x250.5 - meter going full scale - whaaaaat?

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Friend of mine has an x250.5
He recently got some second hand ribbon speakers.
We believe they are faulty as the gauge on the amp is going almost full scale while trying to get 'reasonable' volume from them.
He has no issues with any of his other speakers.

He also has a parasound A21 that goes into protection well before what the x250.5 can deliver.

So, question is, just how much power / current is being generated by the amp to get that needle right up near the end of the scale ?
 
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I'm curious. Have you tried to measure resistance of the ribbon speakers while not connected to the amp? How about measuring from the speaker cable disconnected from the amp?
What is the brand of the ribbon speaker?
I've seen Parasound mono-blocks go into protection with 7" tall ESLs.
Not fun.

Have you measured the AC at the amp's output posts?
Be careful. I imaging what your are seeing is dangerously high voltage and current.


X250 SPECIFICATIONS
All figures obtained after 1 hour warm up, with regulated 120 VAC power line. See manual notes about AC power line regulation.

Power Output 250 watts maximum @ 1% THD, 1 kHz, 8 ohms

Maximum Output Voltage plus, minus 65 volts

Maximum Output Current plus, minus 20 amps

Power Consumption 270 watts idle, 1200 watts maximum
 
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Friend has limited tools and skills :)
And I'm too far away to drop everything and go there often..

Speakers are (second hand) Ambience 1800 Reference

Sensitivity. 96dB @ 1metre, 2.83volts input.
Power handling 150 watts RMS (long term)
Crimped metal ribbon type.
Twin 180mm SEAS woofers, custom made
specifically for Ambience loudspeakers.
Rear ported bass reflex design.
Nominal impedance 4 ohms.
Crossover 3rd order @ 420Hz
Minimum amplifier power 10 watts RMS/channel.
Ideal Amplifier power 30-70 watts RMS/channel.
* Specifications subject to change without notice


He has more gear than rooms.
Hes aiming to use the x250 in the main room with his normal passive speakers.
In this task it works reeeeally nicely :)

He then bought the ribbons to be powered by the parasound in another room.
When he tries to get "decent volume" the parasound goes into protect.

So his first thought is, lets plug them into the x250.
No comment.............

Hes been in touch with Ambience and they are going to walk him through narrowing down the exact issue.
They believe (as do I) that one or both panels are shorting.

I like the fact that the x250 still managed to drive them :D
Long term I wouldn't place bets though...
 
Update.
I have the speakers here at last.
The crossover can be bi-wired, makes for easy testing.

The panel section on both are perfect. A nice even 4ish ohms across their range.

The bass sections on both have been over driven for a looooooong time.
Both bass systems when swept with dats drop to 0.1ohm around 4khz.
The primary inductor (3rd order crossover) for the bass section on both speakers are no longer inductors.
More like crispy lumps of metal.
My LCR meter and the dats system refuse to even recognise them as inductors :)

Even though their long out of warranty the manufacturer has very generously offered to rebuild both crossovers with all the latest updates as well.

Some companies really do care about after sales service.
Helps to somewhat restore your faith in humanity. :)
 
It’s a tribute to the toughness of the X250 that it could drive that load. The way you describe that inductor it sounds like there may have been DC put on it at some point. I can’t imagine how much music power on average it would take to burn up an inductor like that. I can’t imagine it would sound very nice while smouldering and smoking either.
 
In no particular order;

Pass labs and Ambience seem to be willing to go WELL beyond realistic levels for customer service.
I know a guy with a newish PL amp, and lets just say, I am astounded by what is being done by Kent to sort this guy out.
Um, That's in a good way that is :)

There are others, but this isn't a 'who is who' post :)

The inductor in question is held to the board with cable ties, they have melted through.
There's also a wire running past them, these have had their insulation melted through completely and are showing a good 3+mm of bare copper.

Note that all the inductors are good air core ones that are very well wound.
Nice and square, even, uniform winding.
Now have a closer look at the pics attached........
And no, thats not glue you can see on the inductor. It's melted wire enamel.

I would suspect that a previous owner may have been bi-amping, and either pushing the life out of the bass system, or had a faulty amp delivering some level of continuous dc.
 

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I had that happen to a power transformer in a DIY F6. Must have melted part of a winding because the voltages changed; went higher. One of the secondaries got loose from the PCB edge connector. What can you do but solder...

Glad you are getting things sorted. I'd love to hear a good panel driven by a good power amp myself!
 
And there supposed to handle 150w.

I'm kinda hanging out to hear these myself.
I've heard a few ribbon speakers.
Most leave me, lets say, happier, with my 'normal' dynamic speakers.

Yes they do things dynamic speakers can never do.
But a single large element reproducing a small instrument or voice just doesn't work for me.
Women and men just don't have mouths that are 2+ meters tall.......

Best I've heard to this day is the old quad esl 63 with its segmented panels.
 
Update time #2.
And it's not pleasant.
In the cold hard light of day I have to completely reverse my positive praise for a certain man and his company.
There's a lot I want to say, and one day I might.
IF I can work out a polite way to say it.

But I will say that Nelson and Pass Labs remain in position number one for excellence in every area :)
 
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Try to look at it positively, a great opportunity for some DIY.

:geezer: too.

Hi Nelson.
I did suggest to my friend (owner of the speakers) a possible alternative. Several actually.
But he managed to get the bulk of the repair cost paid by the previous owner as it was very obviously a pre existing issue.


why not right away ..... credit where it's due ....... especially when bad one is the case .....

you can call me (Old'n'Cranky)^2 , considering amount of drek I saw in reputable gadgets , in last few decades of service work

:devilr:

Oh ZM (Old'n'Cranky)^2, you always bring a smile to my face :)

Yes over the years I've seen some horrors. Most of it from repair shops..

I will attempt to do this as professionally as I can.

Friend of mine bought a pair of second (third ?) hand speakers.
Travelled ~1,800 klms (round trip) to collect them. Had other things to do in that area, hence the loooong drive).
Heard them at the sellers place at low volume only.

Got them home, had to make some binding post jumpers as they had none.
Took several weeks before he could try them at home.
One amp went into protection, other amp (x250.5) was pushing serious current to get normal volume.

He contacted the speaker maker and they exchanged various emails, txt's and calls trying to work out the issue.
Eventually he brought them to me as I have a background in audio/speaker repairs/builds/rebuilds etc.

In preparation for them arriving to me, I contacted the maker told who I was, and what was going on, and asked if I could get a schematic purely for repair use.
Maker said when I get them contact him again and he will tell me how to disassemble them etc.

They arrived here and after testing, disassembly and examination I found the bass inductor burnt out on both speakers.
I suspect at some stage in the past someone bi amped them with a faulty bass amp.
I again contacted the maker with photos and all relevant information and again asked if I could get a schematic purely for repair use.
Or failing that, could they just give me the value of the one faulty inductor as this primary inductor is beyond any form of measurement.

I was told they were an old model and many updates had been introduced since then, so I should send them back for examination and repair.

The inference from the tone and wording in the emails was that 'we would be looked after'.
Eluding to the possibility they might be upgraded as goodwill.

I asked several times as to potential costs.
(My friend has very little money and has to count every cent.
These are his reward - midlife spend the kids inheritance - to himself for beating (so far) an aggressive skull cancer.)

I was just recommended to send them in.
So on a friday I sent them off and informed the maker.

Saturday morning I get an email.
We will let you know the cost once we have examined them.

My friend contacts them and asks if theres any progress.
He's told they have been put in line and will be informed in due time.

Not long after I get an email from them stating the primary bass inductors are u/s.
They need to order wire to make new ones, and it will cost Au$385 for the two inductors, plus return freight.

As I work in the industry I know what parts cost, what their worth and trying to save my friend (what I consider an exorbitant amount) again ask if he can provide the value of just these inductors.

The reply was less than friendly.
Will not under any circumstance divulge any information.
Either pay the repair costs, or he will send an invoice for all his time in dealing with us and only once it's paid would he return the unrepaired crossovers.
If he knew he was going to spend this sort of time with it he would never have even talked to us.

So, I now have the crossovers back here with two new 1.8mh 18awg air cores. street value of about $30.

I won't comment on some of their design choices.
Things will be somewhat different when I hand them back to my friend...
Those changes will be at my cost.


**** Disclaimer ****
I have not mentioned any names or brands etc in this post.
I have retained all communications for any proof or defence required.
I am happy for the site owner to edit this post in any form they see fit.

These are someone else's design.
A ten year old design.
That has apparently been superseded multiple times.
Who's major part can't be reproduced (easily).
Yet this one damaged part is super secret because ?$?$?$?
 
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