Cap upgrade question

[Markkr]

Admittedly, while I have some minor electronics understanding... things like this are beyond my current knowledge. I bought caps for my Crack and I think I might have ordered the wrong ones. They do not appear to be the same physical size as others I see in pictures. Can anyone assist in identifying if these (pictured) will work?

 

[Deke609]

Circuit-wise, they should work fine. You've got the same capacitance (100uF) as stock, but with double the DC voltage rating (350VDC vs. stock 160VDC) - that's not a bad thing and they'll probably last for ages. But the increased voltage rating makes the cap fatter than necessary. So the question is whether they'll fit. But Crack builders are famously ingenious at finding ways of making things fit.

cheers, Derek

 

[Doc B]

Since the pleasure received from cap rolling seems to be partly in the conjecturing and hand waving done before actually putting in the cap and listening, I'll throw out the idea that the thicker dielectric required in higher voltage rated caps adds more of the thing that colors a capacitor's sound.

 

[Markkr]

All righty, I’ll give it a shot! Thanks guys.

 

[Markkr]

One more noob question.

On the new Mundorf caps, the shorter wire indicates that its the outer foil... but which side does that translate too from the factory caps?

Short wire = negative factory cap side
or
Short wire = to positive factory cap side

 

[Laudanum]

I believe that you would want to attach the outer foil of the new caps to where the + side of the Bottlehead supplied electrolytic caps were connected.  That said, I'm not sure it will make much difference.  Also,  I could have it backwards so you may want to wait for another member to chime in on the caps orientation. 

Helpful, ain't I?  :-D

 

[Thermioniclife]

It should be connected to the point of lowest impedance, having said that it can be connected either way and you will probably never hear the difference. Perhaps it can be measured. Here is a link.
https://www.aikenamps.com/index.php/where-to-connect-the-outside-foil-on-capacitors

 

[Deke609]

Short wire = to positive factory cap side

Yes, connect it this way.  That's what both Laudanum and Lee were suggesting.

Construction/installation note: once the outer foil leads are connected to where the positive side of the stock caps were connected (T7 and T9), if the remaining leads won't connect easily  to T6 and T10 (where the negative side of the stock caps connected) you can wire them directly to the headphone jack -- i.e., to the same headphone jack terminals to which T6 and T10 connect (with a wire extension, as necessary).  Judging by the dimensions of your caps, you might be able to install both caps on the headphone jack side, with the fat/wide side of the caps running parallel with the long edge of the chassis.  In which case, wiring them directly to headphone jack would be pretty easy.  You'd probably need to run a wire from  T9 along the terminal lug strip to the outer foil lead of the new cap.  And if you do this, you should completely remove  the wires connecting each of T6 and T10 to the headphone jack.  And you can reuse the wires to make the new connections.

cheers, Derek

 

[Markkr]

Excellent, thanks so much everyone!