You only need to pull V2 if it is the left channel you have problems with. If the hum goes the problem is probably in the pre-amp. If it is still there then maybe you have a problem in the output stage or the coupling.
Ok, the hum is still there, so what next Les ?
What are the bias voltages on the two left channel EL34's? They should be more or less the same at around 0.35V as measured across the 10 Ohm bias measuring points.
Ohhh... so that's all it was lol. I didn't touch the bias... Yep on that side I got readings of 0.08 and 0.67. So now the fun of putting the new caps back in
Thanks Les
Pot is 20k. You should be able to find the schematic with a Google search. If you can't find it send me a PM.
You may find this interesting:
http://homepage.ntlworld.com/lez/YAQIN MC10/A LOOK AT THE YAQIN MC10L.pdf
You may find this interesting:
http://homepage.ntlworld.com/lez/YAQIN MC10/A LOOK AT THE YAQIN MC10L.pdf
At your service.
Usefull link: http://www.cathedralspeakers.com/yaqin
An externally hosted image should be here but it was not working when we last tested it.
Usefull link: http://www.cathedralspeakers.com/yaqin
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At your service.
An externally hosted image should be here but it was not working when we last tested it.
Usefull link: MODIFYING THE YAQIN MC-10L
dank je wel !
hum on right channel speaker
Newbie in tubes here>>
This is great thread and forum for Yaqin MC10-L. I have a unit that is about 3 months old and IT DEVELOPED A HUM ON THE RIGHT CHANNEL. I can still hear the music but the hum is there..i checked the bias on V2 and it was 0.06v)
i contacted the seller for help and was told to do the ff:
Move V1 to V2 socket and if there is bias the problem was V2 (EL34).
my questions:
1.is this check enough to isolate that the issue was V2 (l34)? I ordered new ones and on the way..from CAnada..
2. When i put V1 to V2 how long do i have to wait to make a reading? seller says within 3 minutes? is this right?
thanks in advance!!!
Audio0412
Newbie in tubes here>>
This is great thread and forum for Yaqin MC10-L. I have a unit that is about 3 months old and IT DEVELOPED A HUM ON THE RIGHT CHANNEL. I can still hear the music but the hum is there..i checked the bias on V2 and it was 0.06v)
i contacted the seller for help and was told to do the ff:
Move V1 to V2 socket and if there is bias the problem was V2 (EL34).
my questions:
1.is this check enough to isolate that the issue was V2 (l34)? I ordered new ones and on the way..from CAnada..
2. When i put V1 to V2 how long do i have to wait to make a reading? seller says within 3 minutes? is this right?
thanks in advance!!!
Audio0412
Wow, there's a lot of work to do. Do they really have 130V cathode to heater for the 6N1? Unbalanced phase splitter? A quasi-SRPP (badly unbalanced) input stage?
Wow.
They probably believe in "Euphonic distortions". Speaking of 130V cathode to heater, I never had any issue with such voltages.
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Wow, there's a lot of work to do. Do they really have 130V cathode to heater for the 6N1? Unbalanced phase splitter? A quasi-SRPP (badly unbalanced) input stage?
Wow.
What's wrong with the phase splitter?
I was going to say that the apparently "unbalanced" phase splitter was an attempt to correct for the lack of a CCS tail, but then I noticed that the anode resistors were the wrong way round so they increase imbalance rather than correcting it. Either a mistake or an attempt at 'euphonic' distortion.SY said:Unbalanced phase splitter? A quasi-SRPP (badly unbalanced) input stage?
The "quasi-SRPP" looks like the designer could not decide whether to do a proper SRPP or a proper mu follower, so just left it as an unbalanced SRPP - which will be worse than either of them! Given the relatively high impedance load a simple active load stage would be just as good, but Chinese designers do like the SRPP and audio buyers seem to like it too.
The output grid resistors are quite low in value so will load the LTP and increase distortion. Maybe low values are needed to cope with gassy Chinese valves?
Recently had a Krell amp here, the Krell won*, just, by its articulate upper bass. Then I upgraded the caps in the 10L, made a staggering difference. Now prefer the 10L any day.
*My speakers are an easy load to drive, so the Krell would have come into its own with different speakers
*My speakers are an easy load to drive, so the Krell would have come into its own with different speakers
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