minor tweak : re-capping the JPW Sonata bookshelf speakers

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I while back I got some JPW Sonata speakers from EBAY for $67 AUD. They are nice “entry level” English bookshelf speakers of reasonable quality…

Laurie Anderson is sitting on my bed singing to me this evening. Earlier Tom Waits popped in.

Basically, I am gobsmacked by these little sealed boxes. I don’t know if it’s because they are in a small, quiet bedroom, mounted on a solid wall, or because they have an Audio Innovations amplifier powering them. They are sublime and emit this beautiful warmth and richness that makes me not want to leave the room.

I’m not quite as impressed as the above reviewer, but they are very nice little speakers for the size and price, especially for acoustic music.

And the sealed enclosure means they mate very well with a subwoofer.

Opening the back the crossover is a simple first order consisting of a 3.3 uF electrolytic capacitor and an inductor.  Presumably the resistor is to attenuate output to the tweeter.

As the speakers are possibly 18 years old the electrolytic could be getting old, or prone to drifting in value, so a simple upgrade is to replace the capacitor with a better type that wont drift over time.

Interestingly removing the capacitors and measuring them they were 3.5uF and 3.6uF respectively.. still within the rated 10% tolerance. The caps are 50V ELCAPS.. googling reveals their current price of 40p in the UK (72c ?).

An inexpensive but quite reasonable upgrade was some Vishay MKT 1822 capacitors from Rockby

Can I hear the difference? Hard to say. I think they sound better… but then I just upgraded them so my brain “knows” they should sound better.. But they wont be susceptible to aging like electrolytics.

2 thoughts on “minor tweak : re-capping the JPW Sonata bookshelf speakers”

  1. I picked up a pair of these speakers cheap. The cabinets are in fair condition but the drivers look in perfect nick. I noticed one speakers tweeter had less audio output than the other. So changed crossover caps to an MKP type. Highs sound even now on both speakers, but has a lack of low end. Hopefully the caps just need to be run in a bit.

    • If you replace an electrolytic capacitor with a film capacitor, you should add some series resistance to mimic the ESR of the electrolytic cap. A 1ohm 10watt Ceramic wirewound should be somewhere near. Rather than adding another component to the signal path, I’d try replacing the 4.7ohm resistor with a 5.6ohm in the JPW Sonata.

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