Response to capacitor up-grade
Copyright 2017-21 © Troels Gravesen


Quick update on the discovery 4. On your suggestion I replaced one (out of four) 22uf cap for the midrange to superior-z. Very big difference. The sound became a little more smooth/relaxed and enjoyable...the music flows a little better. One day I might replace more capacitance who knows...but for now I am satisfied.



I finally upgraded the crossover components as you recommended and am just amazed that the distortion I was hearing has (almost) all gone! This was not a small change in sound and I'm now less of a skeptic regarding capacitor quality.
The first change I made was from the 1.1mH low pass cored inductor to the air cored version in your kit list. I used the cored version because I had it in my box of bits - same inductance and DCR, but the change in sound was a significant improvement. So I changed the second inductor in the low pass section for an air cored version and same inductance, and again their was a sonic improvement. Not in the mids as with the 1.1mH as I had expected, but in the depth and quality of the bass.
So I spent the big money on the 4 high pass caps as you recommended, and nearly all of the distortion heard on trumpets, sax and the like was gone. Treble Level and dispersion seemed to improve, but I guess this is just as a result of reduced distortion. Then I finally changed the low pass filter caps (except the 22uf) and the sonic character seemed to change again. Gone was the 'naaar' in female voice and in with an open 'laaar'. Tonal balance at last! Listening fatigue seems to have gone, or I've just not been able to listen to music long enough for it to set in, and given a chance I listen all day!
So a warning to other builders that are considering deviating from  your crossover part specification, don't do it. However, the cabinet design and construction seems to be robust to the slight baffle width increase and also to the extension below the tweeter which is the 'sub' speaker and transmission line. The sub woofer is now filling in the lowest octave with a separate amp and 2nd order filter similar to your suggestion, and so now I just listen, and smile.
Best regards



Good day dear Troels!!!!
I took your advice about capacitors. The project was collected from the improvised element base!!! The sound is amazing after a week of warming up. Thank you for your work and the contribution that you make to all music lovers of the world. I enclose in the attachment photo (if you want you can put on your site)
Regards, Alex (Nizhniy Novgorod Russia)
С уважением,
Алексей Морозов.

SEAS Jenzen CA

I am writing to you a two part e-mail, the first part being a review of upgrading the midrange capacitors in my Seas ER from Standard Z-Caps to Silver Z-Caps and the second part being a question.
So, I finally got the money to upgrade the midrange capacitors and I decided to pick Silver Z-Caps this time to see how they sound.
The difference is amazing! I could stop here since it really is amazing and the difference is striking, not just a “maybe it sounds better since I am biased because I’ve just spent ~600 euro’s on capacitors”. This is not the case and I will try to explain in detail what I’ve found.
When I first finished the Seas ER, I’ve chosen Alumen Z-Caps from the start for the tweeter. I used my speakers with Standard Z-Caps for midrange and Alumen Z-Caps for the tweeters for half a year and although the sound was impressive to say the least, I’ve always felt like the tweeter is the best driver in this construction. It has a very detailed presence, very good soundstage width, transparency and so on. I’ve always felt that this is because the tweeter was from the Excel range of Seas drivers and the midrange drivers “just” Prestige.
This all changed when I changed the midrange capacitors to Silver Z. Now I could no longer distinguish the tweeter sound from the midrange and the entire sound coming out of the speakers was special. I’m not saying that the integration between tweeter and midrange was not good, because it definitely was, but something was special about the tweeter. Now with the Silver Z-Caps for midrange and Alumen Z-Caps for tweeter everything blended into something magical. Transparency is noticeably better, the width of the soundstage is better and I also think that the lower bass is much better mixed with upper bass since this upgrade. I want to thank you again for providing these designs to the world! Without it, I may have never heard what a good pair of speakers sounds like since I don’t have endless supplies of cash to try out high end speakers and even if I did it would be a game of hit and miss since you can’t really hear a multitude of speakers to choose the ones that suit you, especially if you’re living in a Eastern European country like Romania. Thank you!
Alexandru, Romania


I just want to report the result of upgrade. Here my what did I do list : All STANDARD-Z were replaced with Superior-Z, 8.2uf Superior-Z on tweeter was replaced with Alumen-Z.
All electrolytics including bass section replaced with same value Cross Caps. Loy-out was completely changed in order to give maximum space between inductors. 
Ok.. I start with electrolytics modification on bass section first. I heard positive effect on lower detail not that huge but ok for me.. I made all others at the same time. Just I want to say WOW !!!  Now higher frequency detail is simply eye catching and very natural.   Detail and naturality both came at the same time.  New Alumen-Z seems to be extremely good. At this point I wasn't able to evaluate electrolytics replacement in tweeter but I'm guessing it had positive effect. Real big improvements was on the mid range. I think that OBL15 should certainly be done using only Superior Z on the input of mids. Huge difference out there. A friend of mine has open baffle setup with crossover-less full range driver.. Now mid range purity of OBL15 reminds me to that setup.
Guney, Turkey


Ellam XT

Recently I started one of your speaker projects, the Ellam XT25 to be precise. Due to the $$ cost of the Jantzen Superior-Z Caps I chose to only get Sup-Z Caps for the tweeters (minus the 10uf), BUT, after a test listening between CrossCaps and Sup-Z caps, I realized there is a small, yet fundamental sonic difference between them: listening some violin music with the CrossCaps, the tweeter played something resembling a violin, and, listening the tweeter through a Sup-Z, you can actually say it was a violin! (I was smiling when listening to the Sup-Z). I was surprised at the fact that many people claim there is no sonic difference, unless you have very high end gear. I got a Rega Apolo cd player and a NAD 326BEE preamp, not exactly high end stuff!
Thanks in advance for your response to my e-mail.
Best wishes Omar, Mexico