My MC240

CarlV

Lunatic Member
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Posted by ronflugelguy on 09-09-2004 06:02 PM:
My MC240

When i powerdown my amp it has started to make popping noises, not loud ,but several that are audible. What could this be and is it serious?

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Posted by crooner on 09-09-2004 07:46 PM:

When you power down? mmmmm
Sometimes tubes make "clinking" sounds when turned off.

I would be much more concerned with noises when the amplifier is actually running.

Mechanical noises are sometimes blamed on the transformers. However, the potting used in the MC240 would prevent this.

I sometimes hear popping sounds coming from can electrolytics, but that's always when turning the unit on. Again, the McIntosh unit has a thermistor that takes care of this.

Regards,

crooner

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"May you live to be 100 and may the last voice you hear be mine." Frank Sinatra



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Posted by CarlV on 09-09-2004 09:01 PM:

Hey Ron,
Have you tried turning it off with no input connected of any type
just to be sure it is the amp? I have had other problems that did that including the light/dark switch on my MX112. Just a thought,
Good Luck with it.

Carl

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Posted by ronflugelguy on 09-10-2004 06:54 AM:

Carl. the way I have it set up, the amp is shut down first, then about a minute or two. the pre shuts down. (Monster cable powerline).

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Flugelhorns Rule!



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Posted by jt1stcav on 09-12-2004 03:25 PM:

I'm no expert, but I sometimes hear either my 5U4G or my 300B pair softly "tinging" or "tinkling" upon power up, and sometimes when powering down. I assume it's only the glass bottles expanding and contracting due to the tremendous change in temperature from cold to hot tubes and vise versa.

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Jim Tidwell

My simple single-ended triode and horns audio system...sounds like real live music!




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Posted by ronflugelguy on 09-12-2004 04:59 PM:


quote:
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Originally posted by jt1stcav
I'm no expert, but I sometimes hear either my 5U4G or my 300B pair softly "tinging" or "tinkling" upon power up, and sometimes when powering down. I assume it's only the glass bottles expanding and contracting due to the tremendous change in temperature from cold to hot tubes and vise versa.
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Hi Jim, Its a popping that comes through the speakers when the amp is powered down. It is even happing when there is no pre amp hooked up.
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Flugelhorns Rule!



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Posted by ron-c on 09-14-2004 09:27 AM:

Popping through the speakers with a McIntosh tube amp is not normal. Sounds like time to install new caps...all of them and be done with it for the next 40 years.

Ron-C


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Posted by ronflugelguy on 09-14-2004 08:52 PM:

I Had most of them done two years ago. I think there were a few that were left. Just talked to my repir guy and he said it sounds like a cap.

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Posted by spkrman57 on 09-27-2004 02:08 PM:
are those caps fixed yet?

I have not heard that problem with my MC-240 or any others so far. but would like to know in case mine starts having probs.

When I bought mine, it worked in the store, took it home and nothing but faint music coming through.

End result, the cap following the voltage doubler had gone out.

Fixed and back in biz. Good thing is, where I bought it I was regular customer and they fixed it up. Not bad for "as-is", just my lucky day.

I hope yours is back good again real soon!!!

Ron


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Posted by ronflugelguy on 09-27-2004 04:40 PM:

Update: Now the popping has stopped the last five or so times I have shut it down. My tech says it may be a dirty tube socket.

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Flugelhorns Rule!



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Posted by ron-c on 09-27-2004 04:48 PM:

Clean the tube pins with a clean wire tooth brush. Most ace hardware stores have them. After the brush I use alcohol to finish.

Ron-C


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Posted by dewickt on 09-27-2004 05:19 PM:

Dirty tube pins respond well to a shot of DeOxit on the pins, in and out of socket several times, and dirty pin problems will vanish. Have done some really nasty pins this way with 100% results. Wire brushes like to shed and get into electronics, if you need to polish them use a scotch brite pad.

__________________
Terry
DeWick Repairs
www.mcintoshaudio.com



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Posted by ron-c on 09-27-2004 06:00 PM:

The brass bristle brushes work fine then clean the lose dirt off with alcohol and q-tips. The idea is to clean the pins without removing the nickle plate. Works for me.

Ron-C


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Posted by dewickt on 09-27-2004 06:20 PM:

Brass, SS, Fiber brushes, Brasso, Scotch Brite, DeOxit, heck any of them will clean the pins. Just don't think its a cap, the only ones that would give a pop are the voltage doublers or a dead main filter causing the B+ to drop like a rock on turn off (pop), any of these caps would result in poor output power or distortion.

__________________
Terry
DeWick Repairs
www.mcintoshaudio.com



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Posted by ronflugelguy on 10-02-2004 08:10 PM:


quote:
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Originally posted by dewickt
Brass, SS, Fiber brushes, Brasso, Scotch Brite, DeOxit, heck any of them will clean the pins. Just don't think its a cap, the only ones that would give a pop are the voltage doublers or a dead main filter causing the B+ to drop like a rock on turn off (pop), any of these caps would result in poor output power or distortion.
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Now its not popping. But I did tap on the tubes and nothing. Just keeping an eye on it!
__________________
Flugelhorns Rule!



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Posted by Jeffrey on 10-14-2004 12:34 PM:


quote:
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Originally posted by ronflugelguy
Carl. the way I have it set up, the amp is shut down first, then about a minute or two. the pre shuts down. (Monster cable powerline).
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Hi Ron,

Are ya using a Monster chasis unit? If so, i would strongly recommend moving your C-20 from a low to high current power outlet. Treat the pre-amp like an amp and give the baby some headroom. I believe the sound will improve and your popping problem may go away.

If that doesn't help, try plugging the 240 into the C-20 and thus only the C-20 into the Monster unit and power both up/down w/ your C-20.

Take care,
Jeffrey


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Posted by ronflugelguy on 10-14-2004 09:38 PM:

Still haven't had any problems since my tech told me to lightly tap on each tube in the 240. He said I should hear something if the pns or plugs are dirty. I did not, but did not hear the popping after that. But Ill try the setup on my power as you suggested.

__________________
Flugelhorns Rule!



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Posted by Jeffrey on 10-15-2004 05:17 AM:


quote:
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Originally posted by ronflugelguy
Still haven't had any problems since my tech told me to lightly tap on each tube in the 240. He said I should hear something if the pns or plugs are dirty. I did not, but did not hear the popping after that. But Ill try the setup on my power as you suggested.
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Hi Ron,

I'll be suprised if you don't prefer the sound of your C-20 w/ a higher power current regardless of whether or not it helps w/ your original concern.

As for your original concern..... when was the last time you had ALL the tubes in your 240 & C-20 tested???

Take care,
Jeffrey


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Posted by ronflugelguy on 10-15-2004 06:11 AM:

5 months on the C-20. Alot longer for the 340.

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Flugelhorns Rule!



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