Sonic characteristics of tubes

in what order of effectiveness do tubes affect the sonic characteristics?

It seems obvious that the output tubes affect the sound the most right? What about the rectifier tube and the others?

Recently I installed a 6SN7 tube in the center socket and it seems that it smoothened out the sound. But a long time ago I installed a Webber SS rectifier rather that going through rectifier tubes rather frequently. They would last 3 to 6 months and the poof! They were toast. The Webber has been in service for 3 years now without a problem. But does the rectifier alter the sound significantly and in what way? What do you feel?

How about the others?

Thanks.

Power tube wise I've tried 6550, KT88, and KT120. (all modern production) To me they all sound pretty much the same. Same goes for rectifiers, differences I find relate more to durability. Driver tubes though is an entirely different matter.

To me the only tubes that significantly alter sound quality are the output tubes. But I imagine they all have some effect.

Why else would someone be willing to spend big bucks on NOS rectifiers. Does anyone feel the other 9 pin tubes alter sound.

If I recall a conversation with Bob Latino correctly the tube that makes the most
difference in the ST-120 (and I assume in the ST-70 as well) is the center tube.

I've found that the closer to the input the More of a difference the tube makes.
Likewise the closer to the speaker the Less of a difference it makes.

I have a small amp in my den that uses 6L6GC for the output tubes.
I've tried KT-88 and 7581A as well as 6L6GC tubes and there was
not nearly the change as when I went to different Driver tubes.

True that the center/amplifier tube makes a big difference. You want to run your 'quietest' tube there. The 12BH7A is good for that or 12AU7 Amperex Bugle Boy and Telefunkens. I also find that good tubes in the phase inverter will make and improvement but not as much as the amplifier tube. Obviously the output tubes will make a difference.

I have used the Weber copper wz64, Groove Tube 5ar4, Genalex 5ar4 and Millard GZ33 in the rectifier position on my M125’s and they all had different sonic qualities.  The Weber has a very tightly controlled bass and effortless power delivery but the treble seems a bit crisp, not objectionably so.  The Groove Tubes were very loose bass and barely adequate at moderate volumes and one of them gave up after a few days.  Genalex’s were a bit soft and plummy in the bass and struggled at higher volumes, I could really tell they were working hard on loud passages and compressing the dynamics a bit.  The Mullard’s are kinda the best all arounders.  Bass is not as tight as with the Weber’s but a lot tighter than the Genalex.  They have have plenty of power at high volumes and treble beautifully smooth and detailed.

I’ve also used Genalex KT88’s and Tung Sol KT120’s. The Genalex have a very tight and controlled bass and can sound incredibly real.  The midrange is lively and presents acoustic instruments with startling realism at times (depending on the recordings). Treble is detailed and extended.  The KT120’s have great bottom end power and drive but I don’t think they are as tight and controlled as the Genalex.  Midrange is beautiful and more what someone might expect with tubes, lush and liquid and velvety.  The highs seem a touch less airy but not lacking detail or sounding closed in.  They are what I’m listening to now.

I’ve used Genalex and Electro Harmonix in the driver and inverter stage and preferred the Genalex.  They had a lower noise floor and have been there for 9 months now.  

tubes with the most gain provide the most difference in sonics, so on the VTA70 or 120 amps, that's the center tube on the driver board.
Recitifier tubes make the least difference, since they aren't really in the signal path.
Amplifier output tubes also make a difference.
On a preamp, the gain stages (usually the first tube or pair of tubes) make the most difference, the output tubes are usually buffers and
don't make as much difference

Dogstar wrote:in what order of effectiveness do tubes affect the sonic characteristics?

It seems obvious that the output tubes affect the sound the most right? What about the rectifier tube and the others?

Recently I installed a 6SN7 tube in the center socket and it seems that it smoothened out the sound. But a long time ago I installed a Webber SS rectifier rather that going through rectifier tubes rather frequently. They would last 3 to 6 months and the poof! They were toast. The Webber has been in service for 3 years now without a problem. But does the rectifier alter the sound significantly and in what way? What do you feel?

How about the others?

Thanks.

If you're talking about an amp, I found that the difference between a good and bad sounding set of driver tubes can be as significant as a good or bad set of output tubes. And of course by "good" or "bad" I simply mean in terms of the sonic characteristics you're looking for.

As far as amplifier rectifier tubes go, in my experience there are two types: Noisy ones and quiet ones.

But if you're talking about a preamp, I found that there are no set tendencies. I've replaced whole sets and heard no change, but changed one buffer tube and it made a big difference. I also found that preamp rectifier tubes can change sound and not just by adding or not adding noise.

Because of these findings, and my recent revelations in passive crossover design, I have to surmise that circuit design is what makes a tube change significant or not.