SVT-IIP and Tubes (?)

Mykk · #1 08-01-2011, 12:01 AM

Hey,

I've got an old SVT-IIP in my rig, I've been using it for over 10 years and it was well played when I recieved it.

Today I decided to replace the 3 tubes with Groove Tube 12ax7c's, the previous tubes were two Ruby 12ax7a and the third is blank with different looking plates.

The two ruby's on the left and the unknown on the right. Can anyone identify the tube on the right?

Right off the bat, upon fire up after the GT 12ax7c replacement, a noticeable amount of the 'edge' has been rolled off. The lows tightened up and the highs are clean, but the mids don't have nearly the snarl or bite to them as previously. It sounds great, and is completely workable. But, since I am now in tinker mode, I am curious if mix matching tubes would be able to provide the best of all worlds. Tight bass, clean highs, grungy/tangy mids.

Do the three tube sockets control various frequencies, example: left is bass, middle is mids, right is highs? Or is the first socket the dominant socket... how does this work?

Also, how many working hours do tubes need to be considered 'broke in' and be able to reflect their true tone characteristics?

Thanks for the help, cheers ~Mykk

JimmyM · #2 08-01-2011, 01:11 AM

You never know how it works until you try. Not sure what the other ones do, but V1 is always the predominant preamp tube in any preamp and the others are usually for tone controls. The V1 tube will make the most difference. And tubes do not need to be broken in. Either they work or they're broken.

bassfreakah · #3 08-01-2011, 06:18 AM

the one on the right looks like a jj telsa. short plates. I have had a 2pro long time and have done much tube rollin........I like Shuguang 12AX7-B
in the pre section.

Mykk · #4 08-01-2011, 08:47 AM

Quote:

Originally Posted by bassfreakah

the one on the right looks like a jj telsa.

Thank you, from what I can see online my unknown tube appears to be identical to a JJ/Tesla 12ax7

I've been tube rolling all morning. Working with the three 12ax7 variations I've got. So far, for me the winning combo is a Ruby 12ax7a in V1 and the GT 12ax7c in V2 & V3.

Amazing how different variants of the same application can differently colour tone.