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Good! :)Quote:
Originally Posted by Qwin
The schematic diagram and the parts do match, and exactly.Quote:
It was like I thought, the diagram and parts do not match, you have to rotate the photo of the parts to get the same orientation as the schematic. That dictates which corners the inputs/outputs are connected to
The layout of the parts is what's different, as there is a bunch of ways you could arrange the parts and have it electrically the same. :)
AoS Policy for threads like this is that we insert a warning regarding the safety of working on the mains. This should have been done earlier in the thread but seems to have been overlooked. I have added the following to the original post, but will repeat it here for the benefit of those who've read this far and missed it.
STOP!
Before you put yourself or others in danger, think very carefully about whether you are qualified to carry out any of this work.
Art of Sound Electrical Safety Advice
The Art of Sound is an open forum for music lovers and a place where all members can share their views on music and the equipment used for its reproduction.
The forum also caters for those who are interested in the DIY aspect of everything related to the audio replay chain, and therefore there will always be a healthy number of DIY articles and discussions in threads across the forum. Given the number of these, it is not possible to monitor or moderate all technical aspects of posts made by members.
The Art of Sound would therefore like to remind all who read such articles that while we encourage discussions on all audio related DIY we cannot and will not accept liability for the information given on any DIY related matters contained in any thread or posts herein.
We strongly advise extreme caution when considering any modification or building projects described, especially those concerning any mains voltage related upgrades, earth modifications and/or any other high voltage related modifications or building projects.
Unless you are suitably qualified or otherwise capable of carrying out such modifications/suggestions, then we strongly advise you consult qualified personnel.
We would also like to remind all our members and readers that some or all of the modifications found within the threads and posts of the forum may not be legal in certain countries and therefore advice on the legalities or otherwise should be sought before carrying out such modifications.
Advice acknowledged Chris.
The thing that confused me is the interpretation of the word "exactly" to me this means identical in every way.
You should be able to overlay one on the other. If the + input is on the left corner on one, it should be on the left corner on the other.
I think it is more acurate to say that Francois prototype follows the design in his rectifier schematic. The physical layout in the photograph does require some reorientation to align with the diagram and as their are no wires connected the hook up was not clear to me.
I've not worked with Diodes before, other than straight replacements on a PCB, so not knowing how their physical orientation compared to a schematic symbol (at the time) had me unsure. A bit of research tells me the stripe marks the cathode end which is the end with a bar the arrow points at on the symbol. I feel confident to proceed on that basis and as advised will test the output from the rectifier before connecting it to the Technics PCB.
I actually have two SL-1200 decks but only one main PCB and one stock power supply between them.
I externalised the stock transformer as in Francois earlier visual guide for one deck. I am now looking at a stage two upgrade allong the lines of what Jim has done for the other deck but will require a Transformer of some kind. I noticed that for the price folks are asking on fleabay for a used Technics Tranny you can actually buy a brand new R core transformer, so that is what I am considering doing.
Hi Ken,
I have to apologise for not giving you full explanations on this part of the circuit. I was not near a computer last night...
I have overlaid my prototype with the schematics, so hopefully it will now make more sense:
http://i835.photobucket.com/albums/z...ps1ae19c13.png
And I have added here the common symbol for diodes and what they look like in reality.
http://3.bp.blogspot.com/-vxFTOtMSUd...pter_diode.jpg
Please don't hesitate to ask more questions, more than happy to help!
You are right, I sometimes assume that everyone know what I am talking about... which in this case could be confusing...
Again, sorry for the poor explanation!
:goodthread:
I was looking for a smiley to say good post really. Well done Francois on making it crystal clear for those with less experience in these matters.
:cool:Alan
My apologies, I didn't know that was a matter of policy. A perfectly sound idea. Thank you for inserting it in the top post, and I will include such things in the future.Quote:
Originally Posted by The Grand Wazoo
No problem Jim, it was our oversight, not yours.
Mnnn - I hate loose ends and I have to be missing something here because Jims diagram doesent make sense to me.
I can't see how you can get 30Vdc output from the circuit using the stock Technics Transformer?
The stock Tranny secondaries are about 30Vac ( Francois measured 31.4).
If full wave rectification increases the voltage by a factor of 1.414 to 44.4Vdc, less a couple of volts for diode consumption, that still makes the output at around 42.4 Vdc not 30Vdc? I know this is not loaded, but would it make that much difference?
This higher output is what Francois found with his Teroidal that had 30V secondries, surely the stock tranny having similar output is going to do the same thing?
Help :scratch:
You are quite right. The diagram has been changed.
Thanks Jim,
As you know I am new to electronics and trying to pick it up as I go, with my various projects. That difference really threw my fairly logical approach to things. I had presumed that your Rectifier and indeed the stock one on the main PCB must be delivering more than 30v so I can relax a bit now.
Ok - This is what I am now considering.
A remote mounted Transformer with 22Vac secondaries, a rectifier as per your scheme, which should turn out about 30Vdc.
Run this through a capacitor/resistor filter as per your build and then through an LM317 regulator/divider to output a regulated 28Vdc.
All housed in a remote steel box.
This (regulated 28v) is the same output as the KAB PS-1200GX supply. I would purchase the KAB DC-1200 20V regulator (about $50) which replaces the stock internal regulator. The 28V supply connects directly to the KAB regulator board with a ground wire running straight to the main PCB ground screw in the bottom left corner (where you grounded your screen). Seems like a plan?
If anyone would like to comment on that proposal, all input gratfully received. :)
I suggest using the stock transformer. If you really don't want to, send it to me, I would love to have a spare, they are very nice, and with the mount and shield would be very useful for other projects. And yours will have the dual primaries... Mine is single 120V
The KAB supply is a SMPS and so in a matter of speaking, pre-regulated. (The KAB is quite nice by all accounts.) I'm not sure if having a 317 based pre-regulator would be all that beneficial in the outboard supply. I would try a shunt regulator or a simple capacitance multiplier in the outboard, (or just more capacitance or RC stages) and then some kind of modern regulator (317 or something more fancy) in the TT chassis.
That said, your ideas seem quite sound, and are worth a go. :)
IF you can wait a bit (I'm out all next week for Captain recurrent training) ((I sit in the pointy end of jets for a living)) I am working on an easy LM317 based reg for inside the chassis. (The KAB DC-1200 is a LM317 design) After that I will try another configuration for the internal reg. (A "Tracking pre-regulator")
I will make a layout, plan and BOM for the simple configuration to be assembled on a small piece of stripboard. I actually knocked it together point-to-point, but a board would make things much easier.
Stay tuned!
I'm in no hurry Jim so I will wait and see what you develop for the regulation.
I have two decks and only one transformer, so I have to buy either a second hand Techie unit off fleabay, or a 22V r-core, which is a similar price due to the genuine Techie parts carrying a premium price. (used item £25/35 +P&P over here)
I will now go and research some of the things you mention to try and appreciate how they effect things.
As allways your input has been appreciated.
As mentioned in various threads here, in the context of the Sl12xx regulation should happen as close as possible to the load. Meaning your LM317 or LT317 should stay within the body of the TT close to the motor and various chips. (let me know if I am talking garbage, as I am in no way an expert in the field)
A wee while ago, there was a debate about the TimeStep external power supply having a LM317 inside and therefore being too far from the load. (again shoot me now if I am talking nonsense)
If you look at some of the regulation modules that Paul HYNES does, they all seem to live close to the main PCB, inside the body of the TT.
Unfortunately I can't explain why this is considered to be a benefit, but I am sure someone here will oblige... (again this could all be nonsense, I am just reading various posts here, and trying to learn)
As per a 'Tracking pre-regulator' I am very excited to read Jim's thread when it is published.
:more:
Finally if you are looking for bespoke regulator modules that can be implemented easily within SL12xx on a tight budget, I would suggest this module I used myself succesfully...
http://theartofsound.net/forum/showt...ics-SL1210-M3D
It's easy and fairly cheap, and Brent is very pleasant and helpful!
Read this - it's fantastic - http://www.acoustica.org.uk/t/3pin_reg_notes1.html (4 pages)
I'm going to try the configuration on page one, with the zener reference. This is the one I've already made, but haven't installed it yet.
The tracking pre-regulator is the 2nd one to try, found on page 4
You don't have a hat!Quote:
Originally Posted by Frankyc2003
Francois you're a star, the vinyl arrived this morning. An excellent choice you made, as it has filled a gap in my music collection.Quote:
Originally Posted by Frankyc2003
Very enjoyable and on 180g :yay:
:cheers:Alan
No worries Alan,
I hope you enjoy it!
:cool:
I have installed the first LM317 based regulator in my SL-1200. There is not a specific schematic in the article, look at the one on page 1 of the off-piste article, and all you do is replace R2 with a Zener reference and make sure you include C2.
I did mine point-to-point (on air?... I think the Queen's English and American English are different in this regard.) and covered up all in heatshrink as I don't want anybody copying me directly, do as I say, not as I do and all that...
It works wonderfully, sounds great, and took about 15min to install.
http://i198.photobucket.com/albums/a...ps16456f72.jpg
Here it is... not particularly exciting.
http://i198.photobucket.com/albums/a...ps141082d8.jpg
Lift the motor PCB and remove the old pass transistor and wires. (You could just cut the old wires and splice if you desire)
http://i198.photobucket.com/albums/a...ps232cb2af.jpg
It mounts in the same position as the old transistor.
http://i198.photobucket.com/albums/a...ps909d9272.jpg
Don't forget some kind of insulator under the regulator - the old transistor was a 'full-pack' and did not need an insulator.
http://i198.photobucket.com/albums/a...psb4161c5d.jpg
The regulator need to be grounded here, at the turntable center ground.
http://i198.photobucket.com/albums/a...ps753e9309.jpg
Schematic
I'm corresponding with a member who is wanting to do this mod, and have put together the beginnings of a parts list from Farnell -
Big caps - http://uk.farnell.com/panasonic/ecos...63v/dp/1198722
Diode Bridge - http://uk.farnell.com/multicomp/gbpc...00v/dp/1621681
Bridge snubber - http://uk.farnell.com/vishay-bc-comp...ial/dp/1215473 (Note that 5 is the minimum quantity. No big deal, they are 19p each) ((use one of these as the film bypass on the big caps as well))
Bleeder resistor (I'm linking to a different value than the one I used, this is better. )
http://uk.farnell.com/te-connectivit...2k2/dp/1751857
Filter resistors - http://uk.farnell.com/te-connectivit...10r/dp/1751825
Hi Jim
The Farnell part links are very usefull for us this side of the pond.
Any chance you could do the same for the regulator?
(Even if instructions on how to build come at a later date).
Farnell have a min £20 order, so its cheaper if you can buy as much in one hit as possible.
Ken - I would be quite happy to. :) :) :)
Regulator - http://uk.farnell.com/texas-instrume...317/dp/9489380
Caps - http://uk.farnell.com/vishay-bc-comp...35v/dp/1165526
Resistor - http://uk.farnell.com/welwyn/pr5-240...ppm/dp/1634034
Diode - http://uk.farnell.com/on-semiconduct...ditmatch=rel_3
Zener (you need 3) - http://uk.farnell.com/american-power...-2v/dp/1651144
I'd just like to say thanks to Jim who has been putting the parts list together for me. It is much appreciated :)
"thanks to Jim" +1 :thumbsup:
Quote:
Originally Posted by 6L6
You can usefully improve this circuit by increasing the current through the Zener, with R1 at 240R you are only passing 5.2mA. The Zener impedance and noise will drop further and the LM317 will work better if you use the recommended value of 100R for R1...this will increase the current to 12.5mA, the Zener dissipation will rise to 240mW but its well within its rating.
You can increase the output voltage a touch and get temperature compensation 'thrown in' by placing a normal diode in the ground leg of the Zener, this will raise the voltage from (19.25+1.25) 20.5v to 21.1v....all as per the acoustica.org.uk site.
Also one tip take is to the Adj pin ground connection to the load directly IE: don't connect to the nearest ground point but ground it at the load itself...
Neal,
Great info!
Why does the zener noise decrease with an increase in current? I'm not familiar enough with this to know about it. I will give it a go when I wire it up on stripboard.
I like the idea of the temp compensation with a 'normal' diode in the reference string as well. (Which will help trim the voltage, as I'm using a string to get to the reference voltage...)
As for the ground, the idea of putting it straight to the load is quite sound. But where would that actually be on the motor board?
Jim – I am trying to do a layout for the regulator. Any chance you could update your schematic to show how the THREE zener diodes on your parts link connect up to each other and the rest of the components?
:please:
I can see from the last couple of posts that this may still be under development, but the info would at least allow me to do my layout on paper.
I am going to mount the components on a Paxolin board using solder eyelets and do point to point wiring on the reverse side – similar to one of my other projects here:
http://www.jkwynn.co.uk/Project_Images/HPD/HPD_003.jpg
I have drawn up the components from your list at full size and will arrange them on the board to suit, when I know how from your schematic. I am going to mount the board using the same fixings used for the regulator holding strap and this picture will give you some idea of what I am trying to achieve:
http://www.jkwynn.co.uk/Project_Imag..._Regulator.pdf
For anyone looking for a piece of insulation to go under the regulator, Farnell do a purpose made piece for the version we are using. Trouble is they’re presuming we are using the mounting hole. They also do a larger version for another application. You can cut off the ear for the mounting hole, leaving a large enough plain rectangle to fit under the LM317 with space to spare.
Find it here (pack of ten £1.42):
http://uk.farnell.com/multicomp/mk33...238?Ntt=520238
Ken -
The diodes go in series in the same spot shown as the zener diode. I'll draw out something... but you have to understand that schematics are not layout diagrams. You could lay out a handful of components tens or hundreds of different ways and it be the same electrically.
Also this would be a better choice for insulator, it's actually the right size for the 317 - http://uk.farnell.com/jsp/search/pro...note-520214-pr
Thanks for that Jim, I can work from that information, though no doubt you will update your schematic for us all at some point.
The parts I have drawn are free standing sub assemblies, so I can move and rotate them till I am happy that I have a space efficient layout, that allows point to point wiring, without any wires having to cross each other. I have allready gone through 6 possible layouts with a single Zener, but I wasn't completely happy with any of them. When I get it right I will update the PDF file to show what I have done, you can have a look see before I warm up the soldering Iron. :D
The insulator you link to is the one I mentioned and had rejected. It requires the use of a fixing screw through the mounting hole and the insertion of the insulating grommet on the screw which normaly aligns the regulator and insulator sheet holes. We do not have a fixing hole on the Technics (unless you drill and tap one) so there is no insulating gromet at the fixing hole, just air insulation and very close proximity between the walls of the hole on the regulator and the Technics mounting platform. This may be down to 0.3mm or less depending on the clearance hole allowance and whether you exactly align the regulator and spacer without it moving. I know the platform is painted and we are talking low voltage and amps, but I would feel better with a physical barrier of 0.1mm Mica, rather than the very small air gap and paint. Just my preference. ;)
Jim, the answers are in the acoustica pages. Also on the Ron Elliot site he talks about setting the current of the zener at 25% or slightly above of its rating so as to operate it at its most linear point which a 100R resistor would just about do or you could bump the current up a touch more if you felt like it.Quote:
Originally Posted by 6L6
http://sound.westhost.com/appnotes/an008.htm
Re the ground connection, I'm not sure, I don't know the circuit layout. What is the regulator powering? It maybe just fine with the original connection point.
Neal, thanks for the update! I will change the resistor on the next go, and research more. :) (Although with 3 zener in series to get the desired voltage, it's probably not going to get in the 'sweet spot' of dissipation...)
The regulator powers the +21V rail, most of the circuitry is downstream of the reg. The stock reg finds ground though the control and reference circuitry, which needs to be bypassed (by simply not connecting it) when using a new regulator. The easiest way to do this is run a wire back to the TT center ground, as shown in the photos.
Also, please check your PM.
Hi Jim. Replied.
A single 19.25v Zener might be better than three in series although if in series they will all pass the same amount of current. The earth connection is probably OK as it is.
A 19.25V Zener would be a great improvement do to the simplification, no doubt. However I can't find any 1W in that voltage.
Jim -
I have compleated my layout:
http://www.jkwynn.co.uk/Project_Imag..._Regulator.pdf
I will wait to see what the out come is for Zener choice and resistor value before going any further.
The layout is optimised for straight line point to point soldering of uninsulated wire.
Further space could be saved if it was optimised for PCB tracks :eyebrows:
I see what you mean! Although there are some 19V SMD available. How about using a TL431, lower impedance still and much quieter as well...something like this:Quote:
Originally Posted by 6L6
http://i94.photobucket.com/albums/l8...17_Control.png
This is for a 5v output from a 9v battery. The Cathode needs a min of 1mA for the TL431 to work hence the 8K2 resistor. I would also bypass the TL431 Cathode to ground just as with the Zener and also bypass the VRef pin (lower resistor) to ground with a small cap, say 0.1uF.
VOut=1+(R1/R2) x 2.5
Make R1 and R2 1% or better.
Ken, That looks sharp! I like it. :)
What output voltage do you want? Depending on which schematic you look at, the regulator's output is 20V to 21V. So anywhere in that range will be fine.
This circuit's voltage will be the summed voltage of the Zener string plus 1.25V. (The 1.25 is the voltage that the 317 will keep between the adjust and out pins) So assuming for a second you want the output to be 20.5V, you will need 19.25V in the Zener string, as 19.25 + 1.25 = 20.5
So what voltage Zeners to use? Well, 19.25/3 = 6.41V, and 3 in series will get you back to 19.2. That's great!
But can you get 6.4V Zeners? That's the issue. You might not be able to. So perhaps you can find (for example) 5.6V and 8V Zeners. Use 2 of the smaller and one of the bigger, they will add up to the 19.2 reference voltage you need and all is good. Or some other combination.
If you can find (2) 9.6V Zener, Robert will in fact be your sister's brother.
Upon the suggestion of NRG (Neal), making the resistor a smaller value, perhaps 100ohm, will keep more current flowing through the Zener string, making it more linear. That seems like a fine idea. Use any resistor value you have between 100-240 ohm, lower is probably better.
Neal - There is something about using a 431 that I don't care for in this. I don't like the idea of having one voltage dependent regulator as the reference for another. (Although I do know that the 431 is a shunt, not a linear regulator) There is a certain elegance to standing the 317 on a Zener stack that I am attracted to.
However - As I have some 431 in my bits box, I will give this configuration a go additionally when I try the 'tracking pre-regulator' scheme. It might be fantastic. :)
No Problem Jim but I see the TL431 as a much better solution that a Zener string! ;) Anyhow if you do go this route you'll need about a 10mA draw on the LM317 so R1 at 1K8 and R2 at 240R would get you close to 21v and draw just over 10mA...
Jim –
20.5v should do, I think that’s what the KAB board puts out.
Will this pair of zeners fit the bill, one 11v + one 8.2v both are 1w with specs as below:
http://uk.farnell.com/fairchild-semi...-41/dp/1467575
http://uk.farnell.com/fairchild-semi...11v/dp/1651545
If ok, I will re-jig the layout for a pair of zeners and go for the 100 Ohm resistor.
Although I have never made one before, I am seriously thinking of making a PCB for this project, using the laser jet toner transfer method. (Iron on acid resist). I am looking into it further as it would appear all you need is access to a laser printer and a design of course, plus some FR4 board and Ferric Chloride to etch it, which can both be had off Flebay for about £10. Probably get 8 boards out of the 100 x 160mm sheet. Mmnn…. May just take the plunge.
Yes, the zeners are fine.
If you make a PCB, put me down for one! (Get a couple spare Zeners and send them on as well, if you are going to make the PCB for two) I'll PayPal you reimbursement.
OK Jim - bear with me as its a new process for me so I won't be as rapid as someone that is familier and I need to send away for the materials.
I've started looking it the track layout, I looked at some of the free PCB design software but it all seems to have a steep learning curve. I am a CAD designer by profession but don't see the point in getting too deeply involved, for something so simple and chances are I will have forgoten how to use it before the next project comes around. I am going to do this very basic layout in Corel Draw, it will do the task just fine.
I'll purchase a bunch of Zenners, at 7pence each its a waste of the parcel space not to. :D
Take your time, I'm certainly in no rush!
I’ve decided to have a go at making the PCB. I first considered the laser thermal transfer system, this is ok for a crude PCB with wide tracks, but is not accurate or reliable enough for such fine work. I decided to use UV sensitive pre coated boards. This is the artwork for it. I printed two copies onto overhead projection sheets using my laser printer. These were glued together to make certain the tracks were solid enough for the light not to penetrate. 8 PCB's will fit on a 100 x 160mm board. I will document my progress and keep you updated as the process may be of interest. Though there are some good tutorials on YouTube, which is what I am using as a guide.
http://www.jkwynn.co.uk/Project_Imag...h/Tech_035.jpg
That looks wonderful! Thanks for the update. :) :) :)
I completed my PCB for the Regulator part of this power supply project.
I worked with Jim on this and it is based on his earlier sketched schematic.
There is an additional 1N4002 diode incorporated for protection and the 240 Ohm resistor was reduced to 100 Ohm as recommended by Neal. The 19.2v of Zener is made by using an 11V and an 8.2V in series.
http://www.jkwynn.co.uk//Project_Images/PCB/PCB_014.jpg
I made a pair as I have two Technics Turntable projects in development.
The board locates using the stock screws and spring clip for the regulator. If you make something like this for the stock deck, you will have to use an Aluminium spacer and longer screws, put the spacer between the die cast platform and the board. This is to raise the board above the level of the main cable entry aperture, the raised lip on this aperture will short out the tracks on the PCB otherwise as they overlap. This LM317 regulator also needs an insulating gasket between it and the metal surface of the deck/spacer.
If you are interested in how you make a PCB you can see how I made this, my first effort, here:
http://www.jkwynn.co.uk/////PCB_HTML/PCB_Thumbs.html
Looks fantastic! Wow!
Test them for proper voltage before installing them in the TT.
Whats the best way of testing the output?
Hook it up to the PSU direct and measure the output before fitting to the deck?
Yes, that will give you the unloaded 21V output. Then test the voltage again when under load (i.e. platter rotating) where there should be only a small voltage drop if the regulator is working correctly.Quote:
Originally Posted by Qwin
:thumbsup:
Thanks Jim and the others for your help. The case is something I've had sitting around for ages . Finally found a use for it . The front is a bit of Corian - something ill be using more often I think ..... I guess the Reg mod is next :
Richard .
Rich - that looks fantastic! Bravo!
Thanks again . I have room to put the Reg in here ..... I have 4 core and 2 ground in the umbilical ..... Can I use them for the Reg ?Quote:
Originally Posted by 6L6
Once the design is finalised ofcourse :D