Gainclone HUM, THUMP problems - The solution

[AndrewT]

Does anyone have a view on whether the two decoupling caps (in post1) should be connected together first and then taken to the Audio Ground?

[Puffin]

AndrewT. I hadn't thought about taking the grounds from the caps separately, as I always thought the considered way was to put a stout piece of wire as the "power" ground.

http://i73.photobucket.com/albums/i239/saxonsex/GC1.jpg

[gootee]

Originally posted by AndrewT
Does anyone have a view on whether the two decoupling caps (in post1) should be connected together first and then taken to the Audio Ground?

My view is that they SHOULD be connected together, near the chipamp, and should also connect to ground very close to each other, there. Otherwise (or even additionally), another small cap should connect directly between the V+ and V- power pins.

[gootee]

Originally posted by gainphile
I got the diagram with no 5W resistor. How do I update the diagram?

See Figure 3, at http://sound.westhost.com/earthing.htm .

[AndrewT]

Hi Gootee,
I have already sent him a private message with instructions on where to find the less dangerous disconnecting network and how to contact the moderators to remove the dangerous diagram and substitute the safer one.

It's just a pity he does not realise how many newbies may have read his first post in the intervening 17days of inactivity.

[gootee]

Originally posted by AndrewT
Hi Gootee,
I have already sent him a private message with instructions on where to find the less dangerous disconnecting network and how to contact the moderators to remove the dangerous diagram and substitute the safer one.

Very good.

It's just a pity he does not realise how many newbies may have read his first post in the intervening 17days of inactivity.

Agreed.

[BWRX]

Originally posted by AndrewT
contact the moderators to remove the dangerous diagram and substitute the safer one.

The image is hosted on photobucket. All that needs to be done is to change the link url in the post to the url of the new image. Post the url of the new image and we can change it.

[gainphile]

The updated diagram is :

http://i188.photobucket.com/albums/z...Grounding2.jpg

How do I update the 1st post? ...

[gainphile]

Originally posted by Mike514ml
I realize that the exact wire gauges may not be critical, but could you give me an idea of the relative sizes of the small, medium and huge ground wires?

Also, I'm currently finishing up a BrianGT 3875 dual mono chipamp kit (it's been lying around here for a LONG time), and was wondering if it would reduce the hum and thump potential more if it's built with single or dual power supply boards.

Hi Mike, I don't understand about wire gauges so I posted that picture (I have medium-size thumb ). Basically the largest wire is from good speaker cable about 4mm in diameter, the smallest is jumper cable about 0.5mm diameter. The middle size is about 1.5mm diameter.

Mine is built using single supply board for 4 channels. I don't know how using 4 PSU will help more as my amp is very quiet ie. no hump/thump...

[BWRX]

Originally posted by gainphile
The updated diagram is :

http://i188.photobucket.com/albums/z...Grounding2.jpg

How do I update the 1st post? ...

You can only edit your posts for up to 30 minutes (I think) after posting. After that you need to ask a moderator to do it.

I've updated the url in your first post so the correct diagram should now show up.