Keantoken's CFP cap multiplier

Im trying to use Kmult in Salas Riaa, but im having some troubles. Input is at 47.5volts, output is 43volts. I read in your guide that output voltage is limited by Q1 Vce. Both BC337 and BC550c have max Vceo 45volts. Does that mean that Q1 is damaged? If so, is there a higher Vceo alternative transistor to use ?
 
Usually the max input voltage is higher, but it depends on the charge time of the preceeding reservoirs. I don't think 47V should be a problem. The BC5x6C would be safe for higher voltages, but not as good for filtering.

Since your output voltage is far below your input, most likely your transistors are still functional. Usually when this happens something is causing Q1's Ib to be very large. In this case, 3.3mA.
 
Hi Kent,
I still have several questions for you and please excuse my knowledge limitation in that sector.
1. For C1 and mostly for C3 - ESR-> Lower ESR is better! - ?
2. I can use KM for the loads lets say 5-15mA, but I need to add dummy-load resistor in order to bring consumer to 25mA consumption as a min. Right?
3. Is any way to buy professionally made PCB for you KMs? I probable need couple of these...

Thank you.

Alex
 
I sent email to that guy with PCBs. So far, no response.
Any other source for these PCBs?
Thank you.

Alex,

I have just got your private message. I check my private message once a year. keatoken alerted me that I had an email which I have not received.

Yes I still have perhaps a couple of PCBs left. I have built them and measured them with a 100MHz oscilloscope and they work very well. The PCB incorporating input snubber and some CLRC with small ground/power planes assists with non resonant, low noise implementation and noise is below what my scope can measure. The only thing that is not very nice is that the gap between the pads/vias and the ground and power planes is rather small and there is no solder mask. I had to do soldering very carefully and checked with a magnifier afterwords to make sure there was no short.

You can use it for two positive rails by swapping the polarity of the diodes, LED and electrolytic capacitors and use the correct transistors with correct orientation on the negative side. However, you must check this yourself as I cannot guarantee that. I spent a couple of minutes looking at it just right now and couldn't see why it would not work. Of course, you can omit the input section and use the KM part only.

As said, all income will be transferred to Keantoken to help his R&D work.

If you need to contact me please send me private email instead of private message.

Regards,
Bill
 
Hi, All,

I have realised that in my printed circuit board design the gap for the power/ground planes is a bit too small and the boards don't have solder masks, making it more difficult to solder. For this reason, I am reducing the price of each board to $30 each, if anybody is interested. Description can be found in post #461 and the photos can be found in post #569. All income generated will be donated to Keantoken for his R&D work.

Regards,
Bill
 
I'm working on figuring out PCB software. I'm using gEDA because it supports arced traces and is not actually that bad to use so far.

So can you guys talk about what you would want from a Kmultiplier PCB design? I want to make a board to get fabricated, and I would help with the design of a board for those who like to etch their own.

So what kind of PCB would be immediately useful to you?
 
... from Cadsoft Eagle to Sketchup...
 

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I have a new design that works with voltages above 45V, but I haven't gotten around to updating the site. I'm sort of embarrassed I didn't do this earlier.

For tube amps you probably want a different version, but this one will work for 100V power amp rails as an example, if you are careful not to blow the 1N400x with inrush. This version would be great for a workbench. Are there better diodes than the 1N400x that don't have higher capacitance, and are not less available than the transistors in this circuit?

It also might not have as pleasant turn-on, since the diodes short it until the inrush is over. So it's not necessary for circuits under 45V.
 

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