just an update on the HITACHI SDT-7785. The replacement stylus I ordered has arrived,
Probably about as far away as you can get from a genuine AT replacement stylus!! Regardless, I have installed it onto the second HITACHI branded AT12 cartridge, guess what? Perfect fit, happy that my little bit of research paid off, regarding the fact the cartridges are both rebranded Audio Technica ones. Listened to my current go to Dave Brubeck quartet album, sounds fine to my untrained ears.
I now have 3 complete headshell/cartridge/stylus set ups Non of which were/are expensive in any way, shape or form the silver one is an eBay special, bought complete for under £20. That’s right, under £20! Probably made by (insert your own Chinese eBay resellers name here) no offence intended I’ve also established that the second HITACHI/AUDIO TECHNICA cartridge works fine
Budget though these are, I’m enjoying listening to the vinyl I have, on inexpensive equipment. I say inexpensive, yes but back in the day the HITACHI was not a cheap system and neither were the LEAK 2060 speakers. They are nowadays though, which is nice for folk like me that just want to have an interest that doesn’t cost a lot! My son started of with an ION USB turntable, followed by a CROSSLEY suitcase type one. My set up sounds immense in comparison, which I suppose it should do but I’m very happy with it. He’s using one of the mini 22 AIWA stacks and an AIWA turntable which also sounds quite nice through a pair of HITACHI bookshelf speakers that the seller of the music centre threw in with it. WIN, WIN.
Barrie
EDIT:
Here it is, the cartridge and new stylus fitted to the tonearm, ready to go!
One for the experts here. I purchased a 5 pin 180* male to 3.5mm female Jack adapter to connect my Bluetooth receiver to the music centre. Did that but now realise that the output to the speakers only works on the right channel. If I adjust the balance to the left, all goes quiet. Also confirmed by the left channel record level VU meter not being responsive. Into the service manual, confirmed pins 1,4 and 2 for input and the same plug utilises pins 3 and 5 for output. I believe whilst not 100% standard, the majority of these plugs/sockets utilised this wiring convention. One of the AIWA component systems uses the same plugs to connect the cassette deck to the preamp so brought that out, connected up, put a tape in and listened to it. I presume a lot higher output than from my phone and I could very faintly make out the left channel with very slight movement from the VU meter.
Now, being the technophobe that I am, I’ve now gone as far as I can. I cleaned the DIN socket with contact cleaner, thinking forty odd years of probably not having anything plugged into it, might have been the cause, but alas, no.
Haven’t gone as far as opening up the unit to look inside, mainly 'cos I don’t know what what I’m looking at!
On that socket pins 3R, 5L are inputs (they each go to a ‘base’ on the transistors), which means 1L,4R are outputs.
I expect the amp is OK, I would suggest the adaptor you are using is not wired for a ‘Tape’ socket
If you look at the wiring for input to the magnetic pick-up circuits immediately above, and if there is a DIN I expect that would be connected on pins 1L, 2G, 3R, and nothing on 4,5 if even present. 5 is the left tape input channel on the amp which you cannot hear because it is not wired in the adaptor.
Thanks Richard, yes I’m sure that you’re correct about the adapter. I read somewhere regarding this matter and folk were buying generic adapters (with reference to MIDI) which didn’t work. I also read that whilst the majority of manufacturers adopted the convention 1 4 2 5 3 for wiring the DIN sockets, not all did? Perhaps Hitachi went a different route? TBH it’s not the end of the world but would be a nice to have feature. I might contact the HiFi repair guys that did the work on the AIWA units, they might be able to make something up for me. They are old school audio guys and might have come across this before.
On another note, having removed the 12" woofer that was misaligned on the LEAK 2060 speakers, I decided to have a play. I undid the four bolts that retain the plates and the magnet at the rear and removed that section. The voice coil and diaphragm all look to be perfect condition. I then loosened the single bolt on the rearmost plate which retains the centre section in position. This leaves a gap between this and the plates/magnet for the coil to move freely in and out of the gap. Big mistake, once the bolt was free, the centre section was pulled magnetically to one side of the circular opening. I’ve never seen a magnet as strong! Impossible to release the centre section from the surrounding plates.
So, with immense difficulty, I managed to split the two plates from the sandwiched magnet and separate the centre piece of steel, around which the voice coil moves in and out.
Cup of coffee and some head scratching later, I made up some shims to put around the centre piece, maintaining an air gap whilst putting it all back together. After several attempts, got the plates/magnet/centre section aligned, bolted back up and guess what? The coil now moves freely with zero rubbing and scraping! Result!
I do not wish to attempt this again though, was very difficult, the outcome was more luck than good management but has succeeded Sorry no pics this time, I was so busy trying to win the magnet force battle that I never got any.
Rather you than me playing wih the speaker magnets! Many, many years ago we tried this at work on a VERY expensive and no-longer available 15" Parmeko dual-driver concentric speaker from an LSU/10 that had a shredded cone after being knocked over. All was well, it came apart really easily - designed to be repairable, until a tiny bit of swarf got trapped in the magnet gap. We were unable to remove it. At the time Goodmans was still in Empire Way in Wembley, so having recently got them to re-cone a couple of Audiom 101 drive units for a pair of Marshall bass speakers I asked them if they could remove the swarf and re-cone the stripped-down Parmeko. No problem, £4 while I waited.
That’s great Richard I was just on Amazon looking at the 5 pin DIN to 4 X RCA phono, hadn’t found the 3.5mm connector so will definitely look into that. As you say, I can play away then various permutations of connections!
Could not believe how much force that magnet applied! I managed to rotate the two steel plates either side so the corners were out of line with the magnet, used a plastic trim tool in the gap created as I used brute force to prise the plates apart. The snap when putting things back into position was ferocious! Nearly lost the end of a finger
Many thanks again for your help. Will post results when I’ve got the bits n pieces together.
Roger, that’s great one way and another, this is going to get sorted, many thanks! After all, how hard can it be I’ve read quite a bit on the AV forums about this issue but no one came up with this solution, so I post on a car specific forum and folk are so knowledgable and helpful with sound advice! Absolutely top drawer!
In and amongst everything else, I’ve been deep cleaning the music centre, it really has come up like new! This one previous owner system has been well maintained, making my job as curator (if that’s the correct title ) so much easier.
Must admit I was a bit surprised when I received my Vinyl Passion “Dust Buster Stylus Cleaner”. From the pictures of the product itself, I was expecting something the size of a shoe polish tin not a 10P piece for £20! I am unable to use the arm lifter to lower/raise the stylus onto the gel as the amount of movement is only about 8mm, so I have to lower and raise it very carefully by hand. Never mind, it can be re-energised and if it does the job that’s great .
The father of a school pal of mine was a physics teacher. He ordered a lightweight but powerful magnet by mail order. Apparently the sight of the postman attempting to remove it from the carrier of his bicycle was something that couldn’t be forgotten.
