Amp for Shure SRH440

Hi Morshu,

I have a pair of Shure SRH840s that I bought a few months ago.  They are also 44 ohm, just like your SRH440s, so you will run into the same issue: current output on your headphone amp.  You need (current) buffers.   

For example, 80mW into 44ohms = 42mA.  The op amp chips in most CMOYs only do 20 - 26mA max.  If you go for a chip amp look for current buffers like BUF634, LME49600, or discrete transistors after the op amp (gain) stage - or an op amp that can do 50-100mA like the OPA551 / 552 or LME49713.

I just bought an off-brand overseas cheapie called a "HA INFO NG98" for $99 on eBay.  So far (only recieved it a few days ago) it works great.  It uses the BUF634 chips and even includes a DAC.  The DAC lets you plug the amp right into your computer USB port (16bit 44khz) or SPDIF port (24bit 192khz) for direct-from-digital audio, bypassing the usually inferior PC sound card.  The DAC also means the amp can insure internally no DC source offset, hence no need for (input) coupling caps in that path. You can read my review/rant about the NG98 here - end of pg 1 and pg 2:

http://www.head-fi.org/forum/thread/476734/ha-ng98-with-switchable-dac-chips

Sorry but I don't know anything about the Millenium HP1.

-agdr

I have the same question as the OP but am thinking about the FiiO E7 amp/dac with my SRH440s. I'm using my 440s at work out of my PCs pos soundcard so I think a DAC would be at least as important as the AMP. Just wondering if the $100 is going to make the SRH440s sound that much better since they don't seem to really need the extra power. I'm not sure if the E7 has the current buffers required or not -- that really went over my head so any feedback on that would be extremely appreciated!!