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Amp/Preamp Asylum: REVIEW: Ming Da MC34AB07 Integrated Amplifier (Tube) by Doc Sarvis

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REVIEW: Ming Da MC34AB07 Integrated Amplifier (Tube)

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Model: MC34AB07
Category: Integrated Amplifier (Tube)
Suggested Retail Price: $1508
Description: Tube integrated/power amp
Manufacturer URL: Ming Da

Review by Doc Sarvis on November 02, 2009 at 11:47:52
IP Address: 67.130.239.55
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The Ming Da MC34AB has been around for a few years in various incarnations, and is known mostly through Ebay sales offers direct from China, and its US distribution through Pacific Valve (this review is for the "07" version available through Pacific Valve). It’s been written about in a few threads here on AA, but like a lot of Pacific Valve offerings, there is very little other information available. I’m hoping to improve the availability of web information with this review; I also wanted to relate my experiences with Pacific Valve as they may be of benefit to potential customers. I’m just an audio hobbyist; I have no other relevant affiliations or interests of any kind.

Pacific Valve is an importer of Chinese-made audio goods. Their extensive, fun-to-browse website claims that they do special buying, exclusive offerings (both models and parts configurations) and unit-by-unit testing to assure high quality standards. They also offer a 30-day refund policy (with a “restocking fee” applicable, of either 8% or 11% of the purchase price – both amounts are listed on the site). The website states that if a return item is “swapped” for another, higher-price item, then the restocking fee is waived. Prices include shipping, but in the event that a return or swap is applied, the buyer pays return shipping. They also offer a one-year warranty, and shipping from a U.S. warehouse.

All in all, I think Pacific Valve has an interesting business model, and I was excited to try them out. The prices on Chinese goods are tempting, and this approach theoretically removes much of the risk. While Pacific Valve’s prices are a bit higher than buying direct from China on EBay, the various protections offered the buyer make the trade-off seem quite attractive. On the downside, I should note that Pacific Valve’s prices have been creeping up steadily since I have been watching them , to the point that there isn’t as quite as much of a no-brainer aspect to the pricing anymore, especially when compared with more established brands in the used market. Of course, this should not really matter if the gear is up to par.

My purchase goal was to find a tube integrated for a system I am building around a pair of Magnepan MMGs. I was hoping to find a single amp that would be able to both "rock the house" with all kinds of music, and sound good at low volumes (this is for an office system). The Ming Da seemed to fit the bill, plus it offered some intriguing extras – switchable between ultralinear and triode mode, and able to be used either as an integrated or a power amp. There were no reviews on the web (one Positive Feedback article discusses the acquisition process but does not really address the sound) but there are a few glowing threads here on AA. Above all, Pacific Valve’s website (which includes a video) shows how cool-looking this thing is: Blue tinted EL-34’s, bulb-style 6SN7’s, and a standalone power supply (they call it a “power humpty”) containing massive transformers. All of those positives, combined with the safety-net return policy, combined to make me willing to pull the $1500 trigger.

I actually placed an online order for a different product, and then changed my mind via e-mail to switch to the MC34AB (the other item was out of stock, even though the website said it was in-house). Pacific Valve managed this without difficulty. I placed the change order on a Thursday, then received notice of shipment the following Monday (the website says that items require 4-7 days to prepare for shipment; I assume that this allows for the individual unit testing). Just in time for the weekend, two gigantic boxes arrived at my door, in which I found a total of three somewhat road-weary-looking inner boxes, replete with mysterious Chinese characters. The adventure was about to begin.

Everything was packed nicely, including tubes, the “power humpty”, cords, remote, and the heavy unit itself. Oddly, the amp itself had a bit of grime on it, and benefited from a gentle cleaning. The feet were not attached, and screwing them on made me notice that they were seemingly not quite up to the build quality of the rest of the unit. Overall the build quality was very nice, not up to the Chinese build-quality standard set by Primaluna, but only one or two notches below – the overall effect was impressive and this unit would definitely be a conversation piece. The brand name Meixing was emblazoned in large white letters across the top. All settings were controlled on the front, but oddly the preamp inputs were on the right side of the unit base, making a clean-looking cable dress quite difficult. Using the unit as a power amp would not have this problem; the pre-in jacks were on the back. Finally, in addition to a tube cage (which had an acrylic top that made the whole thing less pleasing aesthetically; I would guess that most owners would not use it), the box included a Pacific-Valve-written manual that explained setup and operation in clear, concise, native English.

Setup included attaching the power supply using sharpie-marked arrows to indicate which connection went to which jack, plugging in the tubes, and various waiting periods. Everything was carefully sequenced in the manual and I followed along exactly. Each tube box included some cute comments; i.e. “I wonder what it will sound like”, “almost there” etc., and was numbered for placement on the amp. In some cases, the tubes felt a bit loose in the sockets, but this didn’t cause a problem. Based on the website recommendation I didn’t use the supplied 12AT7’s; I immediately inserted a pair of NOS Mullards I had available. (The site had nothing good to say about the supplied 12AT7s, so much so that I wondered why they don’t just replace them during the “testing” process – I suppose it’s a cost issue).

I was almost finished with the tube install when I realized that the base of one of the EL34’s was broken off. I suddenly recalled that a stray piece of plastic had been in the main-unit box; upon examination it was obvious that this was the missing base. Because it was in with the main unit, I assumed that this breakage had happened when the unit was being “tested “ at Pacific Valve. I remember reading on one of the AA threads that another user had the same issue with these blue-tinted EL-34s. I called the Pacific Valve 800 number, and to his credit the proprietor (I’ve since learned his name is Joe) answered, even on a Friday evening. I explained the situation and he promised to send a replacement tube. I asked if the fixed-bias amp would allow me to substitute a spare EL-34 for the broken one in the meantime; he said it would be all right to do so and asked me to call him back once everything was up and running. Good customer service.

Finally, I was ready to begin listening. I used the amp with the Maggies (hooked up to the 4-ohm taps), and a subwoofer coming off the speaker taps (that I used at very low level). I hooked up three components using the integrated setting, CD, vinyl (with an outboard phono stage and MM cart) and minidisc. Here are some of my notes on the sound:

Overall: Did not sound very good at low volume either in triode or ultralinear setting - the amp really started to sound good past about the 1:00 setting on the volume knob. Since most of my listening is low volume (although I like to have the option to crank it up), this made the amp unworkable for this system. Triode sounded too warm and tubey since one could not listen enjoyably at typical lower tube-amp settings (and I've owned several SET amps so I can really like a warm sound), and was too syrupy at high volume. Ultralinear sounded quite cramped until about 1:00 on the knob, when the sound really bloomed out and became very clear and detailed, with nice midrange and highs and solid bass extension (even without the sub).

Classical piano: Detailed and realistic soundstage. Nice highs and very clear decay on individual notes.

Hard rock: Seems like the amp was made for this. The best-sounding CD I tried was AC-DC's Back in Black. The amp obviously hits its stride at high volumes.

Symphonic: The amp seemed a bit underpowered with classical, which was a surprise to me. It did not seem to capture the dynamic range, and I found myself at full volume with more than one classical CD - something that I typically never do. The amp was nicely sweet-sounding with classical however.

Jazz: Combos sounded cramped with boomy bass (both with and without the sub). Results with this genre were the most disappointing - not enough "air" between the instruments.

Bottom line on sound: This is an amp that excels at rock, where there are more compressed dynamics and loud is good. Rock also allows the amp to shine within its more limited sweet spot.

Note: All the comments above are based on using the Ming Da as an integrated. I tried the Ming Da with a McIntosh C46 preamp, and generally got better results - I definitely would prefer this as a power amp instead of an integrated. I was still not happy with the low-volume performance, however.

I was still wrestling with whether to keep the amp, or to take advantage of the return policy. While it wasn’t working for me in this system, I could definitely see where it might fit into a different setup. Ultimately, this thing that made me decide to pass was the difficulty in biasing the EL34s as they age. The amp actually has bias pots, but they are inaccessible without removing the bottom, and the manual indicates a shock hazard in the process. On the phone, Joe said that I would need to take the unit to “a guitar shop” in order to adjust the bias for the eight power tubes as they age. This would have been a problem for me. I don't live in a major metropolitan area and it would have been tough to find a shop that could do this for me. Others may not have the same problem, and whether this is an issue or not is open to interpretation, since a fixed-bias approach is found elsewhere in amps like this. It was an issue for me, though.

So, after making the decision to send it back, I re-engaged Pacific Valve. I tried to find “swap” merchandise and even settled on a demo phono stage, only to discover after ordering online (the process required me to resubmit an order, be charged on the card, then wait for the refund of the other order) that the phono stage was sold – again this status was not indicated on the site. So, I decided to accept the restocking fee and get a refund. I packed the boxes, shipped them back at my own cost, and about three weeks later the refund appeared on my statement.

So, all’s well that ends well. Essentially, this particular situation was a system synergy issue. I can see where the MC34AB would fit nicely in certain systems, ownership experiences and listening preferences, but it wasn’t right for me. I like to listen loud, but I also need flexibility in more intimate settings and the Ming Da didn't provide the latter with these particular speakers. The bias issue would have been a bit bothersome but not insurmountable. And, as stated above, it is a very cool-looking piece of gear – one of the coolest I have seen.

As for the Pacific Valve experience: They obviously have a small staff and sometimes their processes seem a bit rigid and convoluted. But, ultimately they were quite responsive, they knew what they were talking about, and everything went as described (with the one exception that I hope they keep their site inventory lists current – I suggest a call before you order). I will definitely try them again.


Product Weakness: See Review
Product Strengths: See Review


Associated Equipment for this Review:

Amplifier: See Review
Preamplifier (or None if Integrated): See Review
Sources (CDP/Turntable): See Review
Speakers: See Review
Cables/Interconnects: See Review
Music Used (Genre/Selections): See Review
Type of Audition/Review: Product Owner




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Topic - REVIEW: Ming Da MC34AB07 Integrated Amplifier (Tube) - Doc Sarvis 11:47:52 11/2/09 ( 4)