Anyone's opinion about VTL amps?

If the driver tubes affect the sound of the 450 as much as the 750, I would suggest swapping the original Sovtek tubes for something with less distortion and wider bandwidth.

I have not completed my testing, but Brimar and Sylvania Military grade in 12AT7 are excellent. Also, high frequency response was increased, soundstage brought in focus and distortion decreased by replacing the supplied power cord with Purist Dominus. I suspect Elrod, Nordost and Purist would all be excellent choices for this amp, but have not tried them all.

Let us know how it works out if you experiment.

Thanks for everyone's opinion. Mejames! I have tried two modes Triode and Tetrode but my favor is Triode's sound with more musical and dynamic. How is your experience? It should be much better with MB750, isn't it?

Albertporter! I have only tried the Elrod EPS3 Signature and they are the same. I guess the reason is the source (Audiomeca Mephisto IIX is too laid back?)

Sorry, I have not heard the Audiomeca Mephisto so I cannot know if that is the issue.

I assume you’ve tried various feet under the Audiomeca, such as the Symposium Roller blocks? The source end of the system, particularly the CD player and preamp have a great deal of affect on what comes out of the amp.

As for power cords, the Purist is more detailed than the Elrod and less compressed. The price for a pair of input tubes and a set of Roller Blocks is less than the Elrod or Purist. I would consider the less expensive auditions, working my way up as necessary to reach your goal.

I have found, with my MB-185's, that Albert is correct about upgrading the input tubes (NOS 60's Sylvania goldpins recommended by Upscale were better than anything of more recent vintage I had lying around the house). For power cords, I don't play in the same range that he does, but have found that a base model Shunyata cord substantially raises the get up and go factor vs. the stock cord or the other alternatives I've got, and it's possible their top amplifier cords would work even better.

Also, there's the issue of the coupling-capacitor upgrade to the InfiniCaps VTL uses for their Reference series, an available factory option that's said to sound more highly resovled yet more refined as well.

But all this aside, my experience definitely indicates that tetrode mode will yield the best extension, driver control, dynamic impact, spatial delineation, and transparency/resolution these amps are capable of, although at a slight cost in terms of natural tonal balance (a bit leaner below, a bit brighter above) and ultimate harmonic purity vs. the triode mode. So while you might prefer triode for intimate vocals, I'd try tetrode again for larger-scale stuff.

Nguyenchiro I actually owned the 450 signature previous to the 750's yes they are quite a bit better overall. The upper bass is much better much more authoritative and the resolution of detail is improved upon also the dynamics are improved too. I previously used a Audio Aero Capitol Mark 2 CD player have upgraded this with the Wadia combination, neither of these sounded what I would call too laid back. your system shows the Bybee line conditioner are your amps plugged into it? Have you tried the system without the conditioner? If amps are plugged into it try plugging them directly into the outlet. Also is your electrical circuit just on one circuit breaker? Amperage its rated for? What's your cabling currently? current preamp is? Wondering if it's the Cary? They have a reputation for being very laid back. oh are you running with the RCA input or balanced? The balanced sounds a little less laid back.