SL-1200 DC Power Supply DIY

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Originally Posted by Ianmac

Tried ARTA but no better.
I will probably just have to content myself with my ears for now.

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I gave up on measurements, too little space and without a reference it is hard to know what's right even with a proper measurement. Then how do these electrical signals translate to sound? Kind of mystery to me. Btw I focussed on time domain measurements.

I trust my ears but I know the limitations.

Ultimately measurements and listening are the only way to make any further progress.

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The big consolation is that my Deck is now very very good.
It hasnt cost me a lot of money to get there.

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I and of wondered if you a planning to offer regulator pcbs or something. The LT devices have specs that far better match the load regulation requirements of the components on the deck than a 317.

My own experience is that not only the regulator and its implementation matters but also the grounding of input, ref and output. This does not always follow plain logic and it seems to matter a lot.

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...... Im still using the std arm with my own silicon arm damper...... Do I now look at some mods to the techie arm ?

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Tonearm and cartridge lust are always short around the corner. Forget cheap "upgrades" here. I didn't think the Jelco nor the Rega added any value here save for a different sound.
The stock tonearm is actually a very solid design and execution. Bearings are chatter free afaik and the weight suits may carts. The only thing I swapped so far is the cable part from the tonearm pcb to the phono stage. Just cheap and simple "shielded low noise microphone cable (OFC)" with nice plugs. The sure helps though I think the internal wiring is a candidate for replacement.

Yes measurements are not easy, but if I can get an old platter I will still machine it to allow access to the electronics.
I did think of PCB's but there does not seem to be much interest apart from 3 or 4 of us. and we all have regs built.
I have built these very easily using vero board with repeatable results using the minimum number of components.
I could post detailed photos and sketches of the layout if that was helpful.
I have come to respect the LT regulators, and their lower dropout voltage meant I could use a quality off the shelf mains transformer @18-0-18v (allowing for regulation and mains input tolerances)
They are more expensive than the older regs.

I have been looking at modifying a rega arm or building an audiomods version , but Im moving into territory where the is spend more than the deck cost.(all my mods are DIY except a S/H SDS platter plate)
The silicon damper gave me a worthwhile improvement, as did fitting a soft copper washer in place of the rubber gasket between headshell and arm. Is this an indicator that a weak link is the break in mechanical connection to provide a removeable head assembly. If one looks at the dissipation of energy in the form of sound vibration across differing materials and how best to absorb that energy. I might get a clue.
Im debating the fitting of a fixed head support onto the Techie arm, this could be welded on using a low temperature weld rod like lumiweld. Drilling multi holes in the arm and filling with Foam.
A few hours drawing and machining,it wont cost me a lot if it doesnt work
I think Qwin did fit a straight arm to a technics arm bearing using an alum tube with carbon fibre outer sleeve and a Linn head shell mount. Maybe I should drop him a PM .

There could be more people lurking silently around these places. :)

It's just that the 317 already works nicely so there might not be much interest to get things even further, unless an equally easy solution is provided.

Smds are unfortunately a brick wall for most diy people.

Perhaps we can work on something with lt1963 or lm1085?

In any case, as we discussed I can help with pcbs, and even with soldering of smds if this is wjat we decide to work with

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Originally Posted by Ianmac

I have built these very easily using vero board with repeatable results using the minimum number of components.
I could post detailed photos and sketches of the layout if that was helpful.

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That would be very nice!

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I have been looking at modifying a rega arm or building an audiomods version , but Im moving into territory where the is spend more than the deck cost.(all my mods are DIY except a S/H SDS platter plate)
The silicon damper gave me a worthwhile improvement, as did fitting a soft copper washer in place of the rubber gasket between headshell and arm. Is this an indicator that a weak link is the break in mechanical connection to provide a removeable head assembly. If one looks at the dissipation of energy in the form of sound vibration across differing materials and how best to absorb that energy. I might get a clue.

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I removed the rubber gasket once but thought is was much better left in. Is the copper washer a diy effort?

I noted that the headshell leaves considerable axial movement even when clamped.


MOD update:

I proceeded with the "final frontier mod" but encountered some misfortune. Unlike other mods where getting the new reg up and running was sufficient for an improvement it did cost extra effort to arrive at a satisfactory sound. It sounded quite all right without the reg in place but with the new reg every little detail seems to matter. I arrived at a 317 reg that is set up very similar to the main reg for the 21V board voltage. The sound is unfortunately very unstable (sounds different each time I listen) and I suspect the NOS black gate buffer cap to be responsible for this. This is the cap I had lingering around and put in the circuit, they are notorious for their long "break in". Therefore I'm reluctant to call this mod a success yet.

The copper washer is a DIY effort. You can buy a washer of the correct dia ( 12.5mmm OD 8.4mmm ID, 1mm thick or 1/2 " * 5/16" * 1/32") and file a grove in it to just slip over the locating pin.
Before installing it anneal the copper to make it soft. This allows it to form to the shape required to match the techie components.
To anneal copper, take it to red heat on the gas then let it cool, it will remains " soft " for 12 -24 hrs then slowly harden again to its normal state.

Given the wide tolerance of the techie detachable head, the pin is a bit smaller than the locating grove.
,I find it difficult to get a repeatable azimuth setting when changing or removing /replacing the head. I keep mine set hard to the right and hold the head in that position when tightening the clamp ring.

@Ianmac I found a proper copper washer at the nearby carparts store. I filed a slit and heated it red hot on the gas furnace. At first the surface turned silvery but that came off as a powder later. With the washer and new tonearm balance (the copper washer is much heavier) I listened to some tunes. My first impression is that the sound is cleaned up and more dynamic but also a little rough. It reminded me of my first cd player. A second listen this morning learned that the sound is also lacking proper highs. So I won some and lost some. Likely this mod works better in conjunctuon with the viscous damper. For now I prefer the stock rubber washer.

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Originally Posted by Ianmac

I think Qwin did fit a straight arm to a technics arm bearing using an alum tube with carbon fibre outer sleeve and a Linn head shell mount. Maybe I should drop him a PM .

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Do give that mod some serious thought. I did it to my deck (along with better tonearm wire) and it was a very nice improvement. When completed, the arm is lighter and better balanced because the headshell end is lighter than the stock arm. Where this really shines is it's lack of resonance. The aluminum/carbon fiber tube is so much less resonant than the stock tube it isn't even funny. The cost? Less than the price of a good armboard. Scroll down to the eighth pic The Techie tonearm mod

Keep an eye on your cart's compliance and the resonance frequency with your tonearm's mass

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Originally Posted by dimkasta

Keep an eye on your cart's compliance and the resonance frequency with your tonearm's mass

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Well, I'd like to say I did that :whistle:
The aluminum/carbon fiber tonearm tube is both lighter and less resonant. Is that a good thing? My cart is an AT120e and I had to add a 2g weight because the headshell end of the tonearm, now lighter, couldn't get the stylus to set down on the record.

If you did not check the resonance frequency with a test record then you didn't :)

Don't get me wrong. This has nothing to do with your DIY efforts. And nothing to do with actual ringing of the arm.
It just has to do with how your new arm compliments your cartridge.

With commercial arms, you can put your cart's compliance and the effective mass (not weight) of the arm on a calculator and get the resonant frequency. Your goal is to put this frequency at ~8-12Hz. This will make it high enough to not let them resonate with rubble, and low enough so that they do not resonate with bass from your music.

With a DIY arm you have to check it with a record.

If you do not have a test record, an indication that you have an issue with amplified rubble is if you see the cones of your speakers wobble.

But since you decreased the mass, chances are that you are closer to bass frequencies. Check it if you have more issues with jumping/skipping on bassy passages