Yaqin MS 12B phono amp- reviews - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 18th April 2010, 05:52 AM   #1
diyAudio Member
 
Join Date: Apr 2006
Location: Goulburn NSW
Default Yaqin MS 12B phono amp- reviews

I am looking for a valve phono pre-amp as a starting point for my system, does anyone have any experience or feedback on the Yaqin MS-12B MC/MM phono amp, the price is certainly right and it looks good enough but how does it sound?

I am happy to mod it so I can accept some shortcomings if the base unit is good enough.
  Reply With Quote
Old 23rd April 2010, 10:38 PM   #2
frapa02 is offline frapa02  United Kingdom
diyAudio Member
 
Join Date: May 2009
Location: Berkshire, UK
I recently acquired one of these and after some minor work I can say that it does sound very good, especially for the cost (paid £100 plus cost of my mods.)
Basically, you have to check the 12AU7 heater voltage first - this was a serious issue and could ruin some expensive valves. This was alarmingly high at 15.4V here in the UK with 240V mains on a 220V unit. These heaters are fed via a resistor from the unreg supply and I think the resistor was incorrect, even for 220V mains. It was 15R and I replaced with a 22R and the voltage is now much better at 12.90V, with 240V mains. This also cured a small hum problem and some very hot valves! A better option would be to fit another regulator but it was a bit tight.
Next, I replaced the 1uF coupling caps with ICEL 1.0uF 10% 400VDC. These are very cheap but seem to have a very natural sound, although they won't appeal to those who swear by PIOs! Well at least they fit.
Finally, the output coupling caps, also 1uF, were replaced with ICEL 4.7uF 10% 400V. This improved the bass extension when driving solid state amplifiers.
The simple mods made the MS-12B sound like it would challenge a much more expensive unit. So far, the stock Chinese valves have been used and they do improve a lot with use. I will try some more refined ones next.
Another comment, I am beginning to love this as a pre-amp buffer from my home brew DAC. It improves the dynamics and everything sounds more solid. I am not sure why yet.
The only problem I can report is that it takes a while to strip and re-build the unit to work on it.
Paul.
  Reply With Quote
Old 10th November 2010, 12:45 PM   #3
diyAudio Member
 
Join Date: Jun 2010
Location: Virginia..GO ARMY!!
Default Yaqin MS 12 B Mod

Can someone please tell me where the 15R is so I can replace it with a 22R. I don't have the schematics for it. I' pretty handy with a soldering iron. My 12AU7 can get pretty hot at times. This is what I've done so Far.


http://www.expo29.com/audio/yaqin/ms12b/_DS26556.jpg

Thanks in advance!!!

Cheers!
  Reply With Quote
Old 10th November 2010, 07:09 PM   #4
diyAudio Member
 
Join Date: Nov 2004
Location: Bruchsal/Germany
its on the left handside down , near the regulator ,
7 or 1 W , 15 Omega for Ohms .

Greetings from Germany
Juergen
  Reply With Quote
Old 10th November 2010, 10:59 PM   #5
diyAudio Member
 
Join Date: Jun 2010
Location: Virginia..GO ARMY!!
Quote:
Originally Posted by audiotux View Post
its on the left handside down , near the regulator ,
7 or 1 W , 15 Omega for Ohms .

Greetings from Germany
Juergen

Thank you so much Juergen! I lived in Heidelberg, Germany for 12 years and both my sons were born there. It's about gluhwein time!!!
  Reply With Quote
Old 11th November 2010, 12:04 AM   #6
diyAudio Member
 
Join Date: Nov 2004
Location: Bruchsal/Germany
yes Migkiller its Gluehwein-Time !
and all the Christmas Things like Lebkuchen , Dominosteine and so on.
For Tube-Freaks glowing (glueh) is always nice .

Enjoy the _glowing_!
Juergen
  Reply With Quote
Old 11th November 2010, 02:17 AM   #7
diyAudio Member
 
Join Date: Jun 2010
Location: Virginia..GO ARMY!!
Now I have to find out what kind of resistor is best. I know its a 22R, Why can we make our "7" with the line across it? Cheers!
  Reply With Quote
Old 11th November 2010, 01:13 PM   #8
diyAudio Member
 
Join Date: Nov 2004
Location: Bruchsal/Germany
the 7 meens 7 Watt , you can buy a 22R - 7 Watt Resistor
on your local electronic supplier /shop , ask the man behind
the desk .

Juergen
  Reply With Quote
Old 12th November 2010, 08:31 PM   #9
diyAudio Member
 
Join Date: Jun 2010
Location: Virginia..GO ARMY!!
Quote:
Originally Posted by audiotux View Post
the 7 meens 7 Watt , you can buy a 22R - 7 Watt Resistor
on your local electronic supplier /shop , ask the man behind
the desk .

Juergen

Hi Juergen,

Yes, I know its watts but I'm going to have to open it up again to see if its 7 watt or 1 watt. I can't tell from the photo. Also what kind of Resistor? Wirewound? Carbon Film? I'm Learning alot or re-learning. Alot of Fun... Unfortunately, I don't have a local Electronic supplier. Cheers!
  Reply With Quote
Old 13th November 2010, 07:04 PM   #10
diyAudio Member
 
Join Date: Nov 2004
Location: Bruchsal/Germany
Hi Migkiller ,

for example , a simple Metalloxidschichtwiderstand from Mundorf
MR10 , 22R 2% 10 Watt ca. 1,60€ is okay .
You can see that Resistor on www.schuro.de .
So ask at a lokal Shop in your aera for a 10 Watt Resistor and the
job is done !

Jürgen
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yaqin MS-300B SET amp Rodango Tubes / Valves 18 26th November 2010 08:09 AM
Help - MS-6V6 Yaqin schematic wfmali Tubes / Valves 5 6th April 2010 07:55 PM
Yaqin Valve Amplifier UK Sales & Service marktravuk Vendor's Bazaar 3 16th November 2007 04:55 AM
Research Project: Need your op-amp reviews! zagisrule! Chip Amps 5 2nd May 2007 06:33 PM
Tube power Amp matching with SAE Mark M pre amp and AR18 speaker or MS 25i soultribe Tubes / Valves 1 13th August 2006 11:08 AM


New To Site? Need Help?

All times are GMT. The time now is 09:06 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2