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Thread: SL-1200 DC Power Supply DIY

  1. #271
    Join Date: Oct 2014

    Location: East Coast USA

    Posts: 96
    I'm Nathan.

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    I don't have any issues with jumping/skipping on bassy passages but I would like to check it to know it's current resonant frequency. Where would I get such a test record?

    Guys, please pardon us for going off on a tangent here.
    We the willing, working for the unknowing, are doing the impossible for the ungrateful.
    We have done so much for so long with so little, we are now qualified to do anything with nothing.

  2. #272
    Join Date: Dec 2011

    Location: Athens

    Posts: 268
    I'm Dimitris.

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    Yes it would be nice to deduct the effective mass, so that you know which carts it is going to work best with.

    I am using the Hi-Fi news test record.
    I got it from amazon a few years back

    I want to find another one with a better channel separation test, but that is different discussion
    Sources: Modified SL1200 MK2, Salas folded RIAA, Phonoclone, VSPS, Shelter 501 MK2, Modified Pioneer P6D6 as transport, Shigaclone transport, Peter Daniel NOS DAC.
    Amplification: Custom 211 Monoblocks, Electrocompaniet AW120, Audio Research VS110, Gainclone
    Loudspeakers: Tannoy Turnberry, PBN Montana EP Signature
    Cables/stands: Tempflex ribbon and Twinax cables
    Other: Promitheus Signature Passive Attenuator, Custom JFET - transformer preamp.

  3. #273
    Join Date: Dec 2011

    Location: Athens

    Posts: 268
    I'm Dimitris.

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    I found some time today to replace my old 3-capacitor pcb with my new 2-cap one.

    I did some quick listening on low volume, but can't say I noticed anything significantly different. Perhaps some thinness, but it could be from the fresh soldering and parts. I will leave it running tonight and do some proper listening tomorrow. Later this week I will also install the snubber to see if it's worth the trouble.
    Sources: Modified SL1200 MK2, Salas folded RIAA, Phonoclone, VSPS, Shelter 501 MK2, Modified Pioneer P6D6 as transport, Shigaclone transport, Peter Daniel NOS DAC.
    Amplification: Custom 211 Monoblocks, Electrocompaniet AW120, Audio Research VS110, Gainclone
    Loudspeakers: Tannoy Turnberry, PBN Montana EP Signature
    Cables/stands: Tempflex ribbon and Twinax cables
    Other: Promitheus Signature Passive Attenuator, Custom JFET - transformer preamp.

  4. #274
    Join Date: Dec 2011

    Location: Athens

    Posts: 268
    I'm Dimitris.

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    This weekend was a relaxed one so I had much time to listen to music.

    Going to a 2-cap filter on the PSU was definitely a setback. The sound was kinda mushier. But I will compensate for it with an extra RC stage inside the turntable when my regs are finalized. This will also help with transients by reducing the effect that the umbilical cable has.

    For now, I finally installed the Quasimodo snubber.
    And I am just basking in the awesomeness that it brought to the sound. Such a big and nice improvement on the clarity of the sound.

    If you do not know what I am talking about, here is the link to the post with my initial measurements and the schematic/parts.
    http://theartofsound.net/forum/showt...715#post811715

    Thanks again to Mark Johnson for a very nice testing jig.
    Sources: Modified SL1200 MK2, Salas folded RIAA, Phonoclone, VSPS, Shelter 501 MK2, Modified Pioneer P6D6 as transport, Shigaclone transport, Peter Daniel NOS DAC.
    Amplification: Custom 211 Monoblocks, Electrocompaniet AW120, Audio Research VS110, Gainclone
    Loudspeakers: Tannoy Turnberry, PBN Montana EP Signature
    Cables/stands: Tempflex ribbon and Twinax cables
    Other: Promitheus Signature Passive Attenuator, Custom JFET - transformer preamp.

  5. #275
    Join Date: Dec 2019

    Location: Vietnam

    Posts: 8
    I'm Tung.

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    Quote Originally Posted by 6L6 View Post
    This is my go at an external power supply for the SL-1200.

    My most sincere thanks for this thread, it was extremely useful in this process - http://theartofsound.net/forum/showt...chnics-SL-1200

    After a conversation with Wayne Colburn of Pass Labs, learning that he has made a SP-10 PSU for in-house use, a few things became apparent - Get the bridge diodes out of the TT and just have DC on the umbilical. Use 1N4007 diodes, for whatever reason they sound the best, even better than exotic high-speed diodes. Snub the bridge on the AC side with a .22uF film cap. Use multiple stages of RC filtering.

    The biggest improvement is of course, no transformer vibration on the platter, easily done merely by locating the transformer outboard of the TT chassis, and this is what I was originally planning to do - but converting umbilical to DC wasn't much more work.

    Does it sound good? Of course! And the best part is that I'm not even done yet, the stock regulator hasn't been replaced... (mainly because I ran out of time...)

    UPDATE - The first regulator modification can be found here --http://theartofsound.net/forum/showthread.php?26620-SL-1200-DC-Power-Supply-DIY&p=467311#post467311

    -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

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    The first thing to be done is remove the bridge diode and snubber caps.


    These were located in the holes now visible.


    An umbilical is added. The white 3rd wire is capped off, but still there if I need it for something in the future. The bare metal wire is the shield drain, to be attached to ground.


    Fused IEC plug, switch, microphone connectors used for the umbilical.


    All to be placed into this ABS enclosure.


    There is no reason not to use the stock transformer, it's the proper voltage, soft-mounted, has a beautiful mu-metal shield, and is free with the purchase of a turntable.


    (3) 4700uF 63V volt capacitors, (2) 10ohm 3W resistors, .1uF polypropylene bypass cap, all wired up in a CRCRC filter. Why those values? I had them on hand. If I needed to buy new, I would probably use similar values.


    And here it is with the bridge to the side. (The yellow is the transformer secondary.) The eagle-eyed among you will notice the 1K bleeder resistor across the cap bank.


    The final configuration of the umbilical attachment to the PCB. Of note the shield drain wire (the bare one) is not connected to anything at the PSU box. The shield is just at ground potential.


    The insides after the modification. I utilized the now unused AC power switch to switch the strobe.


    A few zip ties to attach the wire to the studs for strain relief, and of course the obligatory ferrite clamp.


    Schematic of the Power Supply.


    This is stage one of my PSU modifications, a different regulator of some sort will be next.

    Questions or comments warmly solicited.

    Thank you for looking.
    Dear 6L6,

    I know your power supply project has been done a long time ago, I am so sorry.

    I have a SL1200 MK3D, I searched for power supply modification and I found your thread. Actually, I can mod my turntable followed your instruction here.
    However, I would like to control the speed so I want to keep the original speed led (in the main power switch of the turntable), but I do not know how I can do. Please give some advices!

    Thank you so much!

    tungh

  6. #276
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    The PSU is only that, it does not control the functions of the deck. The switch on the schematic only connects the PSU to the mains supply, it does not make the deck spin.

    The Start/Stop and 33/45 rpm controls are momentary push button switches that trigger these functions, they connect to the function Chip mounted on the main PCB. These controls are connected to the PCB by the harness and multi pin connector, shown bottom left of the picture above. You can not run the deck without them, or replace them with latching switches, they have to be momentary.

    If you want to remove other items that might generate noise in the system, remove the speed fader and strobe LED and in particular the strobe transistor that causes the 50Hz flicker. Even if you remove the LED's the transistor is still in circuit and firing, so it needs removing, as in theory, this could add noise. The fader and strobe are not required for normal HiFi operation, the deck is self monitoring and maintains very accurate speed, these controls are for DJ use when track merging. EG. When the fader is set to "0" the deck should run at optimum speed. Adjusting the Fader cons the function chip into thinking the deck is not running at the right speed and it compensates, thereby creating a speed change. If you take the fader out, the deck just runs at the correct speed, be aware that if doing this, you have to bridge two of the pins on the fader harness header on the main PCB, or the speed control function will be seen as open circuit by the function chip.

    Note: My own PSU/Regulator project is based on Jim's circuits.

  7. #277
    Join Date: Aug 2012

    Location: Denver, Colorado

    Posts: 458
    I'm Jim.

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    As Ken says, there is no change in functionality to the table controls other than the on/off switch. The pitch slider works, the pitch LED works, the the strobe works, etc... The table merely sounds a LOT better because of the transformer being removed from the chassis.
    SP-10Mk2a, Graham 2.2 tonearm. SL-1200, Graham 2.2 tonearm, AT-150mlx, Benz-Scheu Glider. Jim & Ken Super DC PSU, Oil well bearing, Acromat, Isonoes, strobe lamp switched. Pass Labs Pearl 2. Aleph J amplifier. F6 Amplifier. Nelson Pass Burning Amplifier BA-3. Pass BA-PP linestage, miniDSP 4x10, Linkwitz Labs LXmini speakers, Sony SS-M7 speakers.

    DIY In progress - Syclotron Red Light district valve amp, ZenMod "Iron pre" autoformer jfet preamp, SYclotron 'His Master's Noise' valve phonostage. And about 2-3 other projects in various states at any time.

  8. #278
    Join Date: Dec 2019

    Location: Vietnam

    Posts: 8
    I'm Tung.

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    Dear Ken and 6L6 (I do not know about your real name, but I guest you are JIM)

    Everything is very clear and I could start my project soon. Thank you so much!

    However, as Ken says, I should take off the both fader board and led. I will explorer how I can do that (I am not at home now). If I am not wrong, it links to the mainboard by another multi pin connector, so I will disconnect them.

    For the strobe light, I think when I turn on the outside power, the strobe light is always on, is it right? Because, the DC power will lead from the mainboard to the light, it is not connected to the switch directly. I will try to keep it just for my experience, after that, I will find its wires and cut it off.

    For the switch, I would like to keep it enable. But, could I use the switch to turn the mainboard ON/OFF? It means I will turn on or off the 30v DC from the PSU outside before the DC could reach the mainboard. I do not want AC and DC power together in a wire shell...

    Sorry about my silly questions, because I do not know exactly what is included inside the small board under the switch and I am not a professional in DIY. I am just curious and want to challenge myself in this small project.

    Thanks and best regards,

    tungh

  9. #279
    Join Date: Dec 2019

    Location: Vietnam

    Posts: 8
    I'm Tung.

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    Dear Jim,

    I started my project with the Talema transformer (In 230v - Out 30v) and your schematic. It worked without burning (kidding), everything seems to be good. When I check the output of transformer, it is about 32-34v AC. But the DC output is just 24v DC. Is it normal? Or I have something wrong? I use the 2.2K for BLEEDER.

    Please help me!

    Thanks

  10. #280
    Join Date: Aug 2012

    Location: Denver, Colorado

    Posts: 458
    I'm Jim.

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    30v AC rectified will give you 40v DC before the filter bank. The bleeder won't make any difference. What value did you use for the filter resistors? And please post some well-lit, in-focus photos of your PSU please, can't help without them.
    SP-10Mk2a, Graham 2.2 tonearm. SL-1200, Graham 2.2 tonearm, AT-150mlx, Benz-Scheu Glider. Jim & Ken Super DC PSU, Oil well bearing, Acromat, Isonoes, strobe lamp switched. Pass Labs Pearl 2. Aleph J amplifier. F6 Amplifier. Nelson Pass Burning Amplifier BA-3. Pass BA-PP linestage, miniDSP 4x10, Linkwitz Labs LXmini speakers, Sony SS-M7 speakers.

    DIY In progress - Syclotron Red Light district valve amp, ZenMod "Iron pre" autoformer jfet preamp, SYclotron 'His Master's Noise' valve phonostage. And about 2-3 other projects in various states at any time.

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