Identifying Quad 306 mods + repair questions

[RaggaMuffin]

Thank you! Much appreciated.

[Bonky]

Thank you! Much appreciated.

Hi, please let me/us know your thoughts/conclusions..and what alterations -if any- you are going to make!

Best wishes,

[walpurgis]

Others here might appreciate a look at your photos Richard. If you feel like sharing .

[RaggaMuffin]

Others here might appreciate a look at your photos Richard. If you feel like sharing .

I could share them here, if that's okay with Richard?

[Bonky]

...of course...please do.

I'm sorry my first attempt at picture hosting didn't work as intended.

(You'll may need to rotate the images 90 degrees to match yours).

No copyright issues!

BW

[RaggaMuffin]

Hi, please let me/us know your thoughts/conclusions..and what alterations -if any- you are going to make!

Best wishes,

I notice on your board, you only have 4 decoupling caps, across D1 and D2 on each side. Was there a reason for RedHill Audio not installing all 10 caps, as per the Dada instructions? Also, what are those bits between the PS caps? They look like little metal plates bridging the leads.

Changes so far I'm going to make is reducing the input sensitivity to 1V by changing R6. However, I think before I do that I want to try and find the source of the distortion. I've also just noticed quite a loud hum when I tested it just now. I'm not sure if that was there before or not. I noticed a user called Light Dependant Resistor has a lot of ideas regarding the 306, so I might go through the posts he's made or might shoot him a message.

[RaggaMuffin]

Pics of Bonky's example:

[RaggaMuffin]

Also, when measuring the voltages listed on the schematic, what is an acceptable +/- deviation % before I need to investigate a reading? When I did the Bottlehead Crack kit, it had a wide acceptable variance of +/- 10%.

[walpurgis]

Pics of Bonky's example

Good stuff. I have a couple of these nice amps.

[Bonky]

I notice on your board, you only have 4 decoupling caps, across D1 and D2 on each side. Was there a reason for RedHill Audio not installing all 10 caps, as per the Dada instructions? Also, what are those bits between the PS caps? They look like little metal plates bridging the leads.

Sorry...I don't know/recall. Are the 'bits' between the PS caps just surface-mount resistors or zeners~?

Changes so far I'm going to make is reducing the input sensitivity to 1V by changing R6. However, I think before I do that I want to try and find the source of the distortion. I've also just noticed quite a loud hum when I tested it just now. I'm not sure if that was there before or not. I noticed a user called Light Dependant Resistor has a lot of ideas regarding the 306, so I might go through the posts he's made or might shoot him a message.

Please see above.