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-   -   Juma's Easy-Peasy Capacitance Multiplier (https://www.diyaudio.com/forums/power-supplies/297921-jumas-easy-peasy-capacitance-multiplier.html)

dadod 13th November 2016 04:11 PM

It's really pity not to integrate needed protection in a cap multiplier, like over current and DC offset (loudspeaker) protection.

xrk971 13th November 2016 08:47 PM

Quote:

It's really pity not to integrate needed protection in a cap multiplier, like over current and DC offset (loudspeaker) protection.
You mean speaker protection in general should be used? Protection would be placed after amp output not in front where cap multiplier is.

I want to go with a SS switch one of these days like vzaichenko's 21st century protection.

erik777 14th November 2016 01:31 AM

1 Attachment(s)
If a linear PSU is being used in Jumas Cap Mul, filtering deep in LF audio band would be ideal. C14,C16 is called out to be 220uF. Would replacing the 220uF with 680uF caps be slightly better?

dadod 14th November 2016 05:21 AM

Quote:

Originally Posted by xrk971 (https://www.diyaudio.com/forums/power-supplies/297921-jumas-easy-peasy-capacitance-multiplier-post4885724.html#post4885724)
You mean speaker protection in general should be used? Protection would be placed after amp output not in front where cap multiplier is.

I want to go with a SS switch one of these days like vzaichenko's 21st century protection.

Why not in front?
A cap multiplier uses series active device (bjt or mosfet) and it could be switched off. You need a DC offset detector on the power amp output and triggering circuit to switch off the cap multiplier (or other type of series PS regulator). This was used by John Linsley Hood in his 80W mosfet amp and I use it in my PS regulator here http://www.diyaudio.com/forums/solid...ml#post3907062.
It works very effectively, ones it saved my loudspeaker and amp(some cold solder in the amp caused full DC on the amp output).
It's simple to add overcurrent protection too.
The main requirement is not to have to big caps after the cap multiplier.

xrk971 14th November 2016 09:34 AM

Quote:

Originally Posted by dadod (https://www.diyaudio.com/forums/power-supplies/297921-jumas-easy-peasy-capacitance-multiplier-post4886013.html#post4886013)
Why not in front?
A cap multiplier uses series active device (bjt or mosfet) and it could be switched off. You need a DC offset detector on the power amp output and triggering circuit to switch off the cap multiplier (or other type of series PS regulator). This was used by John Linsley Hood in his 80W mosfet amp and I use it in my PS regulator here http://www.diyaudio.com/forums/solid...ml#post3907062.
It works very effectively, ones it saved my loudspeaker and amp(some cold solder in the amp caused full DC on the amp output).
It's simple to add overcurrent protection too.
The main requirement is not to have to big caps after the cap multiplier.

Thanks for clarifying. Now how to make it simple in keeping with thread's focus of peasy?

xrk971 14th November 2016 12:32 PM

More listening impressions with the cap multiplier. It seems to make the contrast much much better so the "blacks are blacker". I am hearing very low level detail that was probably garbled in PSU noise/ripple before. For the low cost of $4 in MOSFETs and maybe $2 in caps - this is one of the best sound quality upgrades for the dollar. Also, if you listen to rather quiet passages and at lower levels the cap multiplier is a great enhancement.

Build this cap multiplier and and have a listen - it makes a difference. Easy Peasy - no excuse not to. You don't need a PCB. In fact, I think a PCB will take more space here all you need to do is bolt the IRFP to some convenient location inside your case for some heat dissipation (it's not much). Solder up the 3 pins which hold it all together.

https://www.diyaudio.com/forums/atta...tereo-vert.jpg

olafk 14th November 2016 01:14 PM

Are there limitations for higher voltages or changes in component parameters (+-50V) or can the same circuit be used?

AndrewT 14th November 2016 01:40 PM

once up to operating voltage the voltages are quite low so operates at high output voltage just like a 317 can even though it is rated @35V

But you have to look at start up when full supply voltage can appear across some devices.

xrk971 14th November 2016 02:44 PM

Quote:

Originally Posted by olafk (https://www.diyaudio.com/forums/power-supplies/297921-jumas-easy-peasy-capacitance-multiplier-post4886258.html#post4886258)
Are there limitations for higher voltages or changes in component parameters (+-50V) or can the same circuit be used?

IRFP240/9240 are rated 200+ volts? Make sure your electrolytic caps are rated for the voltage and should work.

If someone had a clever way to clamp the MOSFET gate to ground quickly in case of DC at speaker that would be a great speaker safety protect feature as Dadod pointed out.

olafk 14th November 2016 04:14 PM

Thanks for explanations.

regards Olaf


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