Harman Kardon RABCO ST Turntables

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.

Good quality video, clear audio. Interesting background stories. Enjoyed You Are Not Alone; cool blue vinyl.

That was a very well explained detailed video, makes me want to look into finding one of those turntables.

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.

Love the mechanics behind it!

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.

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.

Totally interesting video, I have one of those Technics Linar Tracking TT's and love it.

I have a tangential Bang & Olufsen turntable...always been a gem to this day

Fantastic video! Thanks so much!

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

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.

Excellent video, Thank You! 👍🏻

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.

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.

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.

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 .

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 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.

Very informative