Further to my review of the Graham Slee Solo MKlll and subsequent comments on the mods that brought about the Solo 2004 I'd like to add a few additional comments on the sound quality of the 2004 Solo now I have lived with it for some time.

____What's different?____

Quite a lot of changes have been made to the latest Solo. It features a new circuit board / layout which has been totally reworked around the AD823AN operational amplifier. It features gspaudio's latest ELN (emitter lift network) circuit, "CDO" technology (current drive output) and uprated audiophile output caps.

The totally reworked 2004 Solo featuring ELN and CDO technology

____Graham Slee explains the changes____

ELN / Class A output stage:   "The Emitter Lift Network serves a bidirectional benefit. The output stage emitters assist the op-amp during large output swings and the op-amp assists the output stage during small signals. Although Current Dumping is explained like this, the Solo is not a current dumper. Its output stage is always biased-on and its output will remain within the class A envelope even at elevated listening levels. 100,000uF simulated voltage stage power supply smoothing completely eliminates power supply feedback."

CDO: "Current Drive Output allows the Solo to drive headphones up to 1000 Ohms at realistic volumes. No matter what the headphone impedance is, the Solo output stage produces the same high output which is converted to a current and automatically adjusts to give the same power into any headphone impedance. You can swap between 32 Ohm Grados and 300 Ohm Sennheisers without having to alter the volume control."

____Cosmetics____

The enclosure is now a classy looking effort made from German extruded anodised aluminium with a clam shell construction which is very well finished, sturdy yet sleek. Peripherals are high quality with a Jalco headphone socket, switchcraft DC socket, gold plated phono sockets and a very welcome blue LED...... fit and finish are first rate. 

____Sound Quality____

From the moment you first fire the Solo up, it is obvious that this is a very good sounding amplifier though after a warm up period of 24 hours it becomes very evident that is one very "superior" sounding amplifier....... it certainly does require a good 24 - 48 hours to really kick in and the 3 week recommended burn in period is no joke........ The same was true with the MKlll.

Listening to Martin Taylor's "spirit of Django" the solo reproduces music with a strong sense of presence and solidity with spot on timing and microscopic levels of detail...... the finger plucking of Martins guitar and the resonance of the strings is spookily realistic, at times I could have sworn he was sitting 6 feet away from me..... it was just like being in a smoke filled jazz club, the sheer presence of the musicians was palpable and I could almost reach out and rosin Stepfan Grappellis bow for him, the sense of being there and being involved in the event felt so real.

Play a well recorded live CD and you know instantly you are hearing something close to the real performance...... I was amazed listening to Pink Floyd's "PULSE" album, I felt part of the crowd and even sensed the atmosphere, the lazer beams, the sweat, the emotion of the crowd and sheer scale of the event..... this wasn't like listening from the exit door of the arena this was like being in the third row enveloped by a seething mass of adrenalin filled floyd fans enjoying a live show.

Next on the playlist was Wynton Marsalis & Ellis Marsalis "Joe Cools Blues" Ellis Marsalis's Piano literally shone and I could hear right into the double bass and follow the bassists fingers up and down the frets whilst at the same time fully appreciating the drummer's delicate brushwork. The deep breaths Wynton Marsalis took before pursing his lips and blowing into his muted trumpet, the exhalation after a trumpet solo...... it's all there...... warts and all..... you can even hear the keys being pressed on Wessel Andersons Alto sax, lovers of jazz will marvel in the sheer information the Solo allows through.

The Solo has a very strong harmonic resolution, listen to the way notes decay on this amp and you'll wonder why the heck more amp designers can't make them like this. The solo not only manages to convey the music it also has a canny knack of capturing the emotion and captivating your senses.

Compared to the MK111 The bottom end is both cleaner and more neutral, but the really big changes are further up the spectrum, in the upper midrange, which is a lot less veiled, grainy and congested and possesses a much wider and more transparent energetic overall view and the top end is so much sweeter and delicate.

The current drive output clearly works and "CDO" is not just meaningless technospeak.......the Solo has power in spades, enough to drive just about any headphone of any impedance at any required volume... it drove my AKG K-501's (notoriously hard to drive) with consumate ease and even managed to bring the K-501's bass to life...... no mean feat..... owners of hard to drive headphones looking for an amp to bring the best out of their headphones need look no further, the Solo will deliver the goods, and then some.

____Conclusion____

This is a beautifully presented, well equipped amplifier and the current drive output makes light work of driving headphones whether they be low or high impedance types. It possesses excellent levels of consistency, tonal accuracy and generally sounds just "right"   The Solo will have you exploring your CD collection all night, it's a sonic diamond.

_____Equipment_____

Source: Marantz CD 17 Ki signature
Amplifiers: Graham Slee Solo (2004) & Graham Slee MKlll (used for comparison)
Headphones: AKG K-501 Sennheiser HD-600

Manufacturers Website

Solo MKlll review