SAS Audio Labs TM
Where Music Comes Alive TM
Tube Amplifier Reviews
Bound For Sound Review - Issue #145, Sept, 2002 (SE7.0W amp)
.... Several months later, Bruce returned to my home with a different midrange driver which was a screw-in placement. What a difference!.... With the second midrange driver in place I feel it's a coherent system from about 50 hz to the end of audibility. It's forgiving of placement, and works well with good tube gear - including the Cyrus Brenneman amp recommended by Bruce Edgar (review to follow) and Steve Sammet's (SAS Audio Labs) unit. The Titan images very well, including a convincing rendition of depth, something few horns do. Bruce says its because he uses simple crossovers...."
l. Ascents
In biology there is a principle that systems tend to become more complicated. Bigger, more intricate organisms are capable of doing more work, and different kinds of work. Not all of these experiments are successful, but over time there is a general tendency toward more sophisticated forms.
In audio engineering there is a similar phenomenon. Time, intelligence, hard work and inspiration combine to make more pleasing, more musical designs. It doesn't always work, but talented designers keep tinkering, listening, and incorporating new techniques and new materials into established units. This report concerns two very good designs which have become excellent.
ll. Steve Sammet and the point of diminishing returns.
Steve Sammet's SE7.0WP amplifier is another example of intelligent engineering reaching higher levels of performance. You may remember the extremely simple design: one 12AX7 divided between two channels, with a single 6550 for each output. The original was smooth, quick and very musical. I used it on the 100 db-efficient Edgar Slimline, and thought it was a very good match: terrific sound for quite modest amounts of money. For technical reasons, Steve prefers the 6550 tube to the 300B: more linear, he says. My perspective is that 6550s are significantly cheaper than 300Bs, the favorite tube of single-ended designs. With only seven watts, I thought it did a creditable job with speakers around 90db efficiency, too. I didn't achieve thunderous sound pressure levels, but everything I played was very pleasant.
Steve contacted me a couple of months ago to say that he had developed a new circuit topology, something nobody else had ever thought of. Intrigued, I invited him to visit.
On an overly warm and uncomfy summer day Steve, a friend, and I sat down to compare this new amp to the (SE)7.0DC. My initial impression was not favorable: the thing was slow, rolled off at the top, and lacked rhythmic drive. Steve responded to my observations by unscrewing the bottom plate and replacing a few components. Before the solder had dried, all of us heard major improvements. I made a few more comments, Steve changed another piece or two, and the amp sounded very good. I thought we were done for the day.
Steve is an ambitious, competitive personality who wants to build the best amp in the world. (In this regard he is not alone. The distinguishing feature is that he doesn't want to charge astronomical amounts of money.) "Fire up your amp for comparison," he insisted.
My amp is a VAC Renaissance 70/70 MK. IV, and I think it is the best thing I've ever heard. This is an amp which offers the listener the complete package: musicality, accuracy, power, and speed. It also costs about $17,000.00. I recommend it to anyone who loves music, but I understand that not everyone will get to use it.
So we hook up the VAC, and it's terrific. The Edgar sings.
Okay, switch back to my amp," Steve says.
The smaller amp is not as good. The VAC is more refined, immensely more powerful, with better control of the bottom and a bit more clarity at the top. Then again, it costs about twelve (12) times more money: the tubes alone (eight faintly glowing 300Bs, four bullet-shaped 6SN7s) are twice the price of Steve's amp. The VAC can drive almost any speaker I have encountered, including capacitive loads; the SAS cannot shine without highly efficient speakers. On the other hand we are speaking about a price differential of over $15000.00
Steve offers the amp with a choice of four different brands of output tubes, which allows the listener to alter the sound a bit. Frankly, I think you can distract yourself from the music if you worry about the hardware too much. My advice is: regard the Sammet gear as a point of sharply diminishing returns. If your love of music has not overwhelmed your sense of proportion, I suggest you get in touch (with) Steve, save lots of money and not worry about the small improvement you would realize by spending a great deal more money.
IV. Strivers' Row
Rather than worry about the continuous change of components, I'd recommend that we listen to the music. When we're genuinely ready for something new, people like Steve and Greg (Osborn) will have really exciting products."