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-   -   Keantoken's CFP cap multiplier (https://www.diyaudio.com/forums/power-supplies/177516-keantokens-cfp-cap-multiplier.html)

prasi 25th April 2020 07:23 PM

1 Attachment(s)
thanks keen,
tried with a 500 ohm load, still same thing. grounding arrangement can be seen in the below image.
clean ground (317/337 and CMX share a common ground point near the leds.
rectifier and bulk caps are far upstream.

I will try replacing the 337/327 and see..
my load demand is quite low, ESP HPA. In that case will mje15033/32 pair be ok?
regards
prasi

keantoken 25th April 2020 07:36 PM

That layout looks okay. I notice I didn't recommend the 15033/32 for the Kmultipliers. That is likely because I didn't have any to test, or if I did, they were not stable.

I would suggest finding a way to load the kmultipliers over 25mA, or switching to D44/45H11G. You can also try switching to BC5xxC for the TO92s, that has also worked before.

Just to make sure it is not another problem, please give me the voltage at each transistor pin.

keantoken 25th April 2020 07:58 PM

For everyone else: I do have Kmultiplier boards, but I got them from the fab without being cut apart, and I can't find my shears. Until I do, you'll have to get 4 at a time and cut them apart yourself.

prasi 25th April 2020 10:09 PM

Quote:

Originally Posted by keantoken (https://www.diyaudio.com/forums/power-supplies/177516-keantokens-cfp-cap-multiplier-post6178238.html#post6178238)
That layout looks okay. I notice I didn't recommend the 15033/32 for the Kmultipliers. That is likely because I didn't have any to test, or if I did, they were not stable.

I would suggest finding a way to load the kmultipliers over 25mA, or switching to D44/45H11G. You can also try switching to BC5xxC for the TO92s, that has also worked before.

Just to make sure it is not another problem, please give me the voltage at each transistor pin.

Thanks kean, I will put them to good use in next project with recommended transistors ( an AKSA class A HPA) . meanwhile for this esp hpa , i built up a simple crc+lm317/337 as per Power Supply for Preamps , works fine for the purpose.

regards
prasi

proid 1st July 2020 03:03 AM

Hi Keantoken, i want to use some sot223 transistor for space saving so can i use bcp53/56, pzta06/pzta56 in place of big transistor?

keantoken 1st July 2020 04:06 PM

As long as the transistor can support the power dissipated, it is worth a try. If the transistor is not suitable you will have low PSRR or it may oscillate.

donovas 17th July 2020 01:54 PM

Prasi i was about to something very similar for my hp amp. I believe the original configuration was found in old parasound psu by john curl? My question is tho, since 317/337's max current output is 1.5a, does that influence the k multiplier's performance on where its current limit is set?

donovas 23rd July 2020 06:29 PM

Keantoken, im debating on whether to use this or the typical darlington cmx for my class a headphone amp. Reading up on pros and cons of cfp vs darlington it seems to me that cfp is harder to stabilize vs darlington having more 2h, at least in the output stage. But also i remember seeing that the transistor characteristic of an active psu will show up on the load. Then since darlington has more 2h, can we assume that as a cmx the same characterstic will be heard on the final sound?


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