red_ryder 0 Report post Posted February 6, 2004 My wife and I want to watch movie together at night, so thinking of getting another set of headphones for her. Can a head amp (say the Cayin) drive 2 sets of cans? Share this post Link to post Share on other sites
Mackie 0 Report post Posted February 6, 2004 U can purchase an adapter for this purpose (Homefix, SLS/SLT or even some neighbourhood stores) ie. 1 x 1/4" stereo plug input > 2 x mini stereo plug output. Since U own Beyer 931 which carries an impedance load of 250ohm, another pair of cans of the same impedance connected to your amp's headphone socket via this adapter will result in a combined load of 125ohm. As long as the headphone output circuitry of stereo amp/cdp or headamp can handle this impedance, U might only notice a slight drop in volume. However, problems will arise if the other pair of cans is < 100ohm eg. 32ohm. Resultant load is calculated to be (250x32)/(250+32) = 28.3 ohms. Most headphone sockets on stereo amps/cdps won't be able to handle the voltage swings required to drive this load optimally. I'm coinfident the Cayin HA-1 can perform this task optimally for it can handle a load as little as 6ohm. Share this post Link to post Share on other sites
red_ryder 0 Report post Posted February 6, 2004 Thanks mackie. What if using a 250ohm and a 300ohm? Also, with all the good money spent on neutrik plugs, would it be a waste just to use a generic adapter to connect 2 cans? Share this post Link to post Share on other sites
DIYerStraits 0 Report post Posted February 7, 2004 Don't mind if I butt in. You can use a dedicated hp amp to drive each hp separately, one amp section for one hp. In that way, each hp will be optimised. That is if you don't want to compromise on "quality". On the same token, you will add more parts and cost to the end result. IF you do this (parallel listening) regularly, go for the dedicated amp. If only occasionly, go for the splitter. Share this post Link to post Share on other sites
Firefox 0 Report post Posted February 7, 2004 U can purchase an adapter for this purpose (Homefix, SLS/SLT or even some neighbourhood stores) ie. 1 x 1/4" stereo plug input > 2 x mini stereo plug output. Since U own Beyer 931 which carries an impedance load of 250ohm, another pair of cans of the same impedance connected to your amp's headphone socket via this adapter will result in a combined load of 125ohm. As long as the headphone output circuitry of stereo amp/cdp or headamp can handle this impedance, U might only notice a slight drop in volume. However, problems will arise if the other pair of cans is < 100ohm eg. 32ohm. Resultant load is calculated to be (250x32)/(250+32) = 28.3 ohms. Most headphone sockets on stereo amps/cdps won't be able to handle the voltage swings required to drive this load optimally. I'm coinfident the Cayin HA-1 can perform this task optimally for it can handle a load as little as 6ohm. Actually, no. By paralleling the load, the amp effectively sees a lower impedance. Lower impedance requires less voltage swing but more current to drive. Hence, depending on the design of the amp, you could get away with it. ie. Gilmores are voltage limited as opposed to current limited. It can drive low impedance loads well but high impedance loads require higher voltage power supplies. Opamps are usually more current limited than voltage limited as they're more efficient when it comes to the voltage swing. Share this post Link to post Share on other sites
Mackie 0 Report post Posted February 9, 2004 Actually, no. Err.......do U mean the Cayin is not capable of driving 2 pairs of headphones but please ignore this paragraph if otherwise? FWIW, I've put the Cayin headamp thru this test to validate my earlier conclusion. In any case, I concur with your theoretical understanding and "voltage swings should read current swings". Thanks for the heads up. Share this post Link to post Share on other sites
Firefox 0 Report post Posted February 9, 2004 Err.......do U mean the Cayin is not capable of driving 2 pairs of headphones but please ignore this paragraph if otherwise? FWIW, I've put the Cayin headamp thru this test to validate my earlier conclusion. "No", as in you were wrong to say that lower impedance loads require larger voltage swings to drive. Share this post Link to post Share on other sites