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Crossover circuit; Hales Reference Revelation 3 speakers

Greetings everyone. I have a pair of Hales Reference Revelation 3 speakers that I love.  But I recently noticed that the midrange drivers aren't even working at all.  I tore one of them down to have a look at the crossover circuit, and sure enough there is a capacitor in the midrange section that is absolutely blown out.  Looks like a catastrophic failure.  I presume it's the same on the other side.

As for what caused this, I am not sure...but I do know that if I hit the switch on my turntable without turning my volume down, it sends a tremendous spike through the system and does NOT sound good.  I think one of these spikes may have blown out these caps.  This spiking began when I added a Manley 300B preamp and a Manley Chinook phono stage to my system (which is a phenomenal combo, IMO). I simply got in the habit of turning the volume down before hitting the switch to flip an album.  But wouldn't mind solving that issue...definitely not right.

Which brings me back to the crossover circuits in the speakers.  Basically, I am thinking it makes sense to upgrade the capacitors and anything else in there, and rebuild those circuits with better quality components.  I am pretty handy with a soldering iron, and can handle the actual repairs myself....but looking for some guidance on duplicating the values designed-in for the circuit, how to best match the components in the two different circuits, etc....just looking for the best path forward.  Thanks in advance for any insight or help!

-Scott


sd02720
11 responses Add your response
erik_squires
15,647 posts
 
Hey !! 

You are in the wrong place. Come on over to:

diyaudio.com/forums/multi-way/

You'll find lots of speaker builders there who will help you, plus you can post photos with your questions. I will say that looking at the impedance curve, this speaker looks more complicated than your average three way. Doing a complete electrical analysis will be key. That way you can simulate the power dissipation of each component. 

Best,

E
sd02720 OP
12 posts
 
Thanks!  I will explore that, as well
timlub
2,039 posts
 
There are several people here that can help. I'll see if I can find a schematic and let you know.  
timlub
2,039 posts
 
Scott,  a couple of things,  first, since you have this apart,  pull the mid and try to play the mid without the crossover connected.  Lets make sure that the midrange are not damaged.  Next,  its about a 95% chance that the cap that burst is an electrolytic cap.  So far, I have not found the schematic,  but that should be a simple change.  I would suggest that you get as much film as you can replacing that electrolytic and preferably a Metalized polypropylene or better.  
sd02720 OP
12 posts
 
Thanks, Tim...those are good suggestions.  

I have yet to actually remove the board and have a closer look, to see if I can get a reading on the markings.  There is a hand-written label on there (as there is on all of the caps) which seems to say "504".  Another says "302".  But I'll also see if I can find some markings.  I'll also pull the other board out and do the same.  I'll be sure to test out the mid-range drivers to be sure they weren't damaged, as well
timlub
2,039 posts
 
No Problem Scott, I get private messages fairly often from Agon members. Send me an email and we’ll get you through this easy enough.
mckinneymike
88 posts
 
Contact Paul Hales at http://proaudiotechnology.com/.  He might be willing to share the schematic since he designed the speakers :) 
sd02720 OP
12 posts
 
Hey guys, thanks for the insights.  I replaced the blown components on the crossover boards, and turned out I needed to replace the drivers, too.  Had some help from Madisound finding supposedly similar drivers to match the values of the originals, which are no longer made.  Bottom line, the entire voice of these loudspeakers is changed forever.

I paid 900 for them 6 years ago...time to let them go.  RIP
wjmeier
1 posts
 
Scott,

I own a pair of Hales Rev 3's that I have owned for about 20 years.  I have been tweaking their performance.  I am curious about how you accessed the crossover board.
sd02720 OP
12 posts
 
Sorry I am only seeing your response now.  The whole front panel (containing the speakers) comes off.  Inside the cabinet is a lot of insulation, etc.  The crossover circuit boards are inside
bigkidz
3,311 posts
 
If you have a X-Over that is working you can probably measure the cap.  Are there any specs on the caps?

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