Which crossover network is this?

Carver Speaker Discussions and Questions
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Robert R
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Re: Which crossover network is this?

Post by Robert R » Mon Oct 12, 2015 12:54 pm

To be less vague, "quite a ways" is, at least in the newer style woofers, around one eighth of an inch with a 9v cell.
RR
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UncleMeat
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Re: Which crossover network is this?

Post by UncleMeat » Mon Oct 12, 2015 12:55 pm

But each woofer is stamped "4Ohms"; shouldn't they measure 4? I might have found something; the solder joint where L-1 attaches to the input wire looks funky. I jumpered across the main wire for the woofers directly to the binding post terminal and I think it has higher output. I'm going to try re-flowing and adding solder to that joint if you are in agreement

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Robert R
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Re: Which crossover network is this?

Post by Robert R » Mon Oct 12, 2015 1:18 pm

By all means, if the soldering appears to be birdshit, reflow it, with some flux.

The 4 Ohms is a "nominal" figure, and doesn't accurately denote an actual measurement. The other classic choices were 8 or 16; old tube amps had outputs labeled for just those values. As SS took over, at some point somebody got honest and rated theirs at 6 ohms. But even that is an approximation. It's an impedance, anyway, and therefore frequency dependent, varying with Hz. The published spec for these woofers was 2.7 ohms DC resistance, which is about what you should measure at each one individually, and also across the whole four-way series/parallel array.

RR
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UncleMeat
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Re: Which crossover network is this?

Post by UncleMeat » Mon Oct 12, 2015 1:29 pm

I just re-flowed that joint; now I have good bass; it's hitting without turning the bass dial up! L-1 is connected and it's all low note now.

EDIT: I'm going to re-flow every joint that looks like birdshit; there are 2-3 more. I'll solder the wires back together for the caps also. Now if midrange is still too high and treble rolled off too much what would I look for to correct that problem?
Last edited by UncleMeat on Mon Oct 12, 2015 1:46 pm, edited 1 time in total.

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radioeng2
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Re: Which crossover network is this?

Post by radioeng2 » Mon Oct 12, 2015 1:46 pm

Ahhh...good news! Good job...both of you! Now to get 'er back together, buttoned all up and soon hopefully you'll be enjoying!!

Mark
I was there "At the Fest!" Hope you were too!

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UncleMeat
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Re: Which crossover network is this?

Post by UncleMeat » Mon Oct 12, 2015 1:49 pm

Wait, don't go away yet; I still have low treble on the right and similar troubles on the left!

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Robert R
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Re: Which crossover network is this?

Post by Robert R » Mon Oct 12, 2015 2:23 pm

You never said how the bass is on the right side, or else I missed it. The lower resistance reading there sounds a lot more like the correct one. It seems you had a 1.3 ohm solder joint in this channel...

Waiting to hear if the bass seems normal in your other channel, then how the ribbons sound. It's amazing (sorry!) how much better they sound sometimes when the bass is present.

Is the ribbon circuit set up the way I guessed it, with what looks to be a 5 watt resistor, seen in the upper left of your photo, in series with C2? What is the value of that resistor? I'd like to make an accurate drawing of this crossover. They sold quite a few of these, and the archives could be enhanced by your experience. Also, I'm reading the value of C1 as 300mf @150v. And C2 - is that 175 @150v?

RR
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UncleMeat
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Re: Which crossover network is this?

Post by UncleMeat » Mon Oct 12, 2015 3:27 pm

I have full range on the right side, the bass is a bit muddy with some funky resonances but for the most part it's good (could be because it's not positioned yet, or room reflections). Highs are are still on the weak side, cymbal crashes are dim compared to the AL-III's. 1000% better than it was, thanks!! I'll get back to you on the resistors, etc; I want to try re-flowing joints on the left side for a quick check to see if it's the same problem.

Edit:

I found the problem on the left side! While I was re-flowing joints I noticed the terminal on the right side of the x-over had a wire missing; the wire soldered on had nothing connected to it but the terminal LOL. So I took a look at the right speaker and I saw as I had suspected that the ribbon wire was supposed to be attached there, instead it was connected to the main input and getting full range! ](*,) Good thing these 60" ribbons respond down to 20hZ; and luckily it did not get driven too hard with bass notes. Both speakers sound the same now; bass is better than I thought, the distortion must have been in the music or speaker re-positioning helped. I have full range now on both speakers!!

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Robert R
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Re: Which crossover network is this?

Post by Robert R » Mon Oct 12, 2015 4:25 pm

Placement is important, and there is the tilt-back angle to adjust, too. The height of your listening position is critical when doing that adjustment; it's best done with two people - enlist a slave. Whatever angle you choose, be sure both channels e the same - unless you prefer shitty imaging.

Take your time about the parts id. bit - just wanted to mention it before you went ahead and put the speakers' clothes back on. Can't read the numbers on L1, and there is one cap that can't be seen, as it's hiding under a 2mf that it's in parallel with. And that resistor I already mentioned. The great big resistor might have some writing on it - I strongly suspect it's 4.5 ohms, at maybe 100 watts.

Is there a felt covering on the back side of your ribbons? If not, you might want to add one - Bob always insists it's important, though he didn't have it on there until a year or two into the the Silver/Platinum era. It's not for protection, or looks - it's for sound. I can provide details on that upgrade - what material to obtain and where, the size to cut it, and how to secure it in place. But for now it can wait.

Guess I'll hit the showers.

RobertR
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UncleMeat
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Re: Which crossover network is this?

Post by UncleMeat » Mon Oct 12, 2015 5:57 pm

Thank You RobertR for your technical help and radioeng2 for seeing the bad solder joint(s)!

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pmat
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Re: Which crossover network is this?

Post by pmat » Mon Oct 12, 2015 10:01 pm

Update, he's in sonic bliss and beating the Bishop something fierce.
Power is the aphrodisiac of audio

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UncleMeat
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Re: Which crossover network is this?

Post by UncleMeat » Mon Oct 12, 2015 10:45 pm

pmat wrote:Update, he's in sonic bliss and beating the Bishop something fierce.
[-( =; [-X

Not necessary; I think I just had an Eargasm \:D/

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