[koleidascope]

I have a Yulong D18 and was considering purchasing a fully discrete Yulong A18 for use with a set of Frogbeats C4's, but I read the A18 review here and it stated that there can be a noticeable hum when pairing IEMs to the A18. I'm fairly new to the whole headfi space, and am looking for some suggested alternatives to the A18 that would be nice to pair with the C4s - ballanced if possible??? Thanks guys!

 

[ostewart]

Wait for the new JDS Labs C5, silent with no channel imbalance

 

[koleidascope]

Would you generally recommend a portable amp for a set of high end CIEMs? Would there be any issues or major benefits when pairing the C4s to say something like a beta22? Thanks for the heads up btw!

 

[ostewart]

I personally use an amp with my ciem, a little more clarity and control, also a little wider soundstage

 

[skamp]

Make sure to choose an amp with a known output impedance that's near 0Ω. That should be your number 1 criterion.

 

[ostewart]

JDS C5 has output impedance of 2ohms, fine for all headphones over 16ohms

 

[koleidascope]

Seems b22 is rated at less than 0.01ohm... Any other factors to consider when pairing an amp up to a CIEM?

Just breadboarded up a cmoy btw 1st step towards DIY amp heaven!

 

[tomscy2000]

From what I've seen of the FR and CSD of the C4, you'll want as wide bandwidth an amplifier as possible with as low an output impedance as possible. The C4 is only 25 ohms @1 kHz and will drop to at least as low as 15 ohms in some frequencies, so that's why you'll want a low output impedance amplifier. Damping factor is usually recommended to be over 50, but some people say that it can be acceptable at 30, so if you want adequate damping factor across the entire audible bandwidth, you'll want an amplifier that has <=0.5 ohm of output impedance. You'll also want a volume attenuator that gives you fine control and low gain so that you don't ruin your ears, as the C4 is very sensitive. A b22 will work, if you want to spend the $$$$...

 

[koleidascope]

Do you think using something like a Goldpoint Mini-V Custom attenuator with a LOG curve would work?

http://www.goldpt.com/prices.html

 

[tomscy2000]

Looks good, but someone else with more DIY expertise should answer (perhaps you should ask in the DIY forum); my experience is limited. Stepped attenuators may possibly run into trouble with input/output impedance matching, but I really don't know how it works.