diy ear 834 power supply wiring

[mikelh]

hi, I have bought a power supply for my ear 834 clone (DOUK), it's a LITE LS 56, it seems to be a very capable power supply but I have some troubles to make it run properly, so I ask for some help  



My problem is with the high voltage wiring, here is a pic of the 3 terminals: AC, GROUND, AC


if I wire the 0 + 280 from the transformer to the 2 AC inputs and the GROUND to the common ground, I have no current as you can see from the first picture, I thought it was the correct way to wire,

the guy who sells the boards tells me to wire this way:
 280 v from the transformer to both AC and 0 volts to GROUND input on the board, and if i want the ground also to the common ground, but this way I have a ground loop,

there is no manual or diagram for this board on the internet
I have been looking at others power supply diagrams and the first way seems to be right but I can' t get output voltage

can anyone help me with this problem?

[Tomcat1969]

Are you sure that you have the correct outputs from the transformer going to the correct inputs on the board?

[willbewill]

It would help us to help you if we knew the transformer wiring details and what voltages you are getting from it.

[dtroise]

What terminals are the test prods on ( HV/DC ) ?  you need to start at the a/c terminals . If The TX is a C/T 560 v measure one + leg to 0 =  280 v measure across both + legs = 560 v, If it is not a C/T his instructions could be wrong, did the board come with a schematic if so post it? Impossible to help w/o more info.

[mikelh]

hi and thanks for your prompt replies,
here is a pic of the transformer output:



I have also tried with the EI transformer bought with the DOUK kit which is different from the toroid one on the previous post picture.

I have been swapping transformers and I have a heavy ground loop with both if wired according with the instructions of the seller (a french diy web page).
In this case I have output 290v and music through the speakers but with unbearable hum because of the ground loop,
it is like a ground connexion is missing but there is no instructions/diagram of the board, so I have tried to find another ground point in the board without success, usually those are in the bolt holes but not in this board

well I know it is very complicated to find the problem but all your comments are welcome

The DOUK power supply works with the 0 and 280 volts wired to the ac input of the board and the ground wired to the board ground point which is on the caps rail
in this picture we can see the ac inputs and ground point close to the big cap on the right:



in my douk board there is no problem this way

but if i do the same on the Lite board there is no output, and I guess it is the way to do it because the ac inputs go to the two diodes (by127) on the top of the picture:



note the two inputs on the left are for the heaters 6/12volts and no issue with them, I have also tried the phono stage with the heaters from the douk board and transformer and HT from the Lite board and toroid transformer and the problem is with the HT

[dtroise]

Hi
I am not sure how you wired it but it seems that the earth grnd goes in the middle terminal and the a/c volts go on each side of the center. Without a copy of the schematic posted it is really impossible to help. I have seen some of these boards from China come with the negative in the middle and the positive paralleled to each screw that has a/c next to it. The schematic would show if this is to be wired that way.

It appears that you do not have an earth ground wired in the center, if so then try that and see.

Donald

[Marek]

I found reverse side here so it looks that left and right marked AC are going to diodes. GND in the middle seems to be GND so green/yellow. On bottom is not connected on upper side is going along of PCB. So AC has to be connected to 280V AC secondary output GND for test I would keep not connected and check. Make more pics from transformer secondary winding which color is what ? As you have EU transformer 230 V transformer GND wire should be marked yellow/green. All others have to be hot/cold AC.

In my transformer outputs are marked the same color so red 230V input violet 250 V out and  thick white 6,3V/2A out (black is dividing whites to 2x3,15)

SHOW MORE PICS from transformer wiring and its full description - missing on right side of label



https://www.ebay.co.uk/itm/124325033419

[Marek]

hi, I have bought a power supply for my ear 834 clone (DOUK), it's a LITE LS 56, it seems to be a very capable power supply but I have some troubles to make it run properly, so I ask for some help  



My problem is with the high voltage wiring, here is a pic of the 3 terminals: AC, GROUND, AC


if I wire the 0 + 280 from the transformer to the 2 AC inputs and the GROUND to the common ground, I have no current as you can see from the first picture, I thought it was the correct way to wire,

the guy who sells the boards tells me to wire this way:
 280 v from the transformer to both AC and 0 volts to GROUND input on the board, and if i want the ground also to the common ground, but this way I have a ground loop,

there is no manual or diagram for this board on the internet
I have been looking at others power supply diagrams and the first way seems to be right but I can' t get output voltage

can anyone help me with this problem?

If I see well you connected blue wire to PCB GND and than to brown wire so probably you connected GND point on PCB to AC 230 or 280V. Now question what could be burned on PCB by this connection. I marked it yellow. Check it. Brown color is reserved in AC for hot AC wire blue cold AC wire but both are killers if switched ON. I Can be wrong as this can be GND loop of course.

[JacquesD]

It looks like your Lite board with the two good (?) old BY127 diodes expects a double secondary, say 2 x 260V, with a "center" connection, but that toroid seems to have only a single secondary high voltage winding. You should probably use a bridge rectifier with that transformer.

Maybe some of the previous posts have said so,  too. I've not had enough coffee this morning to notice it.

Success,

[JacquesD]

You could make a bridge rectifier by adding two BY127 or 1N4007 diodes (or similar), of each the cathode attached to one of the HV AC connections, then join their anodes into the GND connector. Given the voltages involved, do it in a tidy way with heat-shrinked coverage of the leads etc.

But don't do this if you're not confident about it. These high voltages can be lethal.

Kind regards,

[mikelh]

hi and thank you all for your inputs,

I tried wiring:

red (260 v) to AC
green (0 v) to GD  - with and without the common ground wired (blue cable in my cabinet), no difference
red (260 v) to AC - it's the same red wire strapped because there is only 1 secondary because the transformer only has 1 secondary as Jacques points out
there is output but with ground loop

so my mistake is to have chosen the wrong transformer

if the board is designed to use a tranformer with 2 secondaries the solution is try with this kind of transformer

once I get one I will let you know
thank you all for your help

regards
Mike

[Marek]

hi and thank you all for your inputs,

I tried wiring:

red (260 v) to AC
green (0 v) to GD  - with and without the common ground wired (blue cable in my cabinet), no difference
red (260 v) to AC - it's the same red wire strapped because there is only 1 secondary because the transformer only has 1 secondary as Jacques points out
there is output but with ground loop

so my mistake is to have chosen the wrong transformer

if the board is designed to use a tranformer with 2 secondaries the solution is try with this kind of transformer

once I get one I will let you know
thank you all for your help

regards
Mike

MIke do not understand

Your transformer as showed on pics in my opinion has two secondaries or more look on label there are two lines  one with high V 0 up to 320V thin cables, second thick cables low V 0-18 high Amps. and maybe more as next is 0-6,3 etc Am I correct ? Check it again Transformers are not cheap

[mikelh]

yes Marek, the transformer has more secondaries but I gues I need dual secondaries like 280 - 0 - 280, dual output at the same voltage

[dtroise]

Hi
A different TX will not do anything other than jumping the positive from the one that you have. Dual feed boards do not need a center tap, they need the negative in the middle and positive on each side. You should read 280 v from each side to the middle terminal and zero when measured across the two positive sides.

If that was a center tap requirement it should say c/t where it says ground.

Donald

[Marek]

yes Marek, the transformer has more secondaries but I guess I need dual secondaries like 280 - 0 - 280, dual output at the same voltage

For What? If it is really required connect it in parallel. 280 V is low amper requirement so that is the way - should work. BUt In my opinion left right AC is just one input and GND is yellow/green. Without schematic you have high risk of PSU destruction.

Looking to EAR design and all mods there is only one 250-280V AC required for PSU and than PSU has two outputs 280V DC - in fact this is one in parallel connection. But OK do not know your design. Pitty that supplier is not showing diagram.  From other side GND is GND and should be not kind of "0" AC port .  Look for wall port - there is brown L-line(always charged)/blueN (when opened-safe but connected is killer)/yellowgreen (safety wire GND - outside of house is physically grounded) - In fact there is not zero for AC when connected. Strange design PCB description. Ask supplier for diagram-schematic.