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Linn 'Majik' LP12 power supply

maccavelli

maccavelli

pfm Member
Hello, it's been a while since I have written on here. Pondering on LP12 power supplies. I know the Lingo and Valhalla, and, years ago they used to do the bare bones version called the Basik. From memory it was £29 (circa 1992) I was wondering how different the 'basic' Majik is now that comes on the base level LP12. Because it aint £29 anymore! Obviously it's 33rpm and nothing more. Having seen a picture of the insides there doesn't seem much in the way of electronics inside the little black box.
 
The old Basik PSU was based around a simple bit of technology called a synchronous motor and a phase shift PSU. The mains frequency in the UK and Europe is VERY tightly controlled, by law, far more so than voltage, and people use this to regulate the speed of electric motors. A synchronous motor's speed is dictated by the mains freq, so you can see how this is going. The purpose of the PSU, in the case of the Basik a simple capacitor, is to generate 2 wave forms, one "out of phase" with the other. Think of 2 waves, one lagging. One wave feeds the stator (non rotating) part of the motor, the other the rotor. Because there is a phase difference the magnetic fields generated by the sine wave going in cause the motor to turn, and because the sine wave is always on the move the rotor has to turn with it *at the same speed as the sine wave is shifting*. There you go, a simple, constant speed, motor. Try to do the same with a DC motor and you will be there for weeks.

The Valhalla was a slightly more sophisticated means of getting the same thing, the Lingo a 50Hz generator. The Armageddon was basically a Basik with a trafo to take out any crud and generate a 110V signal for the motor for less vibration.

I am not familiar with the Magik but it's probably just the Basik rehashed. Magik it isn't, it's a simple bit of physics that any A level student can understand.:) What it costs, well, that's whatever Ivor can get for it. Or these days his son.
 
A bit of online reading suggests there is some filtering of the mains. So probably an upgrade on the old Basik but we aren't talking rocket science to filter out a bit of noise. A capacitor network costing pennies and taking 2 minutes to assemble will do that. The circuit will be in all the textbooks.
 
maccavelli said:
Hello, it's been a while since I have written on here. Pondering on LP12 power supplies. I know the Lingo and Valhalla, and, years ago they used to do the bare bones version called the Basik. From memory it was £29 (circa 1992) I was wondering how different the 'basic' Majik is now that comes on the base level LP12. Because it aint £29 anymore! Obviously it's 33rpm and nothing more. Having seen a picture of the insides there doesn't seem much in the way of electronics inside the little black box.
Click to expand...

The Majik PSU is overpriced IMO. It's built to a much better standard than the old basik PSU but it's electrically very similar, a bit of extra mains filtering but nothing remarkable going on in there.

The same money spent on a mose Hercules or a used mk1 lingo will yield much better results.

For a cheap PSU to get a sondek running, you can use a phase shift board from a mains voltage rega deck, plenty knocking around on eBay and in peoples bits boxes that are left over from decks retro fitted with 24v motors.
So long as you can mount it safely, it'll work fine.
 
The original (1973) LP12 Basik had the phase shift caps on a tagboard screwed to the cross rail! No box. Well, it's all under the hardboard base, that's securely attached with 4 half inch woodscrews, what could possibly go wrong?

The Rega PSU would certainly work. If you can solder it's half an hour to build one, the circuit (if you can call it such) is on the DIY Geddon page. Just ignore the bit about the 110V trafo.
 
stevec67 said:
The original (1973) LP12 Basik had the phase shift caps on a tagboard screwed to the cross rail! No box. Well, it's all under the hardboard base, that's securely attached with 4 half inch woodscrews, what could possibly go wrong?

The Rega PSU would certainly work. If you can solder it's half an hour to build one, the circuit (if you can call it such) is on the DIY Geddon page. Just ignore the bit about the 110V trafo.
Click to expand...

Haha, the original PSU you describe is a bit scarey. It wouldn't be acceptable these days but it was normal back then.
 
linnfomaniac83 said:
The same money spent on a mose Hercules or a used mk1 lingo will yield much better results.
Click to expand...
This comment applies to all parts of an LP12 though. For the £2k of the Magik you can pick and choose Cirkus or pre Cirkus decks, serviced, mint condition (they get looked after, after all), any arm you like, PSU you want, money left over for a cart, and the thing will outperform the Magik all day long. The only one that won't outperform the Magik is the old pre corner brace, Basik, pre Cirkus job from the 70s. Even that is unlikely to be worse, it will just be different with the pre Cirkus bloom evident that users of Naim amps love so much.
 
The even older basic psu s that I've come across were just the capacitor screwed into an electricians 'chocolate bar' polythene strip connector, screwed in turn to the cross brace.

Pennies to make in 1974 and not much more pennies to make now!
 
Part of the art of smoke and mirrors is to put the electronic gubbins into a mysteriousness little box so the workings are unseen, it heightens the illusion that you're getting something 'special' I guess.

When I first got into Linn and Lingo was £600, the Valhalla was about £180 and the Basik was £29, looking at the Basik workings I thought it overpriced back then!
 
Quite so. It's not just Linn, some while ago I got hold of a Michell Iso/Hera phono stage. I unscrewed the lid on the PSU out of curiosity - a toroidal transformer in an MDF box, nothing else. It was about £200 at the time, if I'd paid that I'd have put it through the shop window.
 
stevec67 said:
Quite so. It's not just Linn, some while ago I got hold of a Michell Iso/Hera phono stage. I unscrewed the lid on the PSU out of curiosity - a toroidal transformer in an MDF box, nothing else. It was about £200 at the time, if I'd paid that I'd have put it through the shop window.
Click to expand...

Ever seen inside a Naim flatcap?

I generally hold linn in high regard. The kit I have had has provided lots of enjoyment, proved reliable and held its value well but the pricing on the Majik PSU is daft, and on the keel too, although the keel does improve the deck considerably but for what it actually is....

They will charge what people are willing to pay and if people are mad enough to pay it I can't blame them really, they are a business at the end day.

I have a keel but I got it with the deck at a very good price, no way I'd pay the full asking price.
 
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