34, etc) into the amp -- well maybe it runs and makes music that way, but why do that? 

for me, all these years, i have never wanted to 'mix' tubes in that way - the thinking is, i want consistency between left and right channels, so leaving aside how even the same make of a particular tube type wears over time, i would prefer that the tonal balance stays the same left and right

That PrimaLuna ad caught my eye as well a few years back. I asked (posted) about that particular tube scenario over the Tubes Asylum.(Audio Asylum) The general consensus was that one would end up with the worst characteristic of each individual tube and a general sonic disaster. Just re-enforced what I was thinking all along. Yes, I too prefer to use the same output tube throughout. Plus as already mentioned, one is diminishing tube life of half of a what could be the better quad by splitting them up.

[rotarius]

Each tube amplifies one half of the AC cycle so there should be no benefit to using different tubes.  Even given the same bias, the bias drift of tubes can be different.  Best to used matched sets.

[Crang]

Been wondering this. Had purchased 2 matched quads of RAM tubes for my Music Reference RM9. 2 years later I finally got it working and one tube went bad right away- no warranty. Tried to get some places to match just the one failed one and no one could. So I need a whole new quad. Debating trying a different make/model for that channel as Im not very excited to buy more rebranded Shuguang tubes.......will the left and right channels sound that much different with different quads of power tubes?

[richidoo]

Hello Crang, welcome to audiocircle!
RM9 can also take KT88, with the same 30ma bias. My friend uses it with KT88 for 10+ years.
Gold Lion makes reliable, good sounding tubes in KT77 and KT88.
Gold Lion is the top brand of New Sensor, an American owned tube manufacturer in Russia.
Jim McShane sells Gold Lion tubes, he tests and matches very close, good warranty service and good advice.
I have no affiliation with gold lion or mcshane, just a happy customer.
Good luck