Pavel Dudek's (Upupa Epops) LM4780 amp

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#361
Upupa Epops said:
Every parts of chain can ratify sound, Dinesh, so we can't to tell you, which it cause .... You must to use elimination method, i.e. to try change in turn every parts of chain...
Click to expand...

I agree Pavel, I have been at it. So far, I have tried one other source Alien DAC, which is a lesser source. But neighter of these show any brightness on my Sennheiser HD 650.

I am planning on upgrading my main source to make it more warm or at least more neutral. I had started building a Zen V9 long time back, never got around to completing it. I think I should complete it and see. If either of these fails, it will be the speaker.

I asked the question in hopes, you had seen this and possibly had some suggestions. I have also asked the same question to the speaker's designer on another forum.
 
#362
Zen isn't in this case luckiest solution, 'cos isn't neutral... If I can to give you some recomendation, try to give between DAC or player and PA03 some " line driver ", i.e. stuff which have high input impedance ( 100 k or more ) and very low output impedance ( 50 Ohm or less ). I mean, that you will be very surprised with results... 😎
 
#365
I have finallly fitted the last parts to the amp.😎

I am going to use it as a stero power amp to begin with. If I like it I plan to build more and go active and use several PA03s in bridged mode. I know which jumpers to use to configure appropriately.

However, I have a couple of questions before I power up.

1: Does anyone have a diagram explaining the function of each of the wago terminals?

2: For testing, do I input DC via the WAGO terminals where the AC will eventually go?

Sorry for the Noddy questions

Aidan
 
#369
#370
second amp - no sound

The second one I built has the right voltage on tp1-tp2 tp3-tp4 but no sound.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.
 
#372
Upupa Epops said:
At second case probably temperature protection switch off power amp, because you have not there heatsink. First case is mystery...
Click to expand...

I've put the heat sink.
I hear the relay close but still no music.

Maybe the way I connect the input is wrong(?):
1. I shortcut the mute function as in the picture.
2. I use the +,- pins of jp1 to connect unbalanced input and I shortcut jp3/jp2 (- and groud).

remark:
In the picture is a missing transistor, I added it, so that's not the problem.
 
#376
Upupa Epops said:
Amp will be operating if you get jumper into fiftr or sixth position from left at input multipin connector.... Read again instruction manual....
Click to expand...

I read it, but I wasn't sure about that as it can be vertical or horizontal.

Upupa Epops said:
First case is mystery...
Click to expand...

D1 diode was in the wrong direction, i switched it but still only 6V.
The voltage on the big caps is 25V.
At the out of RECT1 25V as well.
At the out of D1 25V as well.
 
#378
Problem one solved.
The 7812 and 7912 were switched between them.

Now both amps have the click (relays) and ... no sound?
Maybe the mute relay is not the right one (bought it in the components group buy)? I tried to shortcut jp4 and still no sound, so I guess it's not the problem.
 
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