Hi all,
i always thought that my room acoustics affect the stereo imaging when listening to music (right speaker louder than left) until a friend popped in and said that something must be wrong with either the speakers or the amplifier.
After source,speaker,cabling etc swapping we found the problem is with the amplifier.
I fed the input source with 1Khz test tone and set the gain at 1V rms on the speaker outputs.
Left output reads 0.8V and right 1V (no speakers connected).
When i swap the speaker cables on the back of the amplifier the weak speaker sounds louder of course.
I checked everything (capacitors/resistors/bad joints,swapped power amplifier boards, sprayed the volume pot) - everything is ok, the amp is in mint condition.
I believe the problem is somewhere in the pre-amp stage( iruled out the power stage as i used the boards from the power amplifier that i also have and they are identical) or a faulty alps pot
I'm talking about a Roksan Kandy KA1-MK3 amplifier, Roksan asks £199 to repair it plus materials which i find it ridiculous and no way to get any schematics from them.
Find attached some photos and please help before i go crazy.
Thanks
Preamp
Power amp
Volume Pot
i always thought that my room acoustics affect the stereo imaging when listening to music (right speaker louder than left) until a friend popped in and said that something must be wrong with either the speakers or the amplifier.
After source,speaker,cabling etc swapping we found the problem is with the amplifier.
I fed the input source with 1Khz test tone and set the gain at 1V rms on the speaker outputs.
Left output reads 0.8V and right 1V (no speakers connected).
When i swap the speaker cables on the back of the amplifier the weak speaker sounds louder of course.
I checked everything (capacitors/resistors/bad joints,swapped power amplifier boards, sprayed the volume pot) - everything is ok, the amp is in mint condition.
I believe the problem is somewhere in the pre-amp stage( iruled out the power stage as i used the boards from the power amplifier that i also have and they are identical) or a faulty alps pot
I'm talking about a Roksan Kandy KA1-MK3 amplifier, Roksan asks £199 to repair it plus materials which i find it ridiculous and no way to get any schematics from them.
Find attached some photos and please help before i go crazy.
Thanks
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Preamp
An externally hosted image should be here but it was not working when we last tested it.
Power amp
An externally hosted image should be here but it was not working when we last tested it.
Volume Pot
An externally hosted image should be here but it was not working when we last tested it.
I have a carver M200 that is this way.
And sadly no volume pot to blame on it.
I've swapped drivers and pre drivers left to right and the problem does not change sides.
Anyway you may have a volume pot issue - hope it works for you.
Cool.
Srinath.
And sadly no volume pot to blame on it.
I've swapped drivers and pre drivers left to right and the problem does not change sides.
Anyway you may have a volume pot issue - hope it works for you.
Cool.
Srinath.
When i adjust the knob the 0.2V difference between the channels gets even higher, it doesn't remain the same at higher gain.
The 7805 voltage regulator gets hot (60C) but i reckon this is normal, otherwise i would have other issues wouldn't i?
The 7805 voltage regulator gets hot (60C) but i reckon this is normal, otherwise i would have other issues wouldn't i?
Btw, i'm currently feeding the power amplifier from my DAC.Did the same test and the output on both channels is 1V rms.It's like i got my hearing back,lol
Time to fix the integrated
Time to fix the integrated
DC Offset measured 4mV and 21mV.
Don't know how much to set the bias current but i used the power modules from the power amplifier and it didnt make any difference.
The bias and DC offset are measured the same on the integrated and the power amp.
No bad joints, cracks etc
Here is a photo of the power amp (i bought it for biamping):
Don't know how much to set the bias current but i used the power modules from the power amplifier and it didnt make any difference.
The bias and DC offset are measured the same on the integrated and the power amp.
No bad joints, cracks etc
Here is a photo of the power amp (i bought it for biamping):
An externally hosted image should be here but it was not working when we last tested it.
I thought you meant the power amp in the integrated. That would be where to start, bypass the pre amp
Transformer supply:
Left & Right Power modules supply
Left connector says nothing , Right one says Preamp L-R out, both terminated on the volume pot.
There is another cable from the preamp to the pot saying Speakers In if you see the photo with the amp layout
Left & Right Power modules supply
Left connector says nothing , Right one says Preamp L-R out, both terminated on the volume pot.
There is another cable from the preamp to the pot saying Speakers In if you see the photo with the amp layout
The reason I asked you if you used DeOxit to clean your volume pot is because most of the other cleaners dont work anywhere near as good and the volume pot is the first place to look if you have your problem. You should spray both parts of the pot and turn it back and forth about 20 times then try it!
Yes,both channels.Both wipers. I dont know how you can get the deoxit in there, you might have to take it apart?
How could Deoxit equalise a cheap pot?
It seems the imbalance is in the region of 2db, which is probably within specs.
It seems the imbalance is in the region of 2db, which is probably within specs.
Ya. Does relative level difference, say dB, between both channels stay the same?
- Status
- Not open for further replies.