Bypass cap replacement

[Demsy]

I tried looking for a thread about replacing the standard electrolytic cap with a Solen MKP. Will this change make any difference in the sound or any other positive improvement?
I plan to change the base plate of the amps with stainless steel and at the same time change it to 2A3 configuration. To install this Solen won't be easy due to its size. If there is no positive improvement, I won't install them.
Thanks for any input!

[Grainger49]

Which bypass cap are you considering replacing?  The cathode bypass cap will make the biggest difference.  It is in the AC (signal) ground circuit, so the signal path. 

IIRC, there are Ccomp caps on the C4S boards that can benefit from being a better film cap too.

[Paul Birkeland]

I plan to change the base plate of the amps with stainless steel

At one point I thought this was a good plan, but you have to be so careful to keep all the surfaces painted so you don't get rust!

-PB

[Demsy]

Grainger, it's the 47uF/450v cap on the wiper of the hum pot. Is the one that you meant?

PB, I am using the 304 grade stainless steel, mirror finish. I don't think there will be any rust forming on the surface. And if you mean for the contact corrosion, as long as it is dry, there won't be any.

[Grainger49]

Yes, that is the cathode bypass cap. 

BTW, you could clear coat the stainless.  I'll assume it won't react with the other metals that come in contact with it.

[Demsy]

Thanks Grainger, so replacing this cap would bring an improvement. I will try to find a place for this big cap. What could I expect to change?
One thing though, why do you think that a 304 grade stainless steel would rust? And secondly, it is very difficult to have paint to bond properly with stainless steel. You would need a kind of etching primer for that, it's even more difficult on a mirror finished surface. I am using stainless steel because it won't rust, unlike untreated aluminum which will oxidise in the long run, especially in our hot and humid climate.

[Grainger49]

I think you will get greater clarity.  The bass might improve too.

I don't know much about stainless.  I was going on Paul's warning.  If you were to clear coat it you would have to find a clear primer.  I don't know of any.

I live in the hot and humid South.  My 10+ year old Foreplay hasn't oxidized noticeably. 

[Demsy]

That's great, will surely try it out, soon.
The stainless steel won't rust at all without any coating, for sure, it's in the property of this material. I work a lot with this material, up to the food and pharmaceutical grade of it.
Thanks Grainger!

[galyons]

I live in the hot and humid South.  My 10+ year old Foreplay hasn't oxidized noticeably. 

Aluminum oxidizes almost instantly with a thin, hard coating of aluminum oxide, (Al2O3).  Unlike rust, (iron oxide, FeO), aluminum oxide is not water soluble, so it does not flake off like rust does. So the very process of oxidizing stops as soon as the hard aluminum oxide layer is formed.   Really the only way to "notice" the oxidation is to scratch down to shiny aluminum, which, again, will quickly oxidize!!  Cool, eh!?

Cheers,
Geary

[trioid]

Hi All,

I did this electrolytic cap replacement, using Solen caps (47 uF, 630V). You just about need to build a second story to fit those under there, especially putting them next to the 4 uF Auricaps I used to replace the original 3.3 uF caps. One must be quite careful about the placement, using proper insulation, etc. There were a few moments  that I questioned my sanity about trying this.

However -- a clear and welcomed improvement. My system uses the EML 300B (standard version). Those tubes are quite remarkable by themselves. But, combined with this modification, we have hit a new level all together. (I should mention that I also replaced some caps on the CS4 board, earlier)

Cheers,
Jim

[johnsonad]

This is what I plan on using. They are fairly compact and cheap. http://www.mouser.com/Search/m_ProductDetail.aspx?Panasonic/EZP-E50107MTA/&qs=/ha2pyFadui42GvL3EnWS3%252bqghZaxuiDlce4Dl%252bI/%252bUjmz4dTwgMmw==

[Grainger49]

I have replaced every cap in my Paramours except the cathode bypass caps.  I bought some but they are almost the size of the Paramours themselves, larger than the 2A3 tubes by a large margin. 

So, I am a confessed capacitor junkie.  I believe Jim when he says he wasn't prepared for the changes he heard.

Aaron,

You posted as I was typing.  When I clicked on the link I said, "WHAT?"  Then I enlarged the picture and it made sense.  A tall base for Bottlehead equipment has been done and doesn't look odd to me.  Kind of elegant. 

Go for it!

[johnsonad]

They really aren't that large. In a standard Paramount chassis you can easily Velcro them to the wood base (using heavy duty Velcro) and have plenty of room left over. An added plus is that they aren't very heavy.

I plan on super gluing them to the bottom of my much larger chassis plates.