Combined Onaudio thread. (23 threads)

[OnAudio]

28 to go

 

[SPWONG]

Hi,

2 pcs of PCB received in good order. Thank you.

 

[OnAudio]

Hi,

2 pcs of PCB received in good order. Thank you.

Thank you too. Now lets get those results in

 

[Dagwood]

Harrison

Can you upload a photo our your boards assembled, just want to see which compoments you have put on the top and which on the bottom?

Cheers

 

[OnAudio]

Build guide

C6,R20,R27,R30,R31,R33 are mounted on the bottom of the PCB.
R33 is a ground lift resistor that could be around 7.5 Ohms, I would first use 0 ohms and if hum was encountered would then go fancy with the ground lift.

Heres how I do it.

1. Test all your components for defects including PCB

2. Stuff PCB starting with small components working your way to large components i.e. output transistors

3. Examine assembled unit for any solder issues or bent pins shorting others

4. Attach assembled unit to PCB isolating the transistors from heat sink.(Test this)

5. Ensure bias trim pot is set for maximum resistance

6. Attach bulbs on positive and negative rails

7. Do a jig then power up, if bulbs light up, wash rinse repeat, you may have done this in poor light

8. If all goes well, set bias, attach scopes and torture amplifier, if it holds up

9. Plug in your speakers (some use speaker protection)

10. Plug in the "I like to move it move from Madagascar" CD

11. MOVE IT !!!!!!!!!!

12. WE LIKE TO............

Heres a members implementation

 

[OnAudio]

BOM correction

Thanks for catching this kindhornman
R16 should be

1 * R16 * 680 * 0207/10 * Vishay/Dale * CMF07680R00GKR6 * Mouser * 71-CMF07680R00GKR6

 

[Kindhornman]

Your welcome Harrison.
My boards arrived very fast, all the parts are ordered including the R16 resistor that threw me a little and just need to get the correct PSU to make this all work. I'll be following this thread and see if anyone comes up with any tweaks to improve on the response or anything else. Should see all the parts in a few days from Digi-Key and Mouser. I almost felt bad as the cost of parts from Mouser was so slim and Digi-Key got all my money. I am ready to have some fun and even ordered some real 60/40 Kester solder on Ebay instead of that no lead stuff.

 

[evette]

Mr. Harrison Sir,, It seems the boards you shipped me are still setting in some post office since aug.11. I don,t know how they make money the post office. Evette

 

[Kindhornman]

Evette,
Is that on the US side or the Canadian side of the border. I have always heard that customs does that when we send something North, I hope it isn't on our side. Good luck on the project and watch for that mistake with the #16 resistor, the number has been changed to protect the innocent.....

 

[OnAudio]

Your welcome Harrison.
My boards arrived very fast, all the parts are ordered including the R16 resistor that threw me a little and just need to get the correct PSU to make this all work. I'll be following this thread and see if anyone comes up with any tweaks to improve on the response or anything else. Should see all the parts in a few days from Digi-Key and Mouser. I almost felt bad as the cost of parts from Mouser was so slim and Digi-Key got all my money. I am ready to have some fun and even ordered some real 60/40 Kester solder on Ebay instead of that no lead stuff.

Cool. . Yes Digikey did get the larger share, any ideas

Mr. Harrison Sir,, It seems the boards you shipped me are still setting in some post office since aug.11. I don,t know how they make money the post office. Evette

They will get to you. I am also looking forward to your review

 

[evette]

Mr.Kindhornman thank you for the warning but what res is wrong,,Mr. Harrison thank you for the info. Evette Can,t wait to get the boards.

 

[Kindhornman]

Evette,
On the BOM there is resistor R16. The part number is incorrect. This should be a 680 ohm 1/4 watt 1% film resistor
1 * R16 * 680 * 0207/10 * Vishay/Dale * CMF07680R00GKR6 * Mouser * 71-CMF07680R00GKR6

Steven

 

[WSJ]

Initial test with lab supply at +/- 25 V, no load.

 

[OnAudio]

Initial test with lab supply at +/- 25 V, no load.

Thanks WSJ. Looking good. Waiting for more.

 

[evette]

Thank you Mr. Kindhornman. Evette

 

[Kindhornman]

OnAudio,
I see the scope pattern here and I'm not sure what I am supposed to make of that, looks like a nice sinusoidal wave..... Is the +/-25 volt dc rating the recommended psu output or is that just what was used for this test?

 

[OnAudio]

Kindhornman,

Recommended +/- 40, you can push it to +/- 50

 

[WSJ]

OnAudio,
I see the scope pattern here and I'm not sure what I am supposed to make of that, looks like a nice sinusoidal wave..... Is the +/-25 volt dc rating the recommended psu output or is that just what was used for this test?

The signal was just used to test the amp when first powered up.
"I like to move it move from Madagascar" CD is next.
The +/- 25 V was used to test the board, it was the max. output of my lab supply. Current limit was set to 200 mA.

 

[Kindhornman]

So a good SOA is +/- 40 and pushing it would be the +/-50 volt rating then.

 

[OnAudio]

Kindhornman, some links to start you off on that supply

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

R46KF210000N0K Kemet | 399-5986-ND | DigiKey

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

GBPC3506-E4/51 Vishay General Semiconductor | GBPC3506-E4/51GI-ND | DigiKey

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

B41456B8109M EPCOS Inc | 495-4224-ND | DigiKey

Tranny

http://www.antekinc.com/details.php?p=80