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
I'm about to put up some info on the PrimaLuna website about this. First, in preamps all the small signal tubes have an equal effect on the sound and you can change out just one pair if you want.

On power amps and integrated amps the two 12AU7 (in older models 12AX7) that are in the center are the input tubes and they have gain, so they will make the most difference.

I've spent a lot of time on this. The stock tubes are surprisingly good sounding. Fabulous. The French-made 1962 vintage Cifte's will have a little more extension on top, and that's why the mids are not as up-front. But that will change in time. They have a lengthy break in period. I would say a couple hundred hours. But really it takes longer than that.

I've been running 60's vintage Mullard M8136 and they are really nice. I don't know if they are for me exactly. They have more body. The mids are fuller and pretty. But the reason it sounds this way is because it's more laid-back on top.

I've also tried some British-made Brimar CV4003. These are hard to find, but we recently scored a nice quantity of perfect ones. I've always liked them. They are between the two above.

I have customers with really good ears tell me that they love the stock tubes and I agree. I hope this helps. If you guys have questions on this it's really great to put them up here or audioasylum as others DO benefit even years later from your data.

Mechans ;
Yes , Psvane does make a TII 12AU7 . But I have not found been able to find out much about them .
I never invested in a pair of the fancy recent treasure or Psvane tubes believing that they were marketing ploy for Shuguang or Sino brand tubes in a pretty bottle. I had liked the Sino 12AX7 9C version. I think that is it -it is so long since I had used them. They made them and then stopped and just make the 12AX7 8 B. Beats me but I see that Uncle Kevin (Upscale) has made a few comments, I would trust him as I had advised right away.
I've had great luck with ciftes in my prologue 3. The ciftes seemed to extend or clean up the top a bit and added what my wife and I could only describe as 'velvet' to the sound. Mind the break in time though, I have had the same experience noted earlier in this thread. I've found I need 100+++ hours before even starting judgment for either new or NOS. Broken in PL tubes sounded way better than NOS...for a while.
Thanks Kevin for the update. Mine isn't near broke in but so far I like the sound with the stock tubes. I ordered KT120s when Kevin shipped the amp but haven't rolled them yet.