VAC Sig Ren MK2a Headscratcher

Dev- The DNA-500 is the sweetest,most tube-like solid state amp I have ever heard, at any price. I used it in my prior system and am very familiar with how it sounds, especially in the bass area. It is very high quality sound and the rave reviews it received were accurate, IMHO. What I don't know is how it will sound with the VACs, but I suspect it will sound much better than it currently does, as the VR7se's crave power, especially in the less efficient lower bass cabinets, which is what the DNA will be feeding. Ran this past Albert VS last night and he also thought it was a great idea, being familiar with my VACs as well as the McCormack.

Congrats on the tubes - let me know how you like them.

Rgd - I was TOLD by a friend who has had several McCormack amps that mine was all class A. I have a hunch it goes from A to AB at some point, but don't have the manual to confirm where that is. From my standpoint, having heard it extensively several years back, everything I heard sounded like A. In retrospect, I probably should have left out the sound rating comment, since I am *personally* not sure, so as not to unintentionally mislead anyone. Sorry if I caused any confusion by the McCormack "all Class A" comment.

Steve McCormack as quoted in this review:

The DNA-500 is a Class A/B amplifier that's biased fairly rich. Because I don't have to use extremely high voltages, it runs only warm at idle and I don't need a huge amount of heat sink surface area. If it were pure Class A, I would have had to use a huge heatsink to dissipate all that continuous heat. The heat sink in the DNA-500 is actually quite generous and can handle extreme operating conditions, including very low-impedance speaker loads.

As Steve explains elsewhere in the review, the need for extremely high voltages is avoided by incorporating two amplifier circuits, bridged together, for each signal channel (left and right).

Enjoy!

-- Al

Fplanner- yes I look forward to hearing those tubes.

The DNA-500 is an okay amp but really nothing special to me. Your passion speaks volumns, if you feel the 500 is that great why do you have your VAC 300.1's.

I have never heard any solid state period provide the same bass as a top notch tube amp can, once you get the 450's and experience such you will know what I talking about and all will be history.

Al- Thanks for clarifying on the DNA-500 - I feel a bit embarrassed to have caused this mess-up.

Dev-
Kevin talked to me about the 300 for over a solid year before I would even give the 300.1 an audition. I was THAT happy with the DNA-500. It is quite a bit more than an "okay amp", at least to me, all who have reviewed it and most who have owned it. It also obviously depends on the system it is in and what it is driving. It is very far from just "raw power", which is why I'm so excited about trying this little experiment.

I have never heard better midrange than the VACs produce and have come to really like the VAC "sound". The fact that I may be able to free up my VAC amps to only have to drive the glorious midrange and highs with 300 tube watts per speaker is something I really look forward to trying. The sound should be magical with ridiculous headroom :-)

In addition, the ability to finally drive the bass enclosures of my 7se's like they were made to be driven means I should no longer need my sub(except maybe for movies). Since the 500 is only driving the bass enclosures, there could be an enhanced positive effect there as well. The 7se's spec down to 18hz, which is probably more visceral and felt, rather than heard - can't wait to find out!!

I'm visiting Kevin in May - will hear the 450's if he's got a pair handy. Everyone I have talked to who has heard the 450's raves about them - I've yet to hear them. Quite honestly, I REALLY like my 300.1s, and may like them a whole lot more if my little experiment goes the way I hope it does. Thanks for your responses and enjoy the tubes!! :-)

... the ability to finally drive the bass enclosures of my 7se's like they were made to be driven means I should no longer need my sub (except maybe for movies).

I suspect that if you connect the sub you would be connecting it to your Integra processor, and using the preamp's cinema (home theater bypass) mode. If, however, you ever find yourself wanting to connect the sub via its speaker-level inputs, an important point to keep in mind is that the sub's negative speaker-level input terminals must not be connected to the negative output terminals of any of the amplifiers.

Since the DNA-500 is fully balanced, and the 300.1's are being operated in bridged mono mode, all of their negative output terminals have full-range, full amplitude signals on them, rather than being grounded. Connecting the sub's negative input terminals, which presumably are grounded, to the negative output terminals of the amps risks shorting those output signals to ground (depending on the internal grounding configurations of the sub and the amp), and causing damage.

If you want to connect the sub to the outputs of the DNA-500, either of the negative input terminals of the sub should be connected to a circuit ground point on the amp. Chances are that a chassis screw is such a point. That could be verified by using a multimeter to check for continuity between the screw and the ground sleeve of one of its rca input connectors, or between the screw and pin 1 of an xlr connector (while nothing else is connected to the amp).

If you want to connect the sub to the outputs of the 300.1's, since there are two of them one of the negative input terminals of the sub should be connected to a circuit ground point on the preamp.

The two negative speaker-level input terminals of the sub are most probably connected together in the sub, so only one of them would need to be connected externally. The positive speaker-level input terminals of the sub would be connected to the positive output terminals of the amp.

Regards,
-- Al