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Thread: Yaqin MS-12B valve preamp

  1. #1
    Join Date: Apr 2008

    Location: Cheltenham U.K

    Posts: 412
    I'm John.

    Default Yaqin MS-12B valve preamp

    I've just lost a longish post I was creating on this so I'll keep it short now and add more later.

    I read mostly favourable comments about the Yaqin MS-12B on the 'net so I've bought one. I thought that at the very least it would tide me over while the rat's nest on the floor that is my diy Jfet phono stage gets organised into a box.

    I bought it off eBay: http://cgi.ebay.co.uk/FreeShipping-Y...3A1%7C294%3A50

    I didn't want to wait for the free shipping via a slow boat from China so on top of the very cheap 129GBP asking price (can't find a pound sign on this laptop!) I paid an extra 25 for airmail. It arrived in just under 2 weeks, well packed, and extra charges at this end were just under 20 quid.

    The manufaturer's website is good for a laugh: http://www.yaqin.cn/en/company.html

    The circuit diag. is below but I haven't checked it so can't vouch for its accuracy. Yaqin loses a few points imo for having that emitter follower buffer after the phono stages.

    Ergonomically it's a bit odd as you can see, with phono inputs at the front and cd input plus outputs at the rear. It's pretty solidly built, and bigger than I imagined :- 35cm from front to back.

    Early listening impressions were favourable, though it sounded a bit rolled off at frequency extremes and the stage with phono input was a bit restricted in width and depth. After a day or so it began to emit intermittent whistling noises (on both inputs). One of the 12AU7 valves was extremely microphonic.
    More to follow later....
    Attached Images Attached Images

  2. #2
    Join Date: Apr 2008

    Location: Cheltenham U.K

    Posts: 412
    I'm John.

    Default

    My mistake here: I intended to post this in "Analogue Art".

  3. #3
    Join Date: Feb 2008

    Location: North East UK

    Posts: 6,358
    I'm InSpace.

    Default

    Moved.
    Shian7
    --------------------------------------------------------

    Kudakutemo
    kudakutemo

    ari mizu-no tsuki

    Though it be be broken -
    broken again - still it's there:
    the moon on the water.

    - Choshu.

  4. #4
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

    Default

    LOL! I moved it from Analogue Art because it belongs in Blank Canvas!

    Amp discussions don't go into Analogue Art (you should know that, Mikey), so back it goes where it belongs...

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


  5. #5
    Join Date: Apr 2008

    Location: Cheltenham U.K

    Posts: 412
    I'm John.

    Default

    Fine, feel free to continue your game of tennis with my thread, guys.
    Marco leads by 30 points to 15 in the first set....

    To continue: I had expected to be changing the valves when I bought it, so I put in a pair of Sylvania JAN 12AX7's, and Philips JAN 5963's instead of the 12AU7's.
    This improved the sound a lot, and virtually erased my previous criticisms to the point where I was pretty happy with it.

    After a day or so the odd whistling noise reappeared, so I took the bottom off (see pic) and soldered in some 1k grid stopper resistors at the 5963's. This was quite easy to do, by cutting the pcb tracks leading to the grids.
    While I was there I cleaned up the flux that was around. No more whistles to date.

    As you can see, getting access to the components would require quite a bit more dismantling, so it's not very tweak-friendly in that respect.
    It's clear that the large codpiece that is the mains transformer cover contains quite a lot of air!

    To summarise, if you want something that's definitely plug and play I would avoid it. However if you want something that can give great sound at a low price and you are up for a bit of valve rolling and fiddling, it's worth a punt imo.

    There's a guy in Bristol who runs a Yaqin information site and apparently offers repairs and servicing. I know nothing about him though. http://yaqin.slickpepper.org.uk/
    Attached Images Attached Images
    Last edited by jonners; 09-05-2009 at 08:21.

  6. #6
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

    Default

    Hi John,

    I had a Yaqin, albeit an MC-100B KT88 integrated amp design, so I know how good they are (or can be with some modding), so no doubt the MS-12B hits the spot too as a preamp.

    Yaqin are actually a high-end brand in China, therefore this is reflected in the quality of their designs.

    The only thing is their equipment is not safe for use with UK voltage (I know as my MC-100B blew a capacitor when it 'overheated'), so the use of a step-down mains transformer is an absolute must, or better still, upgrading to appropriate spec high quality transformers for UK voltage and caps with a higher reservoir capacity which can cope better with the demands of higher voltage.

    Some of the websites say that Yaqin equipment is suitable for 240V, but I can tell you from experience that this is bullshit!

    If you're using your preamp without a step-down transformer, I urge you to switch it off immediately and not use it again until you've done so, or had it converted for UK voltage, as if left on unattended IT COULD CAUSE A FIRE !!!

    Better safe than sorry...

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


  7. #7
    Join Date: Feb 2008

    Location: North East UK

    Posts: 6,358
    I'm InSpace.

    Default

    Quote Originally Posted by Marco View Post
    LOL! I moved it from Analogue Art because it belongs in Blank Canvas!

    Amp discussions don't go into Analogue Art (you should know that, Mikey), so back it goes where it belongs...

    Marco.
    Well, if you move stuff it might be helpful to say so... ya big haggis!

    'Blank Canvas' is a daft place for amps to be anyway, amps are an analogue device (mostly) but they could easily have their own area!

    TBH, anything could go in the blank canvas section, it's rather 'ill defined'!
    Shian7
    --------------------------------------------------------

    Kudakutemo
    kudakutemo

    ari mizu-no tsuki

    Though it be be broken -
    broken again - still it's there:
    the moon on the water.

    - Choshu.

  8. #8
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

    Default

    Please read:

    Blank Canvas

    General hi-fi discussion. Anything not covered in the categories below goes here.
    Have a look at the categories/rooms below 'Blank Canvas'. Are amps mentioned anywhere at all?

    No. Therefore.................!!

    'Analogue Art' is for T/Ts, phono stages, tonearms, cartridges, tape decks, etc, etc. It's not rocket science, ya wee zoomeroid

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


  9. #9
    Join Date: Feb 2008

    Location: North East UK

    Posts: 6,358
    I'm InSpace.

    Default

    Quote Originally Posted by Marco View Post
    Have a look at the categories/rooms below 'Blank Canvas'. Are amps mentioned anywhere at all?
    No, and they are an item that could easily warrant their own discussion area.... you patronising buffoon!

    Also!... I can't think of any situation where a phono stage would be used except in conjunction with a TT (which was the reason for the purchase of the Yaquin), so I would argue that the phono stage is a turntable ancillary anyway. So there!
    Last edited by Mike; 09-05-2009 at 10:13.
    Shian7
    --------------------------------------------------------

    Kudakutemo
    kudakutemo

    ari mizu-no tsuki

    Though it be be broken -
    broken again - still it's there:
    the moon on the water.

    - Choshu.

  10. #10
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

    Default

    No, and they are an item that could easily warrant their own discussion area....
    LOL. And create even more bloody rooms?

    Read 'Critics Corner' and you'll see that some of our members are complaining about there being too many, ya shilly wee shaushage

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


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