2. amps-preamps
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Help with VTL TL 5.5 Preamp

I recently acquired a Vacuum Tube Logic TL 5.5 preamp. It utilizes 6 tubes: (2) x 12AX7 and (4) x 12AT7. In trying to get to know this preamp, I've rolled several different combinations of tubes, BUT I cannot get the highs to sound smooth and "sparkly."

The preamp images well, has air and texture, is great sounding in the mid-range, good bass slam, etc., but the highs are driving me a little nut... sharp, edgy and too much grain. The highs can get in your face and blow you back a bit.

I've used various combinations Mullard, Telefunken, Mazda and Brimar. Right now, my set up is: (2) Mullard 12AX7A and (4) Brimar 6060 (T-Logo). All the tubes I've tired have been matched.

Any thoughts, suggestions or experiences?
bside123
istanbulu
291 posts
 
Beside123,

In regard to your DAC source (the Tranquility SE) and the treble trouble, have you solved that as yet, and if so, how?

When I read your posting and this thread, I wondered two things:

What USB cable were you using for the DAC? I've had excellent success with the Ridge Street Audio Alethias to conquer a similar situation (just my experience, no endorsement).

I also wondered what power cable you were using with the DAC. Again, my experience: I've found that different power cables affect treble troubles differently, some with greater success than others. These things are system dependent, for sure, so you'd have to experiment here. I've found that the Morrow Audio MAP3 to be excellent and a significant "runner-up" to the Morrow to be the Synergistic Research T3 power cord.

In addition, another variable affecting treble quality is whether the DAC power cord is run through a power conditioner or not. I've noticed this affects the performance of the DAC in the treble range very much.

My experience is with the basic Tranquility model, not the SE, so the variables I've listed here might apply more or less depending...!

Hope my experience helps,

:) listening,

Ed
bside123 OP
21 posts
 
Istanbulu Ed: Thanks for your suggestions. I've got great cables throughout my various systems. I know the sound of those cables very well. For the Tranquility SE DAC, I am using dB Audio's own Essential Cable, but I am certain that the cable and the DAC are NOT the source of my high frequency grudges. I've tried the VTL 5.5 in 3 different systems and have toggled between Analog, CDP as well as the DAC. I have changed configurations, etc. I am certain that I have narrowed down the sound of my complaint to the preamp itself. I am hoping to find a better tube combination and not to just "tame" the high-end with a cable. Anyway, sound is subjective. Many, I am sure, would disagree with me. Again, thanks for chiming in.
desmondjim
67 posts
 
I currently use a VTL TL5.5 with a McCormack DNA 125 while my ST-150 is in for service :( I have had great results with the old American Made Tung Sol 12ax7s. The highs were extended and sparkly but not etched or forward. They integrated very well with the glorious mids these tubes had. I also have had good results with the new issue Mullard 12AX7. I didn't like Telefunkens I tried.

On I side note looking at Steve McCormack's email above I do have the gain issues he wrote of. It is especially apparent using the mc phono input that I feel has excessive gain.

Cheers,
Jim
johnjohn
42 posts
 
Get a Classe CA200 or 300 - much smoother than DNA without giving up bass or resolution. Or just replace the 5.5 with a 2.5 which uses smoother 12AU7 tube.
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