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I am a great admirer of ‘golden age’ Japanese turntables like the Sony Biotracer. However “Now Dear Reader - explain to me why you would spend $50k on a VPI Titan?”. First is the Biotracer is 35 years old and known to have ICs that if they fail are unobtainable turning it into a brick. Everything else is also 35 years old. Have you restored it with full teardown, clean, lube, and reassembly? As an experiment call Sony and tell them you want parts for the Biotracer, let us know how that goes. Second regarding build quality, you’ve got to be kidding? Part of the golden age of Japanese turntable I admire is the level of manufacture and what they obtained with injection molded plastics and die cast aluminum. In comparison the VPI is CNC milled out of machined acrylic/aluminum/acrylic sandwich-design chassis. To my eye pride of ownership is +1,000% in favor of the VPI. Now of course firewall obviously places great store in the obscure technology I have that you don’t aspect of ownership pride. To each his own.
OK….going against my instinct to “don’t feed the trolls” driven by my interest in the (very) short lived emergence of active servo damped tonearms let’s address firewall’s question/slam.In the late 1970s early 1980s just before CD was introduced several Japanese manufactures introduced turntables using active electronic servo damping of the tonearm. Sony called their version ‘Biotracer’ in models like PS-X75, PS-B80 et.al. Later they used the same technology in linear tracking models like the PS-X800. Denon was another proponent of this technology with the DP-47F, DP-62L enjoying a cult following due to their ‘Dynamic Servo Tracer’ servo tonearms, (https://www.tonepublications.com/old-school/denon-dp-62l-direct-drive-turntable/). I think Pioneer may have also dabbled in servo arm technology.The trick of these turntable + tonearm models is where 99.999% of all tonearms ever made have simple bearings allowing the tonearm to track the record in ‘Biotracer’ and ‘Dynamic Servo Tracer’ servo tonearms a set of electrical servo coils, motion sensors, and feedback circuits are added around the vertical and horizontal bearings of the tonearm. This allows the application of electrical damping into the system. It’s rather counter-intuitive unless one has studied servo feedback loops but I will try and explain.Recall in normal tonearm + cartridge systems like the VPI firewall is slamming the effective mass of the tonearm acting with the compliance of the cartridge causes a primary resonance in the system. To keep it outside the nominal audio range the usual target is to have the system resonate at 11-12 Hz. The servo trick is a good engineer can tune the electrical servo coils, motion sensors, and feedback circuits to completely damp out the 11 – 12 Hz resonance. When the mechanical resonance tries to push up the sensor detects that and the feedback loop powers the coil to push down. That over simplifies it, of course its acting in all x,y,z, directions on a band width set to achieve the desired result. Besides the feedback loop disappearing the LF resonance the added servo coils and circuits allow fun party tricks like setting the vertical tracking force, anti-skating, and system damping while a record is playing.Like spring flowers in the desert ‘Biotracer’ and ‘Dynamic Servo Tracer’ servo tonearms flowered during a 5-6 year run then disappeared awaiting rediscovery. Given this was just before and during the introduction of CD I have a theory Sony and Denon, et.al. were practicing building the servo system that are absolutely required to make CD drives work. At the very least it was an obvious cross platform use of the technology. The big downside of ‘Biotracer’ and ‘Dynamic Servo Tracer’ servo tonearms is the added complexity, this limited it to $500 - $1000+ (in 1982 dollars) turntables a segment that essentially disappeared for years after the introduction of CD.Another issue is ‘Biotracer’ and ‘Dynamic Servo Tracer’ servo tonearms address an issue most audiophiles are unaware of and whose systems are largely unaffected by. Unless you have subwoofers with below 20 Hz response the presence or absence of an 11 Hz resonance is a very subtle thing. It’s what I call an “Nth degree effect” that is real but subtle. I would also go as far as speculating that in many system the owner may prefer the sound with the 11 Hz resonance counteracting the speaker’s high pass nature.Specific to firewall’s test subjecting his Sony and the VPI to “120 dB of 17-120 Hz (at the turntable,)” this is a test designed to play to the one trick the Biotracer does best. To me this is exactly like firewall bragging his 1987 Toyota is better than his “buddy” a “rich doctor who thinks that the more you spend, the better the result” who has a Corvette C8. Why is it better? Well because the Toyota gets 32 mpg and the new mid engine Corvette only manages 19 mpg.I am a great admirer of ‘golden age’ Japanese turntables like the Sony Biotracer. However “Now Dear Reader - explain to me why you would spend $50k on a VPI Titan?”. First is the Biotracer is 35 years old and known to have ICs that if they fail are unobtainable turning it into a brick. Everything else is also 35 years old. Have you restored it with full teardown, clean, lube, and reassembly? As an experiment call Sony and tell them you want parts for the Biotracer, let us know how that goes. Second regarding build quality, you’ve got to be kidding? Part of the golden age of Japanese turntable I admire is the level of manufacture and what they obtained with injection molded plastics and die cast aluminum. In comparison the VPI is CNC milled out of machined acrylic/aluminum/acrylic sandwich-design chassis. To my eye pride of ownership is +1,000% in favor of the VPI. Now of course firewall obviously places great store in the obscure technology I have that you don’t aspect of ownership pride. To each his own.
an extremely good post but with one small correction. It should be "W, X, Y" and not Z,X etc. Z can exist, but is under complete control via the tone arm mount. Either way you did quite well.Lets take a trip in old H.G.'s time machine back to 1982 and maybe 1979 thru 1984. What was the hot turntable in that era? A Linn of course (with a full load of options). Then there were some oddities that were seriously great. In Japan they sought after a Micro Seikei (I can't remember the correct spelling) and things like a Dragon or an even rarer Kenwood something or another. Of course we'd have thought it was a Technics SL1200, but there were better Technics tables for bigger cash. Now I've never been on the VPI bandwagon, but respect them a little bit. I think there are better designs, but not wanting a big argument we'll leave that fight for another day. What I saw in the original post was a combination of several issues that might well be resolved with a couple hours of elbow grease. What I saw in the post was a massive distortion test, or who can do the most! 120db. is jet after burner noise!!! Actually just as loud and from 200 feet louder. So we take it down to 17Hz, and I want to know what cartridge was in use that would withstand all the vibration in the air (trust me it's there). Even further; how soon did it take the neighbors to call the Police? What speakers were used? Yet what I most want to know about is what kind of amp(s) were used to obtain 120db. at a rock steady pace. Plus not distorting the signal.Once again I loved your post, and please chime in againgary
He's a rich doctor who thinks that the more you spend, the better the result.
This is a good writeup:https://www.mysonic.space/sony-psx75-biotracer-turntable
Wisdom
