Can you help me choose capacitors for my amplifier's power supply?

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Kuja

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Joined 2005
kujucev.com
#1
Hi everybody,

I have to choose four big power supply capacitors for my amplifier restoration project.

The amp in question is KA-907, Kenwood's TOTL model from 1979.

On this photo you can see the original capacitors:

An externally hosted image should be here but it was not working when we last tested it.


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Only capacitors that are of the right size (that can be physically fitted inside the amp) and that are available to me (I live in Europe), are these Panasonics:

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An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.



Are they OK for this kind of use?


I hope so, since I couldn't find any others that are small enough to be fitted inside the amp.

I'm not sure which ones should I get.

Some people advised me to go for the capacitors with the largest capacitance that can be physically fitted inside the amp (in this case - 33.000 uF, part no. ECEP1KP333HA).

Others told me that I should stick with the original capacitance.

Some told me that I should go for the 80 degree C, others said go for the 100 degree C ... 80V or 100V?

Who should I listen to and why?

I'm kind of a newbie, so little theory wouldn't hurt.

Please tell me what capacitors would you choose from those lists above.
You can use part numbers.

Thanks in advance,

Aleksandar

I'm so sorry for waisting bandwidth, but I also posted the same question in other section of this site, in hope that more people will see it.
I really need to make this decision as soon as possible (while those capacitors are still in stock).

PS
In case this is important, here is also a scan from the service manual, showing the power supply and power amp sections:

http://www.kujucev.com/kx/_amp_web.jpg
 
#2
I have to choose four big power supply capacitors for my amplifier restoration project.
Click to expand...

Hi Kuja

If, as you say, this is a RESTORATION project, the you should pick as close to exact replacements as you can find.

If, however, you want to UPGRADE a bit, the pick the largest capacitance of the same or higher voltage rating that you can fit in the space.

I take it that the original caps are 50mm X 80mm and that they are all 18,000uF/80V like the one shown in the photo.

If it was me, I would pick the ECEP1KP273HA - 27,000uF / 80V listed in the T-UP Series. Why? Well...

1) the more reserve capacitance in the power supply, the more headroom the amp will have (not always, but generally) and the less stressed the overall power supply will be - if you like your music loud 🙂 .

2) there is no advantage to the 100 C temp rating in this application - if the temp inside your Kenwood reaches higher that 80 C then you have a problem.

3) new series caps are generally smaller that their equivalents from 10-15 years ago. Materials technology and manufacturing improvements mean that you can now fit a 50% bigger cap in the same available space. 😀

That's just my opinion, but I have been playing with this stuff for more than 30 years. There are probably others with other opinions.

In the end, you can let cost be your guide if the differences are significant. 😉

Good Luck

Jess
 
#3
Jess,

Thanks a lot for the super fast response! 🙂

Well, you are right - this is a restore/upgrade job.

The original 18,000 uF caps are 50X100mm.

So, can I go for the even larger 33,000 uF ECEP1KP333HA caps,
since they can be fitted too?

Cost is not an issue - I just want to do the best that I can.

Thanks again! 🙂
 
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