kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 2, 2013 8:14:29 GMT
Good day everyone! Best wishes for New Year. My friend from England sold to me MF X-can v2. Standard, no modded, with standard power supply and Philips tube inside. After I received my amp, I got a big problem - always very loud. Very painful to the ears - volume control don't work. My friend suggested, that I open the amplifier and check the contacts tube. I hardly pulled out a volume knob and check tube. I assembled amplifier, hardly returned the volume knob back and tried amp again. After this I first heard my amp and I got a few problems: 1. Permanent white noise in left chanel. If I turn the volume, noise becomes louder. It's just background noise. 2. Volume control continued work poorly. Any time, the following could happen: - sound could deafen (right or left channel at the amplifier request ) - sound could disbalance (left channel louder) - sound could independently disbalance (louder on the left) and independently return to the normal balance back. 3. If I touch volume control, I hear "phono sound" maybe like this: rockgrotto.proboards.com/index.cgi?board=q&action=display&thread=6952I think, volume control is died, becouse I made a very simple improvement (see picture). Now volume control work, but it's not for long time. Can help me anybody? What's the problem? |
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 2, 2013 8:20:28 GMT
This is rubber band
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Jan 2, 2013 12:33:56 GMT
Hi Kirill,
I wonder whether your V2 has taken a bashing in the post?
You're not close to UK, I guess so I'm not sure whether Mike could take it on for you. He works real wonders on the X-Cans but I have a feeling that you're quite a distance away.
It's difficult to understand exactly what is going on from your English. It sounds as though it's making a lot of background noise (which could be the tube) and the volume pot isn't working correctly.
I'm very curious as to what the elastic band is doing!!
It might be an idea to open it up and take a pic of the insides.
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Post by dicky on Jan 2, 2013 12:53:25 GMT
I imagine the pot has a dodgy connection and the elastic band is pulling against the pot and making the connection?
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 2, 2013 13:06:48 GMT
Rabbit,
It is true - all time I hear background noise in left chanel.
It is true - the volume control device is broken.
Rabbit, I will try to explain again. What areyou interested?
Now I can change the volume only with a elastic band.
I think I need to change the volume control. It is correct?
dicky, yes!
elastic band allows connect electrical circuits inside the broken volume control device.
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Post by dicky on Jan 2, 2013 13:48:42 GMT
Kirill, change that pot but be careful - it is very easy to damage the pads on the PCB in these units. PM Mike - he sells these pots for £2 (or an Alps pot for £7). You might find that the noise problem goes away when the new pot is fitted.  |
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Post by pcourtney1 on Jan 2, 2013 14:18:13 GMT
Hi Kirill ( and a big welcome to you on RG )
>It is true - all the time I hear background noise in left channel
can you swap/change the tubes around inside the X-Can, does the noise now change to the right channel ?
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 2, 2013 15:52:52 GMT
dicky,
you wrote an interesting information. How to make the order for the replacement of the parts?
(sorry, the "pot" = "volume control unit"?)
pcourtney1,
I'll do it tonight
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Post by dicky on Jan 2, 2013 18:46:05 GMT
Hi Kirill, just look for any post in any thread by PinkFloyd. He is the owner of this forum and also sells components and repairs/modifies equipment. Just PM him a message and let him know you need a pot - volume control. He'll send you his PayPal details - simples!
There is a 'shop' in the main Rock Grotto website where you can see all the bits and bobs that you can buy to repair or upgrade your V2.
I hope that helps.
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Post by PinkFloyd on Jan 2, 2013 20:03:11 GMT
Hi and welcome to the forum.
There's probably nothing wrong with the pot, it sounds more like a connection problem somewhere.
Take the boards out of the enclosure and carefully inspect the solder pads that are connected to the pot (volume control) you may either have a dry joint or a pad / track break.
Gently rock the pot (volume control) back and forth with your finget whilst examining the solder pads on the bottom of the board..... can you see any movement?
If any of the pads have seperated company with the track then you will have to repair them.... basically scrape the green coating off the track to expose the copper underneath and then flood solder onto the track / pad..... these pad / track breakages are hairline and usually invisible to the naked eye.
That pot is not attached to the enclosure with a securing nut so any knock or bump could cause the pot to part company with one or more pads....
Anyhoo........ that's the area to look at if you suspect the pot, not the pot itself but the solder joints that are securing the pot.
Hope this helps.
Mike.
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 3, 2013 6:01:11 GMT
can you swap/change the tubes around inside the X-Can, does the noise now change to the right channel ? yesterday I swap tube around. Noise also change to right channel. What does it mean? |
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 3, 2013 7:36:47 GMT
Hi and welcome to the forum. thank you for the invitation, Mike ) Take the boards out of the enclosure and carefully inspect the solder pads that are connected to the pot (volume control) you may either have a dry joint or a pad / track break. If any of the pads have seperated company with the track then you will have to repair them.... basically scrape the green coating off the track to expose the copper underneath and then flood solder onto the track / pad..... these pad / track breakages are hairline and usually invisible to the naked eye. Yesterday I looked the pot on all sides. All solder pads without damage. No break, no corrosion, soldering was made excellent. I need re-soldering pads, which connect the pod? That pot is not attached to the enclosure with a securing nut so any knock or bump could cause the pot to part company with one or more pads.... My english friend says that amp worked excellent. And he use "bomb-proof" package - he perfectly packed amp. Nobody could strike/bump pot during shipment. Only one moment: I could even more damage the pot during dismantling the amp. that's the area to look at if you suspect the pot, not the pot itself but the solder joints that are securing the pot. Maybe, Mike. But why pot does not work without elastic bandage? I think, inside pot shaft has no electrical contact without forced bias. Is it possible? |
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Post by dicky on Jan 3, 2013 7:49:28 GMT
yesterday I swap tube around. Noise also change to right channel. What does it mean? it means that the tube is worn out or degraded and probably should be replaced |
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 3, 2013 8:32:23 GMT
dicky
OK, I also think that it is must be done.
Please, tell me about stand-by mode: should I turn off the amp from the AC outlet if it unuses a long time (more 5 hours)?
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 4, 2013 7:04:56 GMT
Good day everyone! Yesterday I had an important experience for tube replacement. I get 2x 6H23P '67 release (only 12GBP for both)  Now I hear the silence! Also, sound became more rich in LF-range. But, I still can't listen to without elastic bandage (( One photo. My serviceman say, that he see the problem soldering.  So it should be? |
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Post by PinkFloyd on Jan 4, 2013 11:19:08 GMT
I can't see the picture, can you try again?
Mike.
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Post by pcourtney1 on Jan 4, 2013 12:01:18 GMT
very nice valves Kirill, your are lucky to be in St Petersburg www.rock-grotto.co.uk/valvetest.htmI hope the pot ( volume knob ) is just a little bit of soldering :-) what heaphones do you use ? what impedance are they ? |
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 4, 2013 12:04:05 GMT
I can't see the picture, can you try again? Mike. Mike, see please again. |
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Post by pcourtney1 on Jan 4, 2013 12:10:02 GMT
dickytell me about stand-by mode: should I turn off the amp from the AC outlet if it unused a long time (more 5 hours)? some people leave amp on all the time, I have seen X-Cans where the amp has been left turned on for 10 years and the PCB has become black in places of the PCB, a bit of cleaning and replacing the caps ( or using one of Mike's kits bring it back to better than new again ) |
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 4, 2013 12:22:21 GMT
very nice valves Kirill, your are lucky to be in St Petersburg I hope the pot ( volume knob ) is just a little bit of soldering :-) what heaphones do you use ? what impedance are they ? - maybe it is "6N23P-EB"? My seller say, that it is military grade tube. also look - www.preobraz.ru/?z=grey&i=43&p=212&id=44313
It is old and modern 6N23P-EB
in russian, they wrote: ('70, '80 and '90) by 8GBP for one.
www.preobraz.ru/?z=grey&i=43&p=212&id=44312
It is modern 6N23P ('90) by 5GBP for one.
laconiclab.ru/6n23p.html
It is modern 6N23P by 2.5GBP for one.
Do you want international busines with me?  About heaphones.I use Sennheiser HD 265 (Irish-made ) They are 150 Ohm impedance. |
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Post by PinkFloyd on Jan 4, 2013 12:26:25 GMT
These need resoldered and is just what I said the problem would be! flow some solder into those joints and it will be perfect  All the best, Mike. |
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 4, 2013 12:43:40 GMT
some people leave amp on all the time, I have seen X-Cans where the amp has been left turned on for 10 years and the PCB has become black in places of the PCB, a bit of cleaning and replacing the caps ( or using one of Mike's kits bring it back to better than new again ) It is not about me ) other people turn on the amp only to listen to music and then turn off when they are finished, and you save some money by doing this Now I'm doing so. but all my gear goes through a quality double sine wave UPS ( which stays on all the time) I use for my HiFi APC Back-UPS 400 (Schuko outlet onboard). |
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 4, 2013 12:50:11 GMT
What do you think, this could happen during the delivery?
The package was excellent! Full cover box of bubble wrap and in the middle - X-CAN.... I could hardly find PSU!
Cover box without damage
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Post by PinkFloyd on Jan 4, 2013 12:56:46 GMT
What do you think, this could happen during the delivery? The package was excellent! Full cover box of bubble wrap and in the middle - X-CAN.... I could hardly find PSU! Cover box without damage No, This has probably happened over time, the solder joins have come apart causing an intermittent connection.... get a hot soldering iron and reflow a small bit of solder into the joints, it will be as good as new... no need for a new potentiometer  Mike. |
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kirill
<100
fan of the English sound
Posts: 14
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Post by kirill on Jan 4, 2013 13:00:16 GMT
Thanks for answer, Mike! I soldered in the nearest future. I think, I buy Alps later ) Alps is  |
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