Martin Logan Vantage Amp board

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m_shiva2003

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One of My Martin Logan Vantage speaker is suddenly stopped working. I can hear only sound from panel but no bass from woofer. I swapped circuit boards from working speaker and found that circuit board "BCFS9LPd" is bad (as shown in the picture). I contacted ML and they mentioned that whole backplate need to be replaced and they are not selling anymore. They said they can repair for $135 PER HOUR plus parts and shipping (no estimated final cost). I can't get it done without having final estimate / worth to fix. Can someone please advise what is the best and reasonable way to fix ?

Thanks in advance
 

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Tosh

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Will ML send you the schematic?
I don't see an amplifier section on that board, just a ton of op amps. Isn't there a class D amp buried in there?
You could ring up Speaker Exchange in Tampa and ask if they know any technicians, but don't just bring it to them. A tech would be able to compare the working board against the failed board, but that's time-consuming with no schematic.
If they were mine I would look into bypassing the internal amp...
 

wrat

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very disappointing to hear that they are not supplying parts for a less than 20 yr old speaker
 

Robert D

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I think many will tell you to just bypass the board and use an external amp with crossover to directly connect to the woofer. Something I've never done, but plenty on here have.
 

baceitc

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Hi, I also have the same martin logan Vantage speaker as yours. My speakers haven't heard for 5 years, now also having trouble with too much bass, I can't hear it, I tried another amp and washed the panel but it didn't get any better.
As for your speakers, I think you should buy them on ebay that sell the same as yours, if possible you can buy replacements for your speaker.
 

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Brandon Hartwick

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I think many will tell you to just bypass the board and use an external amp with crossover to directly connect to the woofer. Something I've never done, but plenty on here have.
We suggest this because Martin Logan makes boards that are basically impossible to service, or they just don't carry them anymore. The other thing I'm finding kinda concerning is that when looking at the schematics from various generations of Martin Logan speakers is that most of them are completely different from eachother. From one generation to the next most of the electronics are vastly different, I feel this is going to make some of these speakers very hard to fix in the future.
 

Robert D

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We suggest this because Martin Logan makes boards that are basically impossible to service, or they just don't carry them anymore. The other thing I'm finding kinda concerning is that when looking at the schematics from various generations of Martin Logan speakers is that most of them are completely different from eachother. From one generation to the next most of the electronics are vastly different, I feel this is going to make some of these speakers very hard to fix in the future.
Then there is the matter that everyone on here that has gone to an external crossover says that the sound is far superior anyhow. I know I would probably go that route.
 

baceitc

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Then there is the matter that everyone on here that has gone to an external crossover says that the sound is far superior anyhow. I know I would probably go that route.
Can you give me the circuit diagram of the crossover that you say? Thanks!
 

Brandon Hartwick

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Can you give me the circuit diagram of the crossover that you say? Thanks!
We're talking about using digital electronic crossovers, such as those in the Crown DriveCore series amps. The OEM Martin Logan bass crossovers in the older models were passive and super lossy, the newer models are different (usually digital) but seem to break sometimes and good luck getting new boards.

Check out my thread, it explains everything.
 

Robert D

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Can you give me the circuit diagram of the crossover that you say? Thanks!
There are some guys on here with experience doing this. I have not. I just know that they bought external crossover devices. You can buy them from companies and all you have to do is plug in everything. I'm not familiar with what companies are good for this. I remember that prices mentioned seemed very reasonable, so you won't go broke.
 

JonFo

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I think many will tell you to just bypass the board and use an external amp with crossover to directly connect to the woofer. Something I've never done, but plenty on here have.
Yep, this is the answer.

A $400 Crown DriveCore XLS 1002 will do what the OP needs. It has built-in DSP crossovers and EQ abilities. Simply configure a low-pass at 400Hz using a 24dB/Octave slope. Set volume levels so they match the panel output.
Inside the speaker, disconnect the feed to the driver, and wire that up to some new binding posts for the bass driver. Feed the output of the Crown to this new binding post.
Parts can be found here:

Extra credit for using REW to measure the system and apply a bit of EQ to match the room (unless you already use Audyssey or another DRC, in which case it will deal with that).

The output of the Pre-amp will need to be split so you can drive the existing amp and the RCA input of the XLS.

Set it up to work with the Vantage that has the blown amp, and once you figure out all the settings. Repeat on the other unit, as that board will soon go.

The Crown amp will last decades.

So for under $500 in parts and materials, you can have better than new Vantages @m_shiva2003
 
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