Its regulation time!

[Frankyc2003]

Straight from California!

The LT317s have landed.

http://i835.photobucket.com/albums/zz275/frankyc2003/47b6a279-a669-4756-943d-1ae4ddca6760_zps69aa4846.jpg

I fell some voltage regulation is coming to my SL1210!

I will keep you updated on my progress obviously!

:cool:

[Wakefield Turntables]

Hmmmm interesting which bit of the pcb are you going to regulate?

[Frankyc2003]

First i am just doing a straight upgrade from the stock regulator...
See how it goes... Add a cap to reject ripple as well!

Then I shall investigate multi regulation...

:stalks:

[mido]

Interested to hear all about it Francois, make sure you keep us updated won't you!!

I will be taking my 1210 over to my mate's next week for him to start modding.

Have to say, it's already sounding pretty good just with a Jelco arm, Isonoe feet and a change of mat :)

[Frankyc2003]

I am glad your are liking your SL1200!
I will surely post my musings here within the next few days!

:lol:

[sq225917]

Is their performance any better than any standard 317?

[Frankyc2003]

According to the datasheet, if using cheap 1% resistor, you are guaranteed an overall power supply tolerance better than 3%.
Basically it's a LM317, with improved regulation performance.

[Frankyc2003]

OK, so here we are after spending my afternoon figuring out the best way to implement the LT317 voltage regulator for my Technics SL1210 Mkiii., I have drafted a semi-impressionistic (;)) diagram of what I am intending to do...
As usual, I am trying to keep as much of the original fittings as possible.
so here we go... Drawing isn't to scale but it helps visualizing the modification...

http://i835.photobucket.com/albums/zz275/frankyc2003/lt317_zps58ec5e80.jpg

I will also cut R2, R4 and C3 from the PCB as they are no longer needed.
BTW, I mean R2 on the original PCB, not R2 from the Voltage regulator obviously :eyebrows:
A few areas of concerns for me, firstly the fact that the pin layout of the LT317 is different to the Q1 used on the Technics. So I have to twist two of the pins... Not ideal!
Secondly, size of the 2200uf Capacitor... I am slightly worried that it might be too wide and starts rubbing on the bottom of the aluminium platter, again not ideal!
So maybe the best implementation is to use the pit left by the traffo, as per the Paul Hynes regulation mod posted here on AOS... It's an idea...

So while I am waiting for my spanking brand new Weller Soldering station, have a good look at my drawing an let me know if any one of you very learned people can notice any abnomalies and just stupid mistakes in my intended modification...

As per usual, thanks a lot for help and advices! And a happy Sunday night!

:cool:

[Frankyc2003]

Aha! I am such a div!

Obviously I can just solder the cables coming out of the regulator PCB according to the new pin layout!!!
Much easier an neater than trying to twist the pins!!!!

:lol::lol::lol::lol:

A problem shared is a problem halved as they say!

[OneyedK]

Hello Franky,

I'd rethink/redraw your grounding scheme.
It's a good thing you chose to earth the new "C1",
but all LT317 related components should use the
same grounding point.
That's the only way to keep the output impedance low.
A bit like "figure 3" of the LT317 datasheet...
If needed, you can always make a small pcb (simple holes and isles) and hang this on the LT317's feet.

[Frankyc2003]

Hi Karl,

Thanks for your advice.
I see what you mean by having a common ground for all components...
I will reconsider my diagram...

Good thing that I haven't started soldering yet...
I will invest in a tiny piece of board to mount all these guys!

Cheers

PS. actually I was thinking, if was to get an radial version of C1 that would make grounding a lot easier, and everyone would share the same ground?
Am I right?

[6L6]

Are you trying to do this? --

http://www.audiocircle.com/index.php?topic=106045.0

It looks like you are. There is some good advice in there about this process.

Also, I really like your drawing - are you an Architect or Draftsman (Draughtsman in the Queen's English...) It's fantastically good for a sketch.

[Frankyc2003]

Thanks Jim,

I am a graphic designer / illustrator, so I guess it helps me visualizing what I am doing!

I did see this post actually, but I am quite keen on the idea of a simple module to fit under the bonnet...
I noticed as well that he didn't use any caps on the input or the output, probably because his filter cap is so close that it's actually directly soldered onto the LT317! Also he hasn't used any protection diode...

Nothing major though, and his mod seems to work a treat...

[Frankyc2003]

Ok, done a few alterations...

http://i835.photobucket.com/albums/zz275/frankyc2003/do_zps018df895.jpg

All will now go on a piece of veroboard in the pit left by standard PSU.
I am on it all Saturday!
Hopefully I will report on the sound later on that day!

[OneyedK]

There's a litte mistake around D1.
D1 should be the way it is, but the output (21V) cannot touch the input.
Also, the 10µF should be film (Wima), if it is, a smaller value is not a problem.

And the clip on the LT317 should be the other way around... Methinks...

A 100nF bypass to C1 would be nice too ;)

[Frankyc2003]

There's a litte mistake around D1.
D1 should be the way it is, but the output (21V) cannot touch the input.
Thanks Karl, I was just following the datasheet. How should the diode connect in reality?



And the clip on the LT317 should be the other way around... Methinks...
The illustration isn't accurate :doh:



A 100nF bypass to C1 would be nice too ;)
Would a 1uF do?

Cheers

F

[Frankyc2003]

:doh:
:doh:
I see what you mean now...

The IN track will be cut to leave OUT isolated from input...
I think my doodle got a bit messy!!!

Cheers for the insights!

F

[OneyedK]

The diode should be as you drew it, cathode to input, anode to output.
But the output from the circuit must also be taken from the anode, not the cathode (as per your drawing).

For the clip, use the LM317 datasheet, there's a better illustration...

And yes, a 1µF film cap is perfect to bypass C1.

[Frankyc2003]

Hopefully, I have now done my homework...

http://i835.photobucket.com/albums/zz275/frankyc2003/20130215_154927_zps42e5014e.jpg

I will prototype it tomorrow...

Cheers

[OneyedK]

This looks perfect...

[Frankyc2003]

Many thanks Karl!

Let's implement this mod, and next to come is a split regulation to different points of the PCB... (obviously entirely inspired by the Paul Hynes modules!)

Hours of fun!!!

:cool:

[sq225917]

Why not just add a gyrator and get another 20db rejection?

[Frankyc2003]

Why not just add a gyrator and get another 20db rejection?

Interesting! How would you use the gyrator on the circuit?:scratch:

[OneyedK]

Why not just add a gyrator and get another 20db rejection?
I'm familiar with the theory behind the gyrator, but I have no idea how to implement it in a power supply like this one.
Can you draw a practical schematic?

While I was thinking, it seems not the best idea to move C1 away from the rectifier.
You want the switching noise to be killed as fast as possible, before it starts radiating away around the board...
Maybe splitting C1 in 1000µF close to the rectifier and 1000µF close to the regulator is a better idea, both bypassed with a film cap...

[sq225917]

let me look at the circuit when i get some time, chopping down trees today.

[Frankyc2003]

I'm familiar with the theory behind the gyrator, but I have no idea how to implement it in a power supply like this one.
Can you draw a practical schematic?

While I was thinking, it seems not the best idea to move C1 away from the rectifier.
You want the switching noise to be killed as fast as possible, before it starts radiating away around the board...
Maybe splitting C1 in 1000µF close to the rectifier and 1000µF close to the regulator is a better idea, both bypassed with a film cap...

Indeed and that can be implemented really easily...

[nat8808]

http://i835.photobucket.com/albums/zz275/frankyc2003/lt317_zps58ec5e80.jpg



That's the best diagram I've ever seen of a DIY project... Thanks for that!

[nat8808]

http://i835.photobucket.com/albums/zz275/frankyc2003/do_zps018df895.jpg



...tut tut, lazy sod.

[Frankyc2003]

Thanks and point taken...!

[Frankyc2003]

There we go, prototype 01 finished!
Not the prettiest of prototypes, but there is always a first time...

http://i835.photobucket.com/albums/zz275/frankyc2003/ca6c5bfb-4826-46bd-a083-913528db9c1a_zps3a513d65.jpg

I went with original value for C1 (2200uF), as soon as I have a second I will drop the module in... And listen to the results...

;)

[OneyedK]

That's huge! ;)

Is the 21V correct?

[Frankyc2003]

That's huge! ;)

Is the 21V correct?

I have no means of checking it at the moment...
But a friend of mine will bring his bench DC PSU, so fingers crossed...

:eyebrows:

I have read in a few places that this modification will do close to nothing to the sound of the Technics, which is fine, since this is always good practice and a fun project to work on...

I have already the project to build a nice bespoke PSU, and regulate more areas of the PCB...

And if all succesful, I might embark on a PSU for my rDac and my SBT!

Fun times:lol:

[Mike_New]

Hi Folks.
I have no wish to appear negative on the above project and the work that Francois has done. However would it not be wiser to put this new regulator in a box together with the tranny and just supply the 21V DC to where it ir required.

Because I am concerned that for those who are not skilled in DIY electronics; when they test the circuit they have so proudly modified, it is too late if they have ballsed it up, and blown up vital components as has happened in the recent past.

[OneyedK]

Hi Folks.
I have no wish to appear negative on the above project and the work that Francois has done. However would it not be wiser to put this new regulator in a box together with the tranny and just supply the 21V DC to where it ir required.

Because I am concerned that for those who are not skilled in DIY electronics; when they test the circuit they have so proudly modified, it is too late if they have ballsed it up, and blown up vital components as has happened in the recent past.
Hello Mike,

While it is a good idea to put transformer/rectifier/first cap in a separate housing, feeding unregulated DC to the deck,
it's not a great idea to move a regulator "far" from it's load, most (if not all) regulators work best as close as possible to the load.

But your warning to not so skilled DIYers is legit.
There's alway the chance of blowing something up.
@Francois: it's time to invest in a multimeter ;)
On the other hand, if you don't start experimenting, you learn nothing.
It's a calculated risk, a new technics pcb can be had for around €250...

[Frankyc2003]

First of all I need to clarify something.
ELECTRICITY ISNT A TOY.
What I am showing in this thread is purely a brain dump for me to record what I am doing.
UNDER NO CIRCUMSTANCES I AM SUGGESTING TO ANYONE TO FOLLOW MY EXAMPLE.
PLEASE DONT DO WHAT I DO, AT THE RISK OF DAMAGING YOUR STUFF OR WORSE HARMING YOURSELF AND OTHERS.
If you want a good PSU and on board regulations, contact some expert. Paul Hynes here does some fantastic modules. All is very nicely documented on AOS.
Now that I have done my disclaimer, (Thanks Mike for reminding me), I should be a little more careful about posting DIY stuff on forums.
Also, just to clarify, my regulator isn't connected to anything at the moment, and it wont be until it gets the all clear by my friend (a confirmed broadcast engineer, ex BBC). I do have a multimeter but I am missing a bench PSU to feed it at least enough DC.
I always keep my modifications fully reversible and non destructive as told by my friend.
As Karl said, if you dont try you wont learn.
So I will keep on trying but I shall be a bit more careful about what I post!