An "amp" for Senns (warning: "long")
Mar 24, 2006 at 8:41 AM Thread Starter Post #1 of 2


New Head-Fier
Dec 27, 2003

First, as a long-time lurker, big thanks to all the good folks here, whose comments and advice have continually entertained and enlightened me.

Second, I apologize for the length of the post. I guess I'm combining an intro for myself with this holler for help. Feel free to skip part A, and go directly to part B.

A). I want to buy a good set of phones and an inexpensive amp for home use, but won't be able to hear them first. After many searches here, I have narrowed my next HP purchase down to the Senn HD595 or HD650 (I am leaning more towards the 595, for its price, and its 50ohm resistance).

And my amp choice for either is coming down (due to process of elimination, if not outright recommendation) to a Rockhopper M3 Basic... well, pretty much: I am tempted by the RSA SR-71 and XP-7 for the 595 or 650, and by the WooAudio 3 or EaxMax for the 650, but they are each a little pricey for me. The Headamp Gilmore Lite is a possibility for the 650, but some here don't like the combo, and also I like the idea of OpAmp rolling (if the amps are good enough to complement the phones). And the Millet Hybrid (at least the Rockhopper version) is no more. I could be tempted by others...

I'm using Foobar through to a DIGI96/8 PAD (I know, I know, but it was one of the best at the time I got it. I'll be upgrading to a EMU 1212m. I thought of the Corda Aria, for either 595 or 650, but shipping from Germany is a problem where I live, and I'd rather upgrade the sound card in my comp anyway. The Micro Stack is too expensive, and it seems that the DAC is the star, even with the Desktop module in the amp.).

I like mostly atmospheric stuff of all types, both easy-going as well as intense/dramatic... trip-hop, shoegazer, IDM, jazz, classic R&B, classic rock, house, New Wave, NoWave, New Age, Symphonic, Pop, film scores, etc., etc.) with an occasional Grunge/Metal headclearing.

I value timbral accuracy, phase/spatial/ambient coherence, and detail retrieval in reproduction over dynamic accuracy and absolute separation of instruments, although that is relative. My favorite speakers are... were
... Apogees. I like some other planars in general (e.g., the ET LFT6 and LFT8, but neither electrostatics nor Maggies, very much). Low-moderate impedance dynamics like Revel and Meadowlark are a distant second. I don't much like horn speakers, even the best of them (AvantGarde). I do like tubes, especially tube preamps in fromt of SS amps.

B). Soooooo... OK... the real question is about OpAmps, and which ones sound better. What are the characteristics of the ones available in the Rockhopper M3 (apologies to Stephen Katsaounis; I hope I don't offend by using his website data verbatim):

* AD8610 (Default)
* AD8065 (Direct Substitute)
* AD843 (Direct Substitute)
* OPA627 (Add $40)
* OPA627/637 combo (Add $40) (OPA627 in ground, OPA637 in L/R; Gain of 8 needed)

Which of these OpAmps do the M3 users out there like/recommend? Is the real critical choice, as might be expected, between the last three? How do the last two differ? With each of those two phones (Senn HD595 and HD650), which OpAmp, specifically, would be better?

Any other suggestions for this newbie (which cables? O Lord... lol) are, of course, very welcome.

Many TIA
Mar 25, 2006 at 12:33 AM Post #2 of 2


500+ Head-Fier
Feb 3, 2005
If you're planning to get a decent amp, I don't see the 50ohm impedance on the 595 as being a benefit. While the price advantage is there, you can sometimes find very nice deals on 650s in the For Sale forum. No slight to the 595 though, they are nice headphones as well, and can be driven out of DAP or sound card headphone plugs better than 650s can.
Can't help you on the opamp questions though, sorry.

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