To Garrett Hongo,
I hope that this finds you well. I am about to get a pair of deHavilland GM70 amplifiers, and I currently have a VAC Renaissance Mk.I preamp. I seem to remember reading in one of your articles that this is potentially going to be a mismatch.
On the subject of dH preamps, what is your sense of the difference between the Mercury and the UltraVerve? From what I read they both have different strengths. I'd appreciate your thoughts.
First of all, congratulations on your acquisition of the deHavilland GM70s, an outstanding pair of mono amps. Though I don't recall any specific warnings regarding the VAC Renaissance Mk.I being a mismatch for any dH amps, I do have some thoughts regarding the Renaissance Signature Mk.I and its high gain.
The Renaissance Signature Mk.I, as you probably know, is the first VAC pre in the Signature line. It is direct-coupled through three tube gain stages and has zero negative feedback, a 120-ohm output impedance, and about 35dB of gain. That last spec is the one that may cause you issues. Gain is very high and adjustments can be extremely touchy. This may have been what you remembered as a concerning thought from one of my reviews.
If that's the preamp you have (you can tell by the power supply -- a lacquered front is the Signature version, a plain matte-black front is the Ren Mk.I), here's my suggestion beyond switching to a deHavilland line stage (which may be optimum), as the VAC Ren Sig Mk.I is so valuable a piece. Why not send it to VAC and have Kevin Hayes and his techs upgrade the pre to a Sig IIa? Gain will be lowered to about 12dB and, among other improvements, finesse will increase to a spectacular level (I've reviewed the Sig IIa). I think the price of the upgrade is around $4000. It's in the ballpark of a new pre from some other companies, but I think you might just like it even better. The VAC Sig IIa is truly an exceptional pre.
If it's the Renaissance Mk.I that you have, its gain is a more normal 12dB and not at all difficult to use with various amplifiers. Nor is it upgradable to a Sig IIa, unfortunately.
You could certainly try the Ren Mk.I with the GM70s and listen for how you like the sound, but I'd not make any definitive judgments in reference to the deHavilland amps until you've heard them with a dH line stage. It's not only questions of relative gain and/or impedance matching, but synergy in general. The dH amps are definitely voiced with a dH pre in mind. As are the VAC amps with a VAC pre. I have found that dH amps perform best with dH preamps -- the Mercury 3 or UltraVerve.
Regarding the dH line stages, there are indeed different strengths.
The UltraVerve is the more popular pre for those who want a more "classic" SET sound. It's saturated, bold -- a tonemeister. Note it uses the 6SN7 tube. Kara Chaffee, chief engineer, really loves the NOS Tung-Sol roundplate 6SN7 for that dark, velvety texture. But you can change its tone with others -- Sylvania chrome top and Sylvania '56 "Bad Boy" have more sparkle, resolution, and extension.
The Mercury 3 has tremendous finesse and ease, especially with choral music. It's my reference and, to me, has a most sophisticated, resolving, and airy quality with voices, operatic and choral. It captures more of the microdynamics of vocal performance than any other line stage I've tried, especially in combination with my dH KE50A monoblocks. It's fine for orchestral as well, as it's tremendously resolving and dynamic with large-scale music. Quick, refined, light-footed.
Those who listen to combo jazz and rock might prefer the UltraVerve, if I can generalize a bit. Those who listen to classical, opera, and choral music might just love the Mercury 3 more.
I have both dH (KE50A monos) and VAC (Phi 200 and PA 100/100) amps, likewise VAC preamps (Ren Mk.III and Sig IIa) and a dH pre (Mercury 3). I tend to use a VAC with a VAC, a dH with a dH. I've tried mixing them, but the results are inevitably superior keeping the electronics consistently matched by brand with each other. . . . Garrett Hongo