I'm going to build a new dummy load to test headphone amps with. But I'm stuck between choosing 16 or 33 ohm resistor.
Previously I was using 33 because I was thinking "16 ohms are probably IEMs that get way too loud before the amp hits its current limit". But now I am thinking, if I want to test with low impedance load, might as well go all the way and choose the lowest common value.
Whatcha guys think?
Previously I was using 33 because I was thinking "16 ohms are probably IEMs that get way too loud before the amp hits its current limit". But now I am thinking, if I want to test with low impedance load, might as well go all the way and choose the lowest common value.
Whatcha guys think?
Some people use 33 ohms, others use 15. That's up to you. It's more important that you have both a low and high impedance dummy load (like 33 & 330, or 15 & 330), and a way to determine output impedance.
For the latter I'd use an R || R-C combo. Maybe 10k || 100R - 470n (polypro). (Hmm, seems a little high still. If you've got bigger film caps floating around, you can try lower R values.) It's easy to calculate output impedance from the resulting FR variation. I have that in spreadsheet form already.
Make sure your Rs can take enough power (for the pure Ohmic loads at least), as some amps can output a few watts. I'd say 2x2 1-watters (long legs) in a parallel-series arrangement at the very least.
For the latter I'd use an R || R-C combo. Maybe 10k || 100R - 470n (polypro). (Hmm, seems a little high still. If you've got bigger film caps floating around, you can try lower R values.) It's easy to calculate output impedance from the resulting FR variation. I have that in spreadsheet form already.
Make sure your Rs can take enough power (for the pure Ohmic loads at least), as some amps can output a few watts. I'd say 2x2 1-watters (long legs) in a parallel-series arrangement at the very least.
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