Primaluna - Rolling pre tubes question...



I'm new to rolling tubes, and have been using the stock 12AU7.
I've a PL Prologue premium integrated with 2 12AU7's per channel. I want to test a new pair(before investing in more), so wondering if front or rear position would best reveal the new tubes character?

Thanks,
Darren
128x128dmhenley
Hi Davide256 I've never used tube dampers in a PrimaLuna. I'll try some for fun. Tube dampers are never "always good" or "always bad" as it depends on that single tube in your hand. A little bit of microphony can be good. It's something you have to try.

I am so glad we went with as many 12AU7's as we have. It's great for tube rolling. There are some new PrimaLuna products coming out that will use 12AU7's and 12AX7's come January.

There will be a tube headphone amp that can be run two different ways. And incredible phono stage designed in a way I've not seen before. And a DAC that is all-tube, dual mono, tube rectified, and uses a tube to address jitter (only found in PrimaLuna)

They are in prototyping now. I won't say anything more. I was supposed to keep my mouth shut.
Not a fan of ceramic sockets for pre tubes like the PL Premium integrated has, much prefer Teflon or composite sockets for better damping at the junction of socket and glass bottom of the tube. Microphony is distortion, pure and simple, never good.
Hi David256 if you look at many products that use tube sockets they are mounted onto PCB's, and it's not uncommon to have that same PCB have the power transformer attached to it. PrimaLuna tube sockets are mounted on to heavy-gauge fully ventilated standoffs. The chassis is so heavy I don't think there's a lot of microphony going on.

It's so easy to demonstrate. You can whack the hell out of the chassis and hardly a peep will show up anywhere on any PrimaLuna component. Compare that tube a number of preamps where you simply flip a switch and it rings through the speakers.

I do like composite sockets too. We used some killer ones when we built the Ah! Tjoeb CD player that were da bomb. But the ones we use never fail (well, maybe one) so that's what we're shooting for.

On the microphony question, I've found that tubes can lose a little air and harden up with dampers SOMETIMES. Every case is different. Some microphony CAN be good, evidenced by the sound degrading if it's removed. Is it a distortion artifact? Maybe. But that's one of the charming aspects of tubes. If distortion were the end-all be-all buy an Aragon. They are electrically perfect.

If the tube is already low in microphony, and the circuit isn't a silly one (like this idiocy of 27dB of gain in a preamp), and the socket isn't mounted to a PCB, why bother. It should be done on a case by case basis. What ever sounds best. They cost nothing so why not.
Hello,

I have a PL Dialogue Premium preamp and I am looking to buy a few tubes.  Just want to be clear so that I don't waste my money.  I only need to replace 2 or 4 of the 6 12au7s?  Please advise!  Thank you.
The 2 front tubes are all you need to replace. They have the most affect on the sound.