Which tubes should I upgrade?

[zingo]

Let's postulate that someone has a limited amount of money. Let's also postulate that the same someone wanted to upgrade the tubes in their amplifier from stock. Would using high quality replacement tubes on the input or output tubes make the largest SQ difference for that someone... ;)

[mhardy6647]

what amp and what tubes?
All things being equal, I'd swap small signal tubes, but I am not a big proponent of tube rolling for its own sake.

[zingo]

It's an amp that I built and it uses two 5670 triode for the input and eight 6005 pentode power tubes.

[mhardy6647]

ahh... sounds like the new S-5 amp kit(?)...
Probably lots of other ways to upgrade that if it is: better coupling caps, hexFRED diodes, stuff like that.

Dunno what sort of alternatives there are for the tubes (haven't looked into it).

[dcmeigs]

I asked the same question of the Vacuum Tube Alley folks and got a big shrug. I think the best answer I got went something like this: The power tubes are rolled to get a different character from the amp. The phase inverter tubes need only work properly. The preamp tubes deterioriate with use and need to be refreshed as the amp fades, however they don't do too much to color the sound.

Having said that, I know that folks report big improvements upgrading the 12AX7 and 12AT7 peramp tubes to Mullards. Go figure.

So, I remain just as curious as you.

I have listened to Svetlanas, Sino EL34s and JJ EL34Ls but I don't think the gods want me tube rolling. You see, I have a set of three sino as one was destroyed in shipping. One of the Sveltana failed after a only couple hundred hours (yesterday- 4th of July early). So now I have two sets of three and one quad set. What do you do with that?

I really did like the Svetlanas though and mourn the death of the one. I still have not burried it yet. They sounded about the same as the JJs when I installed them and then they just kept getting better with time. I'll go back to the JJs soon and report on the differences.

Right now I have a pair of Sinos in the left channel and a pair of Svetlanas in the right and it sounds pretty damn good to me that way, as odd as that sounds. I've been too busy to really listen critically, and the left versus right channel comparisons never work for me anyway. I swear the bass sounds faster, punchier now. Perhaps it is I that has gone punchy.

I'll install my quad set of JJ EL34Ls soon and give them a listen.

I have not rolled the pre tubes so I can't offer you anything there.

Eight paragraphs to say: "humm, good question". It's beer thirthy, I'm outa here.

[MillerLiteScott]

Zingo, What are you trying to accomplish by tube rolling? I am also interested, because I am still thinking about building the same amp.

[zingo]

I'm not sure what I'm trying to accomplish Scott. I think I just get restless and am always trying to "upgrade", whatever that means. :o