Page 1 of 1

CK²III for low impedance cans

PostPosted: February 11th, 2019, 12:54 am
by itsikhefez
Hey,

I'm looking into getting a pair of MrSpeakers Aeon Flow Closed, which are 14ohm, ~93db/1mw.
I originally built the CK2III for my HD650 and its configured with the standard gain setting.

1) I am assuming that the lower gain setting would be better for the AFC?
2) Prior to building the CK2III, I recall that it does not have the current capabilities as the M3. Given the specs of the AFC, would the CK2III be a suitable amp? How much power is it capable of at 16ohm?

Thanks

Re: CK2III for low impedance cans

PostPosted: February 11th, 2019, 1:07 am
by amb
Yes, lowering the gain is prudent for low impedance headphones.

The CK²III’s output stage transistors are rated 1.5A (BD139/BD140) or 4A (MJE243/MJE253). Both types should be ample for headphones.

Re: CK2III for low impedance cans

PostPosted: February 11th, 2019, 1:14 am
by itsikhefez
Wow thanks for the super fast reply.
I believe I have the MJE's installed currently.
Any reason to prefer the BD's over them?

Should the quiescent current stay at 30mA or higher?

Re: CK²III for low impedance cans

PostPosted: February 11th, 2019, 2:52 am
by amb
There is no reason to replace one over the other. They’re just alternatives that I tested and known to work well. Some people seem to like the “sound” of the MJEs more.

You can increase the bias, but be mindful of thermal runaway, depending on how big the heatsinks are on the output transistors.