Vinyl Asylum: REVIEW: YS-Audio SOLO Moving Coil Stepup Phono Preamp by cjfrbw

Model:	SOLO Moving Coil Stepup
Category:	Phono Preamp
Suggested Retail Price:	$400
Description:	Moving Coil Tube Phono Headamp with seperate power Supply
Manufacturer URL:	YS-Audio
Manufacturer URL:	YS-Audio

Review by cjfrbw ( A ) on May 01, 2004 at 18:15:34
IP Address: 24.5.235.220

Add Your Review
for the SOLO Moving Coil Stepup

This is the more complete review of the YS-SOLO Moving Coil Cartridge Tube Pre-Amp and shootout with a Fidelity Research XF1H step up transformer (for cartridge impedance 19-40 Ohm) and the built in JFET head amp of my Sonic Frontiers SFP-1 Signature Phono Amp.
My preliminary impression of the SOLO was published a few weeks ago at:
http://db.audioasylum.com/cgi/m.mpl?forum=vinyl&n=305063&highlight=cjfrbw&r=&session=
Let's get the JFET head amp out of the way immediately. It was outclassed by both the SOLO and the FR by a wide margin. This is not to say it doesn't sound very good, it does. It just has those transistory things that I personally don't cotton to. On smooth material, it could sound occasionally dull. On bright material, it could be edgy. On detailed material, it could lose what should be space and detail to some glare and flatness. With this Sony XL 55 Pro, it could also sound occasionally thin, especially in the lower midrange. This is all qualitative and comparative, though, because we are talking about something very good. The JFET's sounded a little better with the Kontrapunkt a, which however, is a less detailed cartridge than the XL55.
My initial favorable impressions of the SOLO has remained intact throughout the break in period. I did not obtain a WE396a to use with it. However, the D getter GE 2c51 is quite an excellent sounding tube. I think the GE D getters as a rule might be the unsung heroes of the NOS tube world. When I was rolling 12AT7's in the SFP-1, the D getter GE outclassed the Tung Sols and Telefunkens that I tried. I didn't keep them in the SFP-1 only because the triode pairs were 20% off from each other, and I wanted better balance. Compared to the JFET's, the SOLO with the GE has better detail retrieval than the JFET's, and also adds that tasty "triode" sound: smoothness, effortless dynamics, absolute separation of voices and instruments in the soundstage without congestion, natural tones to instruments, and a delicious lower midrange. I guess tube rolling might improve matters, which is an advantage of tubed units. The noise is quite low for a tubed unit. The XL 55 has an output of 0.2 MV, and noise has not been an issue in my system with the SOLO. Again, the stated output of 20 DB of gain is very conservative, and I would estimate the actual gain to exceed 26 DB in practice with the GE tube. I would listen very loud in the range of 72 to 78 on the Sonic Frontiers Line 1. White noise would become evident at my listening position only when the volume exceeded 87 level during silence. I would suspect that noise would not be an issue with a quiet tube with cartridges of .15 MV or higher, but might be with lower output cartridges. Purists might balk at the fact that there is no variable loading for the SOLO, which is fixed at 100 ohm input. However, by report, this is not particularly a problem by report from grinagog on this forum (formerly gware). I think grinagog (gware) stated it perfectly. The SOLO isn't a vishay/auricap/black gate ultrabuilt wonder. However, it is something more interesting, an effective thought product in which the sum is greater than the parts. It is well built, and if you judge by sound quality alone, it is an utter bargain product for what it actually does for the sound.
I have nothing to offer on the FR stepup transformer except virgin ears, because it is the first and only stepup transformer that I have ever heard. I thought that I might be sorely disappointed by it, as grinagog (gware) said that the transformers he used didn't sound that great and the SOLO was better. Also, I had a preliminary prejudice that a stepup transformer would somehow sound metallic and thin.
Well, drag me off the stage with that big neck cane, I was dead wrong. The FR sounds wonderful with the XL 55. Compared with the SOLO, it is definitely a more "neutral" sounding device, in the best sense of "neutral." Whenever I hear something described as "neutral", I think of "emotionless" or "cold", as if coloration is required to preserve and enhance the emotional content of music. The FR is both "neutral" and fully emotional and warm. The SOLO has a bigger soundstage with greater channel separation, but with loss of microscopic detail compared with the FR. You can definitely tell that the SOLO is an "active" device, whereas the FR is more clear and consolidated in its sound. It is also quieter than the SOLO by several DB at the Line 1 settings above 85. However, it has less gain than the SOLO by a about 3-5 DB, but more gain than the JFET's. If you like that lovely "triode" lushness, you might prefer the SOLO. Overall, in this setup, I wound up preferring the FR, to my great surprise.
However, Stepup Transformers seem to be an audiophile minefield of persnickety and perfidous devices, much dependent on setup and synergy, if I judge the ramblings on this forum accurately. I guess that this FR is just very synergistic with my setup.
The SOLO would probably be a bit of magic for Solid State MM stages, by adding a bit of "triode" flavor at the inception of the signal.
Either the FR or the SOLO represent a very strong upgrade to the Head Amp JFET's of the SFP-1 Signature. The FR is, however, an obsolete out of production device. The SOLO allows tube rolling and somewhat bigger soundstage at the expense of neurality and ultimate detail, and doesn't require a great deal of synergy matching compared to a stepup transformer.

Product Weakness: possibly too much noise for cartridges with output below .15MV, requires a high quality, quiet tube
Product Strengths: clean, detailed triode sound at a bargain price, just one tube makes rolling a breeze

Associated Equipment for this Review:
Amplifier:	VTL 450 Signature Monoblocks
Preamplifier (or None if Integrated):	Sonic Frontiers Line 1, SFP-1 Signature Phono
Sources (CDP/Turntable):	Sony XL 55 PRO NOS MC cartridge,SME 10, SME 10 tonearm, Kontrapunkt a
Speakers:	Apogee Stage/upgraded crossover
Cables/Interconnects:	Mogami balanced, Monster
Music Used (Genre/Selections):	Jazz, Classical, C&W, Synthesized, Rock
Room Size (LxWxH):	19 x 13 x 10-16
Room Comments/Treatments:	none
Time Period/Length of Audition:	several days
Other (Power Conditioner etc.):	Powervars, etc.
Type of Audition/Review:	Product Owner

Product Weakness:	possibly too much noise for cartridges with output below .15MV, requires a high quality, quiet tube
Product Strengths:	clean, detailed triode sound at a bargain price, just one tube makes rolling a breeze