Up and running...

[mb1a]

My AMP3 is up and running . Still on a 12V SLA with safety resistor inline with power, but so far so good.

Jan's instructions are clear, and there were no special problems other than some untidy smd soldering and tired fingers from winding the inductors.

Thanks Jan for a very nice kit.

[d-roby]

Very good!
My Amp3 is on the way.. i have to solder only the main chip..

Did you compare AMP3 sound to T-amp?
AMP3 should sound much better...
Regards
Roberto

quote:Originally posted by mb1a
[br]My AMP3 is up and running . Still on a 12V SLA with safety resistor inline with power, but so far so good.

Jan's instructions are clear, and there were no special problems other than some untidy smd soldering and tired fingers from winding the inductors.

Thanks Jan for very nice kit.

[pepijn]

Allright, congrats! Please post your listening results!

Just wondering: How is the 'pop' from the speakers when you turn it on?

[mb1a]

Power-on pop -- yes, a slight noise when powering up. Seems to be on left speaker only, just like my T-amp. [?][?]

Sound compared to T-amp? Quite different. I found the T-amp very clear and bright, although the quality of the treble was good. After just short listening with the AMP3 on batteries, without heatsink (not too warm), it sounds very different. Bass is obviously much better; overall balance quite the opposite if the T-amp. To me it is more neutral and matches my other amps (AKSA 55N, TDA7294 chipamp) closer. I've not pushed it, but so far it has not clipped at around the same listening level where the Sonic Impact clipped.

[bearman]

quote:Originally posted by mb1a
[br]My AMP3 is up and running . Still on a 12V SLA with safety resistor inline with power, but so far so good.

Jan's instructions are clear, and there were no special problems other than some untidy smd soldering and tired fingers from winding the inductors.

Thanks Jan for a very nice kit.

My feelings exactly. Great sounding little bugger.

Thanks Jan

[bearman]

As a side note, I had some difficulties that were overcome. When hooked up, I heard a click on speakers on power, but no sound from input. Checked all components... looked good. Quadruple checked chip and ran a razor blade between each leg. Decided to put the extra cap on C14 and C15. Removed Toroids and sanded ends again and replaced.

Bingo, that did the trick. It was either the chip or the toroids I think. For some reason, I think it was the toroids.

Once it works, The sound is great. Now we start looking for a nice case!

[Jan]

I am glad it sounds great!

One way to check the toroid solders is to measure between the "inward" side (=center of the board) end of the diodes, to the speaker output connectors. Each diode should be connected to one and only one speaker output, via the toroid, from the diodes on both sides of the board. Do this without speakers connected. The outer end of the top side diode are connected to positive supply, the outer end of the bottom side diodes are connected to ground.

Checking the chip: i usually test by using a DVM in beep mode, putting one test pin on the upper end of the chip leg, close to the chip body, and the other test pin on the pcb trace, away from the chip. Then I "walk" with the test pins, testing the same pin and the next, to make sure there is contact between trace and chip, but no contact with the next pin. Putting the test pin close to the chip prevents you from pressing the leg down towards the PCB, giving a false indication of a connection.