Help to make a choice: BAT; VAC; E.A.R.

I think the VAC Renaissance 70/70 would be better than what has been mentioned. It is totally dual mono all the way to the power cords and power switches, and is enormously powerful for a 65 watt amp (that wattage figure is meaningless).

It has automatic bias to take all hassle out of tubes, as well as a protection circuit that automatically kills power to any tube that is malfunctioning. The output tubes are super long life 300-B's. I just replaced my set on my VAC Renaissance 140/140's (the monoblock version of the 70/70) after five years of very frequent use. This is an amp you just turn on and off. No biasing of tubes, no regularly blowing tubes.

The sound is world-class and build-quality can't be beat. Given that they list for $14k and can be had used for almost $5k, they are extremely good value.

Although expensive at $14,000 new, there were quite a few VAC 70/70's sold while the amp was in regular production. They come up for sale used on Audiogon pretty frequently, and can be had for good prices because most people don't know what they are (i.e., how good the amp is).

If you do pursue the amp, make sure to look for a Mk. III or Signature, as the earlier versions do not have the protection circuitry.

The 30/30 and 70/70 are the same basic amp, with the same circuit and parts quality (the "signature" versions, regardless of whether the amp is the 30/30, 70/70 or the 140/140 monoblocks, have the best parts quality), the 70/70 having twice the number of output tubes and power supplies, and thus double the power. I have heard from a good source, however, that the very best sounding amp of that vintage is the "30/30". I do not know if the alleged difference results from running half the output tubes, thereby simplifying, somewhat, the circuit, or is due to something else. The 30/30 is unusually powerful for a 30 watt amp (I know a dealer who, for laughs, hooked one up to a pair of B&W Nautilus 801's, which are very difficult speakers to drive, and managed to get some decent sound out of them and nothing blew up), but it is still a lower powered amp and will compress with a lot of speakers. The 70/70, however, sounds like a 300 watt transistor amp and will drive speakers that some mega tube amps cannot. It won't have the bass control with most speakers that a comparably priced solid-state amp will, but even with zero feedback (which is really the only way to run these amps), the bass control was always acceptable to me -- the output transformers and power supplies are high quality, the result being that the amp can drive tough loads and do a decent job controlling woofers.

If you have really efficient speakers (say, 93 db. or higher) whose impedence is not super low in the bass (not much lower than 4 Ohms at any point below 400 Hz. and no really tough phase angles), and if you do not listen to a lot of orchestral music, then the 30/30 should be fine (i.e., will make your speakers go really loud, cleanly, in most rooms). If your speakers are of more normal efficiency, however, and you listen to the most challenging sources (orchestral music on a good analog rig or good DSD), you want the 70/70. If you want to be certain to be able to drive almost any speaker to loud, clean levels, then you would need the 140/140's, which is a pair of 70/70's wired for mono operation (130 really potent watts per channel).

All of the VAC Renaissance amps (the 300-B amps) are highly transparent and require really good front-end equipment in a carefully designed environment to perform their best, i.e., if you do not intend to use them with truly top-notch partner components, cabling and home electric supply in an acoustically-treated room with a lot of attention paid to speaker set-up, your money is likely best spent elsewhere.

Hope this helps.

Maril555:

It would depend upon the size of your listening room and the type of music you listen to.

The 30/30 will certainly drive the VR4, but my guess is that a 70/70 would be better on any 89 db. speaker. If immediate cost is an issue, you could buy one 30/30 now, and buy a second one later and then have them converted to 30/70 monoblocks, which would be basically the same amp as the 70/70 (the 30/70 monos may have more power supply capacitance and thus better sound, but I am not certain -- you would have to ask Kevin Hayes of VAC). VAC used to charge $500 per amp for this service. The most knowledgeable salesman at Singer in New York runs 30/70's. They are among the handful of best sounding tube amps out there.

As for the above comment about 300-B's costing a lot more than pentodes, that is true, but they also last three to four times longer. The other thing to remember is that the Renaissance 300-B amps auto-bias the output tubes, which increases tube life because the tubes never suffer the stress that can occur when they fall out of bias. I believe the PHi series amps auto-bias the KT-88's used in those amps, but a KT-88 will have nowhere near the life of a 300-B. The PA 100/100, for example, is a lot of amp for the money and sounds damn good, but you have to bias the output tubes and there is no protection circuitry on the amp. A big advantage of the Ren. amps is the auto-bias, the protection circuitry and the fact that 300-B's last so long -- there are simply no tube amp hassles and they are as trouble-free as a preamp. I don't know that I would have the patience to run a tube amp that does not have these features (most do not).

Good point about the heat -- the Renaissance amps are run in Class A and produce a goodly amount of heat. They are not outrageous like a Class A transistor amp, but my 140/140's, for example, will contribute heat to a room, no question about it. Whether this is an issue depends upon the size of the room and the ability to cool the room if there is heat build up.

As for running these amps in anything other than zero feedback mode, I would concede that it is a system-by-system thing, but the beauty of the amp and the design of the circuit is the fact that it is triode and uses no feedback -- the feedback control is a concession to marketing. If feedback is necessary, then I'd say that the amp is wrong for the speakers (on the four speakers I have run with the 140/140's, the amps of course sounded like a normal amp when any feedback was dialed in-- i.e., significantly less good -- there is a reason that high-end two-channel amp designers tend to try hard to avoid using feedback in their circuits).

One other point about the VAC Renaissance amps: for the first seven or eight years they were in production, the logo badge on the transformer housing was this huge, gaudy gold colored thing. They replaced it with a small, ovalular brass logo (... that, to my tastes, is discreet and tasteful) on later production -- they charged me $10 per amp to substitute new, small badges.

Tvad:

Just saw your post. No, I have not heard the PHi amps. I discussed the basic 220's versus the 140/140's with Kevin Hayes in the Spring of 2003, however, and he seemed to indicate that the 220's had a bit more punch, which I suppose makes sense. It is my understanding that the Phi series is a more sophisticated sound than the 220's, so glean from these comments what you may.

I would have to think that the midrange of the 140/140's may be more to the average person's liking than the mids of the Phi amps due to the 300-B's abilities with midrange frequencies, but this is speculation. I would also note that the 140/140's cost almost 50% more than the Phi amps, which is an indication of better parts quality, but maybe the circuit in the PHi amps is more accomplished and the Phi amps just sound better -- this is again speculation. My experience is that hi-fi is definitely no exception to the basic laws of economics -- you get what you pay for.