Yaqin MS 12B phono amp- reviews - Page 5

awkwardbydesign · 2nd January 2012, 11:20 AM

I know this thread is a little old, but if anyone bypasses the output stage, the 1uF phono section caps look symmetrically mounted, but are not! That's why I only had output on one channel. Doh!

frapa02 · 14th February 2012, 01:39 PM

Actually, the output stage is the problem with this pre-amp. I concluded in the end that it was colouring the sound too much and would take too much to mod so I replaced my Yaqin with something more suitable. These are difficult to access and work on. The phono pre part is actually very good.

For the person who used 6N1P for the ECC83 / 12AX7 you should try a 6N2P as this has more gain which is needed in the first stages and will be more correctly biased with the fitted components as it is close to the 12AX7.

6N1P or 6N23P would be good in the output stage but would entail changing the heater wiring and the bias. Same goes for an ECC88 or 6DJ8.

Paul.

bobrown14 · 16th February 2012, 12:33 AM

Quote:

Originally Posted by awkwardbydesign

I know this thread is a little old, but if anyone bypasses the output stage, the 1uF phono section caps look symmetrically mounted, but are not! That's why I only had output on one channel. Doh!

I changed my 1uF output bypass caps and didn't have any issues with a dead channel. Currently not running this pre tho. My re-built Citation 17 sounds better with my CDs and a DIY pono preamp.

Cheers,
Bob

migkiller1971 · 16th February 2012, 03:15 PM

Quote:

Originally Posted by awkwardbydesign

I know this thread is a little old, but if anyone bypasses the output stage, the 1uF phono section caps look symmetrically mounted, but are not! That's why I only had output on one channel. Doh!

Everyone that owns this Yaqin should take a look at the Volume pot. Mine went bad and killed a channel. There is no sense in upgrading the Caps if you got it going thru a 2 dollar volume pot.

bobrown14 · 17th February 2012, 12:20 AM

Quote:

Originally Posted by migkiller1971

Everyone that owns this Yaqin should take a look at the Volume pot. Mine went bad and killed a channel. There is no sense in upgrading the Caps if you got it going thru a 2 dollar volume pot.

What did you use for a replacement?

Cheers,
Bob

migkiller1971 · 29th February 2012, 05:52 PM

Quote:

Originally Posted by bobrown14

What did you use for a replacement?

Cheers,
Bob

A Japanese Alps Volume Pot.

bobrown14 · 29th February 2012, 11:14 PM

Quote:

Originally Posted by migkiller1971

A Japanese Alps Volume Pot.

Linkey??

Cheers,
Bob

morme · 14th April 2012, 06:15 PM

can you please let me know how to do this? did you run the 2 tubes in series off one supply?

any pix of the mod?

Thanks

Quote:

Originally Posted by jonners

I wasn't happy with the 12AX7s, and I'm now happily using Soviet 6N1P tubes. Very cheap, reliable and sound good. But that involved a change in the heater wiring because of the 6.3 volt heaters.

hunsoop · 3rd May 2012, 02:21 AM

Quote:

Originally Posted by frapa02

Actually, the output stage is the problem with this pre-amp. I concluded in the end that it was colouring the sound too much and would take too much to mod so I replaced my Yaqin with something more suitable. These are difficult to access and work on. The phono pre part is actually very good.

For the person who used 6N1P for the ECC83 / 12AX7 you should try a 6N2P as this has more gain which is needed in the first stages and will be more correctly biased with the fitted components as it is close to the 12AX7.

6N1P or 6N23P would be good in the output stage but would entail changing the heater wiring and the bias. Same goes for an ECC88 or 6DJ8.

Paul.

I have ms 12b and like to mod like others...
you mean i need to add one more transformer?

Rolli666 · 13th May 2012, 06:45 PM

Anyone know if a 22r 5w will work ok in the place of the 15r 7watt

13th May 2012, 06:45 PM	#50
Rolli666 diyAudio Member Join Date: Oct 2011	22R 5w Anyone know if a 22r 5w will work ok in the place of the 15r 7watt

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2nd January 2012, 11:20 AM	#41
awkwardbydesign diyAudio Member Join Date: Dec 2005 Location: Plymouth, England	I know this thread is a little old, but if anyone bypasses the output stage, the 1uF phono section caps look symmetrically mounted, but are not! That's why I only had output on one channel. Doh!

14th February 2012, 01:39 PM	#42
frapa02 diyAudio Member Join Date: May 2009 Location: Berkshire, UK	Actually, the output stage is the problem with this pre-amp. I concluded in the end that it was colouring the sound too much and would take too much to mod so I replaced my Yaqin with something more suitable. These are difficult to access and work on. The phono pre part is actually very good. For the person who used 6N1P for the ECC83 / 12AX7 you should try a 6N2P as this has more gain which is needed in the first stages and will be more correctly biased with the fitted components as it is close to the 12AX7. 6N1P or 6N23P would be good in the output stage but would entail changing the heater wiring and the bias. Same goes for an ECC88 or 6DJ8. Paul.