LT DD

[Gordon Steadman]

Not doing too much in the way of hi-fi at the mo as the house and slot cars take up most of my time.

However, someone on our local Google group asked me to try and fix a record player for him last week. Horrible floppy linear tracking arm but a decent DD motor. Incredibly complicated computer controlled everything, track choosing, special tape out etc. Presumably built after CD came out to try and replicate some of the functions. Just more to go wrong then.

Spent ages trying to get the thing to work but all the usual physical things didn't work. In the end I checked few voltages (proud of me Alan?) and in several places, where there you have been volts, there weren't!

He said keep it for spares then.

Had a play with the motor and 12V across a couple of points made it go round and at the right speed too!! So, another project in the offing. I've wanted to have a deck dedicated to our parallel tracking arm for some time but lacked a decent motor unit. Tested this morning and it sounded great. As usual with parallel trackers, the bass is absolutely clean and voices have a real sense of life. This with a cheap Sony cart without the arm properly sorted.

High quality DIY in progress as you can see One of Alan's (Firebottle) external power supplies which apparently is a required improvement for DD decks. I suspect that 10 amps might be adequate. The LEDs say it draws at least .1!!

Anyway, now to design a decent looking TT to add to the collection. Just as I was thinning it out too.


100_7896 by Gordon Steadman, on Flickr

[walpurgis]

Interesting. Any idea how far you'll take this project Gordon? Could look nice re-plinthed.

[Gordon Steadman]

A good question!!

I think I will actually try and make this one to a highish standard. A lot of work went into the arm and it would be a waste if it didn't get used regularly. The main difficulty is going to be arranging an arm lift of some kind. We were so concerned with getting a precise parallel movement that we forgot a practical thing like the lift!! Using it manually is OK but no doubt the hands will get shakier over the next few years.

One other interesting bit will be arranging a cover for the arm - not yer average shape! The obvious design answer is just to make it all round with a side extension for the arm but maybe oval - don't know, will have to sit and draw a few.

I think I'll stick with an external supply but probably not a 10 amp one that was intended for the slot cars!!

[M6NTL]

I just LOVE the Engineering in that arm assembly - spectacular!


Sent from my iPad using Tapatalk

[Firebottle]

In the end I checked few voltages (proud of me Alan?)

Good one Gordon, we'll make a sparky out of you yet.

Good looking project having seen the parallel tracker in the flesh so to speak.

[Gordon Steadman]

That'll be the day Alan. I suspect I should stick to wood.

The engineering in the arm is immaculate. I asked my brother in law to make it for me and he was a top design engineer before he retired.

It must be the most frustrating thing I have ever played with. The mechanism does exactly what it should. There is zero play, it just moves back and forth and, once the level is set accurately, tracks very securely at 2.5 grammes which is the design weight for the Sony. Surprisingly good cart this.

The sound makes you realise how much distortion normal arms introduce. I know we are taking small fractions of difference here but everything is so rock solid and natural that the problems make me weep.

Obviously the designer, guilty as charged m'Lord, forgot a few things. As I said, the arm works perfectly but......not as an arm on a record player. Several things were forgotten. How do I dress the wires? It will need a tether point somewhere at the back about half way across the traverse and quite high and the wires must be dressed so they don't interfere with the movement or touch the record. I've sort of figured out how to get a lift to work but it will entail an extension of the back of the arm and a bar which will press down.

All this becomes somewhat hair shirt and messy. I've seen other parallel trackers that probably wouldn't get a domestic seal of approval and this certainly wouldn't as it is. I keep trying to think about solving the problems, put a record on and just get totally lost in the music and do bugger all to it.

So a curates egg then. I suspect it will be relegated to the pile of worthy near misses that seem to clutter up our home (sorry Ronnie) and will mock me every time I see it. Probably a waste of time in the end....

,,,but OH GAWD.....the sound it makes

100_7906 by Gordon Steadman, on Flickr

[M6NTL]

It is most definitely NOT a waste of time Sir - watching TV is a waste of time, doing something/trying something in whatever field excites us is NEVER a waste of time!


Sent from my iPad using Tapatalk