« A smooth, refined, rare and beautiful hi-fi preamp »Publié le 07/29/11 à 12:08
The JJ 243 is the lone preamplifier in the lineup, and although intended as a synergistic front-end to the JJ 322 and JJ 239 monoblock amplifiers, it can certainly be used as a preamp in front of any other amp.
The JJ243 is an all-tube stereo hi-fi preamplifier with an integrated phono stage. The line stage uses a pair of ECC82 and a pair of E88CC tubes which are exposed on the top plate of the unit, and the phono stage uses an additional four E88CCs hidden internally in the unit.
The line stage offers three inputs. There are also three outputs available: the first is amplified, with volume control; the second is non-amplified, with volume control; the third is neither amplified nor volume controlled. The outputs give you flexibility depending on how hot your amplifier input is, whether it also has a level adjustment, and are also useful for connecting additional amps or active speakers or subwoofers.
The phono stage makes 50db of gain which is suitable for Moving Coil cartridges with medium to high outputs, or Moving Magnet carts which are almost always high output. I have used this phono stage with 47kohm carts with outputs ranging from about 1.5mv to 2.5mv output and it's got more than enough gain for this; JJ claims the stage is suitable for outputs as low as 0.5mv, but realistically I wouldn't go any lower than a medium-output cart of 0.8mv or higher for best results. There are DIP switches on the rear of the unit that allow you play around with different MC cartridge impedances which is a very nice touch, though the higher output carts I've tried have been happiest staying at 47kohm be they MM or MC.
The controls for the JJ 243 are as simple as can be imagined: one nicely stepped rotary switch that feels of solid quality, which selects between the four inputs (one for phono and three line ins); and a volume knob which is a very smooth, wonderful feeling ALPS affair with a great taper. That's it. What more do you need, right?
JJ offers several color finishe combos for the wood cabinets and metal top plate, knobs and PSU cover: wood finishes are a lovely deep red, which is what my unit has, and also a brown walnut and black; metal finishes are gold (which my unit uses), as well as silver.
Opening up the unit reveals quality PC boards and extremely high quality parts, including JJ's own excellent tubes and capacitors in addition to the very nice rotary switch and volume pot, nice tube sockets, and so-on. Construction is cleanly implemented and looks very good. All connection jacks are gold plated RCA-type. The power connection is via a detachable IEC-type which is great for playing with different types of power cords. I have used Zu Birth and DIY VenHaus upgraded cords on my unit to good effect.
The sound of the JJ243 is, in a word, wonderful. The character somehow manages to be smooth, warm, rich, buttery, and clean all at the same time. It is sonically flattering, yet highly resolving. There is never, ever the slightest hint of grain or aggression. The high end is extended; midrange is very well fleshed out and it and the low end have a wonderful tube bloom. The lows are tight yet big and the entire frequency spectrum is produced with a very refined, svelte quality that simply oozes quality tube-ness. It can throw as big and airy a soundstage as the rest of your rig will allow. Its reproduction is simply breathtaking overall.
The phono stage simply offers more of the above sound while amplifying your medium or high output cart of choice. I use it either with my JA Michell Gyro SE turntable with Origin Live Silver2 arm with Benz Micro Woodbody H2, Shure M97xE and formerly Clearaudio Aurum Beta S carts, or my other turntable which was a 70's AR Turntable that has been so heavily modified with Merrill-Scillia parts that it may as well be considered a "FrankenMerrill," with an Audioquest PT-6 arm and either Shure M97xE or Benz Woodbody H2 carts. In all configurations, the results of the phono rigs through the JJ 243's phono stage have been exquisite. The Michell Gyro/Origin Silver/Benz H2 in particular is an unquestionably extremely high end and rather expensive rig, yet the JJ 243 is NOT outclassed by it. They're simply an awesome, mind blowing pairing with as big, smooth, plush, airy, refined and resolving a soundstage and general reproduction across the frequency spectrum as you can imagine through any high end tube amp that's up to the task!
The different output options give you some latitude int he amps you connect to. I have used this preamp in front of a broad variety of power amps ranging from solid state to hybrid to tube amps, from Class A to AB to D and H SS types. This preamp doesn't match play nice with all rigs due to its character which has occasionally been too soft-sounding for some amp types particularly if they have unusual input impedances and particularly some less than flattering Solid State types, but generally it is a smooth operator and is especially happy mated with tube amps. I have mated it long-term in my own rig formerly with a Conrad-Johnson MV-55 Class A tube amp and currently a pair of Manley Mahi Mahi Class AB monoblocks. Both pairings have been simply fantastic, and the JJ/Conrad Class A pair were especially exquisite. The Manleys have unusually hot inputs and I was happy to have the JJ's non-amplified, volume controlled outputs for that particular pairing.
This amp compares very favorably with or in excess of such tube preamps as the Conrad Johnson PV10 and PV14, and shoot-outs have revealed that is can indeed compete with other tube preamps well in excess of the price I paid for it, which is good considering its asking price has climbed a fair bit in the 7 years I have owned it. It was a staggeringly good value when I bought it then, and is still quite competitive even at double that price.
In terms of reliability, I did have a resistor go bad after a couple years and JJ Electronic took great care of me by sending me the part and paying my local tech to do the work so that I did not have to send it cross-country to my dealer and JJ importer, Bob Pletka of Eurotubes in Oregon. The only nitpick I have is that the gold-plated top plate and volume knob have developed a slight patina over time.
In summary, the JJ 243 is a stunning sounding, lovely looking, all tube preamp with a killer tube phono stage. It is unquestionably a rarity; I was only aware of perhaps a dozen having been imported to the US when I bought it in 2004 and probably not loads more since then, as JJ Electronic's focus is on their tube production, but those wanting a very unusual preamp with good fit and finish and a super-refined, smooth sonic reproduction could do well to add this to their shortlist.