ARC...D-90B or D-115MKII? - Driving Maggie 1.6s


I'm about to venture into tubes and don't want to spend a ton of money. I'm looking at these two amps for approximately the same price.

Is one of these better than the other? I'm expecting delivery of my Magnepan 1.6s on Thursday. It seems like both amps would have enough power to drive them w/o much difficulty, so I'm just looking for comments from anyone who's familiar with these pieces.

BTW - The rest of the system will be:

Audio Research CD-1
Audio Research LS-9
Interconnects are Homegrown Audio Super Silver and Audioquest Opal X3. Speaker cables will be either Audioquest GR-8 or Goertz MI2.

Thanks so much,

I've owned both amps you are considering and if I had my choice,I'de go with the 115.More of everything the 90b does.Just make sure the output tubes are in decent shape as they are 100 a pair to replace from ARC.Please feel free to contact me if you have any questions about either piece and enjoy the music.
Hi Danheather, with a few modifications, both amps are very good. I preferred the D-90, but that was with the original CLSs.
Thanks to you both, Brulee and Franklapdog! I'm really leaning toward the D-115MKII.

That's interesting that the D-90 had sufficient power to drive the original CLSs. My good friend just bought a pair and is powering them with an Adcom 5802 (300wpc). Perhaps it's true that tube watts are more powerful than solid state? The CLSs seem to be VERY inefficient. If the D-90 will drive them, then the D-115 should be MORE than enough with my Magnepans, no?

Any advice on which tubes to look for?

Also, since this will be my first experience with tubes, is there any test/calibration equipment that I'll need to keep the amp going. What about resources to learn about biasing the tubes, etc.??

Thanks so much!
I learned all about tubes at
I am driving my 1.6's with Rogue 120 Magnums (120 watts tube) and have just enough power to rock pretty good.
I do not know anything about the ARC amps, but from my experience I recommend the tightest bass and the smoothest highs with all your equipment and cables for these speakers.

I hope this helps in some way.
Hi Dan

I have a buddy that bought my D-115 Mk2 to replace his D-90. It really took him a while to decide which one HE liked better. After rolling some of the inputs on the D-115, he finally sold the D-90 but still felt it better in some respects, sweeter mids. The d-115 does have more powerful bass. All things said, I like the d-115 but it is a preference thing. At the same price I would go with the d-115, feeling it offers better value. If you have the chance to listen to both, don't turn down the opportunity. You may opt for the 90.
I used the D115 MkII for 12 years to drive the MG 3A and 3.5/R. The D115 MKII was an excellent performer, and is highly recommended for the MG 1.6. I would use the quasi-biamping technique with the ARC.
Thanks guys!

I've decided to purchase the D-115. Thanks for all of the advice.

What is the quasi-biamping technique? Is that bi-wiring? If so, I'm definitely intending to do that.


Just a note... I own a D90 (orig w/6550s) and if I recall
the D115 was made in (more or less) the same era. I just purchased/installed the cap upgrade from Audio Research and it was well worth it. I had no idea what I was missing... As an EE and former tech, I still have problems thinking that it would make that much difference, but the fact is that either of these amps run pretty warm and power supply caps will have a degraded lifespan (avg 20-30+ years gets cut down to more like 15+)... I am driving B&W N804s with no problems and lots of reserve power so I can not imagine the 115 not having enough.

Just my $0.02.
I have owned and still own ARC D-90B amps. The original D-90, used the 6550 output tube, as correctly stated by baddlci above, and based its inputs on the 12AX7 tube. The sound of the D-90B was vastly improved over the D-90. A complete change to 6DJ8 and 6L6 occured. There was a smidgen less authority vs the 6550 version, but the B version amplifier was a complete success in 3D, MUSICALITY in spades, utter naturalness and rightness in tone. The D-115 and D-70 series, was a significant step down in my opinion. Air and ambience retrieval seemed less. A sense of dryness entered the picture, and overall less enjoyment. The MK II version, of the 115, improved things greatly, but the 90B magic, was never fully recovered. Things of course went rapidly downhill, into the Classic 60 series of hybrids. ARC, would not recover from this misguided direction, until very recently. The prices today are just too high, for the circuits that approximate the older gear.
The great ones were,
D-75A, D-76A
D-115Mk 2