VAC owners, sound off

An update. Put the PS on some 1.5" butcher block, and that on a glass shelf off the floor. I honestly don't know if that made a difference vs just being on the floor. Whatever it was, it was subtle. I also reversed polarity at the amp, and that did seem to help things, though it wasn't quite the 'a ha' moment I was hoping for. The biggest difference? swapping out the stock Sovtek 12au7's and Chinese 12ax7's for a pair of black plate GE 5751's and RCA clear tops. Big difference. MUCH better bass and weight, dimensionality seems to have increased as well. Though I think the highs are a bit less extended with less decay. At any rate, the musicality has increased, which is what I was really missing.

A big shout out to Andr who turned me on to Joes lore and conversed w/me via email. Because of the tube hunt, I also met and did business with a wonderful tube seller here on the gon -- Aztubes. A relative newcomer here, but an honest, knowledgeable and helpful tube seller with reasonable prices and fast shipping. A class act and highly recommended.

Happy for you ! Amperexes in the 12au7 spot will bring you back some extension in the highs, decay maybe or maybe not. In my preamp, it did but it is a more subtle difference than changing the 12AX7 tubes. Remember to wait at least 50 hrs of running the new tubes in order to hear the best of them.

You say the preamp has a little less decay than with the original tubes. This means it is there somewhere but hidden since you heard it before. You have more bass and weight, obviously your hearing is rebalancing itself. You might just hear your decay back once you are accustomed to it.

Have trials with your speakers positionning and have a look at your acoustics. Don't forget to check your electronics isolation to vibration. Better quality electronics are more sensible to the surroundings. Doesn't cost anything and most of the time does a lot.

Have fun !

Glad you got the RCA Cleartops, they are excellent overall, and do remain a comparative bargain. I agree that Andy at VTS is beyond reproach, and I have also had good luck with Brent Jesse Recordings for NOS.

So I figure I'll just tack onto this thread rather then start a new one. After listening to the pre for about 2 weeks I think I've adjusted to the sound. My impression is that it's, in a word, unremarkable? I find the mids and bass light and lacking. Vocals -- which I think any good pre should do well, are also light and even sound a little boxy and compressed. Presentation is also bit flat. Basically the sound lacks dimensionality and fullness.

Reason I bring these observations up is they seem to fly in the face of the overwhelming kudos to the VAC sound. I'm not hearing it, or at least what I'm hearing isn't what I believe so many people would be raving about.

I do have the unit on brass cones into brass feet, underneath of which are iso-node pods. I do this primarily because the shelves on my custom rack are natural wood and not 100% flat, and the cones are height-adjustable. While the cones also help tighten focus, I do notice that they lighten the mids and bass to a degree (the iso-nodes help counteract that). But I tried the unit on its own feet, with only a slight improvement.

Maybe I'm looking for the wrong things? I listen to hard and classic rock, electronica, some solo acoustic. Maybe this pre sounds better with different music styles. Maybe there's a system dis-synergy. Don't know. At this point I'm ready to put it back up for sale, but thought I'd try here beforehand to see if anyone has any thoughts or troubleshooting ideas.

I surmised the same thing. Outside of impedance matching, is there any other specs to check between pre and amp for compatibility before rolling the dice?

don't know if that contributed to the issue in this case, but gain was exactly as you described -- loud at about a quarter way or less on the dial. Is there a spec to determine if gain on a pre will match up well with your amp?

Thanks Tvad. You're an asset here.

Did you mention Audio Horizons in particular because you think it will better suit my needs or because they are a company with a 30 day? (or both)

I have a Vac amp, which does have a high gain. I believe
38, as opposed to many other tube amps, which are closer
to 30. I only open my V-C to around 9:00 ot 1/4 turn,
which is loud. The manufacturer of my preamp said not to
worry about this because the type of volume control he uses
in his preamps do not change in sound no matter what level
you are playing. FWIW, I also heard a VAC Ren sig 2 on a
VAC amp, and I believe this sound was also loud at around
1/4 turm. My pramp is not a VAC, but does have 20 db of gain, the VAC's I know are higher gain as well. Not sure of the spec. I guess even though VAC amps have the higher
than average gain, Kevin still uses a fair amount of gain in his preamps. When I heard a VAC amp at a dealers recently, he was using the VTL pre. Again, a higher gain pre paired w/ the Vac amps. Regardless, I do feel it would be better to open up the V-C a bit more and/or have smaller step increments on it as well. Just my related experience, hope it helps. It does seem like a synergy issue may be involved though. You may want to call Kevin,
and let him know your amps specs, and then your amp manufacturer, and let him know the preamps specs.

The VAC has an even lower output impedence than the AH. One of the lower ones i've seen in fact @ 350. Based on that you'd think it would mate fine with my amp rated at 55k input.

My last ditch-resort (prob just confirming the unfortunate known) is to put in a call to Kevin Hayes and go over some specs. Plan on doing that today. If that goes as expected, I'll put this VAC up on the 'gon and use the $ to get something that hopefully synergizes better.