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PostPosted: Tue Oct 17, 2017 12:40 pm 
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Location: Chicoutimi, QC, CA
Hi everyone,

I have a Cambridge audio Azur 540A V.1 and I need to replace the volume pot as it is broken on the left side channel.

From what I saw until now, it is a motorized stereo 20k log potentiometer. The problem is I can't find any replacement pot that is 20K Log and motorized.

Is there someone in there that have changed a volume pot on a Cambridge Azur in the past? Or simply someone who can tell me what option that I have on this amplifier?

I'm in the show lighting repair industry for a while but new to Hi-fi amps, and I have to admit I'm a little lost. Any help would be appreciated.

Thanks


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PostPosted: Tue Oct 17, 2017 1:30 pm 
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Have you tried contacting Cambridge? or if they don't want to deal with anybody other than dealers, the Parts Connexion sells the Azur, they may be able to help...


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PostPosted: Tue Oct 17, 2017 1:57 pm 
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Yes contacted Cambridge but no answer yet. I asked my local distributor, they have a repair shop certified by Cambridge, but they told me that part wasn't available from Cambridge anymore. Anyway the original pot is a crappy chinese unit from Soundwell corp and it seems it's a common problem from those amps.


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PostPosted: Tue Oct 17, 2017 2:37 pm 
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Consider using a 25k?

Or ditching the motor?

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PostPosted: Tue Oct 17, 2017 4:07 pm 
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This is very interesting to me! I have a Cambridge 640A V2, and I am certain it probably uses the same volume pot. I am not sure if you listen at low volumes, but I frequently listen at relatively low levels, and have ALWAYS noticed a channel imbalance at low volumes. I've heard this on other amps as well (ie my Rotel when I first start a listening session with volume really low it even has the effect of nothing on one channel and volume on the other until you turn it up just a smidge, then the other one kicks in and then if you turn down, the problem is no longer present). But, it is far more noticeable and repeatable on my Cambridge. I've always found it to be a relatively good quality item and well built, but this problem annoyed me. I went for the 640, as I figure it's likely a bit more powerful and beefier, however, I find using my Focal speakers that it has caused the amp to go into protection just pas 12 o'clock... Which seems a little early for this to happen IMO.

I'd be interested in finding out if there are other options compared to the Cambridge stock, as it is obviously an inferior pot... Considering they say they build with high quality components, this is unfortunate. I also wonder if newer, 650A 651A etc use the same pots? I am assuming no?


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PostPosted: Tue Oct 17, 2017 4:37 pm 
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The Parts Connexion carries an Alps 20k volume control, but without the motor, so you'd loose the remote capability...

They carry a 10k version with the motor, that might be an option...

Based on what I'm seeing, I'd guess Alps makes the 20k with the motor, the issue will be finding someone who stocks it, or will order it for you.

And of course, in all of this, it might not (probably won't) simply plug into the existing location, so modification will probably be necessary.


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PostPosted: Tue Oct 17, 2017 4:48 pm 
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ebay, china....(most likely)

If it is the same pot with different innards and a motor then it is possible to swap out the innards. That any alps pot of identical design, whether it is connected to a motor or not, can have the inner components swapped out to make it another value of resistance.

A bit advanced for the casual diy'er, though. Still, extremely doable.

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PostPosted: Tue Oct 17, 2017 7:21 pm 
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The PC board footprint is going to be your limiting factor. The actual value of the pot will not make a huge difference to the circuit, but may affect volume positioning a bit.
This one may fit.
http://ca.mouser.com/ProductDetail/Bour ... yt6A%3d%3d
At 100k, it's a bit high but it will work fine.

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PostPosted: Tue Oct 17, 2017 7:28 pm 
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Have you contacted Plurison. The Canadian distributor for Cambride Audio? I hope the information below is helpful.

https://www.plurison.com/

PLURISON TECH SUPPORT,

ERIC ADLER
Tech Support / Customer Service
service@plurison.com
866.271.5689 x114

MICHEL ROUSSEAU
Tech Support / Customer Service
service@plurison.com
866.271.5689 x103

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PostPosted: Tue Oct 17, 2017 7:31 pm 
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don't wanna shoot myself in the foot but will a 100k pot possibly introduce noise?

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PostPosted: Wed Oct 18, 2017 4:25 am 
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While possible, not likely in this circuit as it is quite a low impedance circuit.

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PostPosted: Wed Oct 18, 2017 12:12 pm 
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Location: Chicoutimi, QC, CA
Thank you all for your replies.

My first concern is to find a pot with a suitable resistance, and that bolt in the amplifier faceplate, and on which the knob fits also. I'm less worried about pc board footprint as the original pot have very long pins. I must take mesurements to confirm but I think a pot like ALPS RK27 or RK168 would be at least half an inch from PCB when fixed on faceplate, so I can connect the pot to PCB with wires.

Do you think this is possible? And for the motor, I heard different stories about motor impedance and control board of amp going nuts... Do all I have to confirm is motor voltage and current rating?

-- 18 Oct 2017 20:14 --

Teo Audio wrote:
ebay, china....(most likely)

If it is the same pot with different innards and a motor then it is possible to swap out the innards. That any alps pot of identical design, whether it is connected to a motor or not, can have the inner components swapped out to make it another value of resistance.

A bit advanced for the casual diy'er, though. Still, extremely doable.



You say I can order let's say a 20k manual pot for cheap and swap the contacts and wipers with the stock one?


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PostPosted: Wed Oct 18, 2017 1:47 pm 
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I think whats being suggested is that if you can find an identical 20k pot without the motor, you can swap out the internals and use your existing motor, and the new guts. Similarly, if the Alps motor runs at the same voltage levels as your existing unit, you could buy both the motorized 10k and the un-motorized 20k from the Parts Connexion and swap things around to make a 20k motorized...

The better Alps pots are pretty good, they should address your low level channel mismatch issues as well.

Cheers, Dave


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PostPosted: Tue Oct 24, 2017 4:06 am 
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if it is a cheap Chinese part that is causing you issues then it is more than likely that the identical mass produced vol pot assembly has been used in many other audio products of same and lesser (much lesser) quality...but under a different part # that would not cross reference with your part...because maybe some manufacturers don't want to admit their components are used in inferior products.
For instance, that BPC stereo system sitting at Goodwill for $12.99 with a motorized volume control could be the same or VERY close to what you need.
Could the solution be that easy or am I delusional? Don't answer that.
I hope you find what you are looking for and get your Cambridge up and running.

Have you tried AliExpress for parts?

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