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Andy - no, I can't justify that outlay. In any case, this is not for audio amplification where the last word in noise performance could be significant. I think the SR7EHD will be sufficient and the rest of my money is better directed at Tellurium Q cables where I am having very positive results recently.
I'm thinking of getting the P10 at some point this year! And maybe Tellurium graphite balanced interconnects! We'll have to see.
You could not make a better investment in sound, Andy. If there's anything you need to know about it before you decide, just ask.Quote:
Originally Posted by REXTON
MMMMmmmm I have to get my hands on one 1st! My local HiFi dealer is pretty good at getting most things but this could be difficult. :(
Speak to Kevin at Signature Audio Systems. He may be able to loan you one, or at least a P5 to try out?
Thanks :thumbsup:
It's known as boys and toys M8!:)Quote:
Originally Posted by Reid Malenfant
Marco has asked me for an explanation why all these regulators inside the SL1200 affect the sound quality of the deck so much and how their use relates to the SR7EHD power supply performance. I’m not sure how this will read as I am just enjoying a rather nice bottle of Bordeaux, but I will check and, if necessary, edit it tomorrow (probably not until the afternoon as I am on holiday and I am going to finish the bottle).
Firstly, the SR7EHD regulator and the internal regulators have a very low noise error amplifier (0.5 nanovolts root Hz with a 1 Hz noise corner), very wide operating bandwidth (>200 MHz), fast transient response/settling time (<100 nanoseconds),as well as excellent supply line rejection over a wide frequency range (>80 dB DC to 80 KHz and around 60 dB at 1 MHz). For all these reasons, they work very well as an external power supply for the SL1200 and as internal regulators feeding the motor board. They provide a very quiet, clean feed to the motor control board inside the deck.
There is a downside with having the only system regulator in the remote power supply, as the cable connecting it to the motor board reduces it’s ability to damp out voltage fluctuations on the motor board that are caused by load current changes around the various sections of the motor control circuit. However combine this high performance, quiet, remote power supply with internal regulation to each individual stage close to the load and the downside is no longer there. This is where Marco has correctly concluded from his listening tests that the SR7 external power supply is only part of the equation for optimising the whole power supply, with each part playing a significant roll in the overall performance. I have been using this power distribution technique since the 1980’s with excellent results on a wide variety of equipment.
As there is significant impedance in any current path, within the supply distribution wires and tracks, there will always be some voltage drop when current moves around the supply distribution paths. Even the ground point will not have zero impedance. As none of the control integrated circuits will have infinite supply line rejection these voltage changes will bleed into the control signals, mix with them, and reduce the accuracy of the control signals. This situation is likely to get worse as the signal currents increase in frequency, as the supply line rejection of signal processing circuitry gets worse with increasing frequency. The more circuits that are on a common supply, the more there is scope for interaction between all the circuit sections.
Providing separate high performance, wide bandwidth regulators, for each stage in the motor control circuitry reduces these voltage interactions considerably. This allows more accurate signal processing by the control circuitry. The regulators have to have an operating bandwidth that significantly exceeds the signal circuitry operating frequency for the best result so don’t expect to achieve high performance regulation from an LM317, when the signal circuits are processing up to around 4 MHz, as the LM317 has stopped regulating at this frequency!
Another nice benefit of the regulator cascade is that the supply line interference rejection increases dramatically to a level that reduces the effects of mains variations on sound quality significantly. This means you can enjoy listening to music 24/7 instead of approx 12/7. Because of this I wonder if there is any point in using a high performance mains cable with such a high level of regulation? (Sorry David, I couldn’t resist that one, you need to keep an open mind). Actually there is good reason to use a high quality mains cable, as, the more masking distortions you remove from a system, the easier it is to hear the remaining ones when they are removed.
Regards
Paul
On the subject of "off the shelf" regulators,
It’s a very interesting one,
I remember spending a day once comparing the performance of a few of the common ones found in many pieces of Hi Fi kit, and as Paul has already explained the results were in many cases laughable when you compare noise rejection and impedances with frequency etc, therefore I totally agree with Paul’s findings and explanation, I used very similar regulator topology in both my soul-mate preamp and soul power amplifiers so I am well aware of the importance of designing and using the best power supplies you can for a specific application, Therefore I cannot emphasize enough how important power supplies are, and where raw power supplies are concerned i.e.; mains transformers to start the chain etc,there really isn’t any theoretical limit to improvement where size is concerned, just the law of diminishing returns.
Anthony,TD...
was something I've been wanting for a long time. I have no background in electronics but I'm intrigued by the science, unfortunately I've had difficulty tracking down answers to questions that pop into my mind.
Paul's answer nicely covered many of the questions I had and did so in a way that I could understand.
Thank you.