I got the upgrade kit for my 2004 Solo MC approx 1 month ago. If anyone is considering going for the DIY kit but worried about fitting then don't be, it really is simple.
Since then it has been plugged in 24/7 and have clocked up a fair few hours listening now.
I was happy with my Solo but it was mainly intrigue that made me go for the upgrade. I wanted to see if it did behave and sound like a valve amp.
One thing is for sure it is a very different beast to my 2004 Solo.
One immediate observation other than the colour of the LED is with the volume level, on the 2004 the volume level would be pretty much set at the same position with different headphones regardless of impedance. With the Ultra Linear
lower impedance phones such as Grado's do not need as much volume as the higher impedance cans.
From reading about the Ultra Linear, various people have referrenced hum. I can report I personally have had no issues with hum.
I would say it took about 2-3 weeks to come on song in terms of burning in.
In comparison to the 2004 Solo, in terms of sound I have found it to be more refined, more open sounding, more transparent and greater levels of detail. However, with the 600's and 650's it can sometimes be a little laid back compared to
the 2004 Solo. This isn't to say it sounds bad with the Sennheisers, it is just a more polite sound by comparison.
My biggest surprise is how well my RS-1's and SR225's work with the Ultra Linear. I was not a great Grado fan up until getting this amp. I have owned my SR225's and RS-1's for approx 4-5 years and compared to the Senn's they get little
I have never really enjoyed the Grado's on my other solid state amps, however, I have good results with the RS-1's on my Earmax Silver Edition.
The Ultra Linear takes it to the next level, I am really, really enjoying the RS-1's on this amp. I listen to a lot of rock and metal and it is really enjoyable from both vinyl and CD sources.
With the RS-1's it sounds full bodied, dynamic, detailed, sure footed. It is an engaging listen without the fatigue I have found when using them with other solid state amps.
Does it sound like a valve amp... well the only valve amp I have heard is my Earmax, and it is fair to say the RS'1s sound a lot more like they do on the Earmax than with any of my other solid state amps.
Overall I am very pleased with the Ultra linear, it is a great all rounder. I could now happily live with one amp for my vinyl and digital, and get great results from the Senn's and superb results from my now current favourites, the RS-
1's. I never thought the day would come that I would say that about the RS-1's
For reference the digital source I use is a Cyrus CD8x + PSX-R as a transport into a Cyrus DAC-x+ + PSX-R.
For analogue I use a Rega P3-24 with Groovetracer sub platter and platter. An Ortofon 2M Black cartridge into a Pure Sound P10 valve phono stage.