Is Solen better than Vishay-Roederstein?

[Chriszuma]

I recently built an A47 headphone amp, and due to some confusion regarding a mixed-up part number, I ended up with 4.7uF Solens instead of the .47uF Solens I ordered. I bought some .47uF Vishay-Roedersteins from Mouser so I could finish the project, and then Tubesandmore corrected their mistake and sent me the right part. Of course, I had already finished the amp and cased it up by then.

What I am wondering, now that I have both capacitors, is whether or not it would be worth it to open the case back up and replace the VR caps with the Solens. They are slightly more expensive, but I was wondering if anyone knew whether or not it would actually be worth the effort to switch them out. Also it would majorly reduce the resale value (currently 4 dollars. I am cheap.)

 

[Pars]

The input caps on an A47 and other Cmoy-style amps are there to protect against DC-offset coming from the source component (CD player, etc.). These in conjuction with an input resistor to ground form a low pass filter, the pass frequency of which is given by the formula f = 1/(2 * Pi * R * C). Since your input resistor is most likely 100K ohms, with the 0.47uf caps this gives you a -3dB point of f = 1/(2 * 3.14159 * 100000 * 0.00000047) ~ 3.4 Hz. This filter will have some effect above the cutoff frequency, but not alot say above 20 Hz. The 4.7 uf caps will result in a cutoff of 0.34 Hz. Because analog filters are not steep notch filters in actual practice, you could possibly hear some difference. Note that on a normal "stock" Cmoy, the input cap is 0.1uf, which is up around 15-18Hz. A 0.47 - 1.0 uf cap is usually optimal. The quality of such a capacitor is probably of more interest than the value (if it's above 0.1uf) because caps are pretty non-linear devices. I'd try them out to see if I could hear the difference, unless you want to return them or they won't physically fit.

As to whether the Solens are better than the Vishays, I don't know.

 

[Garbz]

A quick bode analysis gives your current values as being down 0.1dB at 20hz, and a 7degrees phase change at the same frequency.

It's unlikely that changing the cap size will give any changes in signal. It's really only a question of the quality of the cap like pars mentioned above. I would leave it but that's generally because I have too much to do.

 

[dsavitsk]

Quote:

Originally Posted by Chriszuma I was wondering if anyone knew whether or not it would actually be worth the effort to switch them out.

I would doubt it, though not because I think the Vishays are any good (I have no idea) but because I don't think the Solens are: http://www.ecp.cc/cap-notes.html

 

[Chriszuma]

Well I can't use the 4.7's because they don't fit in my tiny Hammond case, so I'm basically just wondering if there's a large quality difference between solen and vishay-roederstein.

 

[threepointone]

try comparing the dissipation factors / dielectric absorption ratings. Also depends on which vishay-roederstein series you're using. if you trust the ratings solen gives, they should be better than the vishay-roederstein capacitors. Whether or not the difference is noticable or worth it is questionable, though.