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Topic: 2023 Best Stereo Receiver for Koss Pro/4AA Headphones (Read 553 times) previous topic - next topic
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2023 Best Stereo Receiver for Koss Pro/4AA Headphones

Because I live in a building there's no point in having speakers to listen to music.  I do, however, find that my laptop has zero amp power.  Can anybody recommend a stereo receiver that's compatible w/Koss Pro/4AA headphones? 


Re: 2023 Best Stereo Receiver for Koss Pro/4AA Headphones

Reply #1
The headphone output on a receiver is usually an afterthought so you might not find the specs.     But most will go louder than a laptop or phone.   Another option is a headphone amp.

The Koss specs say 95dB SPL at 1mW, and they are 250 Ohms.    The power (mW) depends on voltage & headphone impedance and since headphone impedance varies so much, the power rating of a headphone amp isn't that helpful.   You need to know the voltage.    

Lower impedance headphones tend to go louder with the same voltage but it depends on how efficient the are.   

0.5V into 250 Ohms is 1mW (Power = Voltage squared/Impedance*)

A doubling of voltage is 4 times the power and 6dB louder ("significant" but maybe still not loud enough for you.)
4 times the voltage (2V) is 12dB louder, etc.   That would be 107dB and probably loud enough.

ASR has lots of headphone amp measurements & reviews as well as DACs, and many DACs have headphone outputs.    He measures receivers (mostly AVRs = Audio Video Receivers) but I don't think he checks the headphone outputs on receivers.    You can sort the reviews by the type of product.    He also reviewed the Pro/4AA...  He didn't like it.  :(

* Technically, it's Voltage squared/Resistance but both are Ohms and for loudness calculations they can be considered the same.

Re: 2023 Best Stereo Receiver for Koss Pro/4AA Headphones

Reply #2
They have been making Koss Pro 4AA headphones for a half century or so.
My very old pair has a voice coil resistance of about 18 Ohms.
Kevin Graf :: aka Speedskater

Re: 2023 Best Stereo Receiver for Koss Pro/4AA Headphones

Reply #3
Does it need to be a receiver?

How about a Topping DX3 Pro+?

Great unit for the price, small and portable. Can be used a DAC source (line out), DAC and headphone amp or DAC preamp (variable line out).
Who are you and how did you get in here ?
I'm a locksmith, I'm a locksmith.