Capacitors

Don't you just love the way putting small caps shifts the tone to the sound of that cap. Not a lot of people know about that. I didn't think so anyway til you mentioned it.

 

Yes, but using bypass caps is detrimental to coherence. That’s why I am quite happy I didn’t need to bypass the MiFlex caps.

 

I usually do it for the supertweeters and in a first order configuration. I haven't had coherence issues with it that way. I should try it for the mids I guess to check what you mean about the coherence issue.

 

I have not experimented with bypassing caps in speakers. My experience is with preamps. I am quite interested to hear what you find regarding coherence with your crossovers.

 

If you bypass a half decent cap with another half decent cap, it will smear the sound.

If you bypass a half decent cap with a really good cap, the audio will improve and you may or may not degrade some of the micro detail in the sound reproduction.

If you bypass a crappy cap with a really good cap and everything just magically improves with no downside........then its a clear sign that you need to upgrade the crappy cap with something else.

A lot of times in project amplifiers there are ways in which you can completely remove the cap and replace it with some other component. The best cap is no cap at all : P

 

Its a polyprop/teflon combo

 

I am finally getting off my backside and acquiring the final parts for a DG300b amp. Are the Jupiter caps still reckoned to be a good option or are there better alternatives without the madness of Duelund pricing? In case it matters to you the OPTs are Finemet by Tribute and the amp will be configured along 2a3 lines. Otherwise pretty much following Tom's design.

 

Been hearing good things about MIFLEX, no personal experience though.

 

I have seen the Miflex caps on the Hifi Collective website. They are around 1/3 the price of the Jupiter which is very persuasive.

 

Slightly off topic, but I didn't think you could get iron from Tribute anymore?
But if you have his iron, I'm sure you'll end up with a great sounding amp.
I plan to order some Miflex caps one of these days for my #45 based amp.

Randy

 

Regarding Tribute, they do not normally entertain DIY work anymore. I also purchased an AVC from them for the amp, which is an off the shelf item. It was when I asked for some advice on OPTs that Pieter Treurnier of Tribute offered to make then for me. Both he and Tom Christiansen of Neurochrome have been extremely helpful.

 

Glad to hear you're pushing on with the 300b mate.

 

It has taken a while to bring all the parts together. Regarding capacitors, I am thinking of getting the Solen that Tom specifies and also the Miflex. Once I do that comparison I can decide if I want to investigate further. And I need to get some of that wire you recommended as well. Nearly ready.

 

What the....? How does the battery help things?

 

Something something bias to improve linearity...

edit: http://www.enjoythemusic.com/diy/0911/charge_coupled_crossovers.htm

 

Intriguing!! The static electric field would reduce the entropy of the molecular dipoles in the dielectric, reducing 3rd order harmonic distortion. Obviously much more a problem for electrolytics than for film caps, but I suppose there could still be a benefit. My concern would be that the battery itself has some internal impedance, absorbing a small fraction of the audio energy in a manner similar to the dielectric absorption of the capacitor. So in the limit of an ideal battery, this seems like a great idea, but for real batteries, it seems there could be a class of capacitor dielectrics where the battery made things worse. Still, a cheap experiment for line-level coupling.

 

Although I am hoping that the Solens are not quite as bad as "ass" I am hoping that there is a worthwhile difference between them and the Miflex. It will be interesting as I have never done anything along these lines before. And then there are resistors...