Tubinhard Posted December 21, 2003 Share Posted December 21, 2003 If I wanted to biamp, and run two different amps -- what spec do I need to know to make sure the output is "matched"? Quote Link to comment Share on other sites More sharing options...
leok Posted December 21, 2003 Share Posted December 21, 2003 I don't know. But keep an eye on your amps. I assume full bandwidth audio is feeding the low and high amps. That means there is no load on the low amp for the hf material and no load on the high amp for the lf material. Running an amp with no load can be tough on output devices (transformers, transistors). I "dual amped" (still using the separate high and low pass functions of the RF-7 crosover) with a couple of my P6 amps for a while, and kept a 100 Ohm resistor across the amp output to absorb some energy when the amps were driving at frequencies unused by the particular speaker section to which they were connected. Leo Quote Link to comment Share on other sites More sharing options...
Tubinhard Posted December 21, 2003 Author Share Posted December 21, 2003 Leo, I don't undersand. The only thing the amp should "care about" is the impedance it sees. If this isn't true, then biamping would never work under any condition. Quote Link to comment Share on other sites More sharing options...
Tubinhard Posted December 21, 2003 Author Share Posted December 21, 2003 My amp is .33 volts "at full output". I was hoping if I found a SS amp rated the same, I wouldn't have to worry about level controls. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted December 21, 2003 Share Posted December 21, 2003 Dean, I think your dreaming no matter what your going to need some form of fine tuning to get things just right. Craig Quote Link to comment Share on other sites More sharing options...
leok Posted December 21, 2003 Share Posted December 21, 2003 Dean, I just keep thinking of an amp connected to the high pass crossover (essentially no load below 1.5KHz) while you listen to a long loud bass solo. The amp is putting out the bass, but there is no load. Maybe it doesn't matter. I've seen some pretty dramatic warnings about operating output transformers with no load, and although I don't understand what the problem really is, I've decided to be a little cautious and protect my investment. In the end, since I wasn't nuts about dual amp results, I didn't pursue it further. Just keep an eye on 'em. I didn't say don't do it. Leo Quote Link to comment Share on other sites More sharing options...
lynnm Posted December 21, 2003 Share Posted December 21, 2003 Dean For the lova Mike ! You are going to be running Khorns ! Those things will rattle the windows with a transistor radio. Why dick around with with Biamping ? At the very least run them as delivered for a time before proving to yourself that you don't know better than the folks who built your speakers and amp. Quote Link to comment Share on other sites More sharing options...
Deang Posted December 21, 2003 Share Posted December 21, 2003 Oh my, relax -- I have no intention of "changing" anything with my Klipschorns. If I was going to do that I would have bought "used" ones. The idea was to use the existing passive network, and biamp, putting a solid state amp on the woofers for more control. I just thought the woofers would be happier with a damping factor higher than 10. Also, the more control over the woofers, the cleaner the lower midrange would be. I just called Mark Deneen, and he explained to me what Leo was talking about. Yeah, bad idea all the way around. Quote Link to comment Share on other sites More sharing options...
Johnny dB Posted December 21, 2003 Share Posted December 21, 2003 I must've missed this, but... why does Dean have 2 handles? Quote Link to comment Share on other sites More sharing options...
Tubinhard Posted December 21, 2003 Author Share Posted December 21, 2003 Because I'm at work now, and forgot to delete my cookies and login using the 'Hepta Bronte' username I'm using now. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted December 21, 2003 Share Posted December 21, 2003 Because he has 2 personalities <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> Quote Link to comment Share on other sites More sharing options...
Johnny dB Posted December 21, 2003 Share Posted December 21, 2003 That's it... lame. I thought it would be more interesting than that. The 2 personalities thing, now that I can see. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted December 21, 2003 Share Posted December 21, 2003 Dean you liar Quote Link to comment Share on other sites More sharing options...
Deang Posted December 21, 2003 Share Posted December 21, 2003 If I'm two people, I can contradict myself and no one can say anything. Quote Link to comment Share on other sites More sharing options...
Tubinhard Posted December 21, 2003 Author Share Posted December 21, 2003 You idiot. Quote Link to comment Share on other sites More sharing options...
NOS Valves Posted December 21, 2003 Share Posted December 21, 2003 Me too !!!! SET IS THE ONLY AMP FOR ME Quote Link to comment Share on other sites More sharing options...
Tubinhard Posted December 21, 2003 Author Share Posted December 21, 2003 LOL Have you heard the details about Mark's new project? I think he needs a new Moniker too. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted December 21, 2003 Share Posted December 21, 2003 To match output levels, you could put a volume control inline with the input to one of the amps. Have no idea how it would sound, but it would just help balance things out, top-to-bottom. 'Course you need a dual output preamp, or Y-jack to split the signal for the additional output. If I'm not mistaken, this will also place the input impedance of your amps in parallel with each other, which might not be the best. That could be altered, though, by adjusting the resistor from grid to ground on the input of each amp. 200K on each amp might be helpful, depending on what the original resistor was. Quote Link to comment Share on other sites More sharing options...
JohnA Posted December 21, 2003 Share Posted December 21, 2003 Leo, Crossovers don't work the way you think. The amp driving the tweeter of your RF-7s sees an increasing impedance as frequency drops. It NEVER see no load on the output terminals. The resistor you added may or may not cause harm, but it is not needed. The crossover adds the impedance at falling frequencies so the the power at those frequencies follows the path of least resistance to the woofers. The woofer section of the crossover does the same thing in reverse. At the crossover point the impedance of each section is double the driver's impedance, cutting output by half. Since you have 2 drivers at half power the output remains flat (give or take a little for real world variances). As an example, at 700 Hz, the tweeter section in your RF-7s might be 50 ohms, but the woofers at 700 might be 7 ohms. The woofers get, say, 98% of the power and the tweeters get the rest. (Note: no actual calculation was made to create this example; it is for illustration only.) Quote Link to comment Share on other sites More sharing options...
Ipso Facto Posted December 21, 2003 Share Posted December 21, 2003 People here messin' with tubes 'n' stuff? Quote Link to comment Share on other sites More sharing options...
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