artto Posted April 20, 2004 Share Posted April 20, 2004 I recall at the Klipsch Indy tour last year the subject came up that you could drive speakers (if efficient enough) with a preamp (no power amp). Is this true? And if so is there anything I need to watch out for? Are there any substantial differences if the preamp is tube vs. SS? Any particular output requirements? Quote Link to comment Share on other sites More sharing options...
3dzapper Posted April 20, 2004 Share Posted April 20, 2004 The prooblem as I see it is impedence matching. Pre's are generally designed to operate into a load of +/- 100K VS a speakers 8. Would this look like a short to the output and overlaod the final stage? That would depend on the design of the pre-amp SS or valve, plate or cathode, direct coupled or capacitive, etc. Rick Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted April 20, 2004 Share Posted April 20, 2004 Look at it this way. In their preamp and source component tests, Stereophile occationally tests an exceptionally good piece of equipment by driving it into a 600 ohm impedence, which they refer to as a "punishing load." For example, the Boulder 1012 DAC/PreAmp (a horrifically priced piece of exceptional engineering) was able to swing 12 volts into the 600 ohm load, before current limiting caused distortion to spike. Using Ohm's law, 12 volts into 600 ohms is 0.24 watts. So, we have a current limit of 0.02 amps. What SPL will you get out of a pair of 104dB, 8 ohm Klipshorns if you're current limited to .02 amps? I believe you'd be constrained at .16 Volts, which would produce .0032 watts. Which means our SPL would be 79dB - about the sound level inside a reasonably quiet car cruising at 60mph. Quote Link to comment Share on other sites More sharing options...
djk Posted April 21, 2004 Share Posted April 21, 2004 Use the headphone jack. A McIntosh C32 headphone jack will drive 12W at 8R. Most common gear will drive 100mW~200mW into 8R~32R phones, enough for 95+ dB on Klipschorns. A 'real' amplifier will sound better. Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted April 21, 2004 Share Posted April 21, 2004 Do you have any idea what the output impedence on the Mac headphone jack is? That sounds like it might be a cool idea... They certainly weren't going to let that headphone amp be phased by any conceiveable headphones, were they... Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted April 22, 2004 Klipsch Employees Share Posted April 22, 2004 we can do it with the stage one...I have done it....Ray is right only about 80 or so db Quote Link to comment Share on other sites More sharing options...
MVklipsch Posted April 22, 2004 Share Posted April 22, 2004 I have a Denon 3803 that gives out 110x7/ch at 8ohms. continuously to all speakers at that wattage. I use the RF25 all around with RW10 sub. Can you please tell me if this is a good Pre-amp/component? Not too sure what is a good wattage. Planning on getting an amp. Oh, is this why my speakers are not produsing the treble level clear enough. Seems to have a little bit missing from that. Can someone educate me since I am new to this? I read that there is current and voltage from an amp. for bi-wiring. Sorry if I am going all over the board. Please guide me to the right site to read. Thanks Quote Link to comment Share on other sites More sharing options...
djk Posted April 23, 2004 Share Posted April 23, 2004 "Do you have any idea what the output impedence on the Mac headphone jack is? That sounds like it might be a cool idea... They certainly weren't going to let that headphone amp be phased by any conceiveable headphones, were they..." Its a real power amp, the output impedance is less than 0.1 ohms. The newer versions are all rated at 20W/8R, the C40 is rated at 0.005% distortion. The general idea was that they could drive electrostatic headphones directly. In the C40 they call it a 'monitor amplifier'. I sold a C32 to a guy with LaScalas. He couldn't afford to buy both the amp and preamp he wanted at the same time. Ultimately he ended up with the matching 200W McIntosh amp with meters. Quote Link to comment Share on other sites More sharing options...
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