Thanks Mark. I appreciate your reply. Do you mean as a straight replacement in the same circuit? And where should the trim pot be connected?
I'm sure you can gather that I'm not proficient with designing electronics circuits. 😛
I'm sure you can gather that I'm not proficient with designing electronics circuits. 😛
You can test IRFP240’s that come in for Vgs. The lowest Vgs ones will give lowest drop. You can always add DC step up boost after 19v smps to diall in any voltage you want (they step ups are available
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Ok, so that's why it's getting so hot. Makes sense.
I've used IRF610 because I read somewhere that it can be used instead of the IRFP240, but now I see it's only for low current use like headphone amps.
Thanks for pointing that out. I'll get the proper component! 😀
Thank you for the Vgs info, X. Is it realistic to expect about 4V drop with IRFP240?
And now that you mention a DC boost converter. It was on my list of ideas. I'll keep that as a last resort.
Hi
Quick question about IRFP240. Is it ok to use IRFP250 in a cap multiplier (for ACA)?
Thanks
Christo
Quick question about IRFP240. Is it ok to use IRFP250 in a cap multiplier (for ACA)?
Thanks
Christo
Thanks Juma
I can get IPFP250 quite easily and cheaply here. IRFP240 is more expensive (different supplier).
I have the boards and they look great but missing IRFP9240 at the moment. Will need to order some. It may be the perfect solution that could replace the typical qnty 8 x 33mF 25V caps in a Class A CRC supply. That's about $35 savings for least expensive CDE brand.
A noob question. I would like to use the basic core cap Mx to feed ACAs running at 24V. I cannot seem to find a BOM. There are 3 resistors (10K, 220 and 1.5 Ohm). What should their safe Watt ratings be?
All 1/4W would be safe. On my PCB, you could fit 1/2W or Vishay RN60D resistors.
Hi prasi,
are there any hints to run this board with +/- 45 V DC?
Ok, the values of the caps have to be adapated. Here actually from 4700µF down to 1800µF/63V and 220µF down to 150µF/63V due to mechanical limitations in size. The whole board is feed by a 2x 30000µF 63V capacitor bank.
are there any hints to run this board with +/- 45 V DC?
Ok, the values of the caps have to be adapated. Here actually from 4700µF down to 1800µF/63V and 220µF down to 150µF/63V due to mechanical limitations in size. The whole board is feed by a 2x 30000µF 63V capacitor bank.
You can run 50v caps on 45v rails. The 4700uF output caps can be made smaller especially if you use this to feed a smaller value CRC to really clean it up. I would try to use 220uF 50v caps if you can fit them. But 150uF is fine too.
Thanks X,
there was a little typo, i mean 54V DC for a Class A/B amp (Iq~ 300mA) , but i think it will be ok with the Capacitors.
BR
Günni
there was a little typo, i mean 54V DC for a Class A/B amp (Iq~ 300mA) , but i think it will be ok with the Capacitors.
BR
Günni
Oh, then use the 63v. You don't want a fireworks display. For those who have not see what happens when you apply 35v to a 16v 220uF cap... you don't want to. It can take out an eye.
I’m wondering if this cap Mx might be the solution to an amplifier hum?
I have a Forte Model 6 amp that I decided to re-cap because of its age and a slight power supply hum. While I had it apart, I figured this was the perfect time to rewire the transformer to convert my Model 6 (class ab) to a Model 4 (class a) and adjust bias.
When put back together and fired up, the same hum was still present!
I also noticed the transformer itself emitted a mechanical hum/buzz. I disconnected the original trafo from the bridge rectifiers and wired up a different transformer outside of the original chassis to bypass the original trafo. This time, when turned on the hum was gone! So, my plan was to remove the trafo from the enclosure and make a separate power supply chassis. At that point I kind of lost interest and put the project on hold.
Back to Juma’s Easy Peasy, now I’m thinking I could remove the huge capacitors, install this cap Mx and a new trafo all in the original enclosure and keep it as a single enclosure unit instead of having a separate enclosure for the power supply.
I have a Forte Model 6 amp that I decided to re-cap because of its age and a slight power supply hum. While I had it apart, I figured this was the perfect time to rewire the transformer to convert my Model 6 (class ab) to a Model 4 (class a) and adjust bias.
When put back together and fired up, the same hum was still present!
I also noticed the transformer itself emitted a mechanical hum/buzz. I disconnected the original trafo from the bridge rectifiers and wired up a different transformer outside of the original chassis to bypass the original trafo. This time, when turned on the hum was gone! So, my plan was to remove the trafo from the enclosure and make a separate power supply chassis. At that point I kind of lost interest and put the project on hold.
Back to Juma’s Easy Peasy, now I’m thinking I could remove the huge capacitors, install this cap Mx and a new trafo all in the original enclosure and keep it as a single enclosure unit instead of having a separate enclosure for the power supply.
It will knock down the hum by -50dB (pretty much inaudible). However, if hum is caused by ground loop, or EMI pickup, it will not help. That was my problem with my M2. You can also use SMPS and DC step up boost to get around the hum as well.