VAC Ren Mk III / Sig mkII Preamplifier with SS Amp

Both VAC preamps are superb with Clayton amplifiers as well
I use M-300....sound is just superb....VAC preamplifiers are special in that they mate so well with most all SS and tube amps, especially VAC.

Dear Knghifi:

I can answer your question. VAC currently makes two preamps.

VAC's current best preamp, the "Signature Mark II", was formerly known as the Renaissance Signature Mk. II and is unusual for tube preamps in that it uses an output transformer. Output transformers on tube preamps eliminate the impedance mismatch issues that almost all tube preamps can have with solid-state amps, as well as eliminate the problems tube preamps can have driving long interconnect runs to amps. A tube preamp with output transformers is effectively like a solid-state preamp for purposes of output impedance - the VAC website says the output impedance is <150 Ohms from 20 to 20k Hz. It should be able to drive amps with 600 Ohm input impedances or less (mid 90's Rowland, professional equipment), which is to say that it will not have impedance mismatch problems and can drive virtually any solid-state amp. It likewise can drive very long interconnects without roll off.

VAC's other current production preamp, the "Renaissance Mk. III", does not appear to feature an output transformer, which would explain why its rated output impedance is listed as "300 Ohms" with no specification for bandwidth. It is likely the case that its output impedance into low frequencies is at least ten times higher, meaning that there will be low frequency roll off with certain solid-state amps featuring low input impedances (as a general rule, the output impedance of the preamp should be at least ten times lower than the input impedance of the amp at ALL audible bandwidths). The good news is that many if not most current production solid-state amps feature input impedances sufficiently high that there is no problem. That said, if you have a long cable run between your amp and preamp, you could very possibly face roll-off problems (as you would with 98% of all tube preamps - the problem is not unique to this VAC preamp).

Both VAC preamps are point-to-point wired, which is highly desirable and rare these days (for cost reasons, most manufacturers use boards). I love VAC equipment and have owned Renaissance amps for ten years.

...as a general rule, the output impedance of the preamp should be at least ten times lower than the input impedance of the amp at ALL audible bandwidths.
Raquel (Threads | Answers)

I'm happy to see Raquel specify the importance of ALL audible bandwidths. Many people mistakenly use the 10x output impedance in relation to a preamp's nominal output impedance, when in fact it's very important to consider a preamp's highest measured output impedance for application of the 10x rule of thumb.

Just waking up this thread in case more responders wish to share their experiences. I am considering a CODA 15.0 Class A solid state amp to be used with a VAC Signature Mk iia preamp with phono. Seems like the VAC preamp is good with most amps, but I was hoping to hear from someone with a similar amp/preamp setup.

I have a Vac standard Le that I've matched with a Coda model 11 100W class A. The Coda will adapt to a lot of units and will let the preamplifier introduce its own signature, which might be uncommon to class A amps. A real cameleon in my sense. My other pramp is a CJ Premier 16 and same thing, the Coda will just let it through.

I always thought my VAC was quite at par with the CJ in terms of soundstaging. It can pinpoint small instruments with a lot of a separation in the dynamics of instruments.And the Coda just follows.

The Coda is a beautiful machine. 100W is quite enough to drive a lot heavy loads, mine are Acoustat Spectra 44 electrostatics and it does it with ease. Does not run as hot as a Pass or a Plinius. This is just a fine long term machine. I will promise you this, the day you will get rid of it, maybe for something more of an upgrade, you will regret it after awhile, like most former owners do.