How much heat is generated by KSC3503/KSA1381?
Does it matter using thermal paste vs. thermal pads?
I see most people have used thermal pads between the TIP142/147 and the main heatsink.
Does it matter using thermal paste vs. thermal pads?
I see most people have used thermal pads between the TIP142/147 and the main heatsink.
Don't worry, I have successfully used these kapton discs in my Aleph5 clone. The pads are also fine for the AB100 😉.
You can use anything for outputs mica+paste or pads (I used cheap silicon ones from AliExpress), just make sure they are isolated from the h/s.
Regarding the 3503/1381 - mine only get warm (maybe 1-2 watts?)
Regarding the 3503/1381 - mine only get warm (maybe 1-2 watts?)
Have a look at my test for heat sink mounting, if you like:
https://www.diyaudio.com/community/...mal-electric-conductivity.376934/post-6789894
AB100 boards are done, except soldering in the output transistors, but I am going to wait until all the holes are drilled and tapped in the heatsink before doing that.
Transformers are Toroidy 250VA PRI 2x115v SEC 2x32v, with two separate mono cases, no soft start required, simple 15 amp switch, no speaker protection circuit. As basic and straight forward as possible. Going against the grain with no anti ringing snubbers based on my interpretation of Tom C's notes on his web site of their necessity.
Any thoughts on how you would lay this out?
Didn't show the front mounted on/off push button switch or the little ground loop break circuit board.
Thank you,
David.
Transformers are Toroidy 250VA PRI 2x115v SEC 2x32v, with two separate mono cases, no soft start required, simple 15 amp switch, no speaker protection circuit. As basic and straight forward as possible. Going against the grain with no anti ringing snubbers based on my interpretation of Tom C's notes on his web site of their necessity.
Any thoughts on how you would lay this out?
Didn't show the front mounted on/off push button switch or the little ground loop break circuit board.
Thank you,
David.
David, I always try to put the transformers in the front of the amp, away from the boards, input and output.
So I know your looking for definitive answers but I looked at the 1381 vs 350 and assuming the compliments are very close. Everything matches up except one that might be critical. The power dissipation of the MJEs is 20W where the KSA series is only 7W. Now if the circuit is not pushing that transistor very hard and they are heatsinked then probably ok. You'll have to see how loaded that driver is though to know for sure.
You need to test stability by yourself.
Do you have an oscilloscope?
Use one pair output only when first test.
Keep input signal low,use a bulb tester in series with the main voltage.
Mje are slow devices when ksa ksc are fast low capacitance drivers.
Hello DaveFred
Great build progress well done .. I have the Gerbers for the AB100 power amplifier but just noticed that lovely PSU that you have as well
Can I purchase the Gerbers or point be in the right direction to purchase the bare PCB's if possible
this would be greatly appreciated
regards
Great build progress well done .. I have the Gerbers for the AB100 power amplifier but just noticed that lovely PSU that you have as well
Can I purchase the Gerbers or point be in the right direction to purchase the bare PCB's if possible
this would be greatly appreciated
regards
The PSU is one I drew up myself and might not be ready for prime time as this is the first time I have used it, it is just elements I took from a number of published designs. I hope I did it right, time will tell...
Take a look at any of the PSUs by Prazi, I think you will be safer with those.
Transistors all mounted on heat sink and soldered in, starting lock things in...
(P.S., I hope I am not annoying the more serious crowd with all my pics, I scoured looking for pics when doing the build and didn't find enough, so I hope this helps other visual learners...)
(P.S., I hope I am not annoying the more serious crowd with all my pics, I scoured looking for pics when doing the build and didn't find enough, so I hope this helps other visual learners...)
I just re listened to papa’s talk at burning amp. I think its been years now that he mentions second negative phase harmonics or positive phase. So my question is whether this type of behavior can be achieved in class ab, or is it only possible in class a?