[eclein]

I have a tube DAC that uses one tube, both channels go thru the one tube. I also have a tube buffer that has two tubes..do you think they are channel specific. One tube is left channel, One is right channel..reason I'm asking is I have hit on a combination of tubes that are the same size but different manufacturers...one tube is xyz brand and the other is abc brand..boy it sounds good.
 If they are channel specific and ultimately create a stereo image than I wouldn't necessarily hear the difference because both channels converge to create one sound. Ignorance is bliss as I didn't know any better and tried two different brands of the same size...hahah..either way unless you guys tell me I'll go up in a puff of smoke soon I'm keepin this setup!!

[srb]

Just as you wouldn't use a different speaker for the left and right channels, I would be more comfortable using a matched set of tubes for the buffer, as each tube might impart a different sound, even having the same tube designation but from different manufacturers.
 
Unless you are listening in mono or only have one working ear.
 
Steve

[eclein]

Ian Grant kindly answered my question on a Saturday night...yes they are channel specific..lots of reasons why this is sounding so good to me one of which is I'm stone deaf....LOL!!!

[bunnyma357]

To answer the original question, I believe it depends. As I understand it, Power tubes are usually single function, so they are almost always channel dependent. Preamp tubes are often dual-triode designs, effectively 2 tubes in one, usually these are still dedicated to one channel or the other, however the circuit can be designed so that one channel uses half the tube, and the other channel the other - although this seems to be less common.

So, there wouldn't seem to be a universal answer, and it depends on the particular circuit. The GF tube buffer is based on a Yaqin design, and they make both a 2 tube version (which Ian told you was channel dependent) and they also make a single tube version, which would have to have both channels pass through the single tube. So, even within one manufacturer, it depends on the specific circuit.

Single tube Yaqin:
http://www.pacificvalve.us/YaqinTB.html

Jim C

[Niteshade]

Tubes are not made specifically for a left or right channel. In a stereo design, both channels should have the same tube part numbers. You can mix different manufacturer's tubes, as long as both channels still have the same tube part numbers.

Then there are dual triodes that can process two independent signals at the same time as was stated.

[eclein]

So as long as the size is correct..mixing manufacturers isn't out of the question. The sound I'm getting with these two different manufacturers tubes is just perfect...if I use matched pairs of each they both have plus' and minus' but using one of each really brings both feature sets to the table. The sound of both speakers/channels converge anyway making for a stereo image so my theory is- a little of this and a little of that make alot of nice!!! 
 

[Niteshade]

Sure- manufacturers can be mixed and the results can be very good as you know, regarding small signal tubes. For example, an RCA 12AU7 and a Sylvania 12AU7 can be used in the same circuit.

Note: I do not recommend mixing power tubes. For stereo amps, either matched quads or duets should be used. You can technically use different brands per side, per duet (as long as they're the same part # and manufacturer). However, matched quads are the best way to go.

[eclein]

Sure- manufacturers can be mixed and the results can be very good as you know, regarding small signal tubes. For example, an RCA 12AU7 and a Sylvania 12AU7 can be used in the same circuit.

Note: I do not recommend mixing power tubes. For stereo amps, either matched quads or duets should be used. You can technically use different brands per side, per duet (as long as they're the same part # and manufacturer). However, matched quads are the best way to go.

I wouldn't try it with a power amp...but with this little tube buffer I have, its great fun. I use the Tube Pre-out of my Grant Tube DAC then into the Tube Buffer and onto Virtue TWO.2...its just the right amount of tube sound-very rich, smooth and "golden". Thanks!!!

[srb]

Tubes are not made specifically for a left or right channel. In a stereo design, both channels should have the same tube part numbers. You can mix different manufacturer's tubes, as long as both channels still have the same tube part numbers.

I agree, tubes are not specifically made for a left or right channel.  But the forum is full of people who have found a difference in the type of sound when "rolling" tubes of different manufacturers of the same tube part number in buffers.  "I found the ABC slightly rolled off on top".  "The XYZ has muddy bass".
 
So if this particularl tube buffer has 1 tube for the left channel and 1 tube for the right channel, why would you use tubes with slightly different flavors and have each channel exhibit a slightly different sound?
 
Now you could get lucky and land on two tubes of different manufacturers that sounded the same, but you could also end up with two distinctly different sound profiles for each channel.
 
The thought that the stereo sound converges into one sound field is kind of silly.  I'll go back to my speaker analogy.  Might as well use a JBL for the left channel and an Altec for the right channel.  It might sound "good" to you, but it will certainly be a step toward inaccurate sound reproduction.
 
Steve

[eclein]

One of the things that Ian mentioned was:

Yes they are channel specific, looking from the front, right one for the right channel. Sounds to me like your speakers either aren't setup perfectly symmetrical to your room or your ears and the one channel is compensating for this missing symmetric, or that you are experiencing what some speaker designers do on purpose to enhance soundstage by making the crossovers just a little different from each other or they are already and your tube combination is bringing it back closer to matched crossovers with better imaging over soundstage.


I have now settled on a matching pair..for today at least.  Its fun to try strange configurations...