Juma's Easy-Peasy Capacitance Multiplier

[schillg11]

Hi,

i have 6 PCB left over. if interested send me PM

BR
Günni

Still remain 2 PCB left over, if interested send me PM

BR
Günni

 

[rephil]

Still remain 2 PCB left over, if interested send me PM

BR
Günni

Hi Günther,

I did recieve today your last two PCBs left over. Nice PCBs 😀 ! Thank you very much for the fast delivery. It has been a pleasure to deal with you.

Best regards

rephil

 

[dimkasta]

I finally found some time to make some test boards. I' m waiting for the mosfets now to test them

 

[snake69fast]

A 100/100mm PCB will be cheaper to order. Maybe next version? 🙂

 

[ZacharyP]

Still any more pcbs? And how much output current can they handle?

 

[xrk971]

IRFP240's are rated 12amps continuous at 100 deg C. I don't think they will be the power limiting bottleneck in your circuit.

 

[xrk971]

Nice work Dimitaska. A separate board for positive/beg?

 

[maouna]

Hello.I ordered this 3.3V-12V In / +-15V Out Dual Power Step up converter to power my preamps from USB or batteries. Can you suggest a capacitance multiplier circuit with low drop voltage to put at the output of the step up converter supposing max output current wont exceed 100ma per rail?

+15V/-15V Dual Power Supply Module 3W DC-DC Step up Boost Converter 3.3V-12V In

 

[xrk971]

That's hard. A BJT based on can do 0.6v drop but that's a different thread. Much easier to get a step up that will take your outputs to much higher voltage and boost by +4v. Dual rail is harder to find. You could take two batteries ea to a MT3608 converter and put in series.

MT3608 Step Up Power Supply Module DC-DC 2V-24V to 5/9/12/28V 2A Boost Converter | eBay

 

[AndrewT]

IRFP240's are rated 12amps continuous at 100 deg C. I don't think they will be the power limiting bottleneck in your circuit.

There is something you have not read or not understood.
The irfp240 must be de-rated to 60W when Tc=100degreesC. (De-rating Factor = (150-Tc)/(150-25) = 150-100/150-25 = 0.4).
At 12Adc that means the Vds cannot exceed 5volts.
If you do match 5Vds and 12A for Ic, then the Tj will be 150degreesC.

 

[xrk971]

Sure Andrew. Nobody runs their amps at 12amps continuous but peak 10amp current can probably be handled just fine for a few seconds. Most Class A amps around here are no more than 1.5amps so 5v x 1.5amps = 7.5w, well within the 60w.

Thanks for reminding us of the SOA, but lets dispense with the "there is something I have not read or understood..." type patronizing remarks.

 

[xrk971]

RaptorLightning made a wonderfully small all SMT version of this cap Mx using a ZVN4306GTA and a 47uF cap. The amp's own rail caps was used instead of the 4700uF used in the schematic. Provides a nice soft-start mechanism to prevent auto shutdown on the battery smart circuit.

Gerbers here:
http://www.diyaudio.com/forums/group-buys/302859-xrk971-pocket-class-headamp-gb-118.html#post5168688

 

[MagicBus]

Hi everyone,
I'm building an alephj mini version with one pair of IRFP240 which needs +/-16V. I would like to use the attached Juma's cap multiplier from post #10. I guess I have to start from a 2x15V transformer but I need to ask what should I change to the resistors' values.

 

[xrk971]

The resistors control the ripple control response rate in combination with main cap value (220uF). Just know that there is a 4v drop across the multiplier. So you need about 20v DC. Under load, the transformer's output will sag about 1v or two. So if you will use the cap values shown in schematic, don't need to change resistor values.

 

[MagicBus]

Thank you very much!

 

[xrk971]

I just received a micro sized Cap Mx based on the Juma Easy Peasy cap Mx design with 100uF 1210 SMT cap and ZVN4306 MOSFET. Literally fits on a dime! Designed for 16v power supply on my Pocket Class A headphone amps.

Thank you RaptorLightning!

 

[ypaudio]

And I made it 🙂 😎
Of course, my version.

sorry I can't find your version. where I can find it?

 

[prasi]

I remember now.. I had started to make a layout for the cap mult as per post 1 and didnt refine it.
seems it can be fitted on a 100mm x 100mm board.

 

[xrk971]

That looks really nice Prasi. A very handy block of PCB to have. Much less ripple than something much larger if done with caps alone. One just needs to spec trafo to give 4v more than usual or about 3vac more rating to compensate for the dropout through the MOSFETs.

 

[xrk971]

Hi Prasi,
It would be nice if your PCB also had option of installing spade connectors for AC in and DC out, rather than screw terminal blocks.
Thanks.

Just something interesting that I noticed: many people in the Pass forum will not install spade terminal pads on their amps as they like flying lead soldered connections to the PCB. Try finding an amp over there that has spade PCB terminals.

Why the Hate for Spades?