[joelongwood]

I picked up a pair of used Beyer DT-831s a few weeks ago. I found them to be, as many others have, incredibly bright, even for my 54 year old ears. Basically unlistenable. I know Jan Meier recommends using them out of a 120 ohm output to tame the brightness, but I don't have an amp with that output.
I tried them out of the RKV.....bright. The Sugden......bright. The Earmax Pro.....bright. With each of these amps, it was if the entire frequency spectrum was shifted upwards.
Then I hooked up my MG Head (Wing modded to no negative feedback). The Head had been in total disuse since getting the RKV. The tubes in it are two Ei EL84s and an old Dynaco 12AX7 from one of my pre-amps. I plugged in the DT-831s and WOW! The brightness is gone.....the sound is well balanced, transparent, and downright fantastic. Guitars, vocals, piano...... everything is reproduced with uncanny realism. Why? Is it possible that this is just one of those synergistic things? Or is the output impedance of the MG Head jack closer to 120 ohms, as Jan recommends. I'm really curious as to why this combination sounds so damned good (to my ears, of course). Anybody have any ideas?

PS: I did a quick A/B with the RKV to see if maybe my ears were just getting used to the brightness. Nope.....the RKV was waaaaay too bright.

 

[Tim D]

I think the OTL or no negative feedback aspect is possibly a big key. Those 831/931 Beyers don't seem to respond well to tight control and its comes off like the screeching and screaming of the phones under an amp from a stranglehold. Also I suspect that MG Heads do not have very low output impedance/very high damping due to their reported performance with low impedance phones. Also their performance with HD600's having a wonderful midrange, but poor frequency extension might do good with Beyers that are frequency extended but with a tepid/sterile midrange by default.

Of course most amps are designed for tight control of the diapghram in mind...in fact that is one of the purposes of having the amp in the first place. Upping the output impedance seems to me like loosening grip or control. The RKV seems like a tube amp big on having strong control and high damping. Earmax Pro is an Earmax variant that is better designed to deal with lower impedance headphones (indicative that it also has lower output impedance). And the Sugden is a high performance SS gear that is most likely low output impedance as well.

 

[joelongwood]

Thanks, Tim......seems to make sense. The symbiosis between the two is amazing. Now I need to try a pair of 931s.

 

[Tim D]

http://www.hometheaterhifi.com/volum...october98.html

I found an interesting article on negative feedback...haven't delved into too much yet, but in summary it talks about no negative feedback which rolls off highs, poorly done feedback which tilts up highs and causes phase issues, and finally the "ideal" ...but than again, we'd like to wish everything was ideal.