AMB M3

Not too insane actually... you can get a portable laptop backup battery/charger for reasonably cheap, which is just enough voltage to run the M3.

 

What op-amps do you like in it, @Armaegis? ADA4627-1 are currently installed, and I think they sound fantastic. Can't speak to any technical virtues resultant from that selection, but this M3 as configured presents a broadly neutral, slightly n-shaped sound. The original OPA627 was too bloated and warm for me.

 

That's one drop dead build Argopo

 

Well I said it was an abandoned project, so I never actually built one...

 

I thought I'd add my recent build here. My first "real" headphone amp was a Rockhopper M³ that I bought way back in 2008. I first paired it with a cheapo Zero Dac (if ya'll remember those) and later a Monarchy NM24. I went through a ton of headphones with it, everything from the DT880, HD555, HD580, HD650, K501, K701, Goldrings Dt 150s or something, a couple of Grados, a couple of Audio Technicas - including the Ath AD 2000 and on on. I distinctly remember favoring the M³ over my Woo Audio 6 with Sophia rectifier but eventually sold both to fund my speaker rig. I finally decided to build a new one this year.

I probably spent around $250 for all parts not including the 2 chassis from Modushop ($400) and the Khozmo stepped series attenuator ($182) So about $830 total. OPAMPS are the stock recommended ad8610s.

Long story short, it is a great amp. Is the premium you pay to get a Schiit MJ3 worth it? IMO Absolutely. The MJ3 out-resolves, out-details and out-sounstages the M³ by more than diminishing returns margins. But its the note separation where the MJ3 really outclasses the M³. I have the ZMF Bokeh loaner in house at the moment and imo the Bokeh needs an amp that excels in note separation to sound its best. The MJ3's superior note separation gives it a obvious clarity edge over the M³ despite the AMB being more lit up in the mids up through the treble.

So, its funny that since finishing the damn thing I have spent probably 60% of my listening time with the M³. It is a great all-rounder. Its crystal clear to my ears - the Khozmo a definitive improvement over the ALPS I originally had installed (worlds better channel matching at low volumes). It hits hard - not as hard as the MJ3, but extremely satisfactory. It sounds amazing after 5 seconds of warmup. But this could all be DIY builder's bias

 

Nice! I still love my M3.

Beg/borrow/steal to get some Focal Clear or Utopia to listen to. At a recent meet, I thought the Utopia from my M3 easily bested my Clear from a DSHA-3FN, so I'd be keen to see how the combo stands up against the MJ3. Switching out the AD8610 for some OPA1611 might narrow the gap as well, it feels a bit snappier.

 

I did switch out the AD8610 for the OPA1611. I don't find them snappier than the AD8610 but it does take the M3 up to a level of a poor man's Mjolnir 3. Given that I kind of enjoy the contrast between the Mj3 and the M3 loaded with the AD8610, I will probably switch back after putting the 1611 through a longer trial.

 

The OPA1611 is probably the best bi-polar out there, as well as the two-channel cousin, the OPA1612. The 1612 was also my favorite in the Little Bear B4.

I would probably also try an OPA1655. It is the single version of the famous 1656. Although I am not sure they would be stable.

 

Yep, I'd definitely worry about stability of OPA1655 if it is socketed. I wouldn't personally consider it unless you could pop the output on a scope, or are willing to direct solder the SOIC adapter.

(One of the things I keep meaning to do is remove my OPAMP sockets and direct solder the OPA1611. Pretty sure my OPAMP rolling days are over for this amp)

 

Christ on a cracker this reminds me that somewhere in the basement I still have one of the original iBasso opamp rolling kit plus a few others that I collected. Are the 627/637 still desirable these days? They were quite expensive back in the day.

 

I didn't even bother with the 627/637 this time around. I don't recall them really being my favorite with the first M3 I owned I always thought it sounded a bit too rounded. Truly the OPA1611 is superior. I just had a lengthy session with the Mj3 and switched to the M3 at the tail end for kicks - the opa1611 is a beast. I'll probably re adjust my M3 for DC just for my own sanity and leave the 1611s in.

 

The OPA627/637 is what, close to 30 years old at this point? I find it hard to believe that designs and process technology haven't improved in all that time. Lots of reports indicate the successor OPA827 is as good or better, and many people think that the ADA4627 was designed to match some of the sonic characteristics.

If you have some genuine OPA627 sitting round they might be fun to play with, but I sure as hell wouldn't pay the $30 they are asking for them now. That's $90 for a 3-channel M3!

 

Assuming people are still running their M3 (I am), I have found discrete opamps can completely transform M3 from a decent amp into a highly dynamic and powerful amp with dense sound and class A warmth.

How many still remember Rockhopper Audio

 

I hard-soldered my OPA1611 last week, so any OPAMP rolling is officially off the table. But i gave a good listen with the Focal Clear after that..... if this amp was any more dynamic, it would blow my f'ing head off!