Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 5string on August 25, 2019, 11:51:15 pm
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New guy here. I'd like to know, from someone that knows, if these Jupiter capacitors are suitable replacements for the Mojo Dijon caps. Here's a list of the Mojo Dijon cap values and Jupiter cap values, side by side. I *think* the Jupiters are suitable replacements but want some confirmation.
Mojo Dijon Jupiter
.0047uf/630v .005uf/600v
.01uf/630v .01uf/600v
.022uf/630v .02uf/600v
.047uf/630v .05uf/600v
Second, I understand that a capacitor's value defines and affects tone. Could/would the slight difference in value between the Dijons and Jupiters alter the tone in any significant way, notwithstanding any differences that might exist between the Dijon and Jupiter brands themselves?
I appreciate your patience with a new-guy-questions and welcome any comments.
5string
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Those are all suitable replacements for each other. You should'n't have any problem. A few are 600v vs. 630v caps but unless you're running one crazy circuit, 600 is plenty.
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Capacitor manufacturing is better now than ever. This being said, some will say a .022uF is the same as a .02uF or a replacement. Well if the caps is within 10% and it is over 10% of is stated value I agree.
No one can hand make a capacitor as well as a machine. The machine reads the value accurately while it is making the capacitor. Do some sound different. Sure. A 10uF will pass lower frequencies than a 10pF. I can assure you your capacitor concerns will get left in the dust the day you really find out what single part voices the amp. Speaker(s).
Example: I got my hands on the Schematic for a Standel 25L15, but was made to swear I would never post it or tell someone. IOW, keep it secret. This is probably the cleanest amp you will ever hear. I built 2. One with Orange Drops because they are supposed to more articulate. The second one built, I used Vishay yellow axial purchased from Mouser a friend of mine uses to build Marshall amps.
I cannot tell which amp is which and I can hear very well. The old amps the people like so much, even me fall into LoFi. Once the resistors drift up and the Fender 22uf caps dry to 5uf and you play that amp you may say it is a little noisy, but it has something special.
Here:
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BTW, if you can afford to spend $13, order one of these. Handheld and it is accurate.
DM6013L Handheld Capacitance Meter Condenser Meter w LCD Backlighting Y5R6 (https://www.ebay.com/itm/DM6013L-Handheld-Capacitance-Meter-Condenser-Meter-w-LCD-Backlighting-Y5R6/263283356804?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649)
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Diverted, thanks for the prompt responses. I thought the Jupiter’s would be fine but needed reassurance from someone with more knowledge and experience. Thank you!
Ed, I just bought the capacitor meter. Thanks for the video and recommendation for the tester. That’s one of the best things about this forum - people not only answer your questions, their answers *inform*. Thank you.
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Capacitors in a circuit interact with reactance and/or resistance and/or inductance to produce frequency filters. The mathematical relationships of various components, means that any changes in desired frequency roll-off point(s) typically require an exponential order-of-magnitude component value change (as opposed to an incremental value change). Hence a 0.05uF value cap will produce something noticeably different to a 0.1uF, 0.2uF or 0.5uF. But there won't be much/any difference if you plug 0.047uF into a circuit designed for 0.05uF, or a 0.2uF into a circuit designed for 0.22uF, or 20uF into a circuit designed for 22uF, and so on...
Here's the math:
f = 1/(2.pi x R x C)
For 0.05uF with a 470k resistor
1/(44/7 x 470,000 x 0.00000005) = 67.7Hz
And for 0.0047uF with 470k
1/(44/7 x 470,000 x 0.0000000047) = 72Hz
But for 0.1uF with 470k
1/(44/7 x 470,000 x 0.00000001) = 33.8Hz
or for 0.2uF with 470k
1/(44/7 x 470,000 x 0.00000002) = 16.9Hz
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> a capacitor's value defines and affects tone.
In small audio, typically the C works with an R to *gently* roll-off part of the audio band.
The roll-off is so gentle that 10% variations have no audible effect. 0.002 and 0.0022 are "the same to the ear".
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One with Orange Drops because they are supposed to more articulate. The second one built, I used Vishay yellow axial purchased from Mouser a friend of mine uses to build Marshall amps.I cannot tell which amp is which and I can hear very well.
I agree with you😊
/Leevi
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BTW, if you can afford to spend $13, order one of these. Handheld and it is accurate.
DM6013L Handheld Capacitance Meter Condenser Meter w LCD Backlighting Y5R6 (https://www.ebay.com/itm/DM6013L-Handheld-Capacitance-Meter-Condenser-Meter-w-LCD-Backlighting-Y5R6/263283356804?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649)
ED, does that meter do picofarads accurately? My auto ranging capacitance meter setting reads off only with picofarads, all other capacitance setting read accurately, meter has leads to test. I have an old BK meter with the only the holes to to test picofarads is very accurate but caps have be out of circuit.
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BTW, if you can afford to spend $13, order one of these. Handheld and it is accurate.
DM6013L Handheld Capacitance Meter Condenser Meter w LCD Backlighting Y5R6 (https://www.ebay.com/itm/DM6013L-Handheld-Capacitance-Meter-Condenser-Meter-w-LCD-Backlighting-Y5R6/263283356804?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649)
ED, does that meter do picofarads accurately? My auto ranging capacitance meter setting reads off only with picofarads, all other capacitance setting read accurately, meter has leads to test. I have an old BK meter with the only the holes to to test picofarads is very accurate but caps have be out of circuit.
It is accurate for the entire range on the meter. I bought 3, 2 for me and one to give a new youngster that is getting tube fever. I checked 2 against each other throughout using a Cap-Ranger.