The Lurcher power supply..

[StanleyB]

OK, not really its name but I though it should be :lol:.
Some time ago Lurcher (Nick) built me a linear power supply with a filter network and two different sizes of DC plugs. That way I could test mods etc. in the Caiman and TC-7520 in near battery like clean mains condition.

It's an absolute must for laboratory type clean power requirement condition. Because I live at the edge of a trading estate that is in use 24 hours a day, my local mains is noisy day and night. So the Lurcher power supply also gets used in my main system when I need to relax. The following is a picture of it during testing of the Silmic Gator mod.

http://www.homehifi.co.uk/aos/P3.jpg

[StanleyB]

I took a picture of the Lurcher power supply next to a Gator PCB so that you can get an idea of how big it is.

I have no idea if Nick makes these on a commercial basis, but if you are after a top notch linear power supply for either my DAC or that of a different company that uses an external DC power supply, and you live in a noise mains supply area,I would recommend that you try out one of these.

http://www.homehifi.co.uk/aos/P1.jpg

[Marco]

Hi Stan,

Do you know how much Nick charges for one?

Knowing Nick, it won't be OTT and it will sound superb. For me, I'd consider one of those PSUs mandatory with the Beresford :)

Marco.

[keiths]

Doesn't David Brook (Main Cables-R-Us) sell Nick's design?

[Ali Tait]

Yes they are great, I use one for my Touch. David sells them -

http://www.mains-cables-r-us.co.uk/22-power-supply

[StanleyB]

Hi Stan,

Do you know how much Nick charges for one?

If I tell you, I'll have to kill you afterwards :eyebrows:. For what it gives in solid performance, he's practically giving them away. I have been loaned some so called Caiman power supplies costing around £300 that don't come anywhere near this in terms of technical and enjoyment performance.
How Lurcher makes anything to live off out of all that work baffles me :scratch:.

[Dingdong]

The price seems reasonable. I don't have anything that needs one though. :doh:

[DSJR]

Has it always been £165? I thought there was one for £100?

[The Vinyl Adventure]

I have the one without the second box.. £100 really bloody good!

[lurcher]

I have the one without the second box.. £100 really bloody good!

the £100 is a single reg design, the £165 ones David sells now and Stan has used has the second regulator in the small box. Its more than just a simple filter network, it contains a mosfet, low noise error amp + voltage ref and as many caps as there is space left.

The idea is the big box produces what is normally considered clean power, and the little box add a shine to it close to the load.

[jostber]

Yes they are great, I use one for my Touch. David sells them -

http://www.mains-cables-r-us.co.uk/22-power-supply

He has a couple of PSUs for the Techie as well. :)

[The Vinyl Adventure]

the £100 is a single reg design, the £165 ones David sells now and Stan has used has the second regulator in the small box. Its more than just a simple filter network, it contains a mosfet, low noise error amp + voltage ref and as many caps as there is space left.

The idea is the big box produces what is normally considered clean power, and the little box add a shine to it close to the load.

Can mine be beefed to the 2 box version should if I chuck it back your way?
Just out interest like :)

[MCRU]

Can mine be beefed to the 2 box version should if I chuck it back your way?
Just out interest like :)

Of course it can matey

I sent one to David Price some time back and he likes it, it is featured in next month's HiFi Choice for the Squeezebox Touch. We have supplied them for the R-Dac, Cambridge Dacmagic +, The rather excellent Caiman DAC, M2Tech Young DAC, MF V-DAC, countless others, the £100 one is being phased out as the 2 box version is miles better. Even NAS drives benefit if they are powered by DC wall wart plugs.

The same 2 box principal is featured on our Techie PSU (http://www.mains-cables-r-us.co.uk/power-supplies/380-technics-sl1200-1210-linear-power-supply.html) where the small box is housed inside the Tech, that one costs a bit more to make but still good value.

Anyone who is going to Bristol and has never met the guru that is Lurcher, he will be alive and kicking on my stand so pop along to benefit from his wisdom. No bullshit he is a clever engineer who is also an audiophile, very few exist!

Here is the idea behind it from the pen of Mr Gorham:-

When thinking of regulation, it’s worth remembering the Roman god Janus. Who was the god of gateways, and was a two faced god looking in both directions. Likewise a good voltage regulator is required to look in both directions at once. From one direction you have the mains supply, with the ever increasing noise, distortion and random variation that exists on our household mains supply. In the other direction you have the device you are supplying power to. The load will be asking constantly varying current, and the job of the regulator will be to ignore the varying load and to supply a rock steady voltage that ignores the changing load.

To ask a single regulator to perform both tasks means that it can not do either as well as it could. We don’t ask our regulators to be two faced, we split the two functions into two separate regulators and put them both where they can do the best job.

The first regulator is close to the mains supply, its job is to take the incoming mains and convert it into a low(ish) noise DC supply, and to isolate the mess that is our household power lines from what follows. In most power supplies on the market, the output of the first stage would be directly connected to the load device, and that would certainly be an improvement over the supplies that most manufactures provide. But we can do better by adding the other face of Janus to the system.

The second regulator is supplied with a clean low noise supply, and its job is to handle the changing demands of the load. To do that, it needs to be as close to the load as possible. So we remove the second regulator from the main box, and place it close to the load, both electrically and physically, that removes it from the noise and interference of the mains supply, and allows it to spend its time looking towards the load. Typical commercial voltage regulator chips are general purpose devices, but are not quiet enough for the task on hand, so the second regulator uses a bespoke regulator based on a low noise multi stage filtered voltage reference, a low noise error amplifier and a high current low resistance mosfet. To allow it to handle the changing load it also needs to supply current on demand, so all the remaining space in the second regulator is filled with low impedance capacitors to act as a local energy source.

Using the two stages of regulator, we achieve a noise floor equal or better than most battery supplies, and a effective source resistance of the order of 0.02 ohm (and the short cable run to the load avoids increasing this valve by adding copper where its not needed, and the use of a discrete regulator design allows that tiny value to be maintained way above frequency any audio device operates at.

[realysm42]

No M-dac loving?

[MCRU]

No M-dac loving?

Is it not AC powered with one of those silly 5 pin din connectors?

[realysm42]

Yes :(

Actually it might be more than 5 pins from memory; does that mean game over?

[MCRU]

If its AC there may be filtering built into the DAC, if its DC then the PSU on this thread will work fine. We have made AC filters before for the Cambridge Dacmagic Mk I which is 12V AC, I have one myself.

[realysm42]

It's 8 pin:

http://www.avland.co.uk/aasp/audiolab/1120/mdac/rearlrg.jpg

[The Vinyl Adventure]

Of course it can matey

A freebee I assume? We like freebies in the office it seems ... It is the dac for the office system after all ;)

[sq225917]

The mdac requires 6 x 15v at about 150ma each.

Nick have you tried using the Q-speed schotky diodes they are quite remarkable devices.

[Canetoad]

David,

I run my Caiman at 15.8 volts to maximize voltage to the replacement regulators I have inside. Is the output voltage adjustable? :scratch:

[MCRU]

bernie

pm sent

[MCRU]

A freebee I assume? We like freebies in the office it seems ... It is the dac for the office system after all ;)

Nothing is free in this life dude (oh apart from a Techy of course :lol:)

Send it back for a turbo charge.......

[The Vinyl Adventure]

Nothing is free in this life dude (oh apart from a Techy of course :lol:)


free, maybe not, but well below normal rate ... ;)

Ive bought a hlly dac off john, when that arrives ill send the camian psu back to you



(oh apart from a Techy of course :lol:)

you asked me bout that the other day ... Its currently in bits, im working on the top plate, its just taking my a while ...

[lurcher]

The mdac requires 6 x 15v at about 150ma each.

Nick have you tried using the Q-speed schotky diodes they are quite remarkable devices.

Not the Q-Speed ones, but I have tried the similar Cree and IXYS parts. Only problem for me is the 600v rating, its a bit low for the amps I tend to make. Great for preamps though.

Of course at the voltages in use in these supplies SiC isn't needed and I just use standard 8A low Vf schotky parts.

[jostber]

I just ordered me one of these PSUs for my Techie. Will be another happy occasion when it arrives in my household. :)

[Cans]

I have used David's services for my m2tech, I have no qualms recommending the linear psu for an improvement in sound quality. I bought a monster size mains cord with it too, you have to make sure that one's pushed in real firmly and then don't so much as brush against it else the power'll go off.
But, as I assume most of you don't move your systems all around the country every day that won't be an issue.
Only reason I mention it is because the first time I put mine on I thought it was faulty, which of course, it isn't:):):):):):):)

[Gazjam]

Ditto. :)

http://theartofsound.net/forum/showthread.php?t=13588