Thursday, October 27, 2011

A Visit with the Yaqin MS-22B phono preamplifier

I first got into audio, way back in the mists of time, because of vacuum tubes. Thanks to hearing a friend's McIntosh MC240 and an old Dynaco PAS (both extensively modified), I heard music in such a way that forever changed the way I look at stereo equipment. Lately I've been dabbling in solid-state; trying to wring out whatever musicality I could from these silicon devices. And to a certain degree, really good SS gear can capture much of the magic of vacuum tube gear without the worry of tube life. However, vacuum tubes have a sheer musicality that is hard to replicate with solid-state. You can call it warmth, dimensionality, or liveliness - but there is something special about valves.

I've heard a number of positive reviews and experiences with the Yaqin MS-22B. This is a simple two-tube phonostage that uses a solid-state buffer. From the pictures, it looked impossibly well-made for only $179 shipped. I was curious enough to give this budget unit a chance, so I ordered one via Ebay. To my surprise, I had it in my hands in a week.

Pulling the Yaqin MS-22B out of the box, I was surprised by the heft. The metalwork also appears to be of a high quality, having lettering for the tube types, power switch and the RCA jacks. The stock tubes are Shuguang 12AX7Bs - known to be a little dark in their presentation - and are covered with twist-on metal shields. The input and output jacks, plus the ground lug are also very nice. The power transformer is mounted on top and is covered with a metal box that looks like a small toaster oven. I've built my own DIY phono preamplifiers, and I know from experience that building something like this from scratch would cost more than the Yaqin asking price.

Okay, how does it sound? Since I only have one turntable that uses a MM cartridge, I could only check out the Yaqin in my second system (listed below). Placing the 22-B on top of my Audio Research SP-7, I soon had the cables switched around. I then turned on the Yaqin, which emitted a nice blue glow through the front logo. Note - there was a nice thunk when powered on, so keep your volume control down when turning the 22-B on.

The first record on was Pete Townshend's classic Empty Glass. Through the Yaqin, the music had a nice bouncy rhythm, a surprisingly extended top-end (considering the Shuguang 12AX7Bs), deep bass, and a engaging character that made the record a joy to hear. I then went and cooked some dinner, leaving the Shuguang on to warm up further. After eating, my fellow audiophile friend came over. We listened to Frank Sinatra's Strangers in the Night and Neil Young's On the Beach, and concluded that the Yaqin MS-22B is one hell of a deal. At least in the confines of this budget system, we heard an extra dimensionality that the Audio Research did not have. The ARC SP-7 is definitely more neutral, detailed, and 'high-end', but the Yaqin was more engaging, musical, and just plain fun. At the price it is being sold, it is also a great bargain. For a budget system - highly recommended, but with some minor caveats.

What are my issues with this phono preamplifier? I did notice a bit of hum at higher volume settings, but this shouldn't be an issue unless you are running high-efficiency speakers or a lower output cartridge. I also found the bass to be a little plummy - perhaps this could be corrected with some tube rolling.

Second System:
Preamplifier: Audio Research SP-7
Amplifier: Audio Research D-52B
Analog: Dual CS-5000 turntable - Audio-Technica AT95E cartridge
Digital: Pioneer DVD-V7400
Speakers: KEF iQ30
Speaker Cable: Canare 4S11 Quadlink
Interconnects: Cardas Crosslink


Matt Bright said...

I recently purchased a MS-22B and am looking for some nice tubes to roll in it. I was wondering if you switched out the 12AX7s in the unit you had and what you would recommend? I'm leaning towards vintage/NOS

DividebyTube said...

no, didn't really have a big chance to do tons of tube rolling. However, my friend who borrowed the unit really liked vintage Mullards in there, along with just about any other NOS stuff.

Les Carpenter said...

I came by a MS22-B but found it totally lack luster, as also did my friends who made me turn it off after 10 minutes. I decided to rebuild it as documented here:-

The results are amazing and more and more people are making the changes.

To answer about 12AX7's, I have tried various but for sheer musicality it is Svetlana winged =C= that get top marks.

Micha Müller said...

Hello, Mr.Carpenter! First of all, please be patient with some of my mistakes (I am german and english in school is some days ago). I am very glad to find your modding documentation of the ms-12b and can't wait to reproduce on mine. I have changed my (2) tubes to these:
Maybe you know this shop.
When I will tune my amp I actually want to use the 3rd tube. Is it important to use the same type of tube like the other ones? I've only read fast the documentation fast this morning. But I've already checked, that my amp is the newer version. Are there any points in the document which are crossing each other, maybe because there was some time between, when you made the changes. I hope you understand what I mean. Is there any possibility to contact you in case of other questions? Are active in any uk forum? Till now I was only reading in german forum's, but not many people know this amp here. It's sold under another label in Germany. I think they do not make any changes, but don't know any details.

Sincerely Daniel

Les Carpenter said...

Hi Daniel, I have only just discovered your post! I have continually updated the pdf that deals with conversion. The latest change is to further increase the HT decoupling capacitors from 68uF to 100uF to prevent very low frequency pumping. This did not occur on any early hard wired prototypes that used much smaller values of decoupling. The problem could be circuit board layout or the effect of the close proximity of the power transformer. But the 100uF does the trick. Yes you can use the same valve for V3 but Psvane or Electro-Harmonix seem to work well too. Regards. Les

David Dennis said...

I have the updated MS-23B model, which appears to be mostly an upgrade / change to the front plate and adds a substructure over the tubes. I've spent a good chunk of this weekend doing some tube rolling, with the stock Shuguang, vintage Sylvania, and brand new Sovtek 12AX7LPS. No hum on my unit (don't know if I got lucky or if the upgrade helped), and swapping out the stock Shuguang tubes for any other gets rid of the turn-on thump (odd).