Senin, 22 November 2010

DIY Audio pot pourri 2 : Woody film capacitor

Long time ago I came across a Dutch web site explaining electrolyte capacitor modification. Recently a fellow (senior) DIYer Mr. Paul also have done similar mod with paper in oil capacitor, DHT Rob reports improvements on replacing aluminum can with wood filled with beeswax. Also mixed results from Pak Paul from what I've heard.

A longtime DIYer friend said that you'll get sound improvement just by lightly sanding the caps. Nothing but subjective result analysis though, but I've found a freeware just for that, detecting difference of the same music signals one as a reference- the other may be through a different cable - more about this in my next post.

I've got 4 Solen MKP capacitors belong to a friend ( Hi pak Johny..) so I'll give a shot. I've made mahogany tubes, soft wood cover. I've broken in the caps before for  very long time on the bench. So here are they. The tools are small PCB drill for the caps leads through the soft wood cover and a tweezer. This soft wood is press fitted to the mahogany tube.

I still have some space left in the tube, so the Solens are wrapped with the tissue and pressed in to the tube. The input and output leads are marked, they do make sound difference how you connect them even the Solens are non polar.

Wrap like this, plenty of excess on both ends, they can be removed easily.

Excess tissue paper removed with tweezer


There you go!. A pair of Woody Solen :). Notice that the leads are not centered. Good idea if you marked them before drilling


I did a comparison in my Sony CDP -M75 - looks awesome!. There are difference in sound - not much but the Woody tend to sounds smoother. Definitely better than the original CDP ouput (with Elna Duorex 2 electrolytes).

 Here my  friend Aphinx using the Woody for input coupling on his D class amp. Originally his input coupling was the Russian MBM 1uF we found the woody sounds better. Below the Woody tested against Ampohm MKP, he likes the Ampohm better . 


So there are differences in sounds when you do this kind of modification, whether the sound is better or worst is another matter. Any explanation on this phenomenon? Let me guess, first the skin effect - greatly influenced by surrounding material or dielectric- nowadays 'we' prefer natural materials - hence the the sanding, beeswax, natural fibre like wood, cotton, silk and paper. Silk? I think one electrolyte maker used it on Elna Silmic...

Secondly vibration - with tight clamping the caps are protected from it. Lynn Olson told stories about 'microphony' effect of vibrated capacitor - it wasn't pretty picture - he said . I believe them because I've heard the mod my self. My Spica TC-50 crossover is placed outboard , guess what? the caps vibrates like crazy there. So, at the very least we should tie, damped and fixed our caps very well. Good luck !

Senin, 01 November 2010

DIY Audio pot pourri 1 : Spica TC50 crossover tweak

During several months I've carried out many small audio tweaks. Not full blown projects though but I think it's maybe quite interesting sharing them :).

First is my Spica crossover tweak, continuing effort IMO still necessary to replace those old ECI lytics. This time I like to tackle the high frequency section. On September 2002 the Spica designer John Bau was interviewed by  Enjoy the and asked what to do to improve his Spica, one of his answer is to change all the electrolytic caps to Film.

So here are the pics, some caps, made some 'risers' for easy soldering and quick caps change.

first on the board are Wima MKC 4.7uF, Green Nichicon Muse's 10+22uF, Black Nichicon BP-S 4.7uF. Left them for 3 days about 12 hours on play, sound? me not like :). So instead of waiting for another 3 days I just pick - place - listen - change. An advantage of working with broken - in and old caps...

The Wima MKC can stay, it sounds well for coupling capacitor on my CDP-M75, so next on the board is 0.1uF K42y Paper in oil bypassed the BP-S, still not liked it, then I went to my garage pick some big 22uF Solen MKP - the last pair I have, this in parallel with poor small 10uF green Nichicon Muse, sit and!..the bass is like I never heard out of this Spica..I wonder though..I'm working here in the high freq region and I get that bass?..well the Solen and the Wima stays!.

Now the job is much easier, that what I've thought and I was wrong. I got better bass & high, same and maybe better staging, but some tracks still give sibilance. Swapping the BP-S to Evox MMK did not help, same with 'old' Yellow Rubycon.

The last 4.7uF film cap I have is a pair of el-cheapo yellow Audiophiler..yuck.., nonetheless I've soldered them and ...its sounds ok, no, they sounds quite well indeed..and  totally acceptable to me, much better than the Evox.. So the Audiophiler stays! After 2 months listening I tend to let this setup freezed and change the 10uF Muse to MKP and maybe another Wima MKC replacing the Audiophiler, I miss the high notes timbre of acoustic piano sometime. 

My lessons here, tweaking the sound for Mid is very difficult, many times proven cheap parts perform well in combination with other. Thanks again for reading guys..

In the pipeline : 
-Part 2 :  film cap gets woody jacket..
-Tubelover 6N1P tube buffer in depth..