Output Capacitor Upgrading Questions

[BNAL]

I think that I will have to give them a try. I'm still burning in the Russian 0.22uF Teflon caps and want to try them first, before I replace the output caps.

[Laudanum]

I saw these caps on ebay. Has anyone tried them. They are big, but think I can shoehorn them in.

http://www.ebay.com/itm/New-100UF-100-UF-RUN-OIL-CAPACITORS-CAPACITOR-370V-/380406832234?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%252BC%26itu%3DUA%26otn%3D5%26pmod%3D380394813619%26ps%3D63%26clkid%3D6098618917369985004#ht_500wt_1156

I have a pair.  Yes, you would have to do some shoehorning. 
I decided not to use them, I didnt want to shoehorn :-)   
I never even clipped them in temporarily so I cant comment on how they sound.
Maybe Ill give them a try at some point.  At the price, I figured I'd hang on to them.

[Grainger49]

When a shoe horn won't work:

http://www.bottlehead.com/smf/index.php/topic,193.0.html

Put the capacitors outside the chassis.  I used heat shrink tubing to insulate the high voltage.

[langendorf]

I have just recived my speedball upgrade, and have a pair of solen 100uf 400v that i will install after the speedball. And was wondering what orientation they have to be mounted? There arent any markings on them

[Grainger49]

The "proper orientation" will only give a slightly lower noise level, it doesn't really have a polarity.  You might contact the maker or importer for which lead is the outer wrap.

[Paul Joppa]

This question made me think, and I came to an interesting conclusion.

Technically, it is preferable to connect the outer foil to the lowest impedance point, usually the output of the previous item. That would be the 6080 cathode in the case of Crack.This allows any capacitively coupled noise (usually hum) to drain to ground most easily.

But Crack is an OTL, with an output impedance that is about the same as the headphones - in the range of 100-150 ohms. So again, at least technically and in theory, it won't make any significant difference - the impedance is quite low in either direction, and you don't know which is higher anyhow, unless you plan to use only one headphone and that headphone is either unusually high impedance or unusually low impedance.

[langendorf]

This question made me think, and I came to an interesting conclusion.

Technically, it is preferable to connect the outer foil to the lowest impedance point, usually the output of the previous item. That would be the 6080 cathode in the case of Crack.This allows any capacitively coupled noise (usually hum) to drain to ground most easily.

But Crack is an OTL, with an output impedance that is about the same as the headphones - in the range of 100-150 ohms. So again, at least technically and in theory, it won't make any significant difference - the impedance is quite low in either direction, and you don't know which is higher anyhow, unless you plan to use only one headphone and that headphone is either unusually high impedance or unusually low impedance.

Thanks for the reply. I just wasnt shure. But is there not a whay to mesure the lowest impedance?

[Paul Joppa]

Sorry, guess I wasn't clear. Here's another shot:

The Crack output impedance, as I said, is 100-150 ohms. Headphones are rated for impedance, usually, between 30 and 600 ohms. If you are using 500 ohm headphones, then they are higher than 100-150 ohms and the outer foil should go to the amp side. If you have 30 ohms phones, then it would go to the headphone side. If the phones are 120 ohms, it shouldn't make any difference. In practice, I doubt it would make a noticeable difference no matter what phones you have, since all these impedance are quite low relative to the reactance of capacitive coupling between the cap and anything else in the circuit.

Of course, lots of unexpected things turn out to be audible. There is only one way to tell, and that's to try it yourself. Because of the DC voltage being blocked by the capacitor, it would be wise to give the cap a hundred hours or so of music after reversing it, to see if there is a break-in effect which needs to be reversed along with the capacitor.

[porcupunctis]

If I remember, the longer leads on the Solens are attached to the outer foil.  You can email them to verify.  Naturally, I forgot to mark my caps before I snipped mine to the desired length.  My amp is absolutely dead quiet so I'm not going to make a point to change anything.  However mine is wired, it is sounding just fine.

[Paul Joppa]

Oh yeah - forgot to mention - you can always wrap the cap in copper tape and ground it, thus shielding the outer foil so the whole thing is irrelevant.  :^)  Like the Gordian Knot, sometimes brute force works best.

[Laudanum]

If I remember, the longer leads on the Solens are attached to the outer foil.  You can email them to verify.  Naturally, I forgot to mark my caps before I snipped mine to the desired length.  My amp is absolutely dead quiet so I'm not going to make a point to change anything.  However mine is wired, it is sounding just fine.

I wasnt concerned about it at all so just got the Mundorfs I used where I wanted them and installed them.  EXCEPT, I intended to orient the second one the other way around so atleast in and out was on the same sides for both caps.  I forgot.  I chalk it up to just another of many "duh" moments for me :-)   
So anyway, assuming that the Mundorfs are consistently labeled, one of them is connected outer foil to input and the other, outer foil to output.  I realized it right after I soldered them in and strapped them down.  Oh well.  Maybe one day I'll flip one of them around.  It's not like I can hear one channel is audibly noiser than the other so it hasnt been a priority. 

[Noskipallwd]

I used a pair of Hovland musicaps in a build recently, and like the Auricaps the manufacturer gives instructions on orientation of the caps. Not much explanation of the consequences of not following the instructions.

Cheers,
Shawn

[Grainger49]

Oh yeah - forgot to mention - you can always wrap the cap in copper tape and ground it, thus shielding the outer foil so the whole thing is irrelevant.  :^)  Like the Gordian Knot, sometimes brute force works best.

I just might try grounding the outer shell of a KK Teflon.  They all come with a metal shell.  I will try to solder very quickly.

I used a pair of Hovland musicaps in a build recently, and like the Auricaps the manufacturer gives instructions on orientation of the caps. Not much explanation of the consequences of not following the instructions.

Cheers,
Shawn

Shawn,

Good point!  That is so often not stated.  The caps are not polarized so they won't blow up if put in "backward."  The result is it might pick up noise or hum without the "proper" orientation.

[HF9]

Good point!  That is so often not stated.  The caps are not polarized so they won't blow up if put in "backward."  The result is it might pick up noise or hum without the "proper" orientation.

Right, the caps will sometimes mark off inner-foil and outer-foil sides. When the outer foil lead is connected to the point of lowest impedance, it can potentially make the sound ever-so-slightly cleaner and more detailed. Read here for more details: http://www.laventure.net/tourist/caps.htm

[Grainger49]

I doubt with the ringing in my ears I would hear it.  Then again I am very sensitive to proper absolute phase.  I guess I will give it a read.

Thanks for the link.