Neil's Turntable Power Supply Page...

Last updated 21/9/01.

The story so far...

OK, when I say turntable power supply I really mean a supply for the LP12. When I first got a Lingo (replacing the Valhalla) I thought it was great. Since then I have tweaked my system a lot and built amps and preamps etc etc, until ending up with a system which is particularly Naim based (or at least tweaked-Naim based). I have always been interested in Naim's approach, opting for the 'simple' solution to powering the LP12. However I have never got around to trying their supply. I was happy with the Lingo.

Then a few interesting discoveries were made by friends regarding the Lingo. A mate (who also uses Naim and tweaked Naim gear) was having his deck serviced and was using a CD instead (no comment) and noticed that when he turned off his Lingo (which was just sitting there not connected to a turntable, but powered up) the sound improved considerably. The Lingo seemed to be degrading the rest of the system

After experimenting, it did indeed seem as if the Lingo was doing something to the mains which the other components of the system (amps mainly) didn't like. Now it's hard to turn off the Lingo and still listen to the LP12! But you can experiment with the Lingo in two ways. Firstly, trying plugging the Lingo into different sockets... perhaps using a long extension lead. This was most aptly demonstrated by a friend who has the luxury of separate spurs for the hifi. When the Lingo was on a spur on its own, everything seemed ok. But plug the Lingo into the same spur as the (Naim) amps, and the soundstage collapsed, became 2 dimensional, and was a lot less interesting and musical. I haven't got separate spurs, so I tried putting little ferrite clamps on the power cable of the Lingo (they are little cylinders of ferrite material, about 2 cm long, that simply clamp around the outside of the cable..... and you can buy them in places like Tandy and Radio Shack I believe). The effect was very good. With 4 or 5 clamps, the worst symptoms of the effect seemed to be more or less cured. I would urge any Lingo user to try them.

However I was beginning to wonder what would happen if I junked the Lingo altogether? The chap with the separate spurs actually bought a Naim supply and reckoned he much preferred it. I tried 3 routes... without actually shelling out for the Naim supply (cheap-skate that I am). Firstly, I rigged up a supply using a variac, a resistor and a cap (like in the Naim supply) and found the music sang. I do believe my amps (and there's quite a few of them) did not like the Lingo much, even with the clamps. I then tried a little supply from Avondale Audio (the Taps). It is interesting as it has switchable output voltage, so you can pick the one you like best. I felt this was pretty good, giving a more civilised performance than the rather crude variac approach. However I'm not altogether sure it matched the sheer raw appeal of the variac.

Finally I put together a cheap supply which is basically a clone of the Naim one (thanks to the people involved for supplying various information to me about this), and it looks like:


 
                A       --------   B
                o------|        |--o---------o winding 1
                        --------   |  ||
  From a                  3K3      o--||-----o winding 2
  500VA coil                          ||
  110V rms                           0.2uF
  secondary
                o----------------------------o common (grey wires)
 

I used a 3 W resistor, and the cap(s) was a polyester type (250 V I think). You can use one 0.22 uF cap (which is what I had on the diagram originally) although 0.20 uF is I think the 'accepted' value, and is obtained easily by using two 0.1 uF caps in parallel. If you want to play around, it is worth noting that each motor winding is about 4100 ohms with an inductance of about 5 H.

The windings 1 and 2 are the blue and red wires on the motor.... as I write this I can't remember which is which off hand. The worst that happens is that the platter turns the wrong way, in which case reverse the blue and red. The coil I have used is a cheapie thing (although it appears 'ok'), although at some point it will be nice to try more exotic coil to see what it does in this role. I find that the results are very good indeed.

I have now had many reports of people trying this supply out and all have reported great success. Some poeple have use 1000 VA coils although I don't know of anyone who has managed a A-B comparison between coil sizes. The use of 0.20 uF (ie, two 0.1 uF caps) rather than a 0.22 uF cap appears to be worthwhile.

There is still some experimenting to do perhaps, but this is fun to try and is relatively cheap in components. Note that the motor windings are being supplied with something of order 85 V rms.... enough to give you a shock, so be careful.

A postscript to all this, is that the original chap who alerted me to the powers of degradation of the Lingo, changed his rather old Lingo for a brand new one, and reckoned it was stacks better. Mine was an old one too, although the one belonging to the chap with the spurs was relatively recent I think. I say this as I suspect the Lingo has improved over the years, although I still reckon it isn't particularly Naim-friendly even now.

A word of warning.... clearly with this type of supply the motor revolves at the frequency of the local mains. In the UK/Europe, the mains works at 50 Hz and indeed all LP12s are sold here with motors which expect 50 Hz. However in the USA the mains is of course at 60 Hz, and so you would have to check that your LP12 motor is a 60 Hz version (ie, the pully is somewhat smaller). This will be the case for LP12s sold in the 'Basik' form as these run from the mains in the same way as the supply presented here. However, the decks with Valhallas (and I suspect Lingos) might well have 50 Hz motors (ie, the electronic supply gives a self-generated 50 Hz waveform). I say this as I know of one person who had a US Valhalla LP12 with a 50 Hz motor, and had to buy a new US Basik 60 Hz motor in order to use his homemade supply (although he was very pleased he did as he reported that the supply made for a "fabulous upgrade").