Posted on Sunday, 30th September 2007 by Auw Jimmy
Still remember my old speaker below? If don’t, please check it here. This weekend, I have some spare time. Hmm… a little tweak is no harm, right?
Currently, my speakers are considered to have a lot of mid tone. The high is somehow shadowed by the mid and the low tones. To tell you the truth, I’m a mid lover. This time, my target is to get a better high frequency. So, I have to play a little bit with the XO.
I have prepared some new components. I have a set of old Siemens Paper-In-Oil (PIO) capacitor. Made around 70′s, old stock. I measure them with my Capacitance and AVO Meter. Hm.. It looks good. I also get a pair of SFernice resistor. I think it will be good as replacement for my old Eagle resistor in my High Pass Circuit.
I also change the F3 for my High Pass Filter. I raise the F3 from around 2900 Hz to around 3600 Hz. From my experience, although the Vifa XT25TG has a low FS (around 500 Hz), but it has a lot of harmonic distortion under 2000 Hz. So the higher you cut it, the cleaner she will be. So this time, I alter the F3 to around 3600 Hz and replace my old Auricap with a set of Siemens PIO.
From the picture above, you can see my Siemens PIO capacitor. I use 3 Siemens PIO (two box size and one cylinder size) configured in parallel to get the necessary capacitance. You also can see the red resistor. It’s the famous and expensive SFernice resistor.
Photo above shows the overall of my XO (crossover). I love the sound of foil inductor from Alpha Core
I’m impress with the Siemens PIO capacitor. It sounds good with my Vifa XT25TG. But somehow, I think the high is a little bit too front (I think have to play a little bit with my input/shunt resistor or simply because I’m using a “hi-fi” solid state amplifier). The detail, expression, and staging are excellent. It’s surely better than my old Auricap as High Pass Filter. The treble is so crisp and detail. The alteration of the F3 to above 3000 Hz surely bring the maximum potential of my Vifa XT25TG. The “Ingram Washington – What A Difference A Day Makes” sounds very good, airy, transparent, and “wet”. I have to pair it with my future EL34 SE tube (on progress) and I think I’m on the right track.
I will play a little bit with the input/shunt resistor and maybe a film bypassing at the Siemens PIO will bring good result. Who knows? But not now, man! That’s enough for today. It takes around 5 hours of soldering and testing, but I do enjoy it.