Hello,
When I first purchased my Yaqin MC-10T a few years ago I remember there being a pretty comprehensive guide hosted on a website somewhere detailing the upgrades that are most beneficial for the amp's sound. I'm thinking of performing some upgrades to the amp but can't find this guide anymore.
From memory the guide was specifically for the MC-10T and outlined a volume pot upgrade as well as a bunch of other modifications that would improve the amp's overall sound. Interestingly and IIRC the person who wrote the guide also did not like the blue back-lit "Yaqin" logo on the amp's front plate, calling it "cheap looking" and hence went about changing it.
If anyone can remember this guide and post a link to it that would be greatly appreciated. If it doesn't exist anymore can someone at least point me in the right direction for upgrading my MC-10T.
Thanks.
When I first purchased my Yaqin MC-10T a few years ago I remember there being a pretty comprehensive guide hosted on a website somewhere detailing the upgrades that are most beneficial for the amp's sound. I'm thinking of performing some upgrades to the amp but can't find this guide anymore.
From memory the guide was specifically for the MC-10T and outlined a volume pot upgrade as well as a bunch of other modifications that would improve the amp's overall sound. Interestingly and IIRC the person who wrote the guide also did not like the blue back-lit "Yaqin" logo on the amp's front plate, calling it "cheap looking" and hence went about changing it.
If anyone can remember this guide and post a link to it that would be greatly appreciated. If it doesn't exist anymore can someone at least point me in the right direction for upgrading my MC-10T.
Thanks.
I remember this manual - it was for the 10L, which uses 6N1P tubes instead of the later 12AT7.
I believe this is the link you are looking for:
http://195.84.101.101/~goranl/projects/nad_stereo/yaqin_mc10l/yaqin_mc10l_service_manual.pdf
6th Street is my blog. My "upgrades" for the Yaqin weren't extensive beyond a cap replace and a retube job. I really disliked the layout of this amp so I didn't do much to it since it was a real pain to work with.
I believe this is the link you are looking for:
http://195.84.101.101/~goranl/projects/nad_stereo/yaqin_mc10l/yaqin_mc10l_service_manual.pdf
6th Street is my blog. My "upgrades" for the Yaqin weren't extensive beyond a cap replace and a retube job. I really disliked the layout of this amp so I didn't do much to it since it was a real pain to work with.
The first thing to do in the case of any Chinese amplifier is to get some proper measurements. You will want to find 1%, 5%, and 10% THD at 1Khz into an 8 ohm resistor, then look at bandwidth at those power levels.
This is really important because a lot of "50-100W" Chinese amps are making a lot less than 20W. If yours is among them, the first thing you will want to address is what's limiting the output power (most often the output transformers).
This is really important because a lot of "50-100W" Chinese amps are making a lot less than 20W. If yours is among them, the first thing you will want to address is what's limiting the output power (most often the output transformers).
Thanks for the replies.
The only reason I am keen on upgrading the amp somewhat is because I'm thinkning I'll have to open it. I have owned this amp for a few years now but as of the last few months the valve in V3 starts to squeal after an hour's worth of play time.
It looks as if the valve is glowing a little brighter than the others. It's not red plating but it is a little brighter. I have checked and rechecked the bias accross all valves and they are within spec.
Currently I have some KT77's in there, but have tried some Tung-Sol's as well as the original Chinese tubes and the same thing happens.
Does anyone know what may be going on here?
I'm pretty bummed about it because I really enjoy this amp in my setup. I'm not overly savvy when it comes to this stuff and it's my first venture into valve technology so I'm going to take it into a reputable shop to get looked at and possibly modded. Just would like some opinions before I do.
Thanks.
The only reason I am keen on upgrading the amp somewhat is because I'm thinkning I'll have to open it. I have owned this amp for a few years now but as of the last few months the valve in V3 starts to squeal after an hour's worth of play time.
It looks as if the valve is glowing a little brighter than the others. It's not red plating but it is a little brighter. I have checked and rechecked the bias accross all valves and they are within spec.
Currently I have some KT77's in there, but have tried some Tung-Sol's as well as the original Chinese tubes and the same thing happens.
Does anyone know what may be going on here?
I'm pretty bummed about it because I really enjoy this amp in my setup. I'm not overly savvy when it comes to this stuff and it's my first venture into valve technology so I'm going to take it into a reputable shop to get looked at and possibly modded. Just would like some opinions before I do.
Thanks.
A more exposed cathode (in the tube center-line) will appear to glow brighter, especially when they are side by side in a PP amp. Is that what you are seeing?
jeff
You could have a stability problem. This will be discovered when you have the amp hooked up to proper measuring equipment.
Possibly. The squealing coming from the tube has me a bit more worried though, and it happens regardless of what tube I put in there, same make or otherwise. That's why I want to get it checked out.
I'll take it somewhere to get looked at and have some tests done.
Thanks for all the info. Cheers.
Try check the bias "after" the squeal has started for a few minutes. Mute the volume and quickly take the measurements. Compare the before and after bias voltages. This might give some ideas of what is going on.
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