1200 mk 2 newbie - PSU?

[Audio Al]

Just move your original power supply into a external box

I had big problems with a AT120e cart on a 1210 , the nearer the cart got to the power supply the louder the hum , Went the external route and no hum

[1200reasons]

which of the common commercial PSUs allow you to keep the original power switch (and LED), and which don't. My 1200 has mechanical hum (particuarly audible with headphones). I'd like to sort it out, but I think I've seen some PSU designs that disable the power switch and transfer the on/off control to the PSU- not what I want

[Stratmangler]

If I'm not mistaken, all the commercially available PSUs perform rectification duties off board, which means that all you'd need to do is connect one of the legs to one side of the switch, and the other side of the switch to the input. you'd need to find out which legs by metering them out.
You will also need to remove the bridge rectifier from the control board, and a couple of diodes as well.

[Marco]

Hi Hugo,

When you say 'LED', do you mean the strobe light? If so, unless you simply like the look of it or use the strobe function, it should also be disabled, as it adds noise to the circuit, which deteriorates sound quality, hence why KAB produce their strobe disabler board (which I have fitted to my T/T): https://www.kabusa.com/sx1200.htm

Any off-board PSU I've used with the Technics (KAB, Timestep and Paul Hynes), is designed to be left switched-on 24/7 (with the on/off switch located on the PSU itself), thus the Start/Stop switch on the turntable remains activated and performs as normal.

Marco.

[1200reasons]

Excellent. Looks like I was mistaken regarding the power switch

Personally I'd like to keep the strobe- Mostly for the functionality, but partially because i wouldn't be able to surpress the "something's missing/broken" feeling. Have you tested the strobe for noise Marco? I can only imagine that your 1200 is very revealing

[Marco]

Hi Hugo,

The effect of the strobe light, in that respect, will be subtle, but for me it just seemed like 'good housekeeping', in the same way as not using a mains distribution block fitted with neon lights. Also, I'm not into aspects of the Technics that make it look like a 'DJ deck', so I was happy to find a way of disabling the strobe light.

Plus, with a Mike New ETP platter, which has no strobe markings on it, the light no longer fulfils any function. When I can be bothered, the pitch control lights will be going too, for the same reason! In fact, the whole pitch control will be disabled and a new bespoke plain 'piano black' top-plate installed instead

My Techy is very much tuned for audiophile performance, so any 'extraneous fripperies' are simply not needed or wanted.

Marco.

[RobbieGong]

Hi Hugo,

The effect of the strobe light, in that respect, will be subtle, but for me it just seemed like 'good housekeeping', in the same way as not using a mains distribution block fitted with neon lights. Also, I'm not into aspects of the Technics that make it look like a 'DJ deck', so I was happy to find a way of disabling the strobe light.

Plus, with a Mike New ETP platter, which has no strobe markings on it, the light no longer fulfils any function. When I can be bothered, the pitch control lights will be going too, for the same reason! In fact, the whole pitch control will be disabled and a new bespoke plain 'piano black' top-plate installed instead

My Techy is very much tuned for audiophile performance, so any 'extraneous fripperies' are simply not needed or wanted.

Marco.

+1 and for the same reasons, although the pitch controls will likely stay on mine simply because I've had too much downtime with upgrades and so on. When she's next up and running it will be for years of playing and enjoying music only - can't bare anymore downtime pain.

[Qwin]

The strobe light offers no function on a technics SL-1200. Its a toy as you can not adjust the speed. All it shows is whether the pitch fader is correctly calibrated.
The speed is quartz locked, monitored and adjusted several times a second by the motor control circuit.
The pitch fader, cons the speed monitoring circuit, allowing +/- adjustments, but if correctly calibrated should be the right speed at zero (middle).
If the pitch fader is removed, speed monitoring is more accurate as there is no override calibration necessary and the deck monitors itself, so the strobe is surplus.

When removing/disconnecting the strobe LED's you need to remove the grounding transistor from the board, which is the main noise generator not the LED's themselves. This component rapidly switching and grounding the LED's causes them to flicker at the right frequency and still operates if they are removed, so it has to go too.

[guardofmagog]

Good point, I wonder if anyone on the forum has any experience with it? It's definitely the least expensive out of all the options.

Hi. Sorry to be a bit late on this but I do have a KAB PSU and i really like it. What is nice is it disabled the internal PSU but you can be reactivate it anytime. It is easy to do A to B comparison and it is incredible how this cheap PSU improves sonic. On top of the strobe disabler, this PSU improves the internal regulator. Definitively money well spent and Big Bang for your buck. I do not see the need to change for "bigger" and more expensive PSU.

The turntable keeps all the on off button function.

Eric.