It had to happen eventually... capacitor upgrade question for the Mainline

[Paul Birkeland]

If I installed a switch to change between capacitors while the Mainline was still on, does anybody see any potential problems associated with this??
Would a higher capacitance value affect the higher frequencies?

I wouldn't recommend the switch.  You'd be switching high voltage DC (even if you switched the cold side of the cap, there will be a charge spike across the contacts) 

The actual construction of the capacitor will influence high frequency tonal balance, but not the actual value itself.

 

[swich401]

Alrighty, so I am about to order 15uF Mundorf Supreme caps for my Mainline, but before I do I want to make sure I've got this right:

A higher capacitance will not cause a change in the tonal balance of the amp, but could lead to greater low frequency extension ??

Main difference would be the cost difference between a 10uF and 15uF capacitor in this case ??

 

[Doc B]

We can't tell you that putting in a different cap won't affect the tonal balance. Putting in a larger cap can move the resonance of the LCR circuit, and that can change the shape of the bass response. Going bigger is usually not too much of a problem. But to be sure of what it going on the best thing to do run a frequency response curve. Beyond that different materials and construction can change the sound in different ways and you really just have to smoke it and see.

 

[swich401]

So I ended up getting 10uF Mundorf Supreme caps, which I will burn in (200-300hrs) and do a review on to let others know how they modify the sound of the Mainline.

Question:
Would you foresee any problems if I also tried running both the Mundorf and the Dayton caps in parallel to see how it would sound?? Probably won't run that combo long term, but thought it may be worth a try  ;D

 

[Paul Birkeland]

There's no harm in trying, but I wouldn't expect to be very happy with the results.

 

[Grainger49]

    .  .  .    Would you foresee any problems if I also tried running both the Mundorf and the Dayton caps in parallel to see how it would sound??  .  .  . 

I would add the Dayton with a pair of jumpers.  This is easier and if you like it you can solder them in.

 

[swich401]

Hmm, I prefer the mechanical stability that comes along with a solder joint. De-soldering is relatively easy using a de-soldering braid or pump.

 

[Grainger49]

But PB/CB said it might not be a positive combination.  I'm lazy and take the easier way out. 

I have paralleled/bypassed several dozen caps.  I always make the sonic derision with jumpers because I have to add the cap, remove it, add it, remove it till I am sure of what I'm hearing. 

Of course, I break in my caps first so that isn't a factor.

 

[mcandmar]

I did exactly that when adding a bypass to the power supply in my Quickie, without being able to switch in/out quickly i would never have been able to tell the difference between the cap and my imagination.

 

[swich401]

Would something akin to the attached image (for each side) work if I wanted a permanent setup where I could switch to one, or both, of the caps on at a time. The switches would only be flipped when the amp was off. Switches would be flipped to discharge when the amp is off to bleed the caps, then switched to the desired setting for which cap I want in the circuit. Would there still be a charge spike across the contacts in this situation if switching was done with amp off?

 

[Paul Birkeland]

It's really not a great idea to switch caps like this with DC across them.  (Note that for speaker crossovers, this does not present any issues)

 

[swich401]

I still don't understand, is it a bad idea to switch them only when the amp is on, or bad idea in general even when the amp is off and unplugged?

My idea was that after I turn the amp off and unplug it, I switch both of the switches to the "discharge" position to bleed them through their respective discharge resistors, then switch both of the switches back to the "off" position, thereby taking both of the caps out of the circuit. Then by switching one or the other switch to the "cap on" position it would essentially be like having only the one cap directly soldered in, then I can plug the amp back in and turn it on??

 

[Grainger49]

The capacitors retain voltage for some time after the amp is turned off.  They have dangerous voltages when it is on.

If you wait 30s after the amp is turned off the voltage should be gone.  But I worry more about your picking up noise due to all the additional wiring.

Bottlehead is very careful in their design of circuits.  The Seduction/Reduction audio path is only about 3" long, maybe 4".  But this keeps the wiring from picking up noise.  You could pick up anything from hum to a radio station.

It is a situation of trying it and see if it picks up any  extraneous noise.

 

[Paul Birkeland]

If you're going to work it like that, you don't need the discharge resistors.

Just put the switches inside the amplifier, and you'll be fine. (This will prevent curious fingers from switching them while the amp is running)

In the Mainline, I would expect those caps to retain charge for a maximum of 10 seconds after you shut the unit off. 

-PB

 

[swich401]

Suffice it to say, the Mundorfs are a *little* bigger than the Dayton caps...

 

[PassionForSound]

LOL. Which Mundorfs are you using (model and capacity)?

Has anyone tried Auricaps? I'm thinking of those as a direct replacement for the Daytons.

 

[swich401]

I didn't want to spend too much; went with the Mundorf Supreme 10uF 600V.

I looked at ratings for the Auricaps in comparison to the Mundorf's (see my previous post with comparison websites), decided that the Supreme's were the ones for me.

For those interested, partsconnexion.com has a sale of 20% off their caps until midnight April 30th  ;D

 

[PassionForSound]

Thanks for reminding me of the links.

I'm left wondering which of the 2 options (Mundorf Supreme vs Auricap) will provide a more faithful, transparent rendition of the recordings? I love the Mainline for its neutrality and don't want to make it overly warm. I love the Mundorf Silver / Gold / Oil Supremes in the S.E.X., but there's no doubt they're a little on the warm side so not sure if the Mundorf Supremes polys will bring the same warmth to the Mainline. Reports suggest that the Auricaps have a little warmth too, but perhaps not as much as the Mundorfs. That said, the write-ups you linked to would suggest that the Supremes offer superior transparency... I'm torn!  ???

 

[PassionForSound]

Sorry for the double post, but this is the sort of review that has me confused. Great info, but I'm not sure if I'm sacrificing something valuable (e.g. high frequency detail) for the other benefits of the Supremes.

Coming from the Auricap, the Supreme was on the other side of the fence, highly musical, entertaining and perhaps not the most accurate sounding of capacitors. Although the tonal balance is quite neutral, the Supreme has a very polished and refined midrange with the right amount of meat throughout the frequency range. Musical notes are presented with texture and fine nuances, making the Auricap sound dry in comparison.

Easily the most pleasing of the caps tested this far, the Supreme combines the weight and treble extension of the Claritycap ESA with the speed of the Wima MKP10. Coupled to its highly resolving and musical nature and affordable price, do consider the Supreme for your next purchase. To nitpick, the only criticism against the Supreme against its competitors so far would be a slight loss of resolution in extreme high frequencies, and its artistic rather than honest approach towards music. The latter point is subjective anyway and you may personally have a preference for this.

Taken from: http://singaporehifi.blogspot.com.au/2010/09/capacitor-shoot-out.html

 

[mcandmar]

Loquah, wait until you have upgraded the .1uf caps in the S.E.X. amp before forming any opinions on the Mundorfs.  I'm pretty sure you are experiencing what i found but in reverse, the .1uf poly caps are what you are really listening to now, not the full range of the Supremes abilities.