Output Capacitor Upgrading Questions

[jrihs]

Since they are on sale, I thought I would order these...100uf / 400V, M-CAP

[Jim R.]

John,

Generally caps are chosen relatively close to their working voltage (safety margin added of course) as in the same circuit the higher voltage cap will generally have higher ESR and inductance.  In this situation, how much that will effect the sound, I can't even begin to guess but I'd say it might be pretty minimal.  Electrolytics are another story though...

HTH,

Jim
 

[jrihs]

Thanks! so to figure the working voltage in this case, I would pick the voltage based on the electrolytic I'm replacing? I think its around 600V if memory is right. Guess I,m wondering what the working V is? Thats what I measure on the upstream side of the electrolytic thats installed?

[Grainger49]

The Crack power supply caps are rated at 250V.  So you can be assured that includes the turn on surge and some safety margin.  Anything downstream will see lower voltages.

I don't know if 200V is safe, maybe someone using 200V caps will chime in.  A 250V rating has to be safe.

[earwaxxer]

Hey John - From what I have read about subjective cap reviews, it appears that the higher voltage versions tend to sound better. Not sure if there is any reason to believe that! If all else being equal and they didnt cost much more I would go with the higher voltage rating.

[Jim R.]

In the Crack, anything above about 160 v is fine for the coupling caps.  Definitely no need for 600v caps in the Carack.

To test the sonic impact of various voltage caps, one would have to have a selection of the same brand and make cap at the same size and different ratings and then break them all in in and then go back and listen to them one at a time.  Which is to say that I'm guessing the higher voltage caps sounding better is more an issue of the construction of those particular caps, and maybe, just maybe a bit better mechanical damping due to a thicker dielectric.  Lots of possibilities to investigate if one is so motivated.

-- Jim

[dwilli852]

I'm using 200v Auricaps in mine without any problems other than being very large 2.52 x 2.80.

[Laudanum]

I went with the 250V versions of the Mundorf M-Caps.  They are smaller and 5 or 6 bucks less a piece.  I would bet my tin ears that I personally wouldnt be able to hear a difference between the 250 and 400V versions so saving 10 or 12 bucks and a little bit of space was fine with me.  YMMV and all that stuff.

[Bolivar]

Anyone know if it would it be possible to implement output capacitor switching on the fly? I can't think of a better way to do A-B tests on caps. Would a switch cause problems for the headphones? Maybe both sets of caps would need to be charged while switching... Any ideas? I'm sure I'm not the first one considering this.

[Jim R.]

Sounds completely doable -- but using a shorting type switch.  Tube cad journal (John Broskie) sells such a switch and small pcb for just this purpose -- go to tubecad.com and check out the glassware store hardware link.  I haven't been there in a while, but I know he used to sell this switch in the past.

HTH,

Jim

[Grainger49]

Anyone know if it would it be possible to implement output capacitor switching on the fly? I can't think of a better way to do A-B tests on caps. Would a switch cause problems for the headphones? Maybe both sets of caps would need to be charged while switching... Any ideas? I'm sure I'm not the first one considering this.

Switching on the output side would keep all the caps charged.  tpatton did this with one of his Seductions.  He had 6 or more capacitors to compare. 

[earwaxxer]

Not sure I would trust my ears to A/B cap switching. I would be more trusting a prolonged audition over some weeks, especially with high grade caps. The changes are so subtle, it takes some time. Much like tube rolling.

[Paul Joppa]

Be sure each cap has its own resistor to ground, so they are all charged up and you don't get huge "pops".

Overall I'm with earwaxxer. You'll hear a difference almost immediately, but judging whether it's a good or bad difference often takes me a long time.

[Bolivar]

Thanks for advice guys. For now I'll do a switch to enable/disable a bypass cap I've had installed for awhile, so all components have already had plenty of time to burn in. I really just want to take the guess work and psychological aspects out of the equation. I mean can anyone really say they can accurately remember what their previous setups sound like if newly installed components are first burned in for weeks or more? Especially if you want the upgrades to sound better, chances are to you they will.

Though the sound itself is not everything. With diy it's fun to tinker with stuff even if the improvement in sound quality is marginal. I suppose there is some prestige in having an amp which has silver wire and boutique caps etc... Some people will happily buy a watch for thousands of dollars when a ten dollar watch will tell the time just the same. And it's fine. I certainly don't intend to criticize what others do, there just seems to be quite a bit of snake oil being sold in the world of high end audio.

Sorry for going a bit offtopic : )

[jrihs]

Hey John - From what I have read about subjective cap reviews, it appears that the higher voltage versions tend to sound better. Not sure if there is any reason to believe that! If all else being equal and they didnt cost much more I would go with the higher voltage rating.

Thanks guys...if they are on sale its been extended till the end of April. Auri-caps are 40% off (partsconnextio) which for us is still 100 bucks each...