The dust problem is a fact when using forced cooling, regardles of how or where you place the fan. The only thing that avoids this is a filter, but that needs to be cleaned every now and then. If one forgets that, the amp will overheat and eventualy die. Just put in a thermal protection and you will overcome that problem to. It's not all rocket science just use common sence 
Regards
Regards
Actualy my soundcard stopped working,that was before I had done any messauring.
And I have to first try the regultor for the fron end,and bolt the 2 heatsinks to the chassis,and solder it togheter with the powersupply.
Better take it cool or I just mess it up.
Just ordered a new soundcard.
And I have to first try the regultor for the fron end,and bolt the 2 heatsinks to the chassis,and solder it togheter with the powersupply.
Better take it cool or I just mess it up.
Just ordered a new soundcard.
Don't. I checked the Diodes and Zeners and they are swapped as reported.
For the Al (pink mouse) boards that is not a real issue as there are 2 of each per kit.
But the Jan kit there were many more diodes and Zeners because of the protection circuit.
I still have not rx'ed replies back from all buyers on the kit type they wanted...
All of the US kits were shipped... I think the ONLY issue thus far has been the diode and Zener swap...
With a good light or with a magnafing glass you can see the writing on them and tell which is which.
For the Al (pink mouse) boards that is not a real issue as there are 2 of each per kit.
But the Jan kit there were many more diodes and Zeners because of the protection circuit.
I still have not rx'ed replies back from all buyers on the kit type they wanted...
All of the US kits were shipped... I think the ONLY issue thus far has been the diode and Zener swap...
With a good light or with a magnafing glass you can see the writing on them and tell which is which.
KSA PSU Configuration
I am considering the following 2 PSU configurations. One with 2 rectifiers per channel, and one with only one rectifier. Any comments on the relative merits of the two schemes, or comments and corrections on the overall design would be greatly appreciated.
Robert
I am considering the following 2 PSU configurations. One with 2 rectifiers per channel, and one with only one rectifier. Any comments on the relative merits of the two schemes, or comments and corrections on the overall design would be greatly appreciated.
Robert
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Dude, I cannot comment on using extra diode bridges, but
ALERT!!! That thing is gonna blow up!
R1 and R3 should be in series between C3 and C5 on the +V rail.
R2 and R4 should be in series between C4 and C6 on the -V rail.
Edit- I see people already mentioned this-- sorry!
I also think you should use 25W resistors insead of 15W as they will get quite hot. You should consider where you are going to physically mount them as they will heat up nearby components and you don't want to cook your capacitors.
For a Krell, lowering AC ripple is not as important as with other designs like the Aleph. I would think that getting rid of the CRC to just use two C's in parallel would give more benefit (double capacitance), but i is just a newbie at this so don't quote me on that.
ALERT!!! That thing is gonna blow up!
R1 and R3 should be in series between C3 and C5 on the +V rail.
R2 and R4 should be in series between C4 and C6 on the -V rail.
Edit- I see people already mentioned this-- sorry!
I also think you should use 25W resistors insead of 15W as they will get quite hot. You should consider where you are going to physically mount them as they will heat up nearby components and you don't want to cook your capacitors.
For a Krell, lowering AC ripple is not as important as with other designs like the Aleph. I would think that getting rid of the CRC to just use two C's in parallel would give more benefit (double capacitance), but i is just a newbie at this so don't quote me on that.
Take a read of Dejan V. Veselinovic's
Designing your own power supply
at:http://zero-distortion.com/start.htm
Regards
Designing your own power supply
at:http://zero-distortion.com/start.htm
Regards
PSU Configuration
What would be the purpose of placing lower ohm resistors in series on the rails? I have seen some schematics that use inductors in series on the rails.....would the function be similar?
I was considering leaving the resistors out entirely as suggested, but I think having the bleeders is a good idea to drain the large caps more rapidly.
Robert
Thanks everyone for your input......I am new at this....obviously! My intent for the parallel resistors is as bleeders just as discussed by Mr. Veselinovic. I see that my ohm values are way too low for this purpose, and should be more in the range of 6kR to 10kR at around 5W? And I guess that one bleeder per rail is all that is necessary....with or without an LED.acenovelty said:
What would be the purpose of placing lower ohm resistors in series on the rails? I have seen some schematics that use inductors in series on the rails.....would the function be similar?
I was considering leaving the resistors out entirely as suggested, but I think having the bleeders is a good idea to drain the large caps more rapidly.
Robert
Hi,
if you keep series R at about 0r5, then Iq=1.9A gives a dissipation of only 1W8. Well below 15W. The average current would have to rise to 5.5A to use the full dissipation of your series resistor. This would be seriously loud continuous music into low impedance speakers;- equivalent to PA use or testing at 240W sinewave into 2ohm. Don't bother raising to 25W, I would use 7W or 10W to save space.
Download PSUD2 and check the effect CC PSU against CRC PSU.
The main advantage of CRC is reduced hum leaking through to the amplifier. However to get best use out of it you need to ensure that the caps AFTER the series R can cope with the intended load i.e. for KSAKlone 47mF minimum, 56mF is recommended.
Also be aware that the ripple on the first Cs of the CRC will be very high (see PSUD2 results) and you MUST ensure the caps can survive this stress/temperature.
if you keep series R at about 0r5, then Iq=1.9A gives a dissipation of only 1W8. Well below 15W. The average current would have to rise to 5.5A to use the full dissipation of your series resistor. This would be seriously loud continuous music into low impedance speakers;- equivalent to PA use or testing at 240W sinewave into 2ohm. Don't bother raising to 25W, I would use 7W or 10W to save space.
Download PSUD2 and check the effect CC PSU against CRC PSU.
The main advantage of CRC is reduced hum leaking through to the amplifier. However to get best use out of it you need to ensure that the caps AFTER the series R can cope with the intended load i.e. for KSAKlone 47mF minimum, 56mF is recommended.
Also be aware that the ripple on the first Cs of the CRC will be very high (see PSUD2 results) and you MUST ensure the caps can survive this stress/temperature.
I spent some time in the tax-free twilight zone in Switzerland.
