Squeezebox External Power Supply

[jtwrace]

I am wondering if anyone has one or if they know Jabberwockie (I think this is it) contact info? I saw that he makes one just wondering if anyone has one and knows how I can get one.

Thank you

[Shuggie]

I know not of the Jabberwockie, but I've recently built a new PSU for my SB3 using a high speed discrete regulator module from Paul Hynes in the UK, who is a well-respected audio designer, specialising in discrete regulators that are phenomenally fast. See www.paulhynesdesign.com where he outlines his designs philosophy etc. He sells a suitable PR3 module set at +5v for £69, which is not on the website at present, but which is available (I got one!). Before I decided on the DIY route, I enquired about a built PSU for the SB3 and was quoted £150, which isn't too bad in my view. Either of these prices are very competitive against the opposition that I know of.

So, how does the Paul Hynes module make the SB3 sound? Well ....... fast! The overall definition of instruments etc is much better than with the standard wall wart, but no surprise there. What is a surprise is the astonishing leading edge definition of strings, drums etc, which is matched by rather good bass grip and focus. I am genuinely staggered that the humble SB3 now reproduces music in a way that betters my £1500 CD player, with the aid of the Paul Hynes PSU. I should add that these observations are with the SB3 feeding an external DAC - I have not tried the analogue outputs.

So, I am very happy and recommend Paul Hynes to anyone wishing to knock up a really top class PSU for the SB.

[P Floding]

I am wondering if anyone has one or if they know Jabberwockie (I think this is it) contact info? I saw that he makes one just wondering if anyone has one and knows how I can get one.

Thank you

I use two sealed 6V lead-acid batteries that I charge alternatively (and swap over manually). They feed a simple regulator (simple, if disregarding the internals of the regulator chip itself).

Sounds very good when feeding the digital signal to my TacT.

[Phil Leigh]

I know not of the Jabberwockie, but I've recently built a new PSU for my SB3 using a high speed discrete regulator module from Paul Hynes in the UK, who is a well-respected audio designer, specialising in discrete regulators that are phenomenally fast. See www.paulhynesdesign.com where he outlines his designs philosophy etc. He sells a suitable PR3 module set at +5v for £69, which is not on the website at present, but which is available (I got one!). Before I decided on the DIY route, I enquired about a built PSU for the SB3 and was quoted £150, which isn't too bad in my view. Either of these prices are very competitive against the opposition that I know of.

So, how does the Paul Hynes module make the SB3 sound? Well ....... fast! The overall definition of instruments etc is much better than with the standard wall wart, but no surprise there. What is a surprise is the astonishing leading edge definition of strings, drums etc, which is matched by rather good bass grip and focus. I am genuinely staggered that the humble SB3 now reproduces music in a way that betters my £1500 CD player, with the aid of the Paul Hynes PSU. I should add that these observations are with the SB3 feeding an external DAC - I have not tried the analogue outputs.

So, I am very happy and recommend Paul Hynes to anyone wishing to knock up a really top class PSU for the SB.

Which DAC are you using?

[Shuggie]

The SB3 feeds a Lyngdorf TDA2200 digital amp, and I am very pleased indeed with the combination. Strangely, I have just bought a QED optical lead to connect my Humax digital TV receiver to the Lyngdorf, and I tried it on the SB3 first. I cannot tell any difference between optical and coaxial leads (DH Labs D75). That surprised me, as I always thought optical was the poorer choice, but maybe Slim Devices have engineered their optical interface properly!

[Phil Leigh]

Thanks. Nice amp. Toslink is not necessarily inferior - it all depends on the equipment you connect by it. In some systems TOSLINK can sound markedly superior because there is no galvanic coupling (for RF or other "nasties").

Your description of the improvements you hear is interesting because I personally I attribute most of those types of sound change to jitter reduction and/or RF interference reduction. Remember we are talking about a digital SPDIF/TOSLINK connection - it's not like the improvement you'd get if you used a "fast" PSU on an analogue circuit. Yes I know that the SPDIF is an analogue representation of a digital signal, but making the square waves "squarer" doesn't change the sound in a conventional way. Don't get me wrong - I'm not saying you are not hearing the improvements...I'm just wondering if the uderlying cause of the problem is a little more complex. Lyngdorf/TACT gear (I have a TACT 2.2x) is notoriously sensitive to the equipment connected to it...and PSU issues.

Did you ever try a conventional linear supply on your SB3?

[Shuggie]

The Paul Hynes PR3 module is a linear supply, although an uncommonly well designed one. When you say 'conventional linear supply' do you mean a simple TX/rectifier/capacitor circuit? Having used Paul's modules in a variety of projects over the years I would not willingly use unregulated circuits, or circuits using the typical 3 pin ICs. I don't know why the PR3 should have such a beneficial effect in a digital system, but it does, and I am not inclined to analyse the situation very much! The following words are Paul's, taken from his website, and hopefully explain why his regulator modules are better than the norm:



Power Supplies for Audio

Supplying power to an electronic circuit is far more complex than most people realise. Electronic signal processing circuits vary in their ability to reject interference from power supply voltage fluctuations. This ability is measurable and is called the power supply rejection ratio (PSRR). Differential signal circuits have a reasonably good PSRR (but only if the circuits are well balanced, which is not always the case) and typical single ended circuits have a PSRR of only a few dB and they require exceptional power supplies to work well. Any fluctuations on the power supply output will be injected into the electronic circuit, at a reduced level, governed by the PSRR of the circuit. For example, if the PSRR is 40 dB, the amplitude of the injected fluctuation will be 100 times lower than the power supply fluctuation itself (60dB is 1,000 times lower, 80dB is 10,000 times lower and 100dB is 100,000 times lower). When this injected power supply fluctuation mixes with the signal being processed, it masks low-level information and causes inter-modulation with the signal. This destroys the integrity of the music and makes it impossible to generate a stable three- dimensional image. Delayed power supply reactions to load transients can also cause instability and ringing, particularly with large amplitude signals. For the highest performance from audio electronics, great care is required in the design of the power supplies to minimise power supply induced problems.


The Ideal

An ideal power supply, to ensure no interaction with the powered circuit, should have no output voltage fluctuations under any load conditions, which means that the output impedance should be zero at all frequencies of operation, as you can't generate a voltage across zero impedance. Also, it should not allow interference to break through from other sources like the supply line, such as rectifier diode switching, digital clocking and radio frequency interference (RFI) via the mains supply. This implies that the power supply should have infinite PSRR of its own power source (supply line). This is called the supply line rejection.


The Practical

Unfortunately, due to the limits of the various power supply design options available, power supply interaction will occur. The level of interaction is governed by the ability of the power supply to approach the ideal performance of zero output impedance and infinite supply rejection of it's power source. It is logical to conclude from the above notes that, the better the power supply performance, the better the audio performance.

Any regulator design worthy of consideration in high performance audio systems must offer a low output impedance over a very wide bandwidth (much wider than the audio bandwidth to deal with digital and RF interference). It should also have a fast settling time for load transient currents (noticably faster than the circuit to be powered to avoid load induced output fluctuations). It should also be quiet enough not to compromise the noise performance of the audio circuits it powers.

[charlychan]

I use two sealed 6V lead-acid batteries that I charge alternatively (and swap over manually). They feed a simple regulator (simple, if disregarding the internals of the regulator chip itself).

Sounds very good when feeding the digital signal to my TacT.

I go with Floding for me the best Power supply is a batterie
Use it also for my cd player with great results

[Phil Leigh]

Yes Shuggie - I was wondering if you'd ever tried a conventional "3-pin reg" supply. I fully appreciate - and agree with - what Paul is saying with regard to audio circuits, but the SB3 connected digitally to a DAC is not an audio cicuit in the normal meaning of that phrase. However, it is possible his design has a beneficial effect on the SB that is particularly noticeable when connected digitally.

Going back to the PH device...is it a board/module? - presumably you added a box and transformer?

I'm quite interested in his design and may well buy one to try.
Regards
Phil

[Shuggie]

Phil,

The PR3 module is built on a smallish PCB, approx 100mmx60mm, with an alloy bracket for fixing to a suitable heatsink. The modest height is accounted for by a couple of electrolytics which are about 30mm high. All components are discrete, eg no proprietary regulators or ICs. The box I used is an alloy one from Maplin (code N93BQ), which is big enough to accommodate the PR3 and a 50VA toroidal transformer (Nuvotem from RS). I use a 9v toroid, as any higher voltage requires much greater heatsinking, and with 9v the enclosure itself suffices in that respect, getting warm to the touch but not excessively hot. Paul told me that a 6v transformer is not enough to drive the regulator for 5v output. I used Kimber twisted pair cable for the 5v DC out, and a bog standard captive mains lead, with a CBE in place of a fuse. I wish I could post you a picture, but the gear is in the UK and I work in Germany!

Anyway, if you are tempted, just give it a go. I am sure that Paul takes stuff back if the customer is not happy (sorry, Paul if that is wrong!), and for £69 I am not aware of a cheaper (or better) alternative.

Regards etc.

Shuggie

[Phil Leigh]

Shuggie - that's great info - many thanks. I will sertainly give it a go...I'll use the parts you mention. I'll drop Paul an email to confirm prices etc.
Thanks again
Phil

[Phil Leigh]

Sorry Shuggie - one more thing if you don't mind...you mention using a CBE instead of a fuse (is that in the mains plug?) which CBE do you use?

[F-100]

Shuggie,
Do you have any pictures of your PR3 module that you can share? Thanks