Analogue tape recording machine gets an upgrade

Louise Davis

Foo Fighters frontman Dave Grohl created a documentary about his love for pre-digital recording in 2013. The landmark film, Sound City, explained how reel-to-reel analogue recording is far from dead in the music industry. But who is keeping this old vintage equipment alive? Here’s how bearing supplier, SMB Bearings helped Soundlock Engineering in its efforts to repair these much-loved vintage tape recorders.

Much of the equipment Dave Grohl used at the start of his career in the early 1990s is still working today, albeit thanks to a little maintenance. According to analogue enthusiasts, analogue recording adds grit and distortion to tracks, providing a supreme sound and recording experience that digital equipment cannot match. Digital music has a tendency to sound very clinical and while some producers try to emulate the analogue feel in post-production, it’s never quite the same.
In this world of digitalisation, however, vintage tape recorders are widely considered obsolete. Therefore, existing analogue equipment must be preserved with expert knowledge and skill.  
Established in London, Soundlock Engineering repairs, services and refurbishes old sound equipment that the music industry is desperate to keep in working order.
The company was formed in 2008 by Chris Roberts. Having dreamt of becoming a recording engineer, Roberts landed a job at a recording studio, but when the studio later closed, he was responsible for refurbishing and selling the old equipment. Suddenly, a new career route began.
Fast forward more than a decade and Soundlock Engineering is still going strong. However, the company was recently challenged with refurbishing two Studer A800s. These legendary tape machines were introduced in 1978 and have recorded classics from Metallica, Stevie Wonder and Tom Petty.
The machine’s owner, a music producer, shared the same passion as Dave Grohl for analogue recording. Therefore, they were investing money into the repair of a machine that held much more than just monetary value. Robert’s was expected to repair the machine to as good as new condition, enabling many more years of premium recording quality.
Upon investigation of these broken machines, it was clear the ball bearings used needed replacing. Bearings play a vital role in the rotation of the tape’s spools and therefore must be manufactured to very high standards.
This is where things got tricky. The Struder A800, as with most sound equipment of its era, is a piece of serious precision engineering. Tolerances are so tight, that engineers must heat parts up to make the metal more malleable, before putting bearings and other components in place. Roberts therefore had to source high quality bearings, manufactured to incredibly tight tolerances.
After a quick search online, he discovered SMB Bearings and called to explain his problem. The technical team advised on the right bearings to use, which in this case were EZO bearings of various sizes, including 6900s and 6203s.
EZO bearings are Japanese-made, providing superior performance over cheaper Chinese alternatives. Their incredible precision enables repeatable and predictable performance, for unbeatably smooth rotation of the tape spools.
To validate the bearings and refurbishment once installed, Roberts performed a ‘wow flutter’ test on the equipment. This industry-standard measurement quantifies the amount of frequency wobble in audio tape machines caused by irregular tape motion, which can be caused by imperfect bearings. The measurement must fall under the specification given by the manufacturer of the machine, which Studer set at 0.04 per cent.
Following the refurbishment of both Struder A800s, the wow flutter measurement was well within acceptable levels, partially attributed to the quality bearings installed during the repair.
“There’s no step-by-step guidebook to refurbishing antique sound equipment,” explained Roberts. “Each device we deal with at Soundlock Engineering has a unique recording history and with it, unique areas of wear and damage to its internal components. Replacing the Struder A800 bearings with substandard bearings — while they may have fit initially — wouldn’t have provided the longstanding premium recording quality usually associated with these machines.”
“As a huge fan of that rustic analogue sound, it is a privilege to help Soundlock Engineering with their tape machine repairs,” explained Chris Johnson, managing director of SMB Bearings. “Naturally, we don’t solely provide bearings for analogue recording devices, but specialise in supplying for many niche projects requiring small or miniature bearings. In fact, we store 2.6 million bearings in our warehouse for businesses just like this, who cannot foresee which bearings will be required for the next job.
“We appreciate that many small businesses need this level of flexibility, advice and speed, and therefore we continue to maintain our inventory, so they have full access to the vast array of bearings they need day to day.”
Dave Grohl has the right idea — long live analogue tape recording. The industry doesn’t want to let go of old tape machines anytime soon but retaining their longevity depends on high quality, expertly engineered bearings.