Graham Slee Bitzie USB DAC/Amp

YoYo JoKeR

100+ Head-Fier
Pros: Pleasing Sonic Presentation, Workmanship, Driving Power, Versatility
Cons: Value

Me: I am a 21 year old student living in a small town in India. I would like to call myself a music enthusiast, rather than an audiophile. I was inspired by music since childhood, and as the time passed, the passion of music grew in me, and that subsequently led me to join Head-Fi. Eventually, I found the pleasure of listening to music mainly by the HD600 and recently, by the seductive LCD2 headphones, and realized the true components of recorded music. I usually like to listen to Indian Classical Music along with Bollywood songs. My main listening genres include classical, vocal, instrumental, jazz and sometimes pop.  With time, my sonic preferences have very much grown. I avidly admire transparency, accuracy along with neutrality, and currently my favorite headphones are Sennheiser HD800 & AKG K812, which I run from solid state amplifiers. I prefer & admire transparent solid state headphone amplifiers simply because they provide best possible accuracy, transparency & reliability.
I am an average consumer & a humble enthusiast, I pen down my thoughts, & I love to express my feelings. I do not receive for any sort financial benefits through this review. My articles are a purely honest writeup aimed for fellow enthusiasts here at Head-Fi community. My profound thanks to GSP Audio, UK for arranging a sample unit of Bitzie for my evaluation.

Intro:  GSP Audio, a brand of Graham Slee Projects, is a company which manufactures high fidelity headphone & phono amplifiers purely by hand, & is based in Britain. They also make custom audio cables. Established in 1998, GSP Audio is one of oldest audio brand existing in Europe. They are very well known worldwide for their well made phono's & amplifiers, owing to their offerings which have great attention, workmanship & high performance. All their products are handmade in the Great Britain.
Brief History On GSP Audio:
Mr.Graham is founder of Graham Slee Projects Audio UK, with an aim to make high end audio products including phono’s, headphone amplifiers, power amplifiers, DAC’s & various performance cables. Mr. Graham Slee, born at Mexborough, England in 1955, apprentice trained engineering craftsman in the 1970s, worked in AV until 1984 when he set up his own electronics and printed circuit design business, working with a number of "blue-chip" technology companies. In 1989 he became senior engineer at Audionics (Sheffield) Ltd, part of the Yorkshire Radio Network (YRN) group, where he designed electronics for broadcast studios - clients included the BBC, and numerous UK commercial broadcasters. 1993 he left YRN to freelance in electronics design with various companies.
In 1998 he established Graham Slee Projects also known as GSP-Audio. In 2004, John Cadman - former YRN installation engineer and wireman - joined as production director and in 2008 Leon Kirkbride who had worked for Carlsbro Sound, joined the team as freelance production engineer. Freelance broadcast engineer and Minster FM DJ Paul Godley often joins in with manufacturing too.
Year 2013 saw the introduction of the Bitzie USB DAC, a palm sized USB audio device having headphone/line outputs and S/PDIF coax and optical outputs - giving higher spec devices the run around for its incredible musical performance. Graham Slee Projects audio products are designed, built and tested in the English North-Midlands and South Yorkshire by engineers - they are truly British made.
Specifications of the Bitzie as Per GSP Audio:
Input: USB, up to 24 bits and 48kHz sampling frequency
Digital Outputs: Coax transformer isolated & Optical 16 bits 48kHz sampling frequency
Analogue outputs: 3.5mm jack & 1/4" jack
Distortion, THD+N: 0.001%
Inter-modulation, SMPTE: 0.015%
Frequency response: 20Hz - 20kHz +/-0.02dB
S-N ratio: 96dB
Distortion, THD+N: 0.001%
Inter-modulation, SMPTE: 0.013%
Frequency response: 20Hz - 20kHz +/-0.02dB
S-N ratio: 96dB
Line-out:  Use supplied adapter for line-out.
Maximum output: 1.55V rms
Distortion, THD+N: 0.01%
Inter-modulation, SMPTE: 0.15%
Frequency response: 20Hz - 20kHz +/-1dB
S-N ratio: 76dB
Output noise (shorted input): -96dB
Headphone out into 32 Ohm
Maximum output: 750mV rms
Distortion, THD+N: 0.08%
Inter-modulation, SMPTE: 0.25%
Frequency response: 20Hz - 20kHz +/-1dB
S-N ratio: 72dB

Packaging & Accessories: Bitzie comes packed in a simple plastic sheet box, with an user manual & a Line out splitter adapter as accessories. Simple & does its job, but could have been a little more attractive.

Design and Build: The Bitzie has an appreciable & supreme overall build quality with perfect workmanship. The outer case is made up of aluminium, and is polished & brush finished; volume knob is rubberized, and has a grippy feel to it.  The Bitzie is very small & compact in size. On the front side, we have Volume control knob, headphone jack is present in both 6.5mm & 3.5mm format. On the rear side, we have USB input port, along with Coaxial  & Optical output ports are present.
Speaking of Internals, Bitzie has a double sided PCB with no manual wirings. All components used are carefully selected; including all dale resistors, Alps pot, premium caps. For D/A conversion, the Bitzie employs a 24 Bits/48 KHZ capable Burr Brown PCM2902 Chip. There are no user replaceable/serviceable parts inside the Bitzie: The DAC output op-amp is AD823A but it is permanently mounted on PCB. Board is well soldered and has a reliable workmanship. As a budding technocrat, I can say the design & engineering in Bitzie is very good & creative compared most of other amp/dac's.
All amplifiers by GSP Audio carry a principle on more efficient volume controlling. Vast majority of amps have conventional and crude volume controlling, which just get louder by twisting the knob, & reach high volumes very early, bu headphones are not driven efficiently. But in Graham Slee amps, more turns on volume knob means better driving the headphones, plus, a very linear & well distributed volume with well driven headphones. The Bitzie is powered solely off the 5V USB line. This makes it also to work straight off an android smartphones, which is a definite advantage for travellers. The Bitzie runs off solely on USB power,  that is around 5V & 100mA. It is really easy on smartphone’s battery life.

Sound:  I feel the Bitzie is ‘natural’, detailed and accurate sounding with a touch of ‘tubeness’ in sonic presentation. Sound-stage width is moderate. Depth is very good. Amazing performance for a DAC/Amp unit running off on 5 Volts & 100mA current.
Lows are strong and fairly accurate and go very deep. Full bodied bass with a ‘punch’. Mids sound clear, slightly intimate & with a touch of ‘valvey-ness’ if I must say; Bitzie has an analogue tubey flavour here in mids. Highs are clean, airy, just right amount of sparkle to keep the music alive.  Again a slight analogue flavour.
Soundstage in Bitzie is very good, and realistic and to some extent, slightly lacking in width. Depth is very good. The Bitzie has a fully circular imaging, but gives out comparatively more depth and lesser width in sound stage. Detail retrieval, and dynamics are excellent, way further than any USb powered DAC/Amp I have ever heard. Overall the sonic presentation is very pleasing.  Absolutely zero audible hiss/noise, and zero EMI pickup & pops.
Driving Power: The Bitzie is powerful when it comes to driving headphones. Drove my AKG K702 well with 20% power still spared. K702 & Bitzie made a good match with a pleasing sound delivery.  Tried my LCD-2’s, Bitzie drove them well, but lacked synergy.
Overall, the Bitzie impressed me in all aspects, considering how compact the Bitzie was, and it does not even need a dedicated power source, performs appreciably well.

Conclusion:  The Bitzie is a very unique & special USB DAC/Amp unit. Bitzie stands as a great option for travellers with smartphones or laptops who demand the same amazing high-end sonic performance on the go.  I can recommend the Bitzie for any music enthusiast who wants a compact portable USB amp/dac with high performance aspect. Bitzie is truly like a swiss army knife: very handy unit that fits in pocket & is very well performing. Its workmanship is of high standards, and thus very reliable & robust in operation.
Though excellent performing & a five star deserving product, I will reduce half a star for its pricing. At the price point of 550$, Bitzie is expensive when compared to similar products. But in return, it has excellent performance, reliability & workmanship. Plus it is purely handmade in England.
1) Design and Build: Bitzie has very well designed and implemented build. It can run off 5V source, eliminating the use for a separate power supply.  It can also run directly on android smartphones. The Bitzie is also very compact, reliable & durable.
2) Sound quality: The sonic presentation on this little unit is neutral but in natural & tubey in presentation. Sonically, performs very well. Powerful enough to drive any dynamic headphones.
Cons:  Value: The Bitzie carries a price tag of 550$, which appears slightly on expensive side. But considering the above abilities of Bitzie, it is well worth the asked price in the long run.


Nice review, very detailed and readable. I'm looking for a portable amp powerful enough to drive my Fidelio X2s which I received today. They have a relatively small impedance of 32 ohms, and I really don't want to spend too much money. Do you have any suggestions?
YoYo JoKeR
YoYo JoKeR
Thank you mate,
May I suggest the Objective2 amp? it is neutral, transparent & has high sonic performance. Costs around 130$, might fit in your budget as well.