On my tube amp from Cary Audio, I have been happily enjoying sound of Jensen Paper in Oil , Copper foil, Alu Case capacitors ( value 0.22 / 630 VDC ) as coupling caps. I like its lush , liquid sound, not harsh. As they are 9 years in use now, I may need to replace them soon. I just found that Jensen has stopped production so was considering a good replacement to match the sound. I get option of Duelund JAM paper in oil , Cu foil Capacitors which are at present available at good price . I like to know if anyone here has used these caps as coupling caps and how is the experience. What change in sound can I expect going from Jensen PIO caps to Duelund JAM PIO caps?
Or does anyone have other recommendations for substitute of Jensen PIO caps?
My amp has a small chassis, hence may be difficult to put large caps.
Your views, comments , suggestions are welcome.
Thanks
Or does anyone have other recommendations for substitute of Jensen PIO caps?
My amp has a small chassis, hence may be difficult to put large caps.
Your views, comments , suggestions are welcome.
Thanks
I do not know if your amplifier uses fixed adjustable bias, or self bias.
For output stages that use self bias, it is easy to check the coupling caps for one problem that can arise . . . they start to be leaky.
Check the voltage on the grid leak resistor.
V / Ohms = current.
That current is only from 2 sources, either the coupling cap, or the tube is gassy.
I even find brand new caps that are leaky.
Some amplifier designers use a cap that is rated with enough voltage to work when the amp is up and running, but not work at power-up with B+ voltage high (output tubes not yet conducting current, and driver tubes not yet conducting current). The capacitor gets this high B+, and the other end is connected to the grid resistor to ground.
Not good!
For output stages that use self bias, it is easy to check the coupling caps for one problem that can arise . . . they start to be leaky.
Check the voltage on the grid leak resistor.
V / Ohms = current.
That current is only from 2 sources, either the coupling cap, or the tube is gassy.
I even find brand new caps that are leaky.
Some amplifier designers use a cap that is rated with enough voltage to work when the amp is up and running, but not work at power-up with B+ voltage high (output tubes not yet conducting current, and driver tubes not yet conducting current). The capacitor gets this high B+, and the other end is connected to the grid resistor to ground.
Not good!
Roughly 15-20 years ago Jensen caps had a bad reputation for leaking voltage after a few years. I installed Jensens in my Cary 40M amps around 2003 and two of the caps failed within the next couple years. Based on that I would be very cautious about Jensen couplers. However I seem to recall Jensen addresses the problem sometime after my experience so later versions may not have the same risk of failure. You say yours are 9 years old so they may be the newer version.
In any case, if I were you I would replace the Jensens just to be on the safe side. I would use Audio Note copper foils. They may cost a bit more but they are worth it, and they should be very reliable.
In any case, if I were you I would replace the Jensens just to be on the safe side. I would use Audio Note copper foils. They may cost a bit more but they are worth it, and they should be very reliable.
Salectric,
Thank you for your suggestion. My tube amp had upgraded Jensen oil caps fitted by Cary when amp was bought, they were 0.22/630 v , then after few years two of them went bad (leaked?) so Cary suggested to replace all four. I got all four new Jensen PIO 0.22/1000 V on it by Cary. Now after about 9 years of use, I just apprehend they may fail someday. So looked up to buy Jensen PIO caps , only to learn they are mostly out of stock. So was offered to consider Duelund JAM ( also manufactured by Jensen) PIO caps, and price is good at $47 each.
I see Audio Note copper foil , Mylar in Oil cap , offered at $ 53 each. I am not aware of difference in sound characteristics of paper in oil versus Mylar in oil. Can you help me to understated? Alternatively, what would you choose between Duelund JAM and Audio Note Mylar in oil? ( Price difference being small, it is not an issue here).
Thanks
Thank you for your suggestion. My tube amp had upgraded Jensen oil caps fitted by Cary when amp was bought, they were 0.22/630 v , then after few years two of them went bad (leaked?) so Cary suggested to replace all four. I got all four new Jensen PIO 0.22/1000 V on it by Cary. Now after about 9 years of use, I just apprehend they may fail someday. So looked up to buy Jensen PIO caps , only to learn they are mostly out of stock. So was offered to consider Duelund JAM ( also manufactured by Jensen) PIO caps, and price is good at $47 each.
I see Audio Note copper foil , Mylar in Oil cap , offered at $ 53 each. I am not aware of difference in sound characteristics of paper in oil versus Mylar in oil. Can you help me to understated? Alternatively, what would you choose between Duelund JAM and Audio Note Mylar in oil? ( Price difference being small, it is not an issue here).
Thanks
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Radni, Everybody has their own opinions when it comes to coupling caps. I recommended the Audio Note Copper foil caps because they have a similar tonal balance to the Jensen caps but with more detail and they are reliable. At the price they are a real bargain in my opinion. I haven’t tried Duelund JAM but I have tried 4 different Duelund CAST values (much more expensive) and did not like them at all. They are not as natural sounding as the AN Copper. I also don’t recommend the lower priced Audio Note aluminum caps; the copper model is one with the mojo.
Thanks all for your inputs.
I liked the tonal balance of Jensen PIO, and wish to broadly retain it. That's one reason I like to go in favor of AN Cu foil, besides its coming in Copper case. My current Jensen are Cu foil in Alu case, so I expect some change for better. AN is smaller in size than JAM, which is very helpful considering the smaller Chassis. On reliability, I like to trust AN this time better than Jensen( which also made Duelund JAM at its facility , so I learn ).
I will go for AN copper foil in copper case.
I liked the tonal balance of Jensen PIO, and wish to broadly retain it. That's one reason I like to go in favor of AN Cu foil, besides its coming in Copper case. My current Jensen are Cu foil in Alu case, so I expect some change for better. AN is smaller in size than JAM, which is very helpful considering the smaller Chassis. On reliability, I like to trust AN this time better than Jensen( which also made Duelund JAM at its facility , so I learn ).
I will go for AN copper foil in copper case.
trying to imagine heart surgeons sitting around discussing which caps they prefer in their heart monitors to improve the soundstage and presence of the signal...
Nope, can't do it because the don't.
Not saying you won't enjoy what ever component you settle on. Just putting the idea here as a thought.
Nope, can't do it because the don't.
Not saying you won't enjoy what ever component you settle on. Just putting the idea here as a thought.
For 0.22 µF/630 Vdc coupling caps I prefer these: MKP4J032204J00KF00 WIMA | Mouser. Why? Because the manufacturer is specialized in high quality and reliable industrial products that don't need to be decorated with audiophoolish babble.
Best regards!
Best regards!
Paper capacitors are a time-bomb in valve circuitry, should be avoided, cheapo polypropylene will out-perform and out-last them easily.
There's a reason paper dielectric isn't used anymore, its a moisture-magnet and chemically unstable over the decades. The moisture leads to leakage increasing inexorable with time,
eventually over-biasing the downstream valve and cooking it, and can also create noise.
There's a reason paper dielectric isn't used anymore, its a moisture-magnet and chemically unstable over the decades. The moisture leads to leakage increasing inexorable with time,
eventually over-biasing the downstream valve and cooking it, and can also create noise.
Well, Mark, I'm sure this exits an audiophool's head by one ear as soon as it has entered it by the other one.
Yes, WIMA capacitors aren't exactly expensive, but they do their job very well, probably much better than some highly praised (among audiophools) other brands'. Big bang for the buck, so to speak. And they surely don't affect the signal more than others.
Best regards!
Yes, WIMA capacitors aren't exactly expensive, but they do their job very well, probably much better than some highly praised (among audiophools) other brands'. Big bang for the buck, so to speak. And they surely don't affect the signal more than others.
Best regards!
Absolutely. Mylar is close to indestructable from what I've read...
http://usa.dupontteijinfilms.com/wp-content/uploads/2017/01/Mylar_Physical_Properties.pdf
Mylar® polyester film will hydrolyze and become
brittle under conditions of high temperature and
humidity, as shown by the effect of steam on the
tensile properties of Mylar® (Figures 7, 8, and 9).
Therefore, care should be taken to ensure that there
is a minimum of water in any hermetically sealed
unit. Adequate removal of water from Mylar® is
usually obtained by heating for 4 hr at 160°C
But if something is properly sealed. I can't see how water is an issue....valid for paper or mylar.
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