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a couple of turntable restorations

Posted: Tue Sep 12, 2017 4:25 pm
by Vinyl-ant
Thought you guys might like to see a couple of turntables I'm restoring at the moment.
a JBE series 3 slate DD and a JVC QL-Y5F.
The JVC is complete and the JBE is ongoing.
The JVC before

ImageDSC_0631 by anthony cresswell, on Flickr

And after, with a lot of graft inbetween

ImageRestoration complete by anthony cresswell, on Flickr

I picked it up last year for not much money as it was in a state, no lid, platter mat, headshell or counterweight. I have sourced a proper JVC headshell for it and in the absence of a correct counterweight have subbed a technics sl1200 one which is the same weight and stub diameter. Its a lovely deck, ive had 3 of them, and this one is the nicest now its been restored. It was never going to be restored back to standard as the plinth and trim were too far gone, but i think it looks great in oak and black.

The JBE is ongoing. It got smashed up by a courier, losing the lid and legs, and having the psu case smashed. The motor and psu have been stripped and rebuilt by me previously, although i will be giving the psu the once over again as there were one or two suspect components last time i looked at it that i didnt replace at the time. And the original owner abused it by butchering the arm cutout.

The JBE this morning

ImageJbe series 3 by anthony cresswell, on Flickr

and now, after using a diamond holesaw to sort out the arm cutout, stripping and rebuilding, and refinishing the plinth

ImageJbe series 3 restoration by anthony cresswell, on Flickr

Next i will need to turn an arm board to fit the new hole and make a new black acrylic cover for the smashed in psu. The cover is badly cracked on the top from when the courier smashed it, The 45rpm speed adjuster pot had to be replaced when i originally rebuilt the psu back to working condition and the impact had punched that control through the perspex. They made a right mess of it.
to be continued.
cheers ant

Re: a couple of turntable restorations

Posted: Tue Sep 12, 2017 6:38 pm
by antonio66
The JVC looks amazing Ant, good look with the JBE.

Re: a couple of turntable restorations

Posted: Tue Sep 12, 2017 9:01 pm
by guydarryl
Quality work - JVC looks lovely.

I remember liking the JBE look many years ago (70's or later?) never heard one though - are they good?

Re: a couple of turntable restorations

Posted: Tue Sep 12, 2017 9:58 pm
by Vinyl-ant
The jbe was produced between 77 and 81-82, this one is a 78 model. Another firm that was hustled out of business by the flat earth movement :roll:

They are very good indeed imo, were ahead of the game at the time. A British design using a proven matsushita motor, and simple electronics. Theres a website dedicated to the history of them.They are fairly bulletproof if looked after, the psu is pretty simple, if it goes another would have to be built for it though as the regs are difficult to find nos and have been superceded 10 times over. There are no ic's in it though as there are in the jvc, so a new psu wouldnt be difficult to make. The motor is fairly easy to get hold of too as it was a cots buy for jbe. No point them reinventing the wheel when it was all available.
It also looks very cool when spinning.....
Cheers ant

Re: a couple of turntable restorations

Posted: Tue Sep 12, 2017 11:00 pm
by CN211276
I seem to recall theJBE out performing the LP12 at a demonstration. Following this Popular HiFI obtained one for a comparison and guess what came out on top. I can remember Chris Frankland giving it a pasting.

Re: a couple of turntable restorations

Posted: Wed Sep 13, 2017 10:11 am
by Classicrock
I thought the pad platter was the main problem regards it producing top sound. Mitchell had the sense to drop the Transcriptors style platter for a solid one. First Rega deck had a similar arrangement. They certainly looked more expensive than the Lp12 and I think they actually were at the time. Also that motor was not a quartz locked type and used in fairly inexpensive Japanese DD turntables. I think in this case Ivor wasn't entirely to blame for their failure. Radfords in Bristol sold them alongside Linn, STD 305 and Thorens but I remember the salesman wasn't keen on it but demoed the STD and Thorens 160s for me. Bought the later (1980).

Re: a couple of turntable restorations

Posted: Wed Sep 13, 2017 11:10 am
by Vinyl-ant
Quartzlock can be applied to pretty much any motor as it is done on the motor controller board, there isnt any physical difference in the motor.
The quartzlock provides a reference for the ic's on the board to compare with what the motor is actually doing.
Sensing what the motor is really doing can be done in several different ways, Sony and pioneer used a system where a magnetic tape head 'read' a ferrous layer sprayed onto the inside of the platter to provide the feedback that was compared against the quartz oscillator reference, the servo loop then adjusted the voltage accordingly.
Having cracked the motor apart on this one, imo its a really high quality. Having been inside the motors of all types of decks, i have to say that there arent many that are of similar quality to the ones the Japanese were producing at the time. Its identical to the one in the trio kd500 other than that motor has a segmented ferrous disc attached to the top of the rotor that was read by a sensor on the kd500 plinth to provide the feedback loop that this one doesnt have.
Re the platter being a possible limiting factor, interestingly the cast alloy solid platter on the jvc fits the jbe motor spindle perfectly, so I could actually see if a solid platter makes a difference
Cheees ant

Re: a couple of turntable restorations

Posted: Wed Sep 13, 2017 11:38 am
by Vinyl-ant
Just had a look at the psu for it to refresh my memory and it is as rudimentary as it gets.
No feedback loop, and a single bfy51 as a current amplifier. Those who say it 'servo hunted' didnt know what was going on inside....

Re: a couple of turntable restorations

Posted: Wed Sep 13, 2017 11:58 am
by Geoff.R.G
Vinyl-ant wrote: Wed Sep 13, 2017 11:38 am Those who say it 'servo hunted' didn't know what was going on inside....
Now why doesn't that surprise me?

Re: a couple of turntable restorations

Posted: Wed Sep 13, 2017 12:56 pm
by Classicrock
Vinyl-ant wrote: Wed Sep 13, 2017 11:38 am Just had a look at the psu for it to refresh my memory and it is as rudimentary as it gets.
No feedback loop, and a single bfy51 as a current amplifier. Those who say it 'servo hunted' didnt know what was going on inside....
Looks like JBE did a lot of cost cutting or just didn't have enough electronics knowledge. Scope for improvement here. As I thought a bit basic under the skin for the asking price at the time. What's the bearing like?