Teflon Bypass

[DaveC]

I like the Mundorf SIO, but I think I'm going with copper foil caps in the future, got a pair of RelCap PCUs in the preamp that are fantastic.

[Face]

IMO, Mundorf caps in general aren't bad, but aren't worth their asking price.

Huge fan of Claritycaps.  For warmth and on a budget, I use ESA caps.  For transparency, dynamics, and when price or space isn't a concern, I use MR caps. 

I'm a fan of Duelund too, but am not a fan of the regular VSF in speaker applications.  Except for large values, I would only use VSF Black or CAST series in speakers.

Claritycap and Duelund are really onto something with their encapsulated/resonance free capacitors.  The competition really needs to catch up. 

[Response Audio]

I'm with you 100% face. I was just thinking he wanted more warmth. The Clarity are a great capacitor and the ESA is a great value. The MR is one of the best capacitors on the market IMHO and why we use it in our upper end preamps. Still not an inexpensive cap at almost $200 for a 22uF.
If the wallet can handle it, the Duelund Cast cannot be beat. They bring to the table more than any other capacitor out there but at a premium price. (you don't want to know what our 10uF with .5uF built in silver bypass cost us that we use in our Ultra GT).

I don't have a problem with the Mundorf S/O but they sound like a completely different capacitor after full break in. One needs to be. Ery patient when using these as not to make premature evaluations of their true characteristics. I do prefer the S/G over the S/O. 

[BobM]

Got my delivery from Sonicraft. I can't put the caps in yet because I'm still waiting for my Russian PIO's. But I did swap out the old resistors for Mills.

Surprising what a good resistor brings to the table. That bit of bright harshness I heard before is gone now. Smooth and extended with a bit more spaciality, believe it or not. And this is with no break in yet.

[Face]

Got my delivery from Sonicraft. I can't put the caps in yet because I'm still waiting for my Russian PIO's. But I did swap out the old resistors for Mills.

Surprising what a good resistor brings to the table. That bit of bright harshness I heard before is gone now. Smooth and extended with a bit more spaciality, believe it or not. And this is with no break in yet.

Mills have a warmish tone to them, that's no surprise.

I wouldn't be surprised if the Russian PIO's have a negative effect on overall SQ.

[BobM]

Maybe, but I've got other 1uF caps that I can substitute for them if they wind up muddying things up instead of giving things the glow that I hope for.

[DaveC]

I replaced Kiwame resistor in my SET amp's plate and cathode positions with Mills and the improvement was dramatic. They are more neutral and less warm and colored compared to Kiwame, with an increase in clarity and detail.

I hope your cap replacement brings further improvements!

[BobM]

I just ordered some of this yesterday to pot the home-made-looking wire air core inductors that all factory Apogees have inside. It is Red Insulating Varnish. Once applied it needs to bake for about 1/2 hour or so to fully harden. Hope it doesn't stink out the oven or the house.

http://www.mgchemicals.com/products/protective-coatings/insulating/red-insulating-varnish-4228/

Why do this? Inductors can hum as the currents heat up the coils due to:
a) loose windings in coils, or coils that are not firmly secured in place, or
b) magnetostriction in magnetic material, or loose laminations in iron, or not fully compressed gap in pot cores. These can be exascerbated by mechanical resonances near the operating frequency.

If they are loosely wound there is an obvious noise source as the wires bounce off each other. Varnishing them is effectively "potting" them so the vibrations are hugely diminshed. (and it is far cheaper and very effective than buying Air Coil's or Erse replacements and still having to deal with different resistance from those new inductors).

[Face]

Have you measured the DCR of your coils?  Except for the woofer of a three way, I would avoid cored inductors whenever possible. 

[BobM]

Got my Russian PIO caps today and put them into the crossover as spec'ed above with the new Sonicaps.

They need time to break in obviously. At first I heard a spaciousness enhancement but also a closed in sound without extension.

Now 3 hours of playback later I hear it opening up while still presenting that sense of space that I had hoped the PIO's would bring to the table. So ... so far so good. I will let it continue to play overnight and tomorrow and hopefully give another listen sometimne tomorrow. I think it may take 100 hours all told to really get a grasp on this though. So time ...

No sound of discontinuity or disjointedness from the mozxed caps. Yet.

[BobM]

About 30 or so hours of break in by Sun afternoon, so most of the heavy lifting should be done, so I sat down to listen and ... began smiling broadly. Nice spaciousness, no shrill or edgy or plasticy sound, open and extended and tight, good imaging. Perhaps one instance where a piano sounded a little nasely on a passage. More break in time will likely fix that.

Next - the insulating laquor should be arriving this week and I will "pot" the inductors sometime in the near future. All in all, it seems to be coming together nicely.

On another topic - there's a thread over at Audiogon about how caps vibrate when a signal is running through them. I'm sure it is very small and only seeable/hearable with a stethoscope or some other sensitive measuring device. But in any case it speaks to the need to make sure caps are hot glued down, or somehow not left dangling in space and securely fastened to their circuit board. I know I have heard improved results doing this in power supplies - using Moretite to fasten the caps down to the board and dampen them. If you look inside many commercial devices it is a bit unsettling how often you will see caps sticking up above the board on their thin little legs, not even securely pressed down before soldered.

[Face]

Securing them to the board isn't enough.  That's why Claritycap and Duelund have their ESA, MR, and CAST series capacitors.

[BobM]

Yes, but it is probably the best a DIYer can do, short of spending a large fortune on those products. And certainly better than doing nothing at all.

[BobM]

So I "potted" my big assed inductors (and the small ones too) last night. I used the MG Red Insulating Varnish from the link above, applied to the bottom first (and let it ooze into the cracks) then the sides and top. Ordered 3 x 2oz bottles of it and glad I did. 2 would not have been enough.

I'm pretty certain I got all the way through the coils of wire because there was plenty that leaked out the other side and left a puddle in the bottom of the external crossover box as it was drying. Looks like a blood puddle, but it did a good job of gluing the coil down too. I finished up by re-tightening the zip locks around the coils to get them as good and tight as possible as they were drying. Messy stuff, for sure, so use gloves.

It dried well overnight and this morning before work I siliconed down whatever else was loose. Letting that dry all day to be sure and will give a listen tonight to see if I can hear any difference in the sound quality.

[richidoo]

Does the varnish dry by evaporating a solvent? Do you think it is fully dry down deep inside the windings? Does it have a strong smell? Tx