Friday, August 7, 2015

Infinity Quantum 5 (Q5) Speakers XO Rebuild

Infinity Quantum 5 (Q5) Speakers

I wanted to come back to a pair of speakers we had in a few months ago.

This is a pair of Infinity Quantum 5's. These are beautiful speakers, with an interesting L-style metal pedestals thats factory and a neat elevated grill snap. These are rated at a nominal 4 ohm load with a driver range of 30-250Watts (38-32KHz +3dB)

One major thing I'd like to highlight on the Quantum series are the EMIT tweeters. Now I absolutely love how these sound, but I haven't come across such a delicate tweeter in my life. At this point in their lives many have started to delaminate the VC tracing from the diaphrams. Another issue with the EMITs are the solder pads for connections, many have developed bad solder joints and simply reflowing will get ya back to reading proper ohms. Thats not to say their bad, the electrostatic design and extreme Cobalt magnetics are nothing to scoff at. 

The lower frequency driver is a dual voice-coil Watkins driver, these are phenomenal drivers that were built like tanks.  The midrange driver is a poly type dome construction sweeping from 600 to 4KHz<.

The bug with these speakers is to pull the EMIT and test them, reflow if necessary and attack the cross-overs. They use two pretty well constructed standard can type electrolytics along with an array of film polypropylenes, three inductors, rheostat and phenolic potentiometer.  The can type electrolytics were replaced with two axial electrolytics in parallel to obtain the correct value, all the original films were replaced with a much higher quality Solen MK type polypropylene capacitor in a similar fashion. (XO Points of perception 600Hz,4kHz)

**one major notation I want to add is the fuse, do not use the original rated value, I highly recommend .5-.750mA fuse as really anything over and you can say good bye to those EMITs.



With correct placement and proper drive these truly sound amazing before and after. They look just stellar with a proper cleaning and the heavily constructed metal pedestals. 

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