Looking for a low ESR version of Sprague Powerlytic caps from the 1980s to upgrade an amplifier so that after market add on bypass caps can be removed. (The bypass caps are the size of orange juice cans and customer added them to bypass audio leakage into power supply.)
The closest mechanical dimensional fit is Cornell-Dublier CGS331T350R2C with the right dimensions and capacitance, but only available in quantity multiples of 100!
Can anyone suggest a source where I can get four of these without spending thousands of dollars?
The closest mechanical dimensional fit is Cornell-Dublier CGS331T350R2C with the right dimensions and capacitance, but only available in quantity multiples of 100!
Can anyone suggest a source where I can get four of these without spending thousands of dollars?
Would this work for you.
https://www.onlinecomponents.com/en/chemi-con/u36d450lg331m35x67hp-12714242.html
https://www.onlinecomponents.com/en/chemi-con/u36d450lg331m35x67hp-12714242.html
Physically, yes, it would fit. But the ESR is rather high at over 700 milli ohms and no spec for 10khz ESR.
See what else might suit at that website, these type of caps are rather scarce these days - and expensive.
For the capacitance and voltage that ESR is not all that bad - and will perfectly fine as long as you are not using it for SMPS or class D applications. As a direct replacement in a piece of equipment it should work with no issues.
Hal
Hal
A KEMET PN ALS30A331DF500 would also work - same case size, .5" lead spacing and and ESR of 420 mOhms.
Mouser: https://www.mouser.com/ProductDetail/KEMET/ALS30A331DF500?qs=P8MLx3uqQOiI5vva7CuL%2BQ==
Mouser: https://www.mouser.com/ProductDetail/KEMET/ALS30A331DF500?qs=P8MLx3uqQOiI5vva7CuL%2BQ==
This is for a customer amplifier where the customer had placed huge (size of orange juice cans) 47uF Solan film capacitors across the main PSU capacitors as bypass, further bypassed by 0.1uF film caps. I pulled all that junk off the power supply and measured the AC component across the caps with the amplifier running 1KHz at full output into a load and all I saw was 120Hz ripple, no audio. I ran it again with 10KHz and again, no audio leaking in to the PSU. So I am advising the customer that those caps are not necessary at all. The original are high quality Sprague Powerlytic caps which would be hard to equal today. So I'm advising customer to leave it stock without the bypass caps.
From my perspective, you are completely correct in all you are recommending. I have a feeling you will have your work cut out for you in convincing them, though...
I also agree on the longevity of the Sprague's. I work on a lot of vintage HP gear (70's) and they are pretty much standard. The only ones I tend to find issues with are the ones in the SCR regulated power supplies where they have to deal with very high current, high DV/DT for years.
Hal
I also agree on the longevity of the Sprague's. I work on a lot of vintage HP gear (70's) and they are pretty much standard. The only ones I tend to find issues with are the ones in the SCR regulated power supplies where they have to deal with very high current, high DV/DT for years.
Hal
If they fit, they should. Don't worry about the ESR, though, it makes absolutely no difference in that application. In fact you don't want the ESR to be much lower than the OEM ones as it can over stress the rectifiers.