Amp/Preamp Asylum: REVIEW: YaQin MC-100B Amplifier (Tube) by drasticsden@yahoo.co.uk

Model:	MC-100B
Category:	Amplifier (Tube)
Suggested Retail Price:	£500
Description:	Ten tube amp using KT88's
Manufacturer URL:	YaQin

Review by drasticsden@yahoo.co.uk on November 14, 2012 at 14:56:23
IP Address: 213.106.135.190 Add Your Review
for the MC-100B

Sound Report Yaqin : Mc-100B

I bought this 100B without tubes, then I bought the valves I wanted to use. So I can’t tell you how it compares to a standard setup.

The pre tubes (12AX7) are TJ Full Music so are the 6SN7’s, all new.
While I waited for the Psvane KT88-T’s to arrive I used the Eletro Marmonix’s 88’s from my Bewitch amp, these have hundreds of hours on them & are a known sound.

So with all the bottle’s installed & after a 15minute warm up the Bias was set to .55v Then a record was played ……………… the sound was truly Awful !
It was really bad! All very shape treble, with some min range & almost no bass. (It sounded like an early small handheld transistor radio that used a PP9 battery, you know the type.)
This was down to the Full Music 6SN7’s, they have a reputation for having a very pronounced sharp top end until they burn in!
Clearly I had to get some hours on these tubes, but it sounded so bad I couldn’t listen to the music ! So I unplugged the TV from the Alto amp & plugged it into the 100B. The TV has tone controls built into it’s menu, so the treble was dialed way down & the bass turned up, now it was bearable to listen to using the TV & DVD (played through the TV). I got 7 hours on the tubes that night.
Later the next day I tried again with a record (same one) My God was this the same amp! It sounded so much better, there was Bass, Bass!!!!!!!!!!!!
and mid range. 7 hours on the 6SN7’s had done the job, after 15 hours I would say the 100B it was out performing my Bewitch amp, no easy task.

Then the Psvane 88’s arrived, what joy! I couldn’t fit them quickly enough, Straight out of their Big Box they sounded great, so smooth with a firm well controlled bass & great clarity.
The Bias was set after a 15 minute warm up & all was well. The sound was so good I canceled an evening out to stay in & play my records.
However after an hour there was a load hum from the right channel & I noticed the V3 tube was glowing bright orange!!!!!! I quickly powered the amp down (still using a Variac) I gave it 1 minute then slowly powered it back up to full voltage, all was well. I guessed the problem could be down to the Bias, when checked that valve (V3) it was well low (.41v) the others were also all over the place, remember I had set them only an hour ago!
I guess the control grid on the V3 valve had failed due to the low Bias voltage which allowed the valve to run wild. The Bias was reset & all was well.
I checked the Bias ever hour, (sounds excessive I know, but very necessary) they were swinging about all over the place.
After about 5 hours they were starting to stabilize, in the next two hours they changed very little on the Bias voltage, now all seemed well.
The amp sounds so good, very accrete, firm solid bass well controlled, instruments sound so real, I play a “Rickie Lee Jones” LP (180gram) & it sounded like she was in the room, I looked behind the sofa for the band, but no sign of them! nor could I find where Diana Krall had hidden her Grand piano in my lounge? The 88’s now have about 10 hours on them & about 24 hours on the Full Music tubes, so their far from being burn it, and can only get better, hard for me to believe that’s possible, it sounds so good now.

So to sum up, she's a great amp, but like any valve amp she'll only sound as good as the bottles you use!

If you go for some of these Exotic black bottle power tubes, check the Bias Every Hour for the first 6 hours.

Up Date : She's been running for 6 months now, with no problems, a real nice amp with a great sound, buy one you'll love it!

Product Weakness:	Stock Shuguang tubes need to be replaced at once! IF in the UK you need the 240v version, dont run a 220v unit directly on uk mains, use variac, or you'll have a 40 volt overload on the HT rail!
Product Strengths:	Great sound quality with good tubes,black version looks cool,very well built,good design,very good value for money.

Associated Equipment for this Review:

Amplifier: Integrated.
Preamplifier (or None if Integrated): Has input for external pre amp.
Sources (CDP/Turntable): Turntable (3 inputs)
Speakers: Ditton 44's
Cables/Interconnects: Yes
Music Used (Genre/Selections): Wide range
Room Size (LxWxH): 18 x 11 x 7
Room Comments/Treatments: Lounge
Time Period/Length of Audition: 6 months
Other (Power Conditioner etc.): Surge GG
Type of Audition/Review: Product Owner
Your System (if other than home audition): Fed from Gyro SE turntable only.

Amplifier:	Integrated.
Preamplifier (or None if Integrated):	Has input for external pre amp.
Sources (CDP/Turntable):	Turntable (3 inputs)
Speakers:	Ditton 44's
Cables/Interconnects:	Yes
Music Used (Genre/Selections):	Wide range
Room Size (LxWxH):	18 x 11 x 7
Room Comments/Treatments:	Lounge
Time Period/Length of Audition:	6 months
Other (Power Conditioner etc.):	Surge GG
Type of Audition/Review:	Product Owner
Your System (if other than home audition):	Fed from Gyro SE turntable only.