JTM60 capacitor question

joelchoy · 12th February 2008, 11:32 AM

hello,

i have a few question to ask. i have a JTM60 Mashell Amp and the 550VDC 47uF capacitor leaked and it needs to be replaced. i did some online search and cant find a replacement cap for it. i was wondering if i can use a 47uF 600VDC cap instead.

another thing is, can i run the cap in series? like one 70uF 250V cap and a 200uF 300V cap? because if it is in series, it is around 47uF and the voltage is around 550V? correct me if i'm wrong because i'm not too sure myself.

jmateus · 12th February 2008, 01:44 PM

47 uF/600 volts is perfectly fine, not other caps with a rating voltage of 250 V.
Two 250 V caps don't add up, as far as rating voltage is concerned.
Use the first one

zigzagflux · 12th February 2008, 03:45 PM

Furthermore, your series capacitors will only divide the voltage up equally when their capacitance is identical (and their leakage is identical).

Placing 70uF and 200uF caps in series, the 70uF cap will have higher reactance, so will drop more voltage. The 70uF cap will drop about 400V, and the 200uF cap about 150V.

Instead of a resistive divider (what we're most familiar with), you have a capacitive divider, based on their reciprocals (1/C).

joelchoy · 15th February 2008, 05:32 AM

can i use this Mundorf TubeCap 47uF 600VDC? http://diyparadise.com/shop/index.ph...products_id=18

i checked the dimension and the 47uf 600vdc cap is too big and wont fit. are they any websites that you recommend?

12th February 2008, 11:32 AM	#1
joelchoy diyAudio Member Join Date: Feb 2008	JTM60 capacitor question hello, i have a few question to ask. i have a JTM60 Mashell Amp and the 550VDC 47uF capacitor leaked and it needs to be replaced. i did some online search and cant find a replacement cap for it. i was wondering if i can use a 47uF 600VDC cap instead. another thing is, can i run the cap in series? like one 70uF 250V cap and a 200uF 300V cap? because if it is in series, it is around 47uF and the voltage is around 550V? correct me if i'm wrong because i'm not too sure myself.

12th February 2008, 01:44 PM	#2
jmateus diyAudio Member Join Date: Mar 2003 Location: US, New Jersey	47 uF/600 volts is perfectly fine, not other caps with a rating voltage of 250 V. Two 250 V caps don't add up, as far as rating voltage is concerned. Use the first one __________________ JLH 2005, Cyrus and so on...

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12th February 2008, 03:45 PM	#3
zigzagflux diyAudio Member Join Date: Oct 2006	Furthermore, your series capacitors will only divide the voltage up equally when their capacitance is identical (and their leakage is identical). Placing 70uF and 200uF caps in series, the 70uF cap will have higher reactance, so will drop more voltage. The 70uF cap will drop about 400V, and the 200uF cap about 150V. Instead of a resistive divider (what we're most familiar with), you have a capacitive divider, based on their reciprocals (1/C).

15th February 2008, 05:32 AM	#4
joelchoy diyAudio Member Join Date: Feb 2008	can i use this Mundorf TubeCap 47uF 600VDC? http://diyparadise.com/shop/index.ph...products_id=18 i checked the dimension and the 47uf 600vdc cap is too big and wont fit. are they any websites that you recommend?

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