Tube question

[AKA_Hyfi]

After recently re-tubing my VAC CLA-1 MKII Pre-Amp with the exact tubes that VAC uses in newer Pre Amps I got to wondering.

Are the tubes that come in new gear the best tubes for that unit?
Or, do the tubes they use just meet a recommended measurement and then they use the cheapest tubes that fit that requirement?

What they set me up with was a set of NOS 12au7s and a set of Chinese 12ax7s and with shipping the cost was around $90.

Now, they also use these same exact tubes when they sell you a new $10k or $14k pre amp so that is my confusion. There are so many different sounding tubes at many different price ranges so what do you think an MFGs process is for specifying out the tubes that will go into a new unit?

So VAC uses $20 tubes in a $14k unit as well as a $4500 / 15 year old unit. Seems odd that the choice would be to keep the cost down in this case. What would another $100 be to someone dropping $14k on one of these awesome units.

Any thoughts or actual reasons from anyone here in the business?

[cmalak]

Manufacturers look for reliability of supply and tube quality (to meet min. measurement standards). They know tube afficionados will roll tubes to suit their own sonic preferences in general.

[Puma Cat]

Cyril's right.

Conrad-Johnson's top three requirements for tubes used in products are:

1) Availability of supply
2) Durability (tube life)
3) Sound quality

[AKA_Hyfi]

Thanks for the replies.

It makes some sense but I still would think a $14k unit would have better than a $20 tube in it. That said, the tubes they supplied me brought my VAC pre back to the sound it had when it was new and the original owner had just purchased it.

I don't really have the cash at the moment to start rolling but if I did, VAC told me to start with the 12au7s BUT, when this unit is in Passive Mode, it uses ONLY the 12ax7 and I do switch back and forth. I usually switch it to Passive when I want to listen at lower levels since I can get great sound without all the gain if someone else is trying to sleep.

I guess at some point, I would like to try the PSVane tubes which keep getting rave reviews.

[drrsutliff]

I have rolled many tubes through my VAC per and ultimately found that the ones that Kevin recommended (same set you stated they supplied for yours) had the best overall sound and presentation. I have rolled some Telefunkens and some Mullards and each brought a unique characteristic that initially was enchanting, but ultimately was not as complete as it is voiced with the VAC supplied set.

Sent from my iPad using A.Aficionado