Very informative and great story on how you acquired the turntable. I am always amazed how these early pioneers solved problems and the solutions they created to do so. So cool to keep that spirit alive.
Thanks for the info on these fine tables. I bought an ST 7 last week on a gamble. It needed work, but hadn't been messed with. Grimy with a couple of small scratches. Missing the carriage Rabco cover and dust cover. Needed new bulbs. It came with a really nice owners manual and service manual which is required reading. New bulbs are here and the missing cover and alignment gauge and new belts are on their way. I replaced the gooey tire with a #31 plumbing o-ring, but it's slightly narrow. Oh well, it now tracks on the tracking roller well. Cleaned and lubed the lift mechanisms and it seems to stop and raise well. This gamble might pay off! We'll see when all the parts get here.
Many years ago in the 1970s, a friend of mine acquired a used Rabco SL-8E tonearm which he proceeded to completely modify in an attempt to get it to work properly. About the same time, I bought a used Rabco ST-4 (which was shown in your video). I had no issues with it. Interestingly, my then-roommate referred to it as the “Ronco Bottle Cutter” a bizarre late-night TV gadget that could turn beer bottles into glasses. The comparison is strangely apt. I have always wondered about the Harmon Kardon Rabco models, your video is really informative and answered most of my questions. By the way, my friend, Michael Bettinger (owner of the aforementioned SL-8E) has had a long career in the high-end audio field, most recently as VP of engineering at VPI. He has devoted much of his life (and his considerable talents) to the audio world. His preamp designs are some of the best ever made.
Thank you for this video! I am purchasing an ST8 today, and this has helped me to understand the functions, and what to examine for problems before making an offer.
Records often have holes slightly off-center , so linear trackers have to be able to track both toward the center and toward the edge . The distance between 2 adjacent grooves varies with loud low frequency hits , so a tonearm that moves at a constant speed inward is incorrect . Many Japanese DD LT units had LED's with optical sensors to detect divergence from tangency and arms that featured both vertical and horizontal pivots .
I had a Rabco ST4 when in college with an ADC XLM. It ran on heavy duty use for a few years before the nylon guide rollers developed flat spots...this was the Achilles heel of this design. Luckily, my roommate's Dad knew Henry Rabinow professionally and they lived in the same area of Maryland, so I took the table for Henry to repair. The next time that the inevitable occurred, I changed turntables. Years later I had an H-K ST7 with a Denon DL-103S...that was the best I'd ever had up to that point, in 1975. My understanding of the operation of these tables was that their rubber roller continuously "kept up" with stylus motion based on the squareness of the roller sitting on the rotating shaft...any wear factor causing that squareness to change caused the performance to suffer. so it was never a good long-term stable product. In contrast, my Well Tempered table, acquired in 1987 is still going strong.
Thanks for replying and that great information. Harman Kardon switched to an all metal roller with the ST-8. The ST-5 might also have the metal roller.
The main problem is that not all vinyls have the same groove distances, because it depends on the length of the album, so the linear movement has nothing to do with turntable speed.
Thank you for this. I owned an ST 7 in the mid-1970s. It was high maintenance for sure, but well worth it. This past Christmas I acquired a totally refurbished ST 8. I fitted it with a hideously expensive Audio-Technica cartridge. The ST 8 outperforms my Rega 6 and has become my go-to turntable. Your advice on the use of Dynamat to deaden some of the ST 8's frequencies will be taken.
@@audioexpo14 I experimented with several of my pre-amps. Using the Schiit Audio Freya+ in "passive" mode---straight line, no gain whatsoever---the noise from the ST-8 has disappeared as far as I can tell. Still, as soon as I can I will install the Dynamat just to make sure.
I disassembled some of my ST-8 and added dynamat to much of its interior. The turntable still had resonance and vibrations that could be heard at the quiet parts of music. Then I added a Mobile Pro Shop Turntable Acrylic Slipmat. The issue persisted. Then I added a light-weight record clamp to the acrylic mat. Problem resolved. I hear nothing but music through my Magnepan 3.3s and the ST-8.
I see many comments from others who have linear trackers - I have one too - - a Yamaha PX-2 with a PX-1 tonearm & tracking mechanism - I've modified it over the years and kept it current - - HP of Absolute Sound thought very highly of this linear tracker waaayyyy back in the day - although some say there's some drawbacks, I'll take a linear tracker any day, especially the engineering approach that Yamaha took back then - - I'm lucky enough to have an HW-40 too, the VPI anniversary model which of course is a pivot type tonearm turntable - it is superior to the PX-2, but it's a hell of a lot closer (fine by me) than I would have imagined given the massive price difference and the gap in time (I bought the PX-2 in the early or middle 80's) - - thanks for posting, excellent vid - I enjoyed the music too.
Amazing video. I always wanted a st-7. Very interesting table. Never knew how the mechanism functions. Looks very complex but simple at the same time. Prime 60-70s technology ;). Would be interesting to see you make a video on the sony biotracer line or maybe on something like a dual 701.
I love your information about this turntable and it's historically facts and the mechanical design and attention and operational details too! I have two old Bang and Olufsen turntables 5500 and 3300 which are tangential operating systems too and I love them except for the hard to find and ridiculous expensive priority cartridges for them
Hi sir very interesting video I must admit I’m surprised that linear tracking decks have not become more popular over the years considering the technology that is available today, yes there are some really high end examples but not so say in the rege p3 price range. Which happens to be my point of reference. The concept of linear tracking has long been a bowl of contention within the hifi world , but I for one can see many advantages to its use . Mainly in it replicating of how the record was cut in the first place . So maybe we will yet see a return to this format . Who knows for let’s face it the hifi market is always changing direction Best wishes and kind regards 😀👍👍👍
Had one of these back then and worked very well. Very easy to use and to live with. It's a very clean sounding table. A little on the leaner side but detailed.
Really lovely turntable I owned one for years after my father died but they also need to be maintained a good deal keep it as clean as possible mine in the end was not tracking good anymore and I sold it in the end to get something else but stil if the turntable is maintained and loved it will give you a lot of good music thanks for the video and yes they do rumble
I lucked into my ST6 in a second hand shop for 15$. Included a high end AT cart (at14sa) that had plenty of stylus life left. After the tracking wheel replacement and lots of fiddly dialing in it ran great for years. Sadly the motor bearings have become noisy and need replacement so I dug my Denon dp57L out of retirement until I refurb the motor. I had the same thought on the dynamat treatment and plan to do that to mine. They were built like pole barns....
Nice. They sure are quirky, but fun. The ST6 has an AC synchronous motor, right? If you have the time, Definitely try to share the process for refurbing the motor in the audiokarma.org turntable section. If you do that, come back here and leave a link to that thread in the comments!
Interesting turntable. I had a Yamaha PX-3 linear tracking table in the 80’s. Unfortunately, it was regrettably sold. Another one that got away were the Yamaha NS-1000M speakers. I greatly regret selling both.
Love your videos. I have a Beogram 4000 and a Revox B790 in my collection, but I would just love to get my hands on an ST-7 or ST-8 to add to my turntables. Yours are awesome.
i had a tangential turntable that put it to work on a radio station in the late 80´s but i have to say it was perfect and i tested a lot of them but because i have not said nothing about this brand who is good but for a limited number of years compared to other brands , SANYO i have to say that this turntable i refer to worked perfect for a lot of years, one could even choose the number of the track and it played ,the system was very interesting not that i´ve not seen better from other brands as other example the sharp optonica TT´s were also very nice while working, regards
In tropical Singapore the tyre of the arm guide wheel always got turned to goo. Replacing it was quite simple but one must find a rubber washer of the correct size and height.
First off, great video - very well done. Second, you may well have an 8 that was a prototype. I just realized watching again that your 8 has the aluminum sleeve on the left of the carriage (anodized black) - none of the other 8’s in videos or images or my personal experience has that… the ST 7 & 5 both had the sleeve (and the 5 added the rotating upper guide rod a la ST 8 as well). I know you mentioned getting that from Frank H - I believe that may have been an updated version that was never released.
So now to make things even more puzzling… the sticker on the back (@4:51) states st-7… but the 7 never had the rotating upper guide. I am assuming that ST7 sticker, from which you pointed out Frank’s name was the same TT.
So a few more things. But first regarding the st7 decal - i think Frank may have put that on since neither the successors - the 8 nor the 5 - have that decal - plus they were in the bottom not the back. - Does your ‘8’ have a muting circuit that mutes the signal when the arm is raised ? - On the st-8 the upper guide rod is turned by a belt under the aluminum cover to the left of the tonearm. The pulley wheel that drives the main tracking roller is also grooved for this belt - have you looked inside there? Curious if that wheel has that groove. - Does your unit have switchable voltages? - Do you know if yours has a dashpot or an airpot for lowering the tonearm? There’s a long history with these tables (and the Rabco assembly). A friend and i who are both fans of these tables often discuss such variances. Personally I own an 8 that i bought back in the late 70’s and now have the 5 & 7 to go with it. Btw - there are 2 known commercially available versions of the ST8 - differentiated by the name badge (left side or right) and the height of the chassis. Cheers, Tim
I had one mounted on my AR turntable in late 1970. Later I had the wheel type tonearm but don't remember Harman-Kardon nor recognize any of the shown models.
The luxman px101 is truly linear tracking. It uses a photovoltaic sensor. When the sensor senses the wrong amount of light, it moves the arm. When the sensor is adjusted property, the arm travels smoothly and continuously across the record. The issue is the cuing wears out and the arm drops abruptly.
@@audioexpo14 if I could get the arm to drop the stylus gently and pick up quickly at the end of the record, it would be playing records regularly. I am very sensitive to time arrival so the truly zero tracking error suits my ear. When the sensor is adjusted so that it travels smoothly, it is always a half tick behind. But that is easily overcome by rotating the cartridge just enough to offset the slight tonearm angle.
How does this mechanism cope with records with tightly or widely spaced grooves??! I don't get it. There's no standardized spacing of grooves...very strange. Anyone know?
I would guess that it is all about the speed the platter is spinning and how that speed is transferred to the carriage that holds the arm and cartridge/stylus movement. I don't think groove spacing is an issue, but I'm no mechanical engineer 😁
@@audioexpo14 it's a mystery to me. Some records (like compilation LPS) have very tightly packed grooves, other records like 12" singles use the entire same amount of space for just 7mins or so of audio. The arm needs to move at vastly different speeds to cope with both. (some 12" singles are 33rpm, so it's definitely not a 33 vs 45 issue).
Thank you so much for showing the bare bones aspect of the turntable. It has been very helpful in repairing mine. Do you have any footage of player at the end of its cycle when it lifts the needle and turns off the deck? I am having trouble understanding how that works and if I am missing a part. Thank you.
As you probably know, that lightweight arm likes a high compliance cartridge, and those Audio-Technicas fit that description, and sound great. Interesting that we have the same ones! Once my StylusTimer, or ears, tell me it's time for a new stylus I am going to give the Shibata-tipped ATN150Sa a try. Thanks for watching and commenting!
Very Informative Video Thank you for this!! Wondering what are the symptoms when the O Ring turns into Goo. Does the Tracking arm stop tracking right to left? Thank you
Hi Borsan, thanks for commenting. I gave it my best effort to try to answer this question in the comment that came in after yours. Here is a copy of that answer: This turntable's tonearm, and I would think most, if not all linear tracking tonearms, will not play reverse groove records. As far as the "wider grooves" question, it has come up a couple of times in the comments. I am not sure it would be any different than a pivoted tonearm. Ultimately, it is a stylus riding in a groove. As a simple example, let's take a .6 mil conical stylus. I don't think any stereo LP groove would be wider than this. In fact, the groove is tapered and gets narrower the deeper it goes (v-shaped groove). If the bottom of a groove was wider than the narrowest stylus this would be a problem for any tonearm, as the stylus would not be touching both sides of the groove, resulting in it bouncing around in the groove, or riding one side of the groove. If riding one side of the groove, then the left channel or right channel would be much lower in amplitude, or even close to zero. So, I think the question about wider grooves is really about the size of the stylus, not the type of tonearm, and no properly manufactured stereo LP would would have a groove width (at least deep in the groove) that is wider than the narrowest stylus width. Also, something to remember about the Harman Kardon RABCO arms is that the arm is not locked into linear position. In other words, there is some left-right play in the arm. A good example of this would be when the spindle hole in a record is not perfectly centered. It happens more than you think! When this happens, the arm has to be able ride that groove as it shifts left and right, easy with a pivoted arm, but also easy with a linear tracking arm since they all have play in them to deal with off-center records. Hopefully this helps answer your question, and I answered it correctly!
I did not understand from this how the HK arm follows the variable groove pitch employed on just about every modern LP? To accomodate bass cadenzas and high amplitudes, cutting lathes anticipate high cutting stylus excursions, and widen the groove spacing to avoid adjacent groove incursions. How does the HK arm mechanism follow this? It appears to be solidly coupled to turntable rotation, not groove position. I had a Technics linear tracking turntable many years ago. It sounded good, but had many errors in selecting tracks to play. It eventually expired, and not intending to continue to use it, I dismantled it. Yikes! It had several servo drives, lots of servo drive electronics, and lots of things to go wrong. Also, it had a fixed cartridge, not allowing replacement. I wonder if there are any of these still in service, today?
The arm may appear to be tightly coupled to the carriage that moves it, but there is a lot of left right play in the way the arm is connected to the carriage. This gives it the ability to handle variable groove pitch and records where the spindle hole is not perfectly centered. Hopefully that kind of answers your question? That's the extent of my knowledge :-)
And yes, there are many of those technics linear trackers still out there. I've had a couple over the years that I refurbished and sold or gave to family members. I actually have one right now that's a JCPenney MCS branded one. I actually show it in this video as an example how the technics approach differed from this Harman Kardon RABCO 'table.
Great video very informative, however the shapeways link is invalid for the tool that you mentioned, and the o-ring link also does not work from the audio karma website. Any ideas?
@@audioexpo14 the audio, links open, but the o-ring website seems to be dead. Thank you for the update on the stylus alignment tool. And thanks for getting right back to me I have two ST7s that I am rebuilding in the o-ring was a pain in the ass. But I have figured out a very easy way to get the wheel out to put a new one on. But I am looking for the flat tire o ring
How does it deal with records that has wider grooves, like Telarc's pressing och Tchaikovskys 1812, or even worse, the Tacet´'s pressing of Bolero that has a reverse groove (you start at the label and the groove moves outward)?
This turntable's tonearm, and I would think most, if not all linear tracking tonearms, will not play reverse groove records. As far as the "wider grooves" question, it has come up a couple of times in the comments. I am not sure it would be any different than a pivoted tonearm. Ultimately, it is a stylus riding in a groove. As a simple example, let's take a .6 mil conical stylus. I don't think any stereo LP groove would be wider than this. In fact, the groove is tapered and gets narrower the deeper it goes (v-shaped groove). If the bottom of a groove was wider than the narrowest stylus this would be a problem for any tonearm, as the stylus would not be touching both sides of the groove, resulting in it bouncing around in the groove, or riding one side of the groove. If riding one side of the groove, then the left channel or right channel would be much lower in amplitude, or even close to zero. So, I think the question about wider grooves is really about the size of the stylus, not the type of tonearm, and no properly manufactured stereo LP would would have a groove width (at least deep in the groove) that is wider than the narrowest stylus width. Also, something to remember about the Harman Kardon RABCO arms is that the arm is not locked into linear position. In other words, there is some left-right play in the arm. A good example of this would be when the spindle hole in a record is not perfectly centered. It happens more than you think! When this happens, the arm has to be able ride that groove as it shifts left and right, easy with a pivoted arm, but also easy with a linear tracking arm since they all have play in them to deal with off-center records. Hopefully this helps answer your question, and I answered it correctly!
@@audioexpo14 My airtangent has no problems with reverse grooves. But it's movement is completely passive, being an airbearing arm. Never owned a palyer with active movement. The sony style tri-tracer I believe has movement by sensor. It could possibly work with reverse groove, it would be interesting to see. I am searching for one for my Vintage Sony ES stereo I have in my third listening room... :)
Wow, had no idea a tangent arm could be passive. The engineering must be amazing. I checked out the Airtangent website, and they are way out of my price range! My only experience with linear tracking is with these HK RABCOs and Technics style linears from the 80's. Always so much more to learn. Thanks for the info.
The tonearm on the HK RABCO 'tables is very light and, at least in theory, works better with a high compliance (low vertical tracking force spec) cartridge. That being said, you never know exactly how any cartridge will sound with a given tonearm without giving it a try. There are calculations like resonance and such, but experimenting is more fun!
@@audioexpo14allegedly the one I am going to see is new old stock, never used. Sounds promising. It's missing the shims for the headshell mounting. Is that critical ?
@@anthonypopovic7626 That sounds awesome! The shims help get the the stylus angle right. Any shim pack with a variety of sizes for a 1/2 inch cartridge mount will work. Search for '1/2" cartridge mount shims' and you should be able to find some. You can also experiment making your own with playing cards, etc.
Great video! Just got my St-8 a week ago,very nice shape but the power switch has a little problem to stay on unless I hold it to the right , otherwise it would shut off!,, any chance you can give me some advice what I need to do ( take it apart and clean??) I never had taken a turntable apart before 😂, everything else is there ( from the original owner) .thanks in advance
Definitely take apart that power switch and clean the contacts. I had the same problem with an ST-7. The power contacts inside the switch were dirty and it wouldn't stay on. I disassembled the switch clean the contacts and reassembled it works perfectly. I think the ST8 is a slightly different switch so hopefully you can still take it apart like you can with the ST7.
Okay, my first attempt to work on the St-8 , I removed the dust cover, removed the lock key rubber washer right above the platter but from DO i need to remove anything else to remove the platter from the deck? It seemed to stuck there !!!! I tried to wiggle,spinning but I couldn’t remove the platter from the deck so I could get inside to clean out the power switch. Any tips guys would be appreciate 😢
@@kenp14 any advice how to get inside the ST-8 so I can clean the power switch? I still have a hard time to remove the platter from the deck . I never worked on turntables before so I don’t want to mess this beautiful tt. Thanks 😅
I have a working ST7 and if set up properly (Big if!!), they sound great.People with no patience and no technical knowledge should definitely look elsewhere.
I once owned a St 7 back in 1977 and more recently a St 8 I bought 5 years ago on Ebay and in both cases the speed would run slow when cold then faster when warmed up so before I played a record I had to run the motor for a couple of minutes first. It was also a struggle to keep the tonearm tracking straight. These were the worst turntables I ever owned.
My ST-8 is used daily, and I haven't had to touch the tracking adjustment in years, it always tracks straight. It is possible you got a bad one, or one that was worn out. I bought mine from one of the original engineers from Harman Kardon, so maybe he tweaked it to somehow run more reliably? :) Speed can definitely be problematic with these turntables. I replaced the fine and coarse speed pots on my STs, and did some other things that I don't recall, and speed reliability has been much improved. When my ST-8 is dialed in at the start of an LP side, it can drift to a little slow by the end of the side, but not always. Ghost in the machine!
In practice the Rabco performed well only if you took the time and effort to set it up properly. Problem was it broke down easily requiring frequent maintenance and repair... plus it was extremely difficult to work on especially the arm which was such a bitch it caused many owners to give up on it. While the Rabco was capable of sounding good if maintained properly, it never performed well enough to justify the hell it put it's owners through.
Very informative and great story on how you acquired the turntable. I am always amazed how these early pioneers solved problems and the solutions they created to do so. So cool to keep that spirit alive.
Thanks for the info on these fine tables. I bought an ST 7 last week on a gamble. It needed work, but hadn't been messed with. Grimy with a couple of small scratches. Missing the carriage Rabco cover and dust cover. Needed new bulbs. It came with a really nice owners manual and service manual which is required reading. New bulbs are here and the missing cover and alignment gauge and new belts are on their way. I replaced the gooey tire with a #31 plumbing o-ring, but it's slightly narrow. Oh well, it now tracks on the tracking roller well. Cleaned and lubed the lift mechanisms and it seems to stop and raise well. This gamble might pay off! We'll see when all the parts get here.
Many years ago in the 1970s, a friend of mine acquired a used Rabco SL-8E tonearm which he proceeded to completely modify in an attempt to get it to work properly. About the same time, I bought a used Rabco ST-4 (which was shown in your video). I had no issues with it. Interestingly, my then-roommate referred to it as the “Ronco Bottle Cutter” a bizarre late-night TV gadget that could turn beer bottles into glasses. The comparison is strangely apt. I have always wondered about the Harmon Kardon Rabco models, your video is really informative and answered most of my questions.
By the way, my friend, Michael Bettinger (owner of the aforementioned SL-8E) has had a long career in the high-end audio field, most recently as VP of engineering at VPI. He has devoted much of his life (and his considerable talents) to the audio world. His preamp designs are some of the best ever made.
Thanks for sharing that interesting info. I have always wanted to try a VPI turntable. Very cool stuff.
I bought an St-8 in 78 or 79 and of all the things I have had this i still have (and a pair of JBL 4311wx. Nice video.
Thank you for this video! I am purchasing an ST8 today, and this has helped me to understand the functions, and what to examine for problems before making an offer.
Records often have holes slightly off-center , so linear trackers have to be able to track both toward the center and toward the edge . The distance between 2 adjacent grooves varies with loud low frequency hits , so a tonearm that moves at a constant speed inward is incorrect . Many Japanese DD LT units had LED's with optical sensors to detect divergence from tangency and arms that featured both vertical and horizontal pivots .
I had a Rabco ST4 when in college with an ADC XLM. It ran on heavy duty use for a few years before the nylon guide rollers developed flat spots...this was the Achilles heel of this design. Luckily, my roommate's Dad knew Henry Rabinow professionally and they lived in the same area of Maryland, so I took the table for Henry to repair. The next time that the inevitable occurred, I changed turntables. Years later I had an H-K ST7 with a Denon DL-103S...that was the best I'd ever had up to that point, in 1975.
My understanding of the operation of these tables was that their rubber roller continuously "kept up" with stylus motion based on the squareness of the roller sitting on the rotating shaft...any wear factor causing that squareness to change caused the performance to suffer. so it was never a good long-term stable product. In contrast, my Well Tempered table, acquired in 1987 is still going strong.
Thanks for replying and that great information. Harman Kardon switched to an all metal roller with the ST-8. The ST-5 might also have the metal roller.
I'm glad that on the st8 the aluminum edges have been rounded off. Many a slipped LP got lacerated by the sharp corners of the st7.
I have a tangential Bang & Olufsen turntable...always been a gem to this day
Good quality video, clear audio. Interesting background stories. Enjoyed You Are Not Alone; cool blue vinyl.
The main problem is that not all vinyls have the same groove distances, because it depends on the length of the album, so the linear movement has nothing to do with turntable speed.
Thank you for this. I owned an ST 7 in the mid-1970s. It was high maintenance for sure, but well worth it. This past Christmas I acquired a totally refurbished ST 8. I fitted it with a hideously expensive Audio-Technica cartridge. The ST 8 outperforms my Rega 6 and has become my go-to turntable. Your advice on the use of Dynamat to deaden some of the ST 8's frequencies will be taken.
Thanks! It's hard to know for sure, but I do think the dynamat helped significantly.
@@audioexpo14 I experimented with several of my pre-amps. Using the Schiit Audio Freya+ in "passive" mode---straight line, no gain whatsoever---the noise from the ST-8 has disappeared as far as I can tell. Still, as soon as I can I will install the Dynamat just to make sure.
I disassembled some of my ST-8 and added dynamat to much of its interior. The turntable still had resonance and vibrations that could be heard at the quiet parts of music. Then I added a Mobile Pro Shop Turntable Acrylic Slipmat. The issue persisted. Then I added a light-weight record clamp to the acrylic mat. Problem resolved. I hear nothing but music through my Magnepan 3.3s and the ST-8.
I see many comments from others who have linear trackers - I have one too - - a Yamaha PX-2 with a PX-1 tonearm & tracking mechanism - I've modified it over the years and kept it current - - HP of Absolute Sound thought very highly of this linear tracker waaayyyy back in the day - although some say there's some drawbacks, I'll take a linear tracker any day, especially the engineering approach that Yamaha took back then - - I'm lucky enough to have an HW-40 too, the VPI anniversary model which of course is a pivot type tonearm turntable - it is superior to the PX-2, but it's a hell of a lot closer (fine by me) than I would have imagined given the massive price difference and the gap in time (I bought the PX-2 in the early or middle 80's) - - thanks for posting, excellent vid - I enjoyed the music too.
Thanks for commenting. I'd love to own one of those Yamahas someday. Hopefully a new video coming soon. It's a lot of work!
Amazing video. I always wanted a st-7. Very interesting table. Never knew how the mechanism functions. Looks very complex but simple at the same time. Prime 60-70s technology ;). Would be interesting to see you make a video on the sony biotracer line or maybe on something like a dual 701.
Totally interesting video, I have one of those Technics Linar Tracking TT's and love it.
I love your information about this turntable and it's historically facts and the mechanical design and attention and operational details too! I have two old Bang and Olufsen turntables 5500 and 3300 which are tangential operating systems too and I love them except for the hard to find and ridiculous expensive priority cartridges for them
Hi sir very interesting video I must admit I’m surprised that linear tracking decks have not become more popular over the years considering the technology that is available today, yes there are some really high end examples but not so say in the rege p3 price range. Which happens to be my point of reference.
The concept of linear tracking has long been a bowl of contention within the hifi world , but I for one can see many advantages to its use . Mainly in it replicating of how the record was cut in the first place . So maybe we will yet see a return to this format . Who knows for let’s face it the hifi market is always changing direction Best wishes and kind regards 😀👍👍👍
Love the mechanics behind it!
My father had a REVOX tangential arm turntable in the late 70s.
Had one of these back then and worked very well. Very easy to use and to live with. It's a very clean sounding table. A little on the leaner side but detailed.
The leaner side? Really? LOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOL Dang, you people crack me up.
That was a very well explained detailed video, makes me want to look into finding one of those turntables.
Really lovely turntable I owned one for years after my father died but they also need to be maintained a good deal keep it as clean as possible mine in the end was not tracking good anymore and I sold it in the end to get something else but stil if the turntable is maintained and loved it will give you a lot of good music thanks for the video and yes they do rumble
I lucked into my ST6 in a second hand shop for 15$. Included a high end AT cart (at14sa) that had plenty of stylus life left. After the tracking wheel replacement and lots of fiddly dialing in it ran great for years. Sadly the motor bearings have become noisy and need replacement so I dug my Denon dp57L out of retirement until I refurb the motor. I had the same thought on the dynamat treatment and plan to do that to mine. They were built like pole barns....
Nice. They sure are quirky, but fun. The ST6 has an AC synchronous motor, right? If you have the time, Definitely try to share the process for refurbing the motor in the audiokarma.org turntable section. If you do that, come back here and leave a link to that thread in the comments!
Interesting turntable. I had a Yamaha PX-3 linear tracking table in the 80’s. Unfortunately, it was regrettably sold. Another one that got away were the Yamaha NS-1000M speakers. I greatly regret selling both.
Those Yamahas are nice, always wanted one of those. Thanks for watching and commenting!
Love your videos. I have a Beogram 4000 and a Revox B790 in my collection, but I would just love to get my hands on an ST-7 or ST-8 to add to my turntables. Yours are awesome.
Thanks! More videos coming soon-ish. I'm new to this, and it is a lot of work!
Very interesting video. Didn't know harman/kardon ever made a turntable.
They even sold a wooden body model back in the 80's that were displaced against Dual at Circuit City .
i had a tangential turntable that put it to work on a radio station in the late 80´s but i have to say it was perfect and i tested a lot of them but because i have not said nothing about this brand who is good but for a limited number of years compared to other brands , SANYO i have to say that this turntable i refer to worked perfect for a lot of years, one could even choose the number of the track and it played ,the system was very interesting not that i´ve not seen better from other brands as other example the sharp optonica TT´s were also very nice while working, regards
In tropical Singapore the tyre of the arm guide wheel always got turned to goo. Replacing it was quite simple but one must find a rubber washer of the correct size and height.
Yes, I think that rubber wheel turned to goo everywhere. I show a picture of one that had turned to goo in the video.
First off, great video - very well done.
Second, you may well have an 8 that was a prototype. I just realized watching again that your 8 has the aluminum sleeve on the left of the carriage (anodized black) - none of the other 8’s in videos or images or my personal experience has that… the ST 7 & 5 both had the sleeve (and the 5 added the rotating upper guide rod a la ST 8 as well).
I know you mentioned getting that from Frank H - I believe that may have been an updated version that was never released.
Wow, thanks for that info! I didn't even realize that. I will have to take a closer look.
So now to make things even more puzzling… the sticker on the back (@4:51) states st-7… but the 7 never had the rotating upper guide. I am assuming that ST7 sticker, from which you pointed out Frank’s name was the same TT.
So a few more things. But first regarding the st7 decal - i think Frank may have put that on since neither the successors - the 8 nor the 5 - have that decal - plus they were in the bottom not the back.
- Does your ‘8’ have a muting circuit that mutes the signal when the arm is raised ?
- On the st-8 the upper guide rod is turned by a belt under the aluminum cover to the left of the tonearm. The pulley wheel that drives the main tracking roller is also grooved for this belt - have you looked inside there? Curious if that wheel has that groove.
- Does your unit have switchable voltages?
- Do you know if yours has a dashpot or an airpot for lowering the tonearm?
There’s a long history with these tables (and the Rabco assembly). A friend and i who are both fans of these tables often discuss such variances.
Personally I own an 8 that i bought back in the late 70’s and now have the 5 & 7 to go with it. Btw - there are 2 known commercially available versions of the ST8 - differentiated by the name badge (left side or right) and the height of the chassis.
Cheers, Tim
I had one mounted on my AR turntable in late 1970. Later I had the wheel type tonearm but don't remember Harman-Kardon nor recognize any of the shown models.
Excellent video, Thank You! 👍🏻
The luxman px101 is truly linear tracking. It uses a photovoltaic sensor. When the sensor senses the wrong amount of light, it moves the arm. When the sensor is adjusted property, the arm travels smoothly and continuously across the record. The issue is the cuing wears out and the arm drops abruptly.
Thanks for that info. I would definitely like to check out that Luxman!
@@audioexpo14 if I could get the arm to drop the stylus gently and pick up quickly at the end of the record, it would be playing records regularly. I am very sensitive to time arrival so the truly zero tracking error suits my ear. When the sensor is adjusted so that it travels smoothly, it is always a half tick behind. But that is easily overcome by rotating the cartridge just enough to offset the slight tonearm angle.
How does this mechanism cope with records with tightly or widely spaced grooves??! I don't get it. There's no standardized spacing of grooves...very strange. Anyone know?
I would guess that it is all about the speed the platter is spinning and how that speed is transferred to the carriage that holds the arm and cartridge/stylus movement. I don't think groove spacing is an issue, but I'm no mechanical engineer 😁
@@audioexpo14 it's a mystery to me. Some records (like compilation LPS) have very tightly packed grooves, other records like 12" singles use the entire same amount of space for just 7mins or so of audio. The arm needs to move at vastly different speeds to cope with both. (some 12" singles are 33rpm, so it's definitely not a 33 vs 45 issue).
I'm picking up an ST7 tomorrow morning! Silver and probably needs a service, but not sure.
Thank you so much for showing the bare bones aspect of the turntable. It has been very helpful in repairing mine. Do you have any footage of player at the end of its cycle when it lifts the needle and turns off the deck? I am having trouble understanding how that works and if I am missing a part. Thank you.
Great video!
Thank you :)
I've got an ST7 with the AT 440ml also. I also have an AT155lc. Interesting that we both have the same cartridges.
As you probably know, that lightweight arm likes a high compliance cartridge, and those Audio-Technicas fit that description, and sound great. Interesting that we have the same ones! Once my StylusTimer, or ears, tell me it's time for a new stylus I am going to give the Shibata-tipped ATN150Sa a try. Thanks for watching and commenting!
@@audioexpo14 My ST 8 is fitted with an Audio-Technica OC9XSH. It has a Shibata stylus as well. Magnificent performance.
Very informative
Thank you.
Hi , I just got the ST-7 turntable .... your video is very detailed and informative.n excellent ... but now looking for suitable cartridges ....
You definitely want something that is a lightweight tracker since the tonearm is very light.
Very Informative Video Thank you for this!! Wondering what are the symptoms when the O Ring turns into Goo. Does the Tracking arm stop tracking right to left? Thank you
Yes, it won't track properly, will get stuck.
Thank you so much for your prompt response:) cheers
I have records that have unequal spacing between tracks (it depends on what dynamic range is played) how this is mitigated?
Hi Borsan, thanks for commenting. I gave it my best effort to try to answer this question in the comment that came in after yours. Here is a copy of that answer:
This turntable's tonearm, and I would think most, if not all linear tracking tonearms, will not play reverse groove records. As far as the "wider grooves" question, it has come up a couple of times in the comments. I am not sure it would be any different than a pivoted tonearm. Ultimately, it is a stylus riding in a groove. As a simple example, let's take a .6 mil conical stylus. I don't think any stereo LP groove would be wider than this. In fact, the groove is tapered and gets narrower the deeper it goes (v-shaped groove). If the bottom of a groove was wider than the narrowest stylus this would be a problem for any tonearm, as the stylus would not be touching both sides of the groove, resulting in it bouncing around in the groove, or riding one side of the groove. If riding one side of the groove, then the left channel or right channel would be much lower in amplitude, or even close to zero. So, I think the question about wider grooves is really about the size of the stylus, not the type of tonearm, and no properly manufactured stereo LP would would have a groove width (at least deep in the groove) that is wider than the narrowest stylus width.
Also, something to remember about the Harman Kardon RABCO arms is that the arm is not locked into linear position. In other words, there is some left-right play in the arm. A good example of this would be when the spindle hole in a record is not perfectly centered. It happens more than you think! When this happens, the arm has to be able ride that groove as it shifts left and right, easy with a pivoted arm, but also easy with a linear tracking arm since they all have play in them to deal with off-center records. Hopefully this helps answer your question, and I answered it correctly!
I did not understand from this how the HK arm follows the variable groove pitch employed on just about every modern LP? To accomodate bass cadenzas and high amplitudes, cutting lathes anticipate high cutting stylus excursions, and widen the groove spacing to avoid adjacent groove incursions. How does the HK arm mechanism follow this? It appears to be solidly coupled to turntable rotation, not groove position.
I had a Technics linear tracking turntable many years ago. It sounded good, but had many errors in selecting tracks to play. It eventually expired, and not intending to continue to use it, I dismantled it. Yikes! It had several servo drives, lots of servo drive electronics, and lots of things to go wrong. Also, it had a fixed cartridge, not allowing replacement. I wonder if there are any of these still in service, today?
The arm may appear to be tightly coupled to the carriage that moves it, but there is a lot of left right play in the way the arm is connected to the carriage. This gives it the ability to handle variable groove pitch and records where the spindle hole is not perfectly centered. Hopefully that kind of answers your question? That's the extent of my knowledge :-)
And yes, there are many of those technics linear trackers still out there. I've had a couple over the years that I refurbished and sold or gave to family members. I actually have one right now that's a JCPenney MCS branded one. I actually show it in this video as an example how the technics approach differed from this Harman Kardon RABCO 'table.
Great video very informative, however the shapeways link is invalid for the tool that you mentioned, and the o-ring link also does not work from the audio karma website. Any ideas?
Updated link to the alignment tool.
www.shapeways.com/product/VS9UDV8JE/hk-alignment-tool-v4?optionId=305025373&li=marketplace
The audio karma links are working for me. Maybe you need to have an account?
@@audioexpo14 the audio, links open, but the o-ring website seems to be dead. Thank you for the update on the stylus alignment tool.
And thanks for getting right back to me I have two ST7s that I am rebuilding in the o-ring was a pain in the ass. But I have figured out a very easy way to get the wheel out to put a new one on. But I am looking for the flat tire o ring
How does it deal with records that has wider grooves, like Telarc's pressing och Tchaikovskys 1812, or even worse, the Tacet´'s pressing of Bolero that has a reverse groove (you start at the label and the groove moves outward)?
This turntable's tonearm, and I would think most, if not all linear tracking tonearms, will not play reverse groove records. As far as the "wider grooves" question, it has come up a couple of times in the comments. I am not sure it would be any different than a pivoted tonearm. Ultimately, it is a stylus riding in a groove. As a simple example, let's take a .6 mil conical stylus. I don't think any stereo LP groove would be wider than this. In fact, the groove is tapered and gets narrower the deeper it goes (v-shaped groove). If the bottom of a groove was wider than the narrowest stylus this would be a problem for any tonearm, as the stylus would not be touching both sides of the groove, resulting in it bouncing around in the groove, or riding one side of the groove. If riding one side of the groove, then the left channel or right channel would be much lower in amplitude, or even close to zero. So, I think the question about wider grooves is really about the size of the stylus, not the type of tonearm, and no properly manufactured stereo LP would would have a groove width (at least deep in the groove) that is wider than the narrowest stylus width.
Also, something to remember about the Harman Kardon RABCO arms is that the arm is not locked into linear position. In other words, there is some left-right play in the arm. A good example of this would be when the spindle hole in a record is not perfectly centered. It happens more than you think! When this happens, the arm has to be able ride that groove as it shifts left and right, easy with a pivoted arm, but also easy with a linear tracking arm since they all have play in them to deal with off-center records. Hopefully this helps answer your question, and I answered it correctly!
@@audioexpo14 My airtangent has no problems with reverse grooves. But it's movement is completely passive, being an airbearing arm. Never owned a palyer with active movement. The sony style tri-tracer I believe has movement by sensor. It could possibly work with reverse groove, it would be interesting to see. I am searching for one for my Vintage Sony ES stereo I have in my third listening room... :)
Wow, had no idea a tangent arm could be passive. The engineering must be amazing. I checked out the Airtangent website, and they are way out of my price range! My only experience with linear tracking is with these HK RABCOs and Technics style linears from the 80's. Always so much more to learn. Thanks for the info.
I have a technics SL-Q2 with a medium compliance MC cartridge the audio technica AT-F7. Would this table be a better mate with my MC cartridge?
The tonearm on the HK RABCO 'tables is very light and, at least in theory, works better with a high compliance (low vertical tracking force spec) cartridge. That being said, you never know exactly how any cartridge will sound with a given tonearm without giving it a try. There are calculations like resonance and such, but experimenting is more fun!
@@audioexpo14allegedly the one I am going to see is new old stock, never used. Sounds promising.
It's missing the shims for the headshell mounting. Is that critical ?
@@anthonypopovic7626 That sounds awesome! The shims help get the the stylus angle right. Any shim pack with a variety of sizes for a 1/2 inch cartridge mount will work. Search for '1/2" cartridge mount shims' and you should be able to find some. You can also experiment making your own with playing cards, etc.
Great video! Just got my St-8 a week ago,very nice shape but the power switch has a little problem to stay on unless I hold it to the right , otherwise it would shut off!,, any chance you can give me some advice what I need to do ( take it apart and clean??) I never had taken a turntable apart before 😂, everything else is there ( from the original owner) .thanks in advance
Definitely take apart that power switch and clean the contacts. I had the same problem with an ST-7. The power contacts inside the switch were dirty and it wouldn't stay on. I disassembled the switch clean the contacts and reassembled it works perfectly. I think the ST8 is a slightly different switch so hopefully you can still take it apart like you can with the ST7.
@@kenp14 thanks so much my friend for the quick response.
I agree with Ken, switch needs to be disassembled and cleaned. Good luck!
Okay, my first attempt to work on the St-8 , I removed the dust cover, removed the lock key rubber washer right above the platter but from DO i need to remove anything else to remove the platter from the deck? It seemed to stuck there !!!! I tried to wiggle,spinning but I couldn’t remove the platter from the deck so I could get inside to clean out the power switch. Any tips guys would be appreciate 😢
@@kenp14 any advice how to get inside the ST-8 so I can clean the power switch? I still have a hard time to remove the platter from the deck . I never worked on turntables before so I don’t want to mess this beautiful tt. Thanks 😅
Had a Sony PSX800.
I still regret having sold mine............
Try the PL-L1000 for linear perfection. This one here is not very good.
I have a working ST7 and if set up properly (Big if!!), they sound great.People with no patience and no technical knowledge should definitely look elsewhere.
I updated the link to the alignment tool, and here it is
www.shapeways.com/product/VS9UDV8JE/hk-alignment-tool-v4?optionId=305025373&li=marketplace
I once owned a St 7 back in 1977 and more recently a St 8 I bought 5 years ago on Ebay and in both cases the speed would run slow when cold then faster when warmed up so before I played a record I had to run the motor for a couple of minutes first. It was also a struggle to keep the tonearm tracking straight. These were the worst turntables I ever owned.
My ST-8 is used daily, and I haven't had to touch the tracking adjustment in years, it always tracks straight. It is possible you got a bad one, or one that was worn out. I bought mine from one of the original engineers from Harman Kardon, so maybe he tweaked it to somehow run more reliably? :) Speed can definitely be problematic with these turntables. I replaced the fine and coarse speed pots on my STs, and did some other things that I don't recall, and speed reliability has been much improved. When my ST-8 is dialed in at the start of an LP side, it can drift to a little slow by the end of the side, but not always. Ghost in the machine!
In practice the Rabco performed well only if you took the time and effort to set it up properly. Problem was it broke down easily requiring frequent maintenance and repair... plus it was extremely difficult to work on especially the arm which was such a bitch it caused many owners to give up on it. While the Rabco was capable of sounding good if maintained properly, it never performed well enough to justify the hell it put it's owners through.
Nice fingernail
Harmon Kardon never made a really good turntable.
Fake drums! Sad. Fake vocals! Very sad.😥😥😥😥😥😥😥😎😎
Fantastic video! Thanks so much!