Tube Rolling - Any tips or caveats

Other respectable tube suppierls are : tubemonegr; Tube depot & brent jesse - you can get good NOS tubes w/o spending a fortune

Be careful pulling out and inserting tubes so you don't mash the tiny plug in the ceramic tube holder

If I want to improve the dynamics of the system is the pre-amp the best place to start?

A while back I upgraded the output tubes of my Mid-monos to KT88s. This did wonders for dynamics, no doubt as a result of the increase in power.

Would upgrading the input tubes (12ax7) of the power amps provide a bigger improvement (in terms of dynamics) than upgrading the phono stage of the pre?

My first experience with NOS tubes has not been great.

For simplicity reasons, I started out by swapping my input tubes on my power-amps (Quicksilver Mid-Monos) with the pair of Telefunken 12ax7s. It sounded great, it tighten the bass and added definition to the imaging of the individdual instruments within the sound stage.

During my second listening session, less than 4hours total I lost the left channel. I let things cool down for a few hours swapped back the old tubes and voila! We were back up and running. Clearly a faulty not so New NOS tube.

Luckily the audio shop agreed to exchange it.

"Would upgrading the input tubes (12ax7) of the power amps provide a bigger improvement (in terms of dynamics) than upgrading the phono stage of the pre?”

Nick sr, I think that’s almost impossible to determine in advance. I can tell you that the potential for improvement by changing the 12ax7s can be huge. Call a reputable pro who guarantees satisfaction with a credit/swap policy. I’ve been most satisfied with Andy at "Vintage Tube Services" and Brent Jessee. Both stand behind their tubes and offer excellent advise. I can’t imagine your regretting the calls.

FWIW, I bought my 12ax7s from Brent Jessee.

http://vintagetubeservices.com/

http://www.audiotubes.com/12ax7.htm