TDA7266M and the 10 Min Amp

[JackSkellington]

Hello,
here's another nice project by our friend chromesphere.

http://www.diyguitarpedals.com.au/shop/boms/10%20Min%20Amp.pdf

https://www.youtube.com/watch?v=LjQpVLtzOOc

I usually don't buy PCB if I can build a thing on veroboard, though PCB are neater, clean, easy, etc...
I search often projects like Smokey Amp, Orange Micro Terror, Marshall MS-2... some of these mini amp. I'd like to build some mini amp more power than 1w, but with some amp with an easy chip or transistor to find, and without big power supply, over 18v or over 2000mA.
So, this TDA7266M could be a nice shot.
I'm pretty sure that the project I linked above is fine, but I find a weird things, or something I don't get.

Schematic by chromesphere:



TDA7762M pinout from datasheet:



This is the PCB by chromesphere:



To count the pins: in the upper PCB side we have to count the pin 1 starting from the upper left hole, then pin 2 is the one downer then up, down, up...
In the downer side PCB the pin 1 start from the upper right hole, then pin 2 is the one downer then up, down, up...

I see the pin 3 goes in the positive of C3, so in the 9v.
The pin 4 goes in the C1 (input track).
I suppose pin 5 is not connected.
I see the 6 and 7 pins linked, because the go in the VR.
I can't see, but I assume, as in the schematic pin 8 and 9 go to the ground. Right?
I see the pin 13 goes in the C4, probably on the 9v side, as in the schematic.

I let the weird thing about the pin 1 and 2 for the last, because they seems reversed on the PCB.

Following the schematic and the pinout, pin 1 should go in the (tip of the output jack) positive of the speaker, and pin 2 in the (sleeve of the output jack) negative of the speaker.

Are those really labelled reversely or I was wrong?

Thanks!

[JackSkellington]

Is no one interested in this project?
I still need to understand those point.

[Willybomb]

Have you tried messaging Chromosphere?  He's here fairly regularly, or email him through his site.

[JackSkellington]

Well, I didn't want to put too much pressure on Chromosphere to answer me, nor specifically disturb him. I was just hoping he would answer if he saw the thread.

[bushidov]

Does this help? These are the pins I assigned.

[chromesphere]

Does this help? These are the pins I assigned.

Thanks Erik!  I hope this answers your question Jack?
Cheers
Paul / diygp

[JackSkellington]

Thank you bushidov.
Honestly I still have some doubt.
I can't see the pin 6 going to the VR (with the pin 7).
And I still se pin 1 going in OUT- and pin 2 going in OUT+. But in the schematic and in the pinout indication those pins should be reversed.

[Aentons]

Thank you bushidov.
Honestly I still have some doubt.
I can't see the pin 6 going to the VR (with the pin 7).
And I still se pin 1 going in OUT- and pin 2 going in OUT+. But in the schematic and in the pinout indication those pins should be reversed.

It does appear that the out lables are reversed on the pcb (speaker would just be out of phase, right?)

Pin 6 and 7 are connected on the back of the board

[bushidov]

Hi JackSkellington,

Aw, you do appear to be correct on the issue of Out+ and Out-. The silk screen is reversed. Thankfully, due to the isolated jack and it being a mono amplifier, there isn't any issue of phase. That's what had me pondering, as I use a 10 minute amp for testing pedals and "it works", so I was a bit confused when I saw this. I have corrected the silk screen for the batches after this, but in this case, flip-flopping the speaker out wires won't matter. As Aentons mentioned, 6 and 7 are tied together on the backside of the board.

[JackSkellington]

Thanks. I guess my doubt has been clarified.
I'd like to try it on veroboard, when I can buy all the parts.
Now, I think it's enough follow the schematic. That is should correct.