Rebuilding Duntech Sovereign Crossovers

[jkess114]

I just picked up a pair of older Sovereigns. Ouch. I'm making preparations to rebuild the Crossovers. I have settled on Mundorf MOX resistors, but have not settled on which capacitors. There are some rather large caps in there and I can't see a voltage rating on them, so I cannot even know where to start. Each X-over has:

2 @ 50uf (Giant. approx 4" long and 1 3/4" diamter.)
5 @ 20uf (also huge for 20uf. Certainly the same voltage rating.)
7 @ 10uf
4 @ 3.3uf

All of these must be rated at the same voltage. Do any of you know what that is?


Next question is: What are y'all using to recap these? Pros? Cons?

Thanks very, very, much,
josh

[phivates]

Maybe those caps are ok. Have you measured them?

[bear]

there is/was a prior thread on the same or similar subject matter, probably worth a look...

[Bare]

they.. Need rebuilding? Already ??
Only Superman can hear differences in foolish priced crossover Resistors But Hey! Maybe yer from Krypton?
There's not too many volts in a speaker .

[VaNarn]

A picture would help.I have an idea that the capacitors may be of the same type used in early Australian built Dynaudio speakers and these were power factor correction metallised polypropylene types rated for 250 V. a.c. operation.If this is the case then you may not in reality be upgrading unless you can test the capacitance value to the tolerance used by the designer and actually improve on dielectric characteristics etc. of the exiting components

[kouiky]

In all seriousness, I would simply use metal film resistors (no carbon types), non-inductive wirewound in higher current areas, and simple film capacitors rated for the highest voltage feasible for a lower ESR. Match them at a close tolerance and bypass the larger values with small bypass caps. I had my day with expensive caps, what a waste.

[AllenB]

The reputation of Duntech particularly with the Sovereign would have me cautious about changing anything. In particular, you should identify the capacitors which are of the type that don't typically change with age, and leave those. Same with the other components but check carefully for damage, particularly evidence of heat damage while you have them out.

If you didn't like the sound of them then that would be another story.

[jkess114]

Hi again-

Before I continue, I'd just like to thank you very kind people for chiming in and offering your wisdom. . .its much appreciated. I'll add some backstory: I am a musician and I've played professionally all of my adult life. I also have run and owned a recording studio for 12 years, specializing in tracking, mixing, mastering, film scoring, & overdubbing. As a rule, I think that people have gone insane with audio-quests. I have spent a lot of time ABX testing components and in my time come across, surprising results - in both directions. At one point I was convinced that I was getting a different result when mixing digitally that just wasn't there upon prodding from others to test my results with different methods. Also, I have debunked major manufacturer claims of recreations of equipment, aided by my main tech and his AP2500.

Another story. . . we were doing some intense AB comparisons between console modifications and upon patching some cables in at one point we both looked at each other at the same time and said nothing. We both heard a difference between different colored patch cables. This was repeatable and we could each tell the which color was being used in the patch. Two things about that: 1) We were working on other more important things at the moment, so after ten minutes of playing with that and checking our sanity we did nothing further with regard to that experience. 2) From that day to present, I care not which color patch cord goes into what, and only think about that to remind myself what is important.

So on to these speakers and their crossovers. While I know my way around recording gear very well, repairing said gear, and having spent more time behind a soldering iron than just about anyone who isn't a technician, I find that I feel stupid in the world of HI-FI. I have no idea really, which components or technology fall under "technically superior" or "silly wastes of money". At the end of the day, its all electrons anyway.


Here is a link to an album containing all the pics for my speakers, including shots of the crossover. Sent to me was a photo of someone else's rebuilt crossover. I sent pics of my crossover to Duntech and the response was that I would hear a very worthwhile degree of improvement if I were to rebuild them. I called Madisound and their techs opinion was I would notice an improvement as well.

So what say you folks who've been around the block a time or two? Here is a link to pics of my speakers and crossovers:

Duntech Photos by jkess114 | Photobucket


Thanks so very much!!!

josh

[AllenB]

Notwithstanding legitimate maintenance, changing components can sometimes make a small difference. Sometimes this is due to distortions they may contribute to, and sometimes these distortions are a desired thing. Sometimes this is pursued in an attempt to mask the more important speaker issues that ought to be dealt with first. This is all I'd like to say on this issue.

If Duntech themselves suggested a rebuild, I'd want to be interested in why they believe so. Did they give any clues or make any suggestions?

[Inductor]

Understanding John Dunlavy's Crossover Designs Crown Prince