Ascent Crossover mod

[miljac]

I have modified my Ascents' crossovers using Obbligato Gold caps several weeks ago.

I changed caps only and did not touch the inductors.

The results were very good, and the last bit of the modification came today: a polypropylene replacement for the bipolar electrolitycs.

It's Jantzen 270uF/400V MKP caps. These are real monsters! There is a photo of the bipolar original and the Jantzen for comparison.

First results: much cleaner bass. Need to burn them in though.

The final looks of the crossovers are in the photos.

One more thing: all big polypropylene caps are bypassed with 10nF Vishay-Roederstein MKP1837. This gives a clean and nice sound,
but putting the Wima MKS4 10nF/630V polyester across all polypropylene caps make the speakers really shine.
The sound simply flows through the speakers, never before heard them play so beautifully.

With new panels and this crossover the Ascent is a very different beast, sounding several classes above its original price category.

As the big Jantzens burn in, will report on the effects.

Maybe some day I'll try new resistors and inductors, but this can wait, I'm so happy with the results.

 

[Dan Osib]

Here's some free advice for you. At best the jantzen caps are very middle of the road in terms of sound quality compared with the best available. The worlds finest film capacitors available at any price (super super exotic!) are the v-caps which are also extremely expensive, you won't/can't find better anywhere!! Full stop! And i'll stake my life on that. Second best in the world are the mundorf supreme silver/oils (significantly more affordable), these are also the most detailed sounding model that mundorf makes, even more so than any of their more expensive mundorf supreme silver/golds. The finest aluminium housed resistors available at any price are the mills mrc 50 (non inductive/non magnetic version), these are more transparent sounding then the equivalent 'aluminium housed' (magnetic!) vishay resistors. Use a mundorf silver/oil cap in place of the 'middle of the road' sounding wima for a significantly greater sound enhancement. Do all your bypassing with Mundorfs too.

 

[miljac]

Jantzen is parallel to the woofer coil and is definitely a far better choice than the original bipolar electrolytic capacitor. Now it is very clearly audible how
the electrolytic caps stored the energy in them - the bass is now clean and fast, without ringing. So Jantzen is actually very good for this particular application
(apart from its size, but it's a 270uF foil).

For the rest I think it suffices to say that the whole recap + new panels have cost me a little more than I would have paid for the complete Mundorf recap even
with silver/oil, not to speak of silver/gold (I actually prefer the "dry" capacitor types in the signal path of the high pass filter).

The Mills WW - yes. My late friend Allen Wright (of Vacuum State) always recommended them as anode resistors.
OTOH I know that Vishays are not bad either [and he knew it too]. I have to try them in a loudspeaker crossover though.

Moral: a great upgrade does not need to cost a fortune. My recap was something like 250 EUR total.

 

[TrumpetDoug]

OK I'm smitten. Anyone local interested in helping a brother out? Lets tear my Ascents apart and try this.

Doug - out

 

[Dan Osib]

MILJAC,

Actually Mills have recently been taken over by Huntingdon Electric. So now, the latest resistors Mills are knocking out have a Huntingdon badge on them instead, perform exactly the same though. The aluminium box housed Vishays are not particularly good in my eyes simply because the legs on them are 'Magnetic/Inductive' which is a definite no-no for optimum hi-fi use. As I previously explained - the Mills alternative for that particular resistor is 'Non Magnetic/Non Inductive' A definite plus here, and they cost only a few dollars each.
The reason I highly recommend the Mundorf Film Capacitors is because they will add a definite improvement in the Warmth of the sound, which is necessary to combat that slight Thinness/Leanness that Martin Logans generally suffer from.
Finally, for a decent Inductor replacement you need to be looking at Foil Inductors like Goertz or even better Alpha Core (only 15 dollars each) http://www.soniccraft.com/products/inductors/alphacore_inductors.htm The standard 'Erse' Oxygen Free Copper inductor already in your Ascent's are pretty good but it is generally well known that Coiled Flat Foil inductors produce slightly deeper bass with more kick than your typical 'round' wire coiled inductors like the Erse's.

 

[miljac]

OK. After a burn-in period I promised to report what I hear.

So in short

what I hear:

- deeper and wider sound stage (considerably)
- great macro- and micro- dynamics
- mids and highs flow effortlessly from the speakers
- bass is as already reported faster and cleaner
- natural colors

What I don't hear

- harshness
- "grainy" sound
- distortion

All in all - the speakers perform well above their original price class (as already stated)

I cannot say enough good things about Obbligato Golds - I'm using them within the crossover (evidently), as coupling and as power supply bypass capacitors in my tube amps. Given the price it's an absolute no-brainer to get them and they perform exceptionally, especially when properly bypassed. All caps that are on the signal path are bridged with Vishay MKP1837 and MKP1839 in parallel with Wima MKS-4, both 10nF. Actually the 1839 is the same capacitor as 1837 but in an axial housing which is easier for bypassing physically large capacitors. Using them in tube amps (630V rating).

Overall - a great success. The modification gives a new life to my speakers, and having been very happy with them over the years I can say that I'm all that happier for taking the pain of opening them and doing the mod. I have rediscovered Ascents and now I know how magnificent they are. I'm sure I could have done even better with spending four times as much on components as I did, but every cent was extremely well spent here.