In amplifiers, not speakers. Some amps used axial electrolytics.
Axial? Do axial caps exist in low leakage, nonpolar, or "audio grade"? What are some capacitor brands/models that are good for amplifier use?
Radial with the legs spread wide? It seems like this would be less rigid mechanically and more susceptible to vibration than the original axial caps
Axial? Do axial caps exist in low leakage, nonpolar, or "audio grade"? What are some capacitor brands/models that are good for amplifier use?
Radial with the legs spread wide? It seems like this would be less rigid mechanically and more susceptible to vibration than the original axial caps
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Radials work fine. If you are concerned over vibration, dab glue on them. If you have room, lie them on their side rather than sticking up.
Where mounting the radial lead cap is a problem, I use cinch type solder terminal strips held to the board or tube chassis with screws & elastic stop nuts. Cinch doesn't sell them anymore & I have to buy the the import copies from surplus houses instead of major distributors. Tack them on wire or transformer or used circuit breaker orders.
In amplifiers, not speakers. Some amps used axial electrolytics.
Axial? Do axial caps exist in low leakage, nonpolar, or "audio grade"? What are some capacitor brands/models that are good for amplifier use?
Radial with the legs spread wide? It seems like this would be less rigid mechanically and more susceptible to vibration than the original axial caps
You can't really infer the internal connections based on the external axial vs radial. In the end the manufacturer will do whatever to connect as long as it satisfies the design goals and purpose. WIMA caps are essentially axial caps in a container where the legs both exit the same side (ie down to the PCB).
I like to physically secure caps regardless of type. To me they tend to be the heavier of components and supporting the weight on modern thinner lead leads seems a folly.
If you want to reduce vibration then for tubes, you already want a low vibration mounting so they're the least of the worries. You could mount to a sub plate then shock damp mount that to the main chassis (taking care to also to connect the earthing between the mount and chassis).
Tie-wrapping the body of the standing radials together will provide sufficient stability. HP did this to a lot of the tall caps in their large switchers.
Vishay was still making excellent quality axial caps last time I needed some. Check with Mouser/DigiKey, etc. Illinois is another.
A friend rebuilt an old HP low distortion solid state sine wave oscillator a few weeks ago and he was able to source all of the axial capacitors used.
A friend rebuilt an old HP low distortion solid state sine wave oscillator a few weeks ago and he was able to source all of the axial capacitors used.
All the vishay axial lead caps I've seen had service life 1000 hours or less. Yes they are good quality, meet the specified life. I don't want to re-e-cap my amp every 2 years. I've done one 4 times already. dynaco originally, then sprague atomlytic, then CDE. 7000 hours radial caps from nichicon rubicon or panasonic can be bought; I'll expire before those will.
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OK thanks for your posts everyone 
And just to clarify...this is a "what if" situation. I don't currently have an amp with axial electrolytics. But there are some out there that I would consider, such as older BGW pro amps for example, that had axials installed originally.
And just to clarify...this is a "what if" situation. I don't currently have an amp with axial electrolytics. But there are some out there that I would consider, such as older BGW pro amps for example, that had axials installed originally.
WIMA says (https://www.wima.de/wp-content/uploads/media/WIMA-Audio.pdf)
"Modern WIMA high-performance capacitors are produced as radial components with end surface contacts. In comparison to conventionally manufactured axial wire contact versions, parasitic self-inductance is reduced to a minimum in modern plastic film capacitors.The old types of axial designs often still offered as special audio capacitors, have the striking disadvantage of unnecessarily lengthening the conduction paths on the PC-boards and, because of the larger structure and longer remaining length of the leads, they have considerably higher self-inductance. The pulse behavior of axial constructions is therefore always much worse than that of modern radial ones. The old axial versions may just offer slight advantages in the installation of crossover networks in outdoor wiring. For such applications, however, radial WIMA components are also available with long leads."
"Modern WIMA high-performance capacitors are produced as radial components with end surface contacts. In comparison to conventionally manufactured axial wire contact versions, parasitic self-inductance is reduced to a minimum in modern plastic film capacitors.The old types of axial designs often still offered as special audio capacitors, have the striking disadvantage of unnecessarily lengthening the conduction paths on the PC-boards and, because of the larger structure and longer remaining length of the leads, they have considerably higher self-inductance. The pulse behavior of axial constructions is therefore always much worse than that of modern radial ones. The old axial versions may just offer slight advantages in the installation of crossover networks in outdoor wiring. For such applications, however, radial WIMA components are also available with long leads."
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^^^ Interesting post above, but it refers to film caps, not electrolytic.
Does anyone know about construction of electrolytics axial vs radial as regards lead attachment or routing?
Another consideration...it would seem...in using a radial electrolytic to replace original axial electrolytics would be the relatively longer length of the leads necessary for a radial to mount in a space originally designed for an axial, yes?
Would there be higher inductance because of the longer lead length needed to fit a radial in a position designed for an axial?
Does anyone know about construction of electrolytics axial vs radial as regards lead attachment or routing?
Another consideration...it would seem...in using a radial electrolytic to replace original axial electrolytics would be the relatively longer length of the leads necessary for a radial to mount in a space originally designed for an axial, yes?
Would there be higher inductance because of the longer lead length needed to fit a radial in a position designed for an axial?
Good point; I had temporarily lost sight of the topic at hand. I don't know the answer to your questions, but I distinctly recall someone posting that modern radial electrolytics are far better constructed compared to axials, and thus worth the hassle of the longer lead length.
I've replaced about 400 radial caps for axial caps in Hammond & Wurlitzer organs from the sixties and an Allen organ from 1980. Plus dynaco equipment. I've never had a problem with oscillation or bad sound.
I do make the occasional bad solder joint.
These are not radios or switcher power supplies. A little extra inductance doesn't matter. The inductor at the back installed to keep the AM/CB/police band radio out of the signal stops anything coming out either. The Allen had a dodgy power up silence relay at the back, which kept oxidizing the contacts & going silent. When I removed it, it delivered sports talk radio for a service until I wound a 11 turn inductor and installed it in the amp chassis.
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Don't sweat it, you don't need to change caps every 2 years, it's a urban legend from people with no understanding of capacitor technology.
If you read the datasheet of e.g. the 021 series which is Vishay's most basic axial capacitor, you will see that 1000 hours is a worst-case scenario, at the maximum temperature of 85°C, for the smallest voltage ratings of the series. At a much more realistic 40°C, the quoted lifetime is 70,000 hours, not 1000. And 200,000 hours for the larger cans.
BTW Vishay's axial 042 series are specified for 20,000 hours (at 85°C, and 100,000 hours at 70°C with the maximum current applied permanently).
The MacIntosh salesman suggested my first cap change when the ST70 was putting out 14 watts. 1970, 9 years after build. About every 6 - 8 years it would lose wattage again, exhibited by low voltage out on speaker. Polite sound with no peaks. New caps & every 14 years new rectifier & output tubes necessary.
The next to last cap, a CDE from stereocostcutters dynaco inventory buyout, lasted 2 hours.
The last caps, panasonic + nichicon 4000 hour units, are still in.
My primary amp gets 2000 hours/year of use, so 4-6 years is about right on a 1000 hour cap.
This is another urban legend. Or have you found any actual source in the litterature that backs this?
I'm pretty reticent to buying axial 'lytics for repairs from distributors anymore, especially high-voltage ones. My last two buys had date codes in the mid-2000's and 10-12 Ohms ESR. The CS rep said "Yeah, we just don't have inventory turnover in those parts".
I don't have this problem when buying Vishay axial caps from Farnell or the other major providers. So far they have all been made two years or less before I bought them, and well within spec for capacity and ESR (I systematically test them just before soldering).
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