Deciding what caps to use

[dlucy]

I'm going to start a new thread to post the BOM shortly.

Excellent! Be sure to take the URL of the new thread and post it here (or edit your above post to include the URL). Congrats!

 

[cuda440]

Here it is:

http://audiokarma.org/forums/index.php?threads/pioneer-sx-737-bom-2-24-18.811708/

 

[fromnowon]

This thread has what I think is a very good point,

The KSC2383 is different. It is not low noise. But it is bigger, so it can dissipate more heat. And it can handle up to 1A of current. So, on a power-related board where the KSC2383 is doing voltage regulation or switching duty, instead of amplification, then the KSC2383 is better (than a low current device like the KSC1845F).

To confirm, for the SX-737 / SX-838 Protection board transistors, ksc2383 would be preferable in all 5 spots like this (correct?):



Thanks!

 

[markthefixer]

This thread has what I think is a very good point,



To confirm, for the SX-737 / SX-838 Protection board transistors, ksc2383 would be preferable in all 5 spots like this (correct?):

View attachment 1975069

Thanks!

Incorrect. q1, q2, q3 q4 are all gain (and low current) operations, as opposed to current drive like q6 and the ksc2383, or q7 and the ksc2690.

Q6 has a unique function - it MUST discharge a fairly powerful charge in a capacitor. And not be destroyed by it, short or long term.

Thus q1, q2, q3, q4 should be the ksc1845. q5 the ksa992, q6 the ksc2383 and q7 the ksc2690,

I suspect you have pushed power supply "rules of thumb" into areas where they break themselves.

 

[fromnowon]

Thanks for taking the time to explain. I bought KSC1845s for those spots then noticed a kit for sale for that board with five 2383s in the photo! Reading more added to my confusion. Glad to have it confirmed now. I’m going to use the KSC1845s!
I sincerely appreciate all you do for us on here, MTF. It’s invaluable.