Greetings,

Does anyone use a highly efficient,low impedence headphone like a Sennheiser HD-555,595 or 280PRO with their RR2150 ?

If so , is there any buzz in the background ? It's easist to notice by just plugging them in with nothing playing. I'm having a hard time finding an amp that is quiet for headphone use ..... the two I did find that were quiet were no good for me with speakers(too bright) .

I'm not a hardcore headphone user , so a seperate headphone amp would be a bit over the top for me .... considering many of the good ones cost more than the rr2150 alone.

Anyone have any experience ? Thanks

I'm using Grado 325i's. Turned the main volume to about 1 o'clock and the headphone volume control up full on cd/dvd--no buzz. Never heard any on while listening to cd's which is at considerably lower volume level. Your question piqued my curiosity so I tried them out on my nearly 30 year old Marantz, didn't get any buzz till 12 o'clock on AUX about 11 o'clock on phono 1, phono 2 was a bit quieter. These volume levels also exceed normal listening. Both units are on cheap surge protector type power strips, neither of which offer any power conditioning. My house was built in 1960 so I only have two prong recepticles powering the untis.

I'm glad your ears survived ! Thanks for the reply. The noise I hear is easiest to hear with zero volume and no inputs going. It does not increase with volume . It is the same kind of electrical noise that every SS amp makes when you put your ear up to it ..... the zzzzzzz sound.

I see your Grados are listed as 40 ohms, with a 96db sensitivity. My Sennheiser HD-595's are 50 ohm , but 112db sensitive. They can be driven easily by a $10 FM walkman, they're so efficient. I'm kind of wondering if they're a liability because they're so efficient, I can hear any deficiencies of a given amp. Some amps (HK in particular) are far worse than others. Again , this noise is easiest heard with nothing playing and it's a constant low level zzzzzzz, never increasing with the volume.

I suppose if you try your Grado's by just plugging them in with no volume they'll be quiet. 96 to 112db is a huge difference, akin to standing next to your amp and listening to the sound it makes vs. putting a stethescope on it and listening! I'm wondering if they aren't a liability at this point. I've been making them a little less efficient by using a y-splitter and adding a cheapo second headphone to the line.... this helps some to lower the noise floor.

I just bought these darn things this summer and they sound great to me, so I hate to depart with them. I think the next thing to do is call Outlaw tech support and ask if someone has some similar Sennheisers to plug in a 2150 and listen.