I've been interested in getting a tube amp for some time, but the prices of these things, starting at $1,000 plus, are a bit daunting. However, I ran into several references in forums on the Net in recent months about some Chinese built audiophile amps that are apparently quite good and affordably priced.
So, after some research, and running into a Yaqin MC-10L for sale on ebay from a Canadian seller, I decided to take the plunge. The cost was about $480 with shipping. You can see the manufacturer's site, obviously translated through some kind of software that puts the word "gallbladder" in their product descriptions, here.
The Yaqin MC-10L, according to my friend Stuart who's an electronics and audiophile guru, is a very simple design that's quite similar to the Dynaco ST70, a classic audiophile tube amp sold from the 1950s into the 1970s. Output power is about 52 watts (at 8 ohms) per channel using four EL-34-B tubes for the power amplification stage and four 6N1's, a common Russian/Chinese tube, for the preamp section. (There are speaker connectors on the back to run it at 4 or 8 ohms.)
The amp has four line level inputs, a power switch and a volume control and that's about it. It's an "open top" design, so you can let the heat dissipate and have easy access to adjust bias for the tubes. The MC-10L has been offered by Yaqin for a few years and has been through two or three different versions that involved minor tweaks and cosmetic changes.
Before getting the Yaqin tube amp, I was using a Yamaha Natural Sound home theater amp for my system (HTR-5480) that I paid about $700 for when I bought it six or seven years ago. I liked this amp and Stuart thought it was pretty good for a mid-range priced consumer unit.
I'm using a pair of Monsoon FPF-1000 flat planar speakers (running at 4 ohms) and, for the purposes of testing the amp out of the box, a Stanton STR8-150 turntable with a Trackmaster V-3 cartridge. Later, when I have more time to rejigger everything, I'll be running a Denon DP-47F with a moving coil cart on the system.
Overall, I'm very pleased - it's a major upgrade in sound from my solid state amp and the build quality of the MC-10L looks quite good. For the price I paid, it's really a bargain - you're getting some seriously good sound for not much money and makes a great entry tube amp with plenty of power for many listening situations.
Here's some test listening using some sources I'm familiar with and a few random notes.
Jazz Meets the Bossa Nova
Paul Winter Sextette
original Columbia stereo pressing
A mid-1960s Columbia stereo lp, this is one I enjoy because it's really well recorded and mastered. I could really hear a better sense of a sound stage and better stereo separation. Also, there's some type of low frequency percussion instrument they use that's kind of buried when I've listened to it before; it's very clear with the new amp.
Borodin - Complete Orchestral Music
Loris Tjeknavorian, National Philharmonic Orchestra
original RCA pressing (promo copy)
A kind of mundane RCA release from the 1970s. Typical of RCA releases of the period, the sound isn't very dynamic and sounds compressed, but it did improve with the tube amp. I could pick out some horns and other instrumentation that weren't as clear before. Overall, it makes this lp sound a little richer and warm.
original Capitol pressing
Really nice stereo separation on this recording. The tube amp lets you hear some of of the electronic "noise" with more clarity - some of it actually sounds harsher and sharper. I could even hear slight hiss from the master tapes on this one that wasn't readily apparent on the Yamaha amp.
original 1970s UK pressing
This is an album I'm really familiar with and the tube amp really shines with this lp. Compared to my solid state amp, it's like some layers of curtains are removed and you can hear much more detail of the mix, especially in passages where the music is dense with strong bass, drums and guitars. The bass and drums themselves are very defined; the hiss of cymbals and snares have more clarity and "bite". On "I'm So Tired", the amp revealed some distortion "fuzz" on John's guitar amp I'd never noticed before in the opening bars of the song and you could begin to hear some of the ambiance of the studio where the recording was done. Again, I could hear the slight hiss of the master tape that wasn't as apparent on the solid state amp unless you cranked it up a bit.
XM Satellite Radio
I was actually surprised at how good and how bad sat radio sounded on the amp. Satellite radio channels are digitally compressed, so the amp allows you to hear more of the compression artifacts in some cases. However, overall, the music is much cleaner - I was surprised with the clarity of some low frequency percussion and strings in one piece on the Classical channel. The amp really shines on XM's 40's channel - it reproduces brass and reeds really nicely from early hi-fi big band and vocalist recordings of the period. On the Classic Radio channel, which plays old radio shows from the 30's and 40's, the amp revealed how much the channel is compressed and full of artifacts. (I restore old radio shows, similar to ones they play on this channel, and I know how good they can sound when reproduced correctly.)
- Overall, the sound is really flat and accurate - a bass really sounds like a bass instrument and the highs are really crisp and clear. The Yamaha sounded less accurate with highs and the bass was muddier and a little tubby. The tube amp has a flatter overall response - the Yamaha was a bit bass heavy.
- The tube amp gives a better sense of a soundstage and instruments playing in a space; the solid state amp is a bit more of a "wall of sound".
- This amp is rated at 52 watts per channel. However, it produces almost the same volume as the Yamaha amp, which specs at 100 watts per channel.
- It runs warm, but not as hot as I thought it might. (Again, it's my first tube amp, if you don't count some antique radios or a wire recorder I've owned.) After turning it on, the sound comes in and is stable after only a few seconds.
- Packed really well - the foam fits around the amp and there are slots underneath it for the tubes, which are in projective jackets. The power cord and hex screwdriver for adjusting the bias are underneath the bottom layer of foam in their own slots.
- Really solid construction - it weighs forty pounds - with really good quality switches, pot, and connectors.
- The speaker connectors can take bare wire or banana plugs, which is convenient.
- The instruction manual, provided by the ebay dealer in Toronto, is clear, simple and well written. The tubes are marked showing which one goes where, based on how it was biased at the factory with the included tube set.
- Has a three year warranty for parts (one year for labor and parts), excluding the tubes.
- There's a user-changeable fuse in the slot where the power cord goes and it includes an extra fuse in the slot.
- Some small yellow plastic caps are included to place over unused input jacks to keep dust out (nice touch).
- The light up blue logo on the front looks like some kind of Satanic symbol with that pitchfork shaped "Y".
Some online resources:
MC-10L schematic and bias adjustment guide
Sells a rebranded MC-10L for $995.
Tube Amp Store
Sells the Markhill-branded MC-10L; has a frequency response chart for the amp.