Parasound's New JC3+ MM/MC Phono Preamplifier Offers Feature and Sound Refinement
According to Parasound’s Richard Schram, the original JC3’s design began as a phono preamp retrofit for the JC2 line stage with separate small circuit boards for each channel. The smaller the better, he said to reject noise that larger antenna-like copper traces would attract.
Designer John Curl decided to keep the circuitry simple, choosing purity over adjustability. Therefore the original JC3’s MC loading was limited to either 100 ohms or 47kohms, with 47k also for the MM input.
Curl believed then and I’m sure continues to believe that the vast majority of MC cartridges are suited for 100 ohm loading and I concur. The original JC3 featured custom made gold-on-silver contact NKK selector switches for the choice of 47K or 100 ohms. For Curl, low noise trumped loading flexibility and he wanted to avoid the noise added by potentiometers.
Schram understood that the loading limitation might lose a few customers but he let Curl call the shots. Why would he do that? For you youngsters, let me quote the late Stereophile founder J. Gordon Holt from 1988: “Few people in the audio business would deny that John Curl is an audio design genius—arguably the greatest one of our generation. He designed and built the electronics for Mobile Fidelity's SuperMaster and David Wilson's (of Wilson Audio) UltraMaster tape recorders, two of the three best analog recorders in the world. (The other is Keith Johnson's home-brew unit.) He designed the JC-1 head amp and JC-2 preamplifier sold under the Mark Levinson name some years ago….”.
However as we all know the customer is always right even when wrong and customers demanded greater loading flexibility. So Curl and circuit board designer Carl Thompson set about finding a way to include variable load impedance adjustability but only if the arrangement met certain stringent performance requirements and used Vishay low noise resistors.
Unfortunately, no Vishays met the specific requirements but the company agreed to develop and manufacture in small quantities for Parasound the appropriate part, which is a special low noise, dual-gang 50-550 ohm potentiometer. So the new JC3+ offers on the back panel a switch that fixes loading at 47k for MC or via the potentiometer variable 50-550 ohm loading, as well as 47K MM loading.
While the designers were at it, they made other improvements to the new edition including narrowing the spectrum of Johnson/Nyquist (thermal) noise in the input loading stage's resistor in order to maximize its low noise capabilities and further tweaking the phono module board to include 24 karat gold plated traces where each part is soldered, which Parasound claims provides "unprecedented transparency and musical detail".
MC S/N ratio has been improved from 75dB to 87dB, A-weighted. That is a very large S/N improvement! MM gain has been increased 1dB from 47dB to 48dB while MC gain has been lowered from 68dB to 64dB to prevent possible line stage overload when using high output MC cartridges. 64dB should be sufficient for virtually all MC cartridges.
The JC3+ power supply has also undergone a significant upgrade with 47% larger low-ESR power supply filter capacitors for greater current reserves and what the company claims are "head-snapping" dynamics. You have been warned. A new 82% larger R-core power transformer provides greater reserves for low-end impact that the company says is "beyond imagination", so please don't try imagining this at home, especially if you are alone.
To gild the illumination lily, at the behest of the few, the finicky and the fanatic, the front panel's illuminated "P" logo can now be switched off via a back panel switch.
When I reviewed the original JC3 Schram said its passive RIAA EQ parts are identical to those used in the Vendetta ($3000 in 1992). The active circuit uses very low noise parts chosen both for noise levels and for noise spectra, which Schram says is critical to how we perceive noise. The circuit is DC servo fully direct coupled with no coupling caps in the signal path and the output stage is a true dual differential balanced design. The output is either single ended via RCA jacks or balanced XLR.
Two low carbon steel partitions isolate the transformer from the phono circuit modules. The power supply also implements a large inductor and ultra fast/soft recovery diodes among other components. Each gain/EQ module is housed in its own extruded aluminum enclosure and the JC3+ includes a built-in AC line conditioner as well as an AC polarity invert switch that can be useful in eliminating phono hum.
Finally, there’s a front panel “mono” switch that activates relays within each module. When set for “stereo” the signal remains within each extruded housing. The signals meet each other outside the shielded housing only in “mono” mode.
I reviewed the original JC3 a few years ago and didn’t have one around to compare to the new JC3+ so I can’t offer a sonic comparison. If you own the original should you upgrade to the new one? Again, I can’t answer that one for you but I’d say “no” unless you are thoroughly unhappy with the 100 ohm loading.
I ended up at 100 ohms for the Lyra Etna (4.2 ohm internal impedance) but closer to 50ohms for the Ortofon Anna (6 ohm internal impedance) and the Transfiguration Proteus (1 ohm internal impedance). Though 100 ohms for all still sounded more than acceptable to my ears.
Even using the ultra low output Anna and Proteus, the JC3+ proved subjectively to be a very quiet phono preamp. The quiet helps produce wide dynamics and high resolution of low level information. In terms of low noise, the JC3+ sounds (or doesn’t sound) like a far more costly phono preamplifier.
A lack of noise doesn’t just mean quieter or blacker backgrounds. The quieter the background, the greater will be the enhancement of image three-dimensionality and instrumental textures. The information added because of the lower noise floor doesn’t appear as separate information. Rather it gets added to and enhances the higher in level information. In that regard, the JC3+ performed well above its price point.
While the JC3+’s bass was tight, well-defined and punchy (producing excellent rhythm’n’pacing as they call it in Stereophile), it couldn’t produce the explosiveness and depth charge bombs (authoritative, fully extended bass if you prefer) thrown by more costly phono preamplifiers most of which incorporate large, massive often outboard power supplies.
Unless your speakers are full range, you’re not likely to have an issue with this because the JC3+’s lower midbass attack both timbrally and texturally was so well defined you won’t miss what you don’t get.
Drop in a far more costly phono preamp like PBN’s $22,000 Olympia PXi (review coming soon) and the bass weight, control and dynamics are the first things you notice. It can be powerful and dramatic when it hits you. Through that costly preamp you really do get the head snap Parasound promises!
While auditioning it I played Roland Kirk’s version of “Alfie” played on what sounds like a baritone sax. When Kirk slams the opening note, your head does snap back! Less so through the JC3+, but I take Parasound at its word that the + version does produce improved dynamics.
But back in the real world where even $2995 is a lot of money, had you gone to the great expense of buying speakers that could really express ultra-wide dynamics and full low frequency extension, you’d likely be spending a great deal more than $2995 on a phono preamp.
Sometimes I wish I could be a young, inexperienced reviewer with a modest system and gone from a matchbox sized under $1000 phono preamp to the JC3+ because I know what such a switch would elicit in terms of reviewer enthusiasm, superlatives production, etc. The JC3+ really deserved it for what it offers at its price point.