Caps For Dummies

[Stanshall]

Evening, gents.

I've ordered a couple of 100uf Mundorfs after reading a fair bit on here about this being a decent first cap upgrade but I've realised that:

1. I don't for certain know how to install them.

2. I don't know if I need to bypass them, or anything else, at the same time.

Anyone got any pointers, please? My assorted reading on here has given me inspiration but not necessarily a clear idea of what's needed to go off-piste with caps.

Thanks.

 

[Strikkflypilot]

Great post.
I have the same questions.
I have planned on connecting one end of left film capacitor to B3, the other to terminal 6.
For the right film cap, one end to B6, the other to terminal 10. I think it doesnt matter if You use B3 or terminal 7, and B6 or terminal 9 but Im no expert. Just think it makes sense to connect directly to tube connector to make extra leads as short as possible if not completely redundant.
I also understand that outer/inner side of capacitor might matter although they are not supposed to be polarity sensitive. As I understand it, if You look at the cap, the side the text starts is usually the outer side and should be connected to terminal 7/B3 for right cap and terminal 9/B6 for left cap and the other end to terminal 6 for right cap and terminal 10 for left cap.

Make sure the leads are sleeved to prevent a short.

If You decide to addtionally install 1uF bypass caps, they are soldered in paralel to the cap to be bypassed.

This is how I have planned and hope is correct.

Edit: Oh, and the 100uF should be somewhere from 200v or upwards, 250 should definitely be safe. The bypass caps (1uF) should at least be taking the same voltages or higher than the former caps

 

[Grainger49]

Capacitors have a number of specifications.  The ones you always see are the voltage rating (sometimes in AC and DC) and the capacitance value. 

There are other properties that capacitors have.  There is equivalent series resistance (ESR).  This one is important because the lower it is the faster the capacitor can release the stored voltage. 

There is also a equivalent series inductance, parallel equivalent resistance and parallel equivalent inductance.  We pretty much ignore these.

None of these properties tell you what the capacitor will sound like.  You just have to give them a try.

As for bypassing a signal path capacitor I am of the TRY IT philosophy.  Get some jumpers if you don't have any.  Put it in, take it out and repeat till you have a good handle on the sound it imparts on the music.  Solder it in if you liked the results.

I have bypassed the cap in my DAC, decided not to in my Eros.  It is a matter of taste and what you listen to.

 

[mcandmar]

Out of interest Grainger what capacitys and type of caps did you use in your bypass?  Did you stick to the /100 rule?

 

[JamieMcC]

Is it also ok to use a capacitor rated for vac with dc current? I have seen a few post that hint at it being ok and that generally the dc rating would be slightly higher the ac rating? As an example I have seen capacitors listed with 250vac rating being described as also 300v dc?

Its a tad confusing.

 

[Strikkflypilot]

Hey guys.
Great input, but at least kinda over my head.
If I read the OP correctly, there is the need for an easy to follow
walkthrough. Is mine ok?

 

[Grainger49]

Out of interest Grainger what capacitys and type of caps did you use in your bypass?  Did you stick to the /100 rule?

I bypassed the Ack! dAck! 2.2uF Auricaps with 0.1uF KK Teflons.  I use what I have on hand.  This took about 4 swaps in and out and I was convinced I liked the bypass.  Whereas I tried one and two 0.22uF KK Teflons on my Eros and didn't like the parallel combination as much as a single cap.  I ultimately ended up with a 0.47uF Silver/Gold/Oil Mundorf.

Jamie, sometimes.  I have a pair of motor starter "oilers" in a DPMPS feeding the right and left channels of my FP 2.  A DPMPS is Dual Pseudo Mono Power Supply.  I went from the existing second stage cap (usually only 2 stages for FP 2) and "Y adapted" with two 1k Ohm resistors feeding 100uF oilers.  Then from them to the two channels separately.

 

[Grainger49]

The question about directionality comes up very often.  Polarized (usually only electrolytic) capacitors must be installed with one lead at a higher voltage than the other lead.  If not they explode.

There are probably film caps with polarity marked on them.  The ones I have used don't have this.

But ... there is always a "but."  Most film caps are rolled like jelly roll.  There is an outer wrap attached to one lead and the inner wrap is attached to the other lead.  If you attach the outer wrap to the lower voltage, closer to ground or to ground, you get some additional noise rejection.

Whether or not this is needed depends on your individual situation.

 

[Strikkflypilot]

Cool stuff.
Jamie, did You connect your film caps to terminals 6+7 / 9+10, or 6+B3/ B6+10?

 

[Stanshall]

Thanks, Strikkflypilot. Good to see someone in the same boat. The topic quickly went over my head again but I fitted the 100uf 250v Mundorfs and all going well. Definitely more treble going on and seems like a marginally bigger soundstage, bass seems a little more bloated, though. I kind of expected this from what I've read and I assume they need a good bit of burn-in. I'll be giving them a good 8hrs a day for the next few weeks to get them up to speed.

 

[JamieMcC]

Hi when putting my 100uf's in I connected them to *exactly* the same terminal positions that the electrolytic capacitors I removed were connected to. I don't have my manual or Crack to hand to check the terminal numbers.

 

[Strikkflypilot]

Cool Stanshall. Got pictures?
Thanks Jamie, I considered direct soldering to octal connectors to avoid extra wires.
But we'll see. Mine are still underway

 

[mcandmar]

Is it also ok to use a capacitor rated for vac with dc current? I have seen a few post that hint at it being ok and that generally the dc rating would be slightly higher the ac rating? As an example I have seen capacitors listed with 250vac rating being described as also 300v dc?

Its a tad confusing.

From what i can gather the conversion is roughly 1.41 from AC to DC, i.e. the same as calculating rectified voltage.

e.g. 240vac RMS (240v * 1.41) is ~338v. So i would call a 240vac rated cap a 340vdc rated cap.  I'm sure its more complicated than that but thats kind of close enough ish, but as always over rate a bit and use a 400v cap in a 340v application and you should be good.

P.S. Sorry guys i dont own a crack so i cant directly answer your queries..

 

[Grainger49]

  .  .  .  I kind of expected this from what I've read and I assume they need a good bit of burn-in. I'll be giving them a good 8hrs a day for the next few weeks to get them up to speed.

They will probably take 100 hours to get to full burn in.

 

[JamieMcC]

Thanks Grainger and Mark

 

[Strikkflypilot]

I was thinking of solderinging in a 1uF Mundorf Supreme in parallell as a bypass from the start. Thoughts?