* * * Zero reading on ribbon binding post * * *

Hello everybody,

I originally started a thread on my ALS III burnt smell issue on the other Carver forum and while that is still unresolved except by cosmetic means(sprayed the foams with Febreze as suggested by Kevin, a forum member), I'd like to add that a bigger puzzler has emerged. As suggested by the Rabbit, I tested the binding posts and came out with 4.5 readings on the woofers. I read 2.5ohms on one ribbon and 0 on the other when I should be reading 3.5-3.7 as per the Rabbit). When I pointed the probes on the ribbon solder point at the bottom of the back panel, I read 2.3ohms. With the jumpers installed, I read 4.5-4.7ohms on both speakers. The speakers sound normal to me bi-amped or single-amped. But why is there no impedance/resistance reading from the ribbon binding post and yet there's sound coming out of the ribbon ? What could be wrong? I'd appreciate any comment on this and hopefully, someone had a similar experience and found the fix for it.
Thank you.

Regards,
Nicco

A friend of mine still owns my old AL-III Pluses and he measured his ribbons just out of curiosity one day and they both measured 0. He asked me about it and I said I dunno.. we both walked away scratching our heads but he still listens to his every day with no issues.

Testing at the binding posts is useless as you are not reading the woofers or ribbons, you are reading the crossover.

As for your burnt smell, you've likely cooked a resistor. Pull the crossovers, you should be able to see a cooked resistor.

if they are not the plus model, the knob resistors adjustors are typical to get toasted when overdriven.

I forgot to address this before.

But why is there no impedance/resistance reading

You cannot obtain the impedance of a speaker by testing with a DVM at the binding posts.

A friend of mine still owns my old AL-III Pluses and he measured his ribbons just out of curiosity one day and they both measured 0. He asked me about it and I said I dunno.. we both walked away scratching our heads but he still listens to his every day with no issues.

Hi Jjptkd,

That's a little re-assuring to know. Did he tell you where he did his measurements?
Thanks.

Nicco

I forgot to address this before.

But why is there no impedance/resistance reading

You cannot obtain the impedance of a speaker by testing with a DVM at the binding posts.

Testing at the binding posts is useless as you are not reading the woofers or ribbons, you are reading the crossover.

As for your burnt smell, you've likely cooked a resistor. Pull the crossovers, you should be able to see a cooked resistor.

Hi F1nut,

The burnt smell comes from the ribbons themselves. I unscrewed the CO panel and everything looks new- no burnt odor or toasted resistors/capacitors, hardly any dust. Again, I tested wires coming from the ribbon and got nothing. I can only get a reading from the solder point on the bottom of the ribbon at the back panel and it's 2.3 ohms. Assuming I made the measurement at the right spot, is this a good, normal impedance reading?
Thanks.

Nicco

if they are not the plus model, the knob resistors adjustors are typical to get toasted when overdriven.

if they are not the plus model, the knob resistors adjustors are typical to get toasted when overdriven.

Hi Angelo,

I have the Plus model. The burnt odor comes from the ribbons. It helped that I sprayed the foams with Febreze but that only masks the odor. Could it be that this is normal after all and it just shows the age of the ribbons? Or is it an omen of a more expensive problem to come? I hope not. Do me a favor(I think you have the III's). If you don't mind, can you check your ribbons and see if you can detect this burnt smell?
Thanks.

Nicco

Hello Nicco,

I have a few questions, and hopefully I can give you answers!
1) Do you have pets?
2) is the foam on the front of the ribbon starting to crumble?
3) Has anyone other than yourself owned / tinkered with your AL3+'s?

1) if you have pets, dander & fur can get down into the bottom of the ribbon and as the ribbon is driven and heats up, it can cause a "burning". For this, take out the SQUARE HEAD wood screws and remove the ribbon driver, pull on the wires gently to pull a little extra wire out of the box & lay it down on a pair of chairs. Take a can of air & blow a very light jet of air down into the last pair of slots in the ribbon driver, this should remove any dander, dust & fur.
2) same steps as one
3) if someone else has owned or tinkered with your AL3+'s there is a chance that the circuit boards are crossing the traces and making a short in the speakers. Also, unless you cut the wires from the ribbon to the crossover, you will not get an accurate reading from the ribbon, you will still be measuring the ribbon and the crossover.

Hope all this helps,

Alex
CarverAUDIO Ribbon Repair

The burnt smell comes from the ribbons themselves.

I see Alex has made some comments addressing your issue. I'll add that I don't see how it is possible for the ribbon to smell burnt considering the materials they are made from.

Hello Nicco,

I have a few questions, and hopefully I can give you answers!
1) Do you have pets?
2) is the foam on the front of the ribbon starting to crumble?
3) Has anyone other than yourself owned / tinkered with your AL3+'s?

1) if you have pets, dander & fur can get down into the bottom of the ribbon and as the ribbon is driven and heats up, it can cause a "burning". For this, take out the SQUARE HEAD wood screws and remove the ribbon driver, pull on the wires gently to pull a little extra wire out of the box & lay it down on a pair of chairs. Take a can of air & blow a very light jet of air down into the last pair of slots in the ribbon driver, this should remove any dander, dust & fur.
2) same steps as one
3) if someone else has owned or tinkered with your AL3+'s there is a chance that the circuit boards are crossing the traces and making a short in the speakers. Also, unless you cut the wires from the ribbon to the crossover, you will not get an accurate reading from the ribbon, you will still be measuring the ribbon and the crossover.

Hope all this helps,

Alex
CarverAUDIO Ribbon Repair

Hi Alex,

I'm sorry for the late reply and thanks for chiming in. I've just had the III's for two weeks now but I noticed the burnt smell on day one. I didn't notice this at the seller's living room and I don't know if he or the first owner was a smoker. The foams don't lay flat to the ribbon frame(they are bulging), look, and feel their age. Could it be possible that ribbons somehow produce enough heat over the years and cause the foams to produce this burnt smell which then gets radiated back to the ribbons because of close proximity? But then, why don't other owners notice and report this phenomenon? In the meantime, I sprayed the foams with Febreze and it really helped mask the smell. I haven't checked if this has in turn neutralized the smell on the ribbons themselves. It doesn't look like anyone has tinkered with the ribbons as the felt backing and screws look undisturbed.
As I mentioned earlier, I can't get any reading form the ribbon binding post on one speaker but could get a reading of 4.7 ohms on the woofer binding post. I tried the ribbon/wiring solder points on the bottom of the ribbon at the back panel and measured 2.3 ohms. I repeated this with the other speaker and got 2.3 ohms and 4.7 ohms on the ribbon and woofer posts, respectively.
As you mentioned, these readings are not accurate, with the drivers connected to the crossovers but shouldn't there be at least measurable impedance from the ribbon binding post? The speakers sound normal to me although I noticed once that my Sunfire 200x5 felt warmer than usual after about an hour of normal listening(not concert levels!) and stayed warm to the touch an hour after being turned off. Is it being over-driven by the III's? If there is a short somewhere in the ribbon, wouldn't it show from the sound? If I didn't notice the smell and didn't do any impedance testing, I wouldn't think anything wrong with them from the way they sound. But please bear in mind that this is my first experience with ribbons so I don't know exactly how they
are supposed to sound normally. I listen with a wait and see attitude and it's very uncomfortable.
That's about everything I can relate about my experience with my III Pluses and hopefully, nothing's seriously wrong with them.
My deepest gratitude to every one trying to help.

Regards,
Nicco

Hello Nicco,

I have a few questions, and hopefully I can give you answers!
1) Do you have pets?
2) is the foam on the front of the ribbon starting to crumble?
3) Has anyone other than yourself owned / tinkered with your AL3+'s?

1) if you have pets, dander & fur can get down into the bottom of the ribbon and as the ribbon is driven and heats up, it can cause a "burning". For this, take out the SQUARE HEAD wood screws and remove the ribbon driver, pull on the wires gently to pull a little extra wire out of the box & lay it down on a pair of chairs. Take a can of air & blow a very light jet of air down into the last pair of slots in the ribbon driver, this should remove any dander, dust & fur.
2) same steps as one
3) if someone else has owned or tinkered with your AL3+'s there is a chance that the circuit boards are crossing the traces and making a short in the speakers. Also, unless you cut the wires from the ribbon to the crossover, you will not get an accurate reading from the ribbon, you will still be measuring the ribbon and the crossover.

Hope all this helps,

Alex
CarverAUDIO Ribbon Repair

Hi Alex,

I'm sorry for the late reply and thanks for chiming in. I've just had the III's for two weeks now but I noticed the burnt smell on day one. I didn't notice this at the seller's living room and I don't know if he or the first owner was a smoker. The foams don't lay flat to the ribbon frame(they are bulging), look, and feel their age. Could it be possible that ribbons somehow produce enough heat over the years and cause the foams to produce this burnt smell which then gets radiated back to the ribbons because of close proximity? But then, why don't other owners notice and report this phenomenon? In the meantime, I sprayed the foams with Febreze and it really helped mask the smell. I haven't checked if this has in turn neutralized the smell on the ribbons themselves. It doesn't look like anyone has tinkered with the ribbons as the felt backing and screws look undisturbed.
As I mentioned earlier, I can't get any reading form the ribbon binding post on one speaker but could get a reading of 4.7 ohms on the woofer binding post. I tried the ribbon/wiring solder points on the bottom of the ribbon at the back panel and measured 2.3 ohms. I repeated this with the other speaker and got 2.3 ohms and 4.7 ohms on the ribbon and woofer posts, respectively.
As you mentioned, these readings are not accurate, with the drivers connected to the crossovers but shouldn't there be at least measurable impedance from the ribbon binding post? The speakers sound normal to me although I noticed once that my Sunfire 200x5 felt warmer than usual after about an hour of normal listening(not concert levels!) and stayed warm to the touch an hour after being turned off. Is it being over-driven by the III's? If there is a short somewhere in the ribbon, wouldn't it show from the sound? If I didn't notice the smell and didn't do any impedance testing, I wouldn't think anything wrong with them from the way they sound. But please bear in mind that this is my first experience with ribbons so I don't know exactly how they
are supposed to sound normally. I listen with a wait and see attitude and it's very uncomfortable.
That's about everything I can relate about my experience with my III Pluses and hopefully, nothing's seriously wrong with them.
My deepest gratitude to every one trying to help.

Regards,
Nicco

How do the stock woofers sound?

Are you bi-amping with the 200x5? My buddy's using a Sunfire 200x5 that was just rebuilt to drive his AL-III's and at first he tried running them off just the front two channels. It worked up to reasonable volumes but the amp would actually shut down if pushed at all. Now he uses 4 of the 5 channels on just the AL-III's and it drives them perfectly without any problems or heat.

Hello Nicco,

I have a few questions, and hopefully I can give you answers!
1) Do you have pets?
2) is the foam on the front of the ribbon starting to crumble?
3) Has anyone other than yourself owned / tinkered with your AL3+'s?

1) if you have pets, dander & fur can get down into the bottom of the ribbon and as the ribbon is driven and heats up, it can cause a "burning". For this, take out the SQUARE HEAD wood screws and remove the ribbon driver, pull on the wires gently to pull a little extra wire out of the box & lay it down on a pair of chairs. Take a can of air & blow a very light jet of air down into the last pair of slots in the ribbon driver, this should remove any dander, dust & fur.
2) same steps as one
3) if someone else has owned or tinkered with your AL3+'s there is a chance that the circuit boards are crossing the traces and making a short in the speakers. Also, unless you cut the wires from the ribbon to the crossover, you will not get an accurate reading from the ribbon, you will still be measuring the ribbon and the crossover.

Hope all this helps,

Alex
CarverAUDIO Ribbon Repair

Hi Alex,

I'm sorry for the late reply and thanks for chiming in. I've just had the III's for two weeks now but I noticed the burnt smell on day one. I didn't notice this at the seller's living room and I don't know if he or the first owner was a smoker. The foams don't lay flat to the ribbon frame(they are bulging), look, and feel their age. Could it be possible that ribbons somehow produce enough heat over the years and cause the foams to produce this burnt smell which then gets radiated back to the ribbons because of close proximity? But then, why don't other owners notice and report this phenomenon? In the meantime, I sprayed the foams with Febreze and it really helped mask the smell. I haven't checked if this has in turn neutralized the smell on the ribbons themselves. It doesn't look like anyone has tinkered with the ribbons as the felt backing and screws look undisturbed.
As I mentioned earlier, I can't get any reading form the ribbon binding post on one speaker but could get a reading of 4.7 ohms on the woofer binding post. I tried the ribbon/wiring solder points on the bottom of the ribbon at the back panel and measured 2.3 ohms. I repeated this with the other speaker and got 2.3 ohms and 4.7 ohms on the ribbon and woofer posts, respectively.
As you mentioned, these readings are not accurate, with the drivers connected to the crossovers but shouldn't there be at least measurable impedance from the ribbon binding post? The speakers sound normal to me although I noticed once that my Sunfire 200x5 felt warmer than usual after about an hour of normal listening(not concert levels!) and stayed warm to the touch an hour after being turned off. Is it being over-driven by the III's? If there is a short somewhere in the ribbon, wouldn't it show from the sound? If I didn't notice the smell and didn't do any impedance testing, I wouldn't think anything wrong with them from the way they sound. But please bear in mind that this is my first experience with ribbons so I don't know exactly how they
are supposed to sound normally. I listen with a wait and see attitude and it's very uncomfortable.
That's about everything I can relate about my experience with my III Pluses and hopefully, nothing's seriously wrong with them.
My deepest gratitude to every one trying to help.

Regards,
Nicco

How do the stock woofers sound?

Hi Kingman,

The woofers sound very good. Before agreeing to buy the III's, I specifically asked the seller about the woofers' condition and he told me that they're in great shape. He related to me that the original owner was a philharmonic orchestra player and listened exclusively to classical music and that he himself couldn't play them real loud because of an elderly neighbor. The III's are in very good cosmetic condition, sounded great, and the rest of his gear was top-notch. I checked the surrounds by running my hands around the foams and they felt smooth, firm yet bouncy, just like normal working woofers in my other speakers. Their mid-bass response complement my subwoofer nicely.

The fact is, the speakers sound great. What's worrisome is the burnt smell from the foam/ribbons and the fact that one of the ribbon binding posts doesn't give impedance reading and yet give off sound. Would this mean that the channel that drives that ribbon is really being over-driven and could ultimately get damaged? I haven't checked if the ribbons still have that smell after spraying the foams with Febreze on both sides and re-installing them. Any guess what's causing all this? Or is this simply too much ado about nothing?
Thank you.

Regards,
Nicco

Are you bi-amping with the 200x5? My buddy's using a Sunfire 200x5 that was just rebuilt to drive his AL-III's and at first he tried running them off just the front two channels. It worked up to reasonable volumes but the amp would actually shut down if pushed at all. Now he uses 4 of the 5 channels on just the AL-III's and it drives them perfectly without any problems or heat.

Hi jjptkd,

Yes, I am bi-amping with the 200x5. The first time I pushed them comfortably louder than normal(but not way too loud), the Sunfire felt a lot warmer than usual and SF's are supposed to keep their cool I've always read. And the amp was still warm one hour after shut-off! With the jumpers installed, I tried driving the III's with my Crown PSA-2D and this amp gives out at least 465watts/channel @4ohms and they sounded great.
Just wondering, when driving just two speakers, aren't Sunfire amps designed to "borrow" power from the other unused channels when pushed to high volumes, which in the 200x5's case, extra 600 watts to borrow? Or do I mis-understand the concept?
Thank you.

Regards,
Nicco