New Paul Hynes SR5 Power Supply

[Mike_New]

Hi Marco,

Hi Martin,

Quoi??

This is impossible... After all, we're talking about the WORLD's No1 Technics guru, no less!!!


Marco.

And he says he lectures to NASA as well, no less!!!
Self appointed garu I think

Let this be a lesson to all the deciples, who believe his every word.
What does the instruction sheet say?, for those who have installed their own PS??
I have measured the effective resistance from the top point to the proper earth tag and it is approx 0.08ohm. Although this will vary from chassis to chassis.
The worst part is the possible "noisy" earth return that this connection point will cause. This is why Technics did what they did!!!

I was made aware of the possible situation some 6 months ago but stupidly did not beleive that it would be common practice!!! and that it was a one-off mistake. And so I did not make any mention of it untill recently.

[MartinT]

I played a 12" 45 single earlier this evening and something wasn't quite right. I could hear pitch instability. I selected another 45 with sustained piano notes and could hear it more easily.

Something in the back of my mind recalled Dave Cawley saying that the MD mod was designed for the standard Techie platter and may not work as designed with a heavier rotating mass. So off came the Achromat and the Vaseline and the platter (2nd time tonight) and I cut the MD mod components out. After rebuilding I listened carefully and the instability had gone. Everything is rock steady at 45rpm and remains so at 33rpm. So I recommend that if anyone is going to use the Mike New or other heavy platter solution, remove the MD mod if fitted.

Things sound superb at the moment with even more treble and midrange purity. Just the Neutrik connector to go.

Picture showing the incorrectly placed 0V tag (circled top-right) and motor dynamics mod components (circled bottom-right).

[leo]

Hi Marco,


And he says he lectures to NASA as well, no less!!!
Self appointed garu I think

Let this be a lesson to all the deciples, who believe his every word.
What does the instruction sheet say?, for those who have installed their own PS??
I have measured the effective resistance from the top point to the proper earth tag and it is approx 0.08ohm. Although this will vary from chassis to chassis.
The worst part is the possible "noisy" earth return that this connection point will cause. This is why Technics did what they did!!!

I was made aware of the possible situation some 6 months ago but stupidly did not beleive that it would be common practice!!! and that it was a one-off mistake. And so I did not make any mention of it untill recently.

Nothing like keeping those ground paths short and clean

[Mike_New]

Martin,

I played a 12" 45 single earlier this evening and something wasn't quite right. I could hear pitch instability. I selected another 45 with sustained piano notes and could hear it more easily.

Something in the back of my mind recalled Dave Cawley saying that the MD mod was designed for the standard Techie platter and may not work as designed with a heavier rotating mass. So off came the Achromat and the Vaseline and the platter (2nd time tonight) and I cut the MD mod components out. After rebuilding I listened carefully and the instability had gone. Everything is rock steady at 45rpm and remains so at 33rpm. So I recommend that if anyone is going to use the Mike New or other heavy platter solution, remove the MD mod if fitted.

Things sound superb at the moment with even more treble and midrange purity. Just the Neutrik connector to go.

Picture showing the incorrectly placed 0V tag (circled top-right) and motor dynamics mod components (circled bottom-right).

Much earlier this year I enquired as to what values Cawley was using for his motor dynamics mod. The response was: "The motor dynamics mod reduces the torque to make it sound more like a LP-12, I'll probably take it off soon!"

I have been studying the circuit today and would sugest that you all take it off (if fitted) as it serves no purpose in my judgement and can only impair the sonic performance.

[MartinT]

Excellent advice, Mike. Looking at Dave's oscilloscope captures I'd say it wasn't just the torque that was reduced but the motor circuit's ability to respond quickly to change. Tallies with what I heard, anyway.

[MartinT]

4-pin Neutrik connector now soldered in place of the 5/2.5mm plug. I've been having a listen just now and I realise that the sum total of small changes have added up to quite some more insight. To recap:

- 0V tag moved to correct earthing point on Technics PCB
- motor dynamics mod removed
- cable shortened to just long enough
- Neutrik plug installed at SR5 end
- Small sorbothane feet placed under SR5

I am noticing a lot of small cues in the recording that bring it more to life. Pitch is rock steady and this seems to make the high midrange and treble sound purer. Treble in particular is noticeably cleaner than CD. Dynamics are at quite another level and very exciting on some recordings. Surface noise and the odd blemish are not intrusive. 45 and 33 rpm sound similar but the sheer clout of some 12" singles is something to behold. The sound is big and full of impact and makes me want to keep playing more.

[Wakefield Turntables]

- 0V tag moved to correct earthing point on Technics PCB

Been following this for a while and i cant believe some of the comments I have heards about the Timestep powersupply. I opened up my 1210 to find that I too had followed the instructions and had incorrectly earthed the power supply and I notice a faint hum in the backgroud. Just to clarify, where does the power supply need to be properly earthed? It beggars belief that a "technics 1210 guru" hasn't a clue on properly earthing an external power supply. Incidently I too notice that small record cues in the background and also agree with the stability of notes with the mods that MartinT has done as I too have virtually the same mods, the only difference is that I dont have the SR5 which I may decided to purchase!!

[MartinT]

Just to clarify, where does the power supply need to be properly earthed?

As you look at the deck from the front, the earthing post and 0V point is at the bottom-left corner of the main PCB.

[JazzBones]

As you look at the deck from the front, the earthing post and 0V point is at the bottom-left corner of the main PCB.

For what its worth, I down load one of the better pictures of the 'opened'
1200/10 and then make a colour print photo to say a A5 size or something I can see clearly and then use a marker to notate the corrected point of connection. Also you have a visual on hand for any other reference once the deck has been put together again.

This saves time in having to come back to the PC, find the relevant advisory post and then hot foot it back to the operating table as it were....it works for me

Ron

[Mike_New]

It would seem that I have opened a hornets nest, with my observation and advice about the earthing point. I did not make mention of this before as I would never have believed it to be so!!!

May I sugest to Marco that maybe he sets up a sticky page that is a collecton of all the more pertinant advice concerning the earthing point and the motor dynamics mods and names it accordingly. This way unfortunates from other forums may be able to benefit from the advice provided by AoS.

Also an incorrectly fixed earth could have repercussions directly on the audio signal per se. because the earth return current from the motor control circuit is now partly spread over the chassis!! and the earth point for the Tone arm is in the vacinity. I will leave Paul to comment on this as he is far more experienced in this area than I.