Mini-Review: Grahm Slee SOLO SRG w/PSU1Part 1 - Solo warm-up, and testing with modded APS V2 cabled D2000, APS V3 cabled HD600 and RS-1:
I am using the regulated PSU that came with it, and the ground wire too. I have not tried it without the ground wire. I am using a CD5001 > Synergistic Research active shielding coax digital > Apogee mini-DAC > ALO SXC XLR > Single Power Sq Wave > loop out SXC RCA > Woo WA6. And then the Apogee 2nd line-out > ALO SXC mini-RCA > directly to Solo SRG. My HD600 and woodied recabled D2000 both have APureSound 4-pin XLR cables, with a single ended adapter and balanced adapter (dual 3-pin). My RS-1 are single ended APS cable. I also tried it with my Westone ES3X customs.
It has been running for about 5 hours now and I don't believe I have heard a SS amp that changes with warm-up as much as this Solo SRG does. Out of the box it was a little duller, thinner and less spacious (flatter soundstage) than either my cold Woo WA6 or my warm Single Power Square Wave XL (which also has no power switch and has been running since 2/14/09 without being shut off). I tried it with all the phones listed above, all with the same impression - before being warmed up it was very similar to my Apogee mini-DAC headphone out. That didn't seem like much of an upgrade to it at all - certainly not much more of an upgrade than the NOVO was.
After about an hour it was starting to wake up and become warmer and richer, and now at this point (and since about 3 hours of warm-up) it is sounding very good with my HD600. I didn't realize that I had spent this much time listening to Diana Krall "Live in Paris" on repeat (I started typing this 45 minutes into the warm-up period). I found that I like the Solo SRG much more than the NOVO. It is smoother, more refined, and with better bass and richness than the Beta NOVO. The soundstage is also a little more seamless. Hugely different from when it was cold. The changes with a 24, 48 and 72 hour warm-up as recommended to me were fairly smaller than what I heard in the first 6 hours.
My Square Wave XL when running single ended sounds very similar once the Solo SRG is warmed up, but when using my HD600 or D2000 as balanced on the single power it pulls ahead slightly ($1250 amp with blackgates upgrade). The warmed-up single ended maxed WA6 with Sophia rectifier has no trouble keeping up with the Square Wave XL, and many times I like the WA6 a little better than the Sq Wave, even when the Sq Wave is run in balanced mode. So, it goes without saying that I prefer the WA6 ($1250 maxed) to the SRG as well.
I have previously compared my Amphora to the Sq Wave and Woo, and thought Amphora kept up with the balanced Sq Wave and was slightly behind the Woo WA6. This would put the Solo SRG a little behind the Amphora, but not by a whole lot. When I returned from CanJam I did compare these and found that to be the case. The SRG is definitely a step ahead of how I recall the NOVO sounding, and in direct comparison it is ahead of my Apogee mini-DAC, Travagans Red with upgraded opamps, or my Head-direct EF1.
Right now as I type this part I am still listening to the SRG with my HD600, and haven't thought to swap over to one of my other amps. I have also decided I like the HD600 most with it, with RS-1 slightly behind, and D2000 in 3rd. The gap between RS-1 and HD600 performance narrows when I use them with the WA6, and widens when I use them with the Sq Wave. With the ES3X the Solo SRG is wonderful, and there is minimal but still audible hiss with these high sensitivity customs. The hiss is less than my Amphora or Macbook headphone out, and I think the SRG and ES3X are a good match.
As I leave for CanJam I was left thinking that if I did not already have a maxed WA6, upgraded Sq Wave XL or ALO Amphora, with an Eddie Current ZDT on order, once the SRG was warmed up and I got used to it I would be wanting to keep this amp.
Part 2 - Solo with new HD800: (HD800 has about 24 hours of burn-in during CanJam, and another 24 as I write this)
I really liked the Solo SRG with my HD600 before I left for CanJam. I felt that after a lengthy warmup the solo could likely offer some competition with the Single Power Square Wave XL or ALO Amphora, and was just a little behind my Woo WA6. HD600 synergy was best, but not enough to make me sell any of my amps to get one.
With the HD800 the Solo still sounds good, and on the SRG you can still tell the HD800 are better than the 600's. But the 800 are just not quite as immersive in the performance with the Solo as they are with the other three amps. I haven't been able to put my finger on it yet, but it may be slightly brighter with the HD800 than I would like, and not quite as smooth. The HD800 has good bass on the Solo, with comparable levels to a 600 but with better speed and detail. The soundstage of the HD800 on the Solo SRG is not quite as big as when using the HD800 on the other amps, but it does not sound compressed or flat once it has warmed up. When the HD600 or 800 are used single ended, then the Solo is about on par with the Single Power when it is used single ended as well. Once I go balanced the single power pulls ahead (4-pin XLR with single ended adapter) and is very close to the maxed WA6 in synergy with the HD800 (for tonal balance and large soundstage). I think the 800 improve more when balanced than the HD600 do, and the balanced HD600 sound didn't pull away from single ended sound as much as it did with the HD800.
The Solo SRG does not struggle to drive the HD800 in terms of power. I use my Apogee mini-DAC as a preamp, so I set the volume of my amps to 3 o'clock and then use the DAC to control the volume of the three amps connected to it. I have never come close to running out of power with the HD600 or 800, although I listen with about an extra hour on the dial with the 800. (never need to take both amp and pre-amp past 3 o'clock). The 800 are not as hard to drive as some people make out - it is more of an issue of does it have synergy. I can even get nice sound out of a $200 Head-Direct EF2 tube hybrid with the HD800 - and yet the EF2 is certainly an amp that DID struggle audibly to drive the Head-direct RE5 planar magnetic headphones at CanJam. I am not saying all you need is a $200 tube hybrid for the HD800, as the Solo is still noticeably ahead in terms of soundstage, tonality and power; but I am saying that the HD800's favorite amp are not solely governed by how powerful the amp is.
After the initial half of my evaluation (and before I got my HD800) I felt that if I didn't have the other amps around the house that I could have been happy with just the Solo. The HD800 change that slightly, in that I'd want that extra last bit of performance that I am missing, which the WA6 or my balanced amp offer. It's only when you have heard how good the HD800 can be that you know what you are missing.