DMF Posted March 12, 2004 Share Posted March 12, 2004 On the avsforum, I've been holding forth on my opinion that bi-wiring is a waste of copper and $$. Then some guy pointed me at the Sunfire amps that have a "Voltage Source" and "Current Source" off each channel. The technical explanation is a little thin, just this so far: http://www.sunfire.com/pdf/sunwhite05.pdf (This is Bob Carver writing?) As far as I've been able to learn, one side has a fat 1 ohm resistor in series. That's all. Sounds like snake oil to me. Same garbage that "exotic speaker cable as filter" salesmen push. Anyone know anymore about this? edit: Here's pic of the butt end of one of the amps: http://www.sunfire.com/images/details/Signature600FrontPR_Rear.jpg Quote Link to comment Share on other sites More sharing options...
tubeglow Posted March 12, 2004 Share Posted March 12, 2004 Sounds like snake oil to me. Mark. Quote Link to comment Share on other sites More sharing options...
RFinco Posted March 12, 2004 Share Posted March 12, 2004 I was just reading about this actually cause I like CARVER stuff; here check this out in regards to the "current vs. Voltage" set up... Source: Sunfire Cinema Seven Signature Edition 400 Watts x 7 Home Theater Power Amplifier November, 2003 by Kris Deering http://www.hometheaterhifi.com/volume_10_4/sunfire-cinema-seven-power-amplifier-11-2003.html "...Like previous Sunfire amplifiers, you have a choice of voltage source or current source outputs, selectable by choosing which set of speaker binding posts you connect to. The principle is based on classic tube amplifiers being current source by design. According to Bob, this gave them their trademark sound, which was warmer and a bit more full bodied than the voltage source designs of most solid state amps used today. Bob wanted the flexibility of offering a choice depending on your taste in sound. Those with electrostatic or ribbon speakers may opt to use the current source connection, while others may use the conventional voltage source outputs. You can also drive separate parts of your speakers with the different output types, e.g., drive the woofers with the voltage source and the tweeters with the current source. This is the recommendation Bob gives for setup in the manual, and I gave it a try. Ill talk more about that in the listening section of the review. After listening to music for a few days, I decided to experiment with the different output configurations of the amplifier. At first I drove the speakers using the standard voltage source outputs. This provided the sound I was more accustomed to and was by far my preferred setup. I thought the amplifier performed its best in this configuration especially in the low end. When driving my speakers full range with two-channel material, this configuration provided the most dynamic experience with tighter more detailed bass, and was evident more in jazz and hard rock. Kick drums and lower bass notes had more report to them. However, this area is the only spot in which I thought the Krell outperformed the Sunfire. The Krell had a low end that was extremely impressive. Using the Krell with my speakers resulted in bass that would almost make a subwoofer unnecessary. The Sunfire did provide plenty of low end power; it just wasnt quite as involving as the Krell was. But this wasnt much of an issue with me, as I rarely ever run my speakers full range. When I switched to current source, I immediately noticed the change in tonal quality. This mode is used to coax a more tube-like sound from the amplifier. It did offer a slightly more laid back sound, but it wasnt really to my liking. I found the lower end a bit too subtle. There have only been a few times that I have preferred a tube sound, and that is mainly in guitar amps with certain types of music. A good example of this is Eric Johnsons music. The richness of his playing is fully complimented by the tube amplifier he uses. I also tried using the voltage source for the woofers and the current source for the tweeters. This was more enjoyable than going all out current source. The soundstage was more defined, and the lower end regained the tighter more pronounced feel. This was more apparent in music playback than film soundtracks though. While I did prefer straight voltage source overall, I love the idea of offering the end user a choice and leaving it up to his/her ears." ok..I'm just the messenger--don't blast me (hear me EAR!! ??) I'm not the reviewer either, nor am I an expert by any means or even a novice about tube sound...I'm just providing some info... Quote Link to comment Share on other sites More sharing options...
RFinco Posted March 12, 2004 Share Posted March 12, 2004 I'm a research junkie so I try to read quite a bit about things, especially before I purchase. I've always liked this site below, its basically a database of reviews by both writers and non-professional consumers http://www.ecoustics.com/ Quote Link to comment Share on other sites More sharing options...
DMF Posted March 16, 2004 Author Share Posted March 16, 2004 Thanks for the link. I couldn't find much there on the topic at hand. Quote Link to comment Share on other sites More sharing options...
joel928s4 Posted March 25, 2004 Share Posted March 25, 2004 BUMP... I am really interested in this topic too so I'm hoping that some one with a good ear and some classic Klipsch speakers has some experience with the voltage source/current source feature on Sunfire amps. I love my Klipschorns and want a tube amp but they are used for Home Theater more than audiophile 2 channel listening so I am hoping that the Sunfires are a "best of both" or at least a happy medium. Thanks, Joel Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted March 25, 2004 Share Posted March 25, 2004 This is one of those situations where the only way you're going to know for sure whether you think the current source mode sounds more like a tube amp (presumeably a good thing) or more like a soft and wumpy sand amp (presumeably a bad thing) is to listen to it for yourself. By putting a resister in series with the output, the output impedence is increased by at least one order of magnitude. The amp will interact with the varying impedence of speaker to a *MUCH* greater degree than without the resister in the circuit. The resulting humps and valleys in the frequency response curve might be to your liking, or might not. The only way to know for sure is to listen. Quote Link to comment Share on other sites More sharing options...
MrMcGoo Posted March 25, 2004 Share Posted March 25, 2004 The Sunfire amp has added a coloration in my view. Whether you like it or not will depend on personal tastes and the speakers being driven. The frequency response will vary with the speaker's impedance curve due to the added resistor. This is usually viewed as a bad thing, but who knows, I might like it. Bill Quote Link to comment Share on other sites More sharing options...
arthurs Posted April 1, 2004 Share Posted April 1, 2004 I had one of these in my house for a few days last year and I did find the current versus voltage differences to be about the same as the review posted earlier in this thread. Current was more laid back and smooth, whereas voltage had more punch. The 2 together driving the speakers was pretty cool, but ultimately not to my taste. This would be worth you taking a listen if you're interested. Check out audioclassics.com, they sell them used/demo at a pretty good discount, and have a trial period where you can try it in home for I think 11 days, and only be out shipping back. Quote Link to comment Share on other sites More sharing options...
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