REVIEW: Graham Slee Solo Ultra-Linear headphone amp
May 10, 2010 at 5:12 PM Thread Starter Post #1 of 37

Zoldar

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This morning I received my Solo (2007, pre SRG model) back from Graham Slee. It has been upgraded to Solo Ultra-Linear. Since I have been only recently initiated in the dark art of head-fi some background follows:
 
I was perfectly content with the K701 and Solo combo. However 2 things nagged:
- there was the occasional flatness in the mid-bass regions, especially in some brighter guitar music (Marillion, Pink Floyd)
- here and there I could do with a little less treble, again in the most complex of pasages the AKG's could get a bit "toppy"
 
In the short time the Solo/K701 has been with me, it has made a head-fi  believer out me. Even my wife who has nothing to do with hi-fi, demanded the Solo be returned promptly. Bizarre. 
 
I also became aware, reading here, that the bass issue had been handled in the Solo SRGII. And that I could upgrade my Solo to SRGII. At the same time Graham Slee announced that there would be a Solo Ultra-Linear. The Solo Ultra-Linear is in the pricelist but not yet "launched" on the web site. The first Solo Ultra-Linear are also being passed for reviews to some of the memebers of GS forum.
http://www.audiocontrol.co.uk/buy-graham-slee-price.htm
 
After mailing back and forth on the above naggins Graham opted to upgrade the Solo to Ultra-Linear. According to Graham, who had been listening to the same music and with the same cans, this would give the extra bass, a valve like sound and less toppy treble.
 
So here it is.
 


 

 
Below are the technical specs from the manual
 

 
And because I am techno noob, the decription of the Solo Ultra-Linear.

 
Listening to the Solo Ultra-Linear
Music (CD): Marillion - Holidays in Eden, Pink Floy - Delicate sound of thunder and  many others?
 
Visually the only thing changed on the upgraded to Solo Ultra-Linear is the now green led instead of the red one it had before and the stickers underside. Plus an autograph from the bloke who’s making this beautiful amp by hand: Graham and co. Nice touch.
 
The Graham Slee Solo has been playing 120 hours non-stop for burning in. I gave it extra time since this amp really goes through A LOT of changes during burn in. This has been written here often and it is still true for the Ultra-Linear. I was tempted to write down initial impressions but I think it’s best to refrain form concluding anything from the burn in period.
 
So how does it sound? I can’t compare it directly to the Solo (2007). I did some A/B with the Solo 2007 and my Marantz CD-52 mkII SE  CD player. So I occasionally used the marantz as a reference point.
 
The most obvious difference I noticed was slightly more oomph from the mid bass regions. There is more heft coming from bass drums in rock music, even when things get complicated or full. The mid bass and bass guitar’s sounds warmer, rounder even than before. I can follow most bass lines al the way through a song.
 
The deep end of bass is still there, rich detailed and when present, giving things a tremendous scale. Put “dance in the dark” from lady gaga on and there is a disco floor in your head.
 
The marantz produced more bass than the Solo 2007. The Ultra-Linear’s bass is more present than the marantz by comparison.
 
Voices have more body, more roundness. For instance: on the marantz the voices sound as flat as a character in a Michael bay film. On the Ultra-Linear they seem to come from real humans with full lungs. The same goes for drums. Body and air around those as well. They benefit of course from the added bass but you can distinguish them more clearly now.
 
Then the highs. I always found that a strongpoint from the Solo 2007. Nice, detailed, delicate. But on my AKG K701 a bit too upfront. There are changes here as well. The highs have taken a step back, there is less sharpness. Yes even this seems a bit “rounder”. At first I thought detailing had gone missing, but al the detailing is still there, slightly rounder and less up front. This is wonderful when listening to complex passages of marillion. Where I normally would have to turn the volume down because of sharp treble, to hot cymbals, blaring guitars and a bass drum which has gone hiding, I can now sit back relax and enjoy. Cymbals are a joy not a pain. I could listen to the Prodigy without being deafened by synthesizers. Now I could close my eyes and be at a rave. Stomping house beats and nice attack from the synths. It won’t turn your K701 into bass cans. Only when the music asks.
 
Musically everything is still very good. With up-tempo songs you find yourself tip-tapping to the music. One song of Tori Amos nearly brought me to tears. That has not happened before. This is where this amp really shines. Conveying emotions.
 
All in all the Ultra-Linear gives the AKG K701 a fuller bass, and a much rounder, a bit warmer presentation. It also takes away some of the glare in the highs. But above all it makes you want to listen and immerse yourself into more music.
 
p.s. does it sound like a valve? No idea, never listened to a tube amp before.

 
 
 
 
 
May 10, 2010 at 5:25 PM Post #2 of 37
Very interested in your evaluation of the new Slee.
 
BTW, that's a fine-looking dog.
 
May 10, 2010 at 5:25 PM Post #3 of 37
I will return to this thread in exactly 64 hours. And don't be late....
biggrin.gif

 
May 14, 2010 at 6:12 AM Post #4 of 37
Visually the only thing changed on the upgraded to Solo Ultra-Linear is the now green led instead of the red one it had before and the stickers underside. Plus an autograph from the bloke who’s making this beautiful amp by hand: Graham and co. Nice touch.
 
The Graham Slee Solo has been playing 120 hours non-stop for burning in. I gave it extra time since this amp really goes through A LOT of changes during burn in. This has been written here often and it is still true for the Ultra-Linear. I was tempted to write down initial impressions but I think it’s best to refrain form concluding anything from the burn in period.
 
So how does it sound? I can’t compare it directly to the Solo (2007). I did some A/B with the Solo 2007 and my Marantz CD-52 mkII SE  CD player. So I occasionally used the marantz as a reference point.
 
The most obvious difference I noticed was slightly more oomph from the mid bass regions. There is more heft coming from bass drums in rock music, even when things get complicated or full. The mid bass and bass guitar’s sounds warmer, rounder even than before. I can follow most bass lines al the way through a song.
 
The deep end of bass is still there, rich detailed and when present, giving things a tremendous scale. Put “dance in the dark” from lady gaga on and there is a disco floor in your head.
 
The marantz produced more bass than the Solo 2007. The Ultra-Linear’s bass is more present than the marantz by comparison.
 
Voices have more body, more roundness. For instance: on the marantz the voices sound as flat as a character in a Michael bay film. On the Ultra-Linear they seem to come from real humans with full lungs. The same goes for drums. Body and air around those as well. They benefit of course from the added bass but you can distinguish them more clearly now.
 
Then the highs. I always found that a strongpoint from the Solo 2007. Nice, detailed, delicate. But on my AKG K701 a bit too upfront. There are changes here as well. The highs have taken a step back, there is less sharpness. Yes even this seems a bit “rounder”. At first I thought detailing had gone missing, but al the detailing is still there, slightly rounder and less up front. This is wonderful when listening to complex passages of marillion. Where I normally would have to turn the volume down because of sharp treble, to hot cymbals, blaring guitars and a bass drum which has gone hiding, I can now sit back relax and enjoy. Cymbals are a joy not a pain. I could listen to the Prodigy without being deafened by synthesizers. Now I could close my eyes and be at a rave. Stomping house beats and nice attack from the synths. It won’t turn your K701 into bass cans. Only when the music asks.
 
Musically everything is still very good. With up-tempo songs you find yourself tip-tapping to the music. One song of Tori Amos nearly brought me to tears. That has not happened before. This is where this amp really shines. Conveying emotions.
 
All in all the Ultra-Linear gives the AKG K701 a fuller bass, and a much rounder, a bit warmer presentation. It also takes away some of the glare in the highs. But above all it makes you want to listen and immerse yourself into more music.
 
p.s. does it sound like a valve? No idea, never listened to a tube amp before.
 
May 15, 2010 at 3:04 PM Post #5 of 37
Tanks Zoldar for taking the time to review the new GS Linear. I opted for the Meier Concerto at the end, which is miles ahead of the GS, of course. Only kidding.
bigsmile_face.gif

I am hoping to have a chance to listen to it at the Brighton (UK) meet in August. I am actually surprised that very few people seem to be interested or bothered to comment about this new SS amp which used (what appeared to be) a new and  innovative technology.
 
May 16, 2010 at 7:36 AM Post #6 of 37


 
Quote:
Tanks Zoldar for taking the time to review the new GS Linear. I opted for the Meier Concerto at the end, which is miles ahead of the GS, of course. Only kidding.
bigsmile_face.gif

I am hoping to have a chance to listen to it at the Brighton (UK) meet in August. I am actually surprised that very few people seem to be interested or bothered to comment about this new SS amp which used (what appeared to be) a new and  innovative technology.



No thanx. Good luck with your inferiour amp
k701smile.gif
. I would love to attend one of these meetings. Pitty there aren't many here in Holland. Please comment on the amps you hear there. Aside from stalking you local hi-fi shop these are the best opportunities to A/B amps. 
 
Or you could do what other head-fi dragons seem to do: hoard them :)
 
 
 
May 16, 2010 at 5:02 PM Post #7 of 37
I can't wait to get my fat fingers on the Ultra-Linear and compare it w/ the SRGII. Should be fun, BTW you should allow that amp to burn-in a long time. If it behaves like 5 other examples of Graham's amps it will need 500-600 hours of burn-in. Cheers.
 
May 16, 2010 at 5:15 PM Post #8 of 37
Quote:real
I can't wait to get my fat fingers on the Ultra-Linear and compare it w/ the SRGII. Should be fun, BTW you should allow that amp to burn-in a long time. If it behaves like 5 other examples of Graham's amps it will need 500-600 hours of burn-in. Cheers.


500hours? OK, its still spinning endlessly. I'll report if it undergoes any other 'mutations' during this peroid. I thought burn in was a myth. Not so with the Solo. It went from stone cold - real temperature and sonicly - to K super sound of the '70 in 2 days.
 
Please report on the differences between the SRGII and Ultra-Linear. I was in dubio whether to upgrade to Ultra-Linear or SRGII.
 
 
May 22, 2010 at 6:55 AM Post #9 of 37
Update after 300 hrs burn-in.
 
Good lord this amp makes me happy !
 
Listening to Marillion -Holidays in Eden, 24 bit remaster.
This was always a rather "cold" and at times glaring recording on my set. Especially when the band goes crazy and kranks up the electric guitars, smashing cymbals and drums and lead singer puts up a great voice. It's excellent music but at times tiring to listen to. It tends to bring out the weak points in the AKG and so is a bit of a test CD for me. 
In complex passages the bass drum seems to go off on a holiday and the guitars beome glaring, the cymbals in the front of the soundstage force you to listen at lower volumes because of some sharpness. This was even so with the Solo '07.
 
Now Solo Ultra-Linear:
Cymbals are so sweet, detailed and delicate. No sharpness or glare. You can hear a distinct snap! when they are struck. I could listen to just them through a song and be very happy indeed.
 
Same goes for the snare drum. It has its own space now, with reverb around it. And it too is being struck. There is so much more air around the snare drum.
And drums being struck form left to right are very, very well placed, have some much needed heft and punch added.
 
Same goes for the bass drum. It sticks around now, even when the rest of the band is going mental. It doesn't turn the AKG K701 into bass cans or transform the balance of the song. But the times I would crank up the bass are far and between now.
 
Then there is the low end bass. Marillion uses synthesizers to ad low end bass and give some song tremendous scale (like movie soundtracks). The Ultra-Linear delivers it in spades and with detailing. Without clouding the rest of the soundscape.
 
Acoustic guitars are sweet, delicate and you can make out the plectrums and hands going up and down the ladder. Spin a "unplugged" cd from alice in chains and it is sweet, warm and musical sound. The decay of notes is longer, the strings reverberating in your ears delightful.  
 
Electric guitars stay beautiful and do not glare. Even at high volumes. Pink Floyds Delicate sound of Thunder sounds great. David Gilmours solo's staying clean and sweet.
 
The soundscape is more clearly defined. I can look "into" the set of Pink Floyd. With Marillion you can distinguish which cymbals are in the front or in the back. Not by their volume but by the echo of where they are in the recording room. It doesn't collapse like a deck of cards when the going gets loud either.   
 
You may wonder that I don't mention "Noise". That's because there isn't any. Not on softly mastered CD's in soft passages or fade outs. Not anywhere. Except if you crank up the volume to max. And hey my NAD amp does that too. But if I press "play" at max volume, I sign a death warrant to my speakers, my lovely and irreplaceable organic ears and a good standing with my neighbors. So wat is the use of such a "test". It's like driving a Bugatti Veyron at 402 km/h into a concrete wall and complaining you are dead.
 
So happy am I with this set I removed the CD-player from the stereo yesterday. It is now solely connected to the Graham Slee Solo Ultra-Linear which feeds the AKG K701. No pre-amp and one less interconnect. This has added more detailing in highs, better placement of instruments and some more air. And no more playback of CD's over the main speakers and amp.
 
And that is just fine.
 
Oct 26, 2010 at 1:22 AM Post #11 of 37
Thanks, Zoldar, for the informative review.  I actually decided on upgrading my SRG I after reading your review.  My DIY Ultra Linear PCB upgrade arrived two weeks ago and I am very happy with the improvement it has brought to my system.
 
Any more changes after the 300 hour mark?
 
Mine is about 300 hours now and has somewhat stablized.  I found the first 100 hours to be quite a roller coaster ride...there were phases within that period it did not sound that great.
 
Oct 27, 2010 at 2:22 AM Post #12 of 37
Thanks for the review.
Interesting, a solid state design claims to conjure up tubey sound.
Given that it could work well with the K701, must have some drive.
Do you have a chance to try it on efficient phones alike such as Grado ?
 
Oct 27, 2010 at 3:29 AM Post #13 of 37
Thanks Kachui. I wish I had more technical expertise so I could have done the upgrade myself. Here's the head-fi set now.
 
 
 

 
The Solo Ultra-Linear has settled down after the 300 hour mark. The burn in period of the Solo Ultra-Linear should convince all non-believers that it isnt a hoax. This amp went from stone cold, tight sound (stone cold out of the box) to wooly, warm, loose sound (all negative things you could point at tubes actually) and finally stelled down to after 300 hours to the very nice detailed and airy SS amp it is.
 
Its still doing lovely things to cymbals in late night sessions. And SACD sound great, open and airy. It also refrains niceley from (solid state) grain when the music gets complex or loud.
 
Does it sound like tubes? Well I dont know since I havent had a chance to listen to a full tube head amp.
 
But the Ultra-Linear has gotten me on a new quest. The quest for tube amplification for my hifí set. I have auditioned some very nice tube gear at dealers and conventions these months. Cary audio designs excellent SLI80 integrated tube amp. An equally impressive GRAAF set. And this weekend an insane set priced north of 80.000 euro's (the amp alone was 60K). These sounds get under the skin and prove why tubes are great. Ultimate treble cleannes and extension, airy smooth mids, the whole rose garden. Sadly at very high prices. At the other end of the tube scale I auditioned eastern electric gear at modest sub 2K prices. And that showed all the weaknesses that solid state guys point at tubes. No punch, no bass, no authority. And that nice clean treble then becomes irksome. But I still hope there is some middle ground in tube land to be had.
 
Where am I going with this? Weirdly, the Solo Ultra-linear has me set on appreciating tube sound. While I can't compare the solo to a woo audio, I do feel there IS some tubiness to its sound. Its very nicely free from grain in the treble, and has a measure of air around notes. You can hear the extended bandwith and the fact that there is less negative feedback compared to my previous Solo.  
I haven't had the chance to plug in grado's. Maybe its time for a head fi meet in the netherlands 
k701smile.gif

 
An update on noise: I found out what was the (small) gripe with mine. My silver interconnects where picking up noise lake antena's. Changed them for van den hul's and there is no noise to speak of.
 
Oct 27, 2010 at 7:53 AM Post #14 of 37
Thanks for the update, Zoldar.
 
Here is my setup:
 

 
I have a tube pre-amp between two sources and the head-amp; I guess you can say the pre-amp is acting as a tube buffer in my system.  I have tried with and without the pre-amp in the chain, but found that I prefer it with the pre-amp.  It gives a fuller and lusher sound.
 
I have a Grado SR80 and it sounds great with the Ultra Linear as well, but I prefer the HD800 so it stays in the system. 
 
Oct 27, 2010 at 10:56 AM Post #15 of 37
That looks SWEET. Nice analogue front end. And I love those tubes in the pre amp. What's the digital front end? 
 
With a little luck I will be having a mini head-fi meet soon to answer some tube vs ultra linear questions. The setup is thus: Graham Slee Solo Ultra-Linear, Darkvoice 336SE. K701 and HD900.  
 

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