Modding the Zu Omen MKII

After intense and red-eye forum nerding, I landed on coated solid copper wire, 2x1,5mm for each binding post. Warning, that is stiff and a bit hard to work with, but sounds great!

I unfortunately broke the posts removing them, installed a plate and new copper terminals.

Hi guys,

Yes I may actually at some time contact Sean, I have been considering changing the elements entirely! 😁

I started with the clarity cap, a decent upgrade it is. But after reading on misc forums, I ended up with Mundorf Supremes 1uf and with a 0,1uf in parallell. I must say, a HUGE difference over the clarity cap!

I added a 63ohm Duelund graphite resistor across the tweeter, that really helped the tweeter relax, without negative effects really..

Reccomended!

/H

I added a solid 1x1 inch oak dowel right underneath the main element towards the back wall. Made it a snug fit, had to force it in place, and glued it in place with epoxy glue. 

Prior to this, I used about 1L of noise-x sound paint (for each speaker) in 3-4 layers all over the insides.

aldso adding new bolts with nuts torqued from the back side of the front plate, allowing for much higher torque.

made the cabinet «talk» vanish, and a much more dynamic sound all over. Good improvement in imaging as well!!

Did I do more.....yes, I probably went over the top..

I changed the stock tweeters for a pair of these;
http://www.usspeaker.com/radian%20475bEpb-1.htm

Radian 475-beryllium

added a suitable Lpad using Mills wirewound resitstors..

those speakers now play in a whole different league.

oh,btw, you can buy a bracket/adaptor for the 475’s and they will fit nicely with the current Omen lenses....

L-pad is an arrangement of resistors to match your tweeter to your main driver. If you go this path there are a couple of things to take note of....

And, did it make a difference, YES!!!

:-) 

I got the 475’s primarily due to avoid the woodwork, keep the cost down and make sure the speakers can be returned original if I for some reason would want to..  

the larger Zu lenses are $$$

also, the 850’s are not really well behaved in the high frequencies, the 475-be are beryllium, they are superb for tweeter duty!

Hi eyrepm

bolts/nuts similar to what you find on Zu web DIY section;

https://www.zuaudio.com/diy/stainless-10-24-t-nut

https://www.zuaudio.com/diy/stainless-m6x25-cap-screw

Paint, something like this, don’t pain the front baffel:
https://www.amazon.com/Acousti-Coat-Sound-Deadening-Gallon/dp/B01AB1S1QW

Caps;
https://www.hificollective.co.uk/catalog/sup8090-600v-supreme-polypropylene-caps-p-1740.html
And in parallell ;
https://www.hificollective.co.uk/catalog/sesg-030-0-1uf-mundorf-mcap-supreme-evo-silver-gold.html

Resistor across terminals on tweeter;
https://www.hificollective.co.uk/content/duelcr-250-62r-10w-duelund-cast-resistor

Not really very difficult though.. ;-)

These values are a result of scaling compared to what I know Zu use to match the 850’s with the 103nd drivers, accounting for the differences 260drivers.

note; these values will work for the 8Ohm 475-be radians.

if you go for the 16ohm Radian 475 version, different values will apply...

This is the values I used for the L-pad;

2 x (RES-M1115) - 3R 12W MRA12 Mills Resistor - £9.18 (£4.59 each)
SKU: RES-M1115, Location: AA04, Tariff Code: 8533210000

2 x (RES-M1135) - 4R7 12W MRA12 Mills Resistor (4.7R) - £9.18 (£4.59 each)
SKU: RES-M1135, Location: AA04, Tariff Code: 8533210000

Also, there are plenty of L-PAD calculators available online.

They will however give you other values than what I proposed above...

I got the bracket of a local supplier, but you can probably buy it together with your 475’s from the same supplier. Just make sure it fits the threads on the original Zu lens. 

The original eminence asd1001 driver has 1 3/8in (18ext.) threads.

did not change the main drivers as I am very happy with the sound right now...

I don’t really understand what they are saying there.

with the bracket the distance will be the same as for your current driver...

if the laws of physics don’t change, when you change the driver, the speed of sound coming from the new driver will be the same as from your old....

If Zu sais that, it means they did’nt get it right on all their Omen’s...

Yes, exactly like that! The cap is the same value you already have.

No worries, this is a bit outside most people’s comfort zone :-)

The 850 will fit, but it will involve purchasing new (expensive) lenses from Zu, and some woodwork... 

There is no way back once you do that.

Using the 475-be’s it can all be returned to original, and you can sell the drivers separate if you like.

Just to be clear, I stuffed the 475-be drivers in there, using the linked bracket. (Or similar) It all fits with no mods, bracket is 1in internal diameter, fits with the Radian 475-be 1in exit. That assembly once mounted will screw right into the Omen MKII lens with female 1-3/8in threads.

Now, remember to put the larger resistor value in parallell/across the teeeter binding posts, and the smaller in series after the cap!

Skip the Duelund (that is for the original tweeter) replace that with the larger value Mills, and you’r good

Sounds strange...

If you did this right, it should sound anything but muffeled.

if you replaced the caps, they will break-in over the next 30-50 hours, and sound great after 200.

make sure that all polarities are correct, + to + all drivers and speakers...

New caps will sound dull from the start, and improve after 10hrs or so

If you have new compression drivers, they may need 10-50 hours of break in aswell, depending og how loud you play..