Yaqin MC 13S Modifications-another giantkiller!

I’m constantly amazed by the results of upgrading Yaqin amps of which I’ve now completed quite a few. I remember my nervousness upgrading the first one as the received wisdom was ‘Chinese transformers are no good’. Yaqin’s transformers are made in house and they claim, are made of Japanese steel.Whatever the ingredients the result is an amplifier that sounds very decent as standard but which can easily be improved with some simple upgrades.

Circuit wise the amp is a fairly standard ultra linear output stage with input and phase splitter. The upgrades this time were to add improved Mundorf coupling caps, to change the grid stopper resistors on the output valves and to add Elna Silmic bypass capacitors to the output valves.

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Once installed the amplifier performs at a new level. The light graininess of the sound disappears, vocals become more breathy, and bass and dynamics improve. All these improvements were heard with the stock Chinese valves and of course these too can be swapped for improved Western designs or NOS types.

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One thought on “Yaqin MC 13S Modifications-another giantkiller!

  1. Just collected my MC13S following David’s mods and I’m stunned! In addition to the mods described above David also fitted a feedback bypass switch and with the negative feedback switched off the resolution of this amp is incredible. I keep wanting to try another track to test the improvements but find myself having to hear the whole track before switching, which is not something that usually happens when I buy new kit. All in all I’m very pleased with these mods….

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