Tubes for VTL 5.5 Preamp

I am currently running two NOS Tung Sol grey plate 12ax7 in my TL5.5. I have also had very good results with Mullard CV4004s. The Tung Sols have a little more punch in the bottom end than the Mullards and are almost as refined in the top end. I would say they are equally good in the mid range. I needed a little more control in the bass in my system and the Tung Sols gave me a boost in that respect. Otherwise I probably would have stuck with the Mullards. I have also used Telefunken ECC83s in the 12ax7 spot. These have a beautiful silky sound, the mid range is to die for but it was a little too laid back in the high end and the dynamics were not as good as the other tubes I have tried. They would be a good bet if your system was a little too strident on the top end. I might use them in my phono section if my Sumiko Blue point doesn't smooth out more in the top end. As for the 12AT7s I have an older version that uses 6350s instead of 12AT7s but I do use Sylvania 6201s in the 12AT7 spot in my VTL ST150. I liked those and Mullard CV4024s. The Sylvanias gave a little more bass punch than the Mullards. I am currently using the Mullards, both the CV4004s and the CV4024 in the phono section of the TL5.5 with outstanding results.

I have not tried them yet but I have been tempted to get some Groove Tube 12AX7M. These are suposed to be as near an exact copy of an old Mullard 12AX7 as any new production tube has gotten so far. I have read reviews from people I respect say great things about these. The price is quite a bit more palatable than some of the NOS stuff.

Have a good one,
Jim

You would do well to change out the Sovtek 12ax7WA in the line stage. I had them in my 5.5 when I got it and they were not very good. The Sovtek 12AX7LPS are a much better tube in my opinion. The new Russian Tung Sol 12AX7 has a very solid bottom end and would be a big improvement over the WA Sovteks. For old production tubes I have found that all the RCA 12AX7s I have tried have great bass. My favorites are still the old American Tung Sol 12AX7.

Your 12AT7s should be good. I would leave them alone unless you know they are used up.

I would change the Chineese 12AX7s in the phono stage. The Sovtek 12AX7LPS are a good bet for the phono stage in the TL5.5, especially if you are using the mc section. That has a lot of gain and requires SILENT tubes.

I don't know if the TL5.5 will ever match the bass definition and speed of the Spectral pre but if you can live with a little softer bass the gains in the mid and top end are well worth it.

Cheers,
Jim