Superior Performance Hi-Fi Products
All Headphone Amps >> Solo SRG II
The Solo stereo headphone amplifier started life in 2001, has seen a decade of continuous improvement and on its way What Hi-Fi? gave it five stars, warning customers to "be prepared to buy it there and then" if they dared to audition it.
Made for studio monitoring, the Solo is often used in commercial editing suites where it captures edit points so elusive to other headphone amps. It was also supplied to the BBC, modified to accept PO 316 (BPO) jack plugs. It is best partnered with studio headphones — for a headphone amplifier geared to driving the most difficult hi-fi headphones see the Solo Ultra-Linear Diamond Edition.
The Solo SRGII is the result of our "Green Solo" beta-test program, where over 100 customers took part. Where energy conservation is a must the Solo SRGII is the only high performance headphone amplifier in the running.
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The Solo SRGII shares the same tape loop monitoring feature of our Solo Ultra-Linear Diamond Edition (see its features tab for details).
Proprietary "in-loop" headphone control feedback system corrects for headphone frequency dips and peaks.
Its AC coupled output stops DC current appearing across your headphones, preventing headphone burn-out.
Headphone sensitivity volume control: unlike conventional volume controls, this one is designed to be used over its full rotation to compensate for a wide range of headphone impedances and sensitivities. This avoids the use of gain switches which would otherwise result in differing performance characteristics depending on the gain setting.
The Solo SRGII headphone amplifier is supplied as standard with a silent running energy efficient power supply complying with world carbon reduction targets.
The Solo SRGII headphone amplifier can also be supplied with the PSU1 power supply (also available for separate purchase - see Power Supply tab here) for those happy with a traditional, more power hungry linear power supply.
Headphone impedance range: 16 to 600 Ohms preferred; 8 to 2,000 Ohms acceptable
Headphone Jack: 1/4 inch (6.35mm) A gauge (BPO B gauge to special order)
(rms, both channels fully driven) 32 Ohms: 27mW/channel; 600 Ohms: 23mW/channel
Distortion (THD plus noise, ref 1kHz): 0.02%
Frequency response (-3dB) 32 Ohms load: 27Hz - 35kHz; 600 Ohms load: 10Hz - 39kHz
Output noise (20Hz-20kHz, CCIR quasi-peak): -84dB
Input sensitivity (for specified power output) 32 Ohms: 250mV rms; 600 Ohms: 775mV rms
Channel balance: better than 1dB, "9 to 3 o'clock" positions
Crosstalk: Left to Right -57dB; Input to Input -68dB
Mute: Signal off mute, non-shorting
Output Stage: Bipolar class AB
Supply voltage: 24V DC
Size: (approx.) W: 107 x H: 50 x D: 185 (mm) inc. controls
Excerpts taken from the Owners Club Forum:
"I thought it would be interesting to go back to the Headmaster to compare the sound quality. Tank styling not withstanding, the SRG/PSU1 was obviously more dynamic and had a firmer grip on the bass - which was perceptibly deeper... What it does tell me is that you don't judge a book by its cover, nor its purchase price.
"I have used the Solo SRGII with the K701, K501, HD580, HE300 (Head Direct), and HE500 (Head Direct). What would you like to know... In short the sound is GREAT!
"I will give you my 2 pennys worth of info, I have just demoed your very cd player with the Solo SRGII & denon ahd7000s.... wow what a sound !
"Hi, update SRGII: after ~200 hrs on-time, of which ~100hrs all operational. Very simple is it: the difference is big and I am pleased. It sounds much more like music now, even from my computer. Much more realistic, subtle and wider smoother bandwidth than the Solo 2004.
"Recently picked up a Solo SRGII with a set of HD650s. Connected directly to a Denon 2901 Player and also via a Headroom Desktop acting as a DAC/Preamp. Really enjoying it so far, it's a lovely little thing that makes the 650s sing.
"Reviewing the Solo MC in 2005 I wrote "The strengths of the Solo are in the extra high frequency extension, a superb transient response and an unsurpassed dynamic range."
...today’s SRG II is a significantly better performer than the Solo MC, with the biggest improvements in the bass and the all-important midrange. Maximum sound pressure levels are higher while the clean treble and lightning reflexes have been maintained. Distortion and background noise are lower than before, making it easier to listen to the music, to enjoy the texture of the instruments and voices.
"That super top end, a wonderfully open midrange and a low noise floor made everything I listened to sound great; the better the recording, the more I heard. So I plundered my CD collection for the best recorded tracks I own, including some SACDs that have been languishing in the drawers. The Solo did the business whether I was listening to Bob Dylan or Diana Krall or my copy of the Stockfisch Records demo disc or if I was working through stuff like Shelby Lynn or the Watson Twins. The Solo does a very good job of deconstructing music like this and laying it out clearly, along with any ambience, venue noise or low-level detail that has been captured, which enhances and expands the “head-stage” while allowing a listener to hear how the various parts of the recording fit together.
"I bought this amp unheard based on the rave reviews from English hi-fi magazines and it did not disappoint. It runs my Grado 325i's as well as my HD650's beautifully. As stated above the volume acts also as a sensitivity adjuster so with the 300ohm HD650's i run it at the 3 or 4 o'clock position and the 32ohm grados at 12 o'clock.
My reviewer vocabulary is not good enough to describe sound characteristics but i do know it was leaps and bounds better than the Firestone fubar IV Plus that it replaced.
A word of advice for anyone wanting to purchase one of these. Buy the PSU1 power supply that is available as a combo. It is cheaper to purchase than if you are buying separately which I did.(US$350) After listening to my amp with the walwart type supply i decided to spring for the upgraded PSU and it made a significant and very noticeable difference in sound quality. Everything was suddenly more vibrant.
Overall I am very pleased with my purchase and am happy knowing that if i decide to keep it for many years it will still be a good quality amplifier.
"Verdict: If you are serious about headphones go and have a listen to the Solo - and be prepared to buy it there and then
[Graham Slee Solo, What Hi-Fi? Sound and Vision, October 2004 and The Ultimate Guide 2004]
"The strengths of the Solo are in the extra high frequency extension, a superb transient response and an unsurpassed dynamic range
[Phil Gold, Graham Slee Solo MC, Enjoythemusic.com, January 2005]
"With Grado SR60 phones, I was greeted with bags of detail and what I really loved, a sound stage with no seams even implied top to bottom
[DVV, TNT-Audio, May 2001]
Solo SRGII headphone amplifier supplied with "green" power supply (see Power Supply tab here): £377.10 GBP (pounds sterling) including 20% United Kingdom VAT. Price does not include shipping.
Solo SRGII headphone amplifier supplied with PSU1 power supply (also available for separate purchase - see Power Supply tab here): £520.80 GBP (pounds sterling) including 20% United Kingdom VAT. Price does not include shipping.