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Old 14th August 2005, 10:18 AM   #11
trex is offline trex  Sweden
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Now I have the IEC ground connected to case and still no humming in the speakers so I'll keep it this way, a little safer I guess.

The Transformer centertap and Supply ground from the Hypex HG Supply unit is hard to get without soldering cause there are no space around the fastons, see my attached picture. So I'll leave as it is now.

The DC mains filter still do no good for the transofmer humming.

Here's the schematic: http://www.lcaudio.com/dcfilterdias.gif

I guess it'll be a support issue for Lc Audio.
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Old 14th August 2005, 11:02 AM   #12
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Trex,

Did you connected the secondaires of the transformer in the right way?????

You have two secondaire windings, red and yellow. The way you have connected it seems to me wrong, the both windings are in phase.

Can you check with a AC voltmeter the voltage between the two AC wires? If you measure 0V you have connected wrong!

Jan-Peter
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Old 14th August 2005, 01:19 PM   #13
trex is offline trex  Sweden
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I've measured red-red and yellow-yellow, both give 44,4V AC (My mains show up a rather high 231V)

The marks on transformer are red 0V red 42V yellow 0V yellow 42V

http://www.lcaudio.dk/zp3trafo.jpg

I've conntected red 0V together with red 0V on the "0" on the PS board. This does indeed not look like your picture with center tap

Shall I instead connect red 42V and yellow 0V (the red and yellow wire that are next to eachother) togheter on the "0" on the PS board?

On the other hand I still meassure +-61,3V DC right before the 400 modules and they play beautifully.

No more power on for me untill this is cleared up
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Old 14th August 2005, 05:43 PM   #14
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Your transformer gives;
0VAC -- 42VAC / 0VAC -- 42VAC
Red ---- red / yellow -- yellow

You MUST connect the middle red AND yellow together to the center tap of the power supply. Please check the following to see if you have connected in the right way; measure on both AC fastons (marked ~ / ~) of the HG power supply a voltage of 88VAC. When you measure 0V you have to change one AC wire with the other from the same colour.

A proper DC voltage doesn't tell you that you have connected everything in the right way! Only measuring the AC voltage tells you if you have connected it in the right way.


Jan-Peter
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Old 14th August 2005, 07:29 PM   #15
trex is offline trex  Sweden
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Changes done and I can meassure 89VAC on ~ / ~ , and transformer humming reduced to complete silence. Everything plays fine so the amp have survived this little misstake.

Moderator: How many posts do you have to make to get rid of the "under moderation time" ?
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Old 14th August 2005, 07:32 PM   #16
Netlist is offline Netlist  Belgium
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Quote:
Originally posted by trex
Moderator: How many posts do you have to make to get rid of the "under moderation time" ?
Depends, you seem to be a nice guy so you are registered now.

/Hugo
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Old 16th August 2005, 04:25 PM   #17
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Congratulations Trex

It was all due to the "center tap" issue after all!
My Plitron Tx has different colors for center tap wires and this makes everything easier.

Some comments/doubts:
1) It seems from the pic that two pairs of speaker BP are connected to the box. Aren't they? If yes, what for?

2) I would recommend placing the UCDs with the T attached vertically to the lateral side of the box (two external UCDs) and the remaining also with vertical T attached to a new vertical metal plate/heatsink. In this maner you could get better heat dissipation and convective cooling plus isolation from the new plate.

Best regards.
Mauricio
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Old 21st August 2005, 10:29 AM   #18
trex is offline trex  Sweden
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maxlorenz your right, ive got 2 different pairs of speaker BP's, I run out of WBT's, so I had to use the Supras for the second pair of amps

The left/right sides of the case actually is big heatsinks.
Maybe I Should mount the 2 ucd's vertically on those instead, obvisosly better, Ill see if I'll do that... It plays pretty damn good

I have a rather high voltage of 61,4 VDC after PS, however its not running scaringly hot either....
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Old 21st August 2005, 01:00 PM   #19
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Default Hi trex:

I'm glad you're glad
They are good, aren't they

I was reffering that BP's seem to be "connected" with the box paint removed... Or maybe the pic is not detailed enough.

Quote:
however its not running scaringly hot either....
What is not hot? The heatsink? If it's not hot it may be good or bad: good if they manage to get rid of heat (as they seem) or bad if the heat never reached them in the first place.
I believe T plate is good for the transistors attached to them but the other sensitive items (output coil, etc...) must use convective air cooling, IMHO
I want mine to last decades...

Best wishes
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