[E-Zee]

I'm looking for some shared expertise if anyone else has experienced or may recognize a similar failure.

The crossover is an NX-Studio, foil inductors, path audio resistors, sonicaps, myflex bypass.




One speaker sounds appropriate. In comparison, the second does not sound correct. The customer is describing the following:
Tweeter output is reduced. Woofer sounds okay but visually you can see the cone moving erratically.

The customer has gone through proper checks by swapping channels on amplifier, swapping drivers between cabinets, and has ruled out external contributers to be confident that problem exists within the crossover.

My question is if anyone has experienced anything similar or might know a cause that could produce that outcome.  I'm a little perplexed.  I'm confident with the crossover layout as it has been used successfully many times and triple checked each time. If one of the solder joints was failed or inadequate I don't know that it would cause that result. Ultimately I'm offering to rebuild it at no cost, but still perplexed as to a possible cause. If all of the connections check out to be secure and no separate wiring connections have bridged themselves, what else should be considered?

I've never heard of a bad inductor. I don't suspect a path audio resistor failure, nor a sonicap failure.  Drivers have been swapped to confirm it's not the driver.  I could suspect possibly something in the internal wiring connections but customer has compared the two speakers and the other functions correctly. 

Any thoughts.  I'd like to help get this sorted out and hoping someone has possibly has had a similar experience.

Elon

ezeescrossovers.com

[Danny Richie]

I looked at those crossovers and they look nicely done.

Some of the wiring looked like it came from somewhere else. So there may have been a compromise there, but I don't think that's the problem.

I would check those path resistors and make sure the two resistors have not been swapped. If so it would sure knock down the tweeter output.

Also, those things have a shield leg that can be grounded. So that cannot be one of the legs used.

[E-Zee]

The photo above was of course before it shipped to the customer.  Aware of course that things can happen in shipment, I realize that something may have compressed or a connection bent, but customer is confident that separate connections are not touching each other.

 I wonder if the copper foil lead from inductor getting pressed down onto the copper body of the path audio resistor could have any affect.  I wouldn't immediately expect that result unless the copper outer sleeve bridged a connection to something else also in contact.  Any thoughts regarding copper body of path resistor?

[E-Zee]

Danny, thanks for looking at them.   The shield leg of resistor is tucked under edge of resistor and cut so that its open end doesn't extend out beyond the end of resistor.   Could the leg have grounded to the copper body  and caused impact?

The small piece of red tinned solid core wire is used just to stretch the lead out to where it can be reached and joined to internal wire connection and should have no significant impact.

[SoCalWJS]

Can the Customer send you photos of the installation? Might tell something, either transit issues or wiring at the installation end.

[Hobbsmeerkat]

For anyone curious what happened with these crossovers:

After they came in, I brought over one of my studios from the listening room and we hooked up both crossovers.
First crossover measured fine, second showed no tweeter response.

Using a multimeter showed a resistance of 49ohms on the first tweeter..
The resistor in the "good" crossover measured correctly.

Partsconnexion was out of stock on more of that values, so we offered to swap them out for Mills resistors, since we still had a couple.

I fixed them up that evening. However before sending them out, I tested them again, just to be safe..

This time the "good" one now measured  the tweeter circuit 1dB higher than the fixed one. 
The fixed one even measures identically to both my "cheap-o" & "overkill" crossovers..

Danny suspected it might be the other resistor im shunt, but we couldn't check, as it is in parallel with the smaller inductor.
After talking to the customer, he said to go ahead and swap those out for Mills as well.

After snipping the resistor from the originally "bad" crossover, it read correctly. Doing the same with the originally "good" crossover gave a reading that was nearly double what it should have been.. Bingo!

I swapped them out for the Mills, and now they both measure identically!

I dunno how common this issue is, but to have 2 separate bad resistors is not a good look for Path.. especially when they cost $25-30 a pop... But it's really hard to say what happened..
At least Mills are still a really good quality resistor and the difference in performance will be somewhat minimal.

I checked both of my "overkill" crossovers at this point, just to ensure they did have any such issue. They were spot on, and were never more than 1/10dB different from one another. Which was a relief, especially since mine have two "half values" per location, instead of the "closest single" value.  (For example 2.5+2.5 ohm vs 1x 4.8 ohm.)

At least the customer will have a great time enjoying them once they are back in his hands and fully assembled. 

But if you plan to get Path resistors from Partsconnexion in the future, it might be a good idea to pay the extra $1 for the "matching" service. So if there are any defective units, they'll get caught by the seller, not once your crossover is assembled.

[Shives]

Morning.

So, I’ve been reaching out and learning more and more about audio, devices and components/parts. I’ve heard from many others that parts like, Mills resistors, and path audio have had very wrong values. I’ve done and been told to measure each part that has come across my eyes in more then one way if possible. This will help the possible issues. Even then it may measure good, and still have some sort of working issue.

     It’s seems as tho the parts manufacturing process have been… flawed, least some have. Not on purpose I don’t think.  Now, could be due to COVID workers doing things not used to, or other areas or reasons.

Good find! I’m sure this customer will be quiet happy.

[jmac]

Hi guys, I am very happy. Cant wait to get them back. John

[kyrio_s]

@Hobbsmeerkat - Thanks for the writeup, it helps a lot!  Just to be sure, were both wrong values for those Path resistors picked up straight away on a multimeter (once fully disassembled), or did one of these show a correct value on initial test, but still functioned incorrectly when hooked up to the crossover? 

[Hobbsmeerkat]

@Hobbsmeerkat - Thanks for the writeup, it helps a lot!  Just to be sure, were both wrong values for those Path resistors picked up straight away on a multimeter (once fully disassembled), or did one of these show a correct value on initial test, but still functioned incorrectly when hooked up to the crossover?

The one at the beginning of the circuit we could test without removing a multimeter, which is how we found the first bad one, reading over 10x higher than it should, and showing no tweeter output when measured
The other one is in parallel with an inductor, so it cannot be tested with a multimeter, but it's issue was immediately evident in the measured response as one being 1dB higher than the other.
Once one leg of the inductor was removed from the circuit, then we could use a multimeter and it's resistance was 2x higher than the other. Which explained the difference in the measured response.

Far as I know, they likely both measured incorrectly from the beginning. But it wasn't until we fixed the issue and measured both of them after the first repair that we knew there was another bad resistor in the other crossover.

[kyrio_s]

Gotcha, thanks!  Bizzare QA issue for Path Audio resistors. 

[jmac]

Got the crossovers back with the the new Mills resistors. The speakers are just breaking in and sound great. Problem solved! I want to thank GR Research for the fantastic customer service. John Mac

[Hobbsmeerkat]

Glad we could help you out!

You're well on your way to some killer sound!