A $249 Transimpedance MC Phono Stage From Andover Audio
this thing is ridiculously good!
A manufacturer arrived the other day to install a costly turntable that I won't identify here. We played some records and you can be sure it sounded really fine. I could probably write the review after that first listening session but of course I won't. Then I went into my utility room and played a record we'd just played, on the Michell Gyro SE (the review will shortly be published). He couldn't see the turntable nor did I identify it. But he heard how good it sounded playing the same record on a turntable costing a small fraction of what his cost. Did it sound as good as his? No. But it sounded very, very good we both agreed.
When I told him the phono preamp used cost $249 he just about lost it. When I told him it had a transimpedance MC input and an adjustable MM input and an aux input as well that you can use with another aux level input in case the Spinstage uses a needed aux input on your preamp and that it has a subsonic filter and offers four MM resistive load choices (18k, 22k, 47k and 100k) because 47k is a "convenient" but not necessarily accurate "standard", and that it has fifteen capacitive loading choices, well he did lose it. Fortunately it was just his keys, which he later found.
What got us both "lost" was that this $249 phono preamp, when not compared to anything else didn't call attention to any obvious deficiencies. Its bottom end was well-controlled and robust, its top end was sweet, smooth and free of the usual cheap phono preamp deficiencies—and I'm going to use the term "cheap" because $249 is cheap! The Spinstage was as quiet as it was cheap. I mean dead quiet ears to the speakers quiet.
After he left I played a record I'd recently cleaned but not played since cleaning: Milton Nascimento, Lo Borges' Club Da Esquina (Polysom 33293-1) a double LP Brazilian import first released in 1972 (this is a reissue). I don't know how to put a thingie atop the "o" of Mr. Borges's name. Sorry. Club Da Esquina is also the name of a musical collective the two were in and I'm not going further into it here other than hoping you can find a stream of it because finding the record isn't all that easy and it's a wonderful, eclectic set with George Martin-ish string arrangements popping up out of nowhere. Bossa Nova it's not!
Milton Nascimento, Lo Borges' Club Da Esquina (Polysom 33293-1)
All I can write here is that if you heard this record played through the $249 Spinstage without knowing it, you'd say "damn fine phono preamp". Well, that's not enough because with transimpedance circuits that basically show the cartridge a short circuit, the cartridge's electrical characteristics are critical and while low internal impedance is important it's not the only important spec.
But look, this costs $249 so if your cartridge is a low output MC with a low internal impedance, say 10 ohms or under, you can try this and hear how well it mechanically damps your cartridge and makes it sing (or not). I didn't get to try the MM input because I don't have an MM currently installed (no pun intended) and I wanted to get this review published.
But, according to Andover, “The design choice was that for a $250 price point, including two completely different circuits wasn’t financially prudent. Both stages would need to be compromised to keep the price point. We thought it better to not compromise the fundamental circuit, and make the signal path as efficient as possible while avoiding any redundancies. So the MM stage pretty much defines the sonics for both the MM and MC cartridges. The transconductance stage works as an input buffer in front of the MM stage to properly load a MC cartridge.”
if you've got $249 to toss around and want to hear what a transimpedance circuit does for MC phono cartridges, you ought to try this!
Specifications
RIAA Equalization Accuracy: +/- 0.1dB typ, 0.2dB max
Overall Frequency Response: 0.5Hz - 50kHz +/- 1dB
Signal to Noise Ratio (unweighted): MM - 78dB, MC - 76dB (Referenced to 50 Ohm source)
Input Impedance, MM (selectable): 18k Ohm, 22k Ohm, 47 kOhm, 100k Ohm
Input Impedance, MC:Effectively 0 Ohm
Input Capacitance, MM (Selectable): 0pF, 22pF, 47pF, 69pF, 100pF, 122pF, 147pF, 169pF, 220pF, 242pF, 267pF, 289pF, 320pF, 342pF, 389pF
Nominal Gain, MM: 40.5dB
Nominal Gain, MC: 66.5dB (with 10Ohm source)
Subsonic Filter: 20Hz, 12db/Octave. Bypassable.
Typical Output Level: 500mV RMS
Max Output Level: 8V RMS
Input Overload, MM: 120mV @ 1kHz
Manufacturer Information
Andover Audio L.L.C.
15 High Street North Andover, MA 01845
(978) 775-3670
