[SP Wild]

Quote:

Originally Posted by BmWr75 /img/forum/go_quote.gif Tried this amp with my Audio Technica ATH-AD700, 32 ohms I think, and experienced no hum. In fact, the AT cans sounded great with this amp!!!!

With my D7000 25 ohm it does hum - though it still sounds good. The D7000 does not need any more bass and it can be sibilant with a minor recession to the midrange - well thats just about opposite of this amp. Perfect ... but that hum.

I must say this amp looks much better in the flesh. My one has golden trims surrounding the valve cutouts that are not depicted in photographs. With the golden accents, jade colored "vu meter" (is it magically operated?), and wooden finish this amp looks "artistically Chinese".

With the exposure of so many variants of the "valve" sound, each a pleasure to behold (or is that beheard) and with tube rolling yet to come - I am done with solid state.

 

[moodyrn]

The only reason I sold mine is because I just got some HE-5s. This amp does hum with low impedance headphones. At least for me it did. I did have luck with rolling the 12ax7s to 5751s. It went from humming with cans below 250ohms to only humming with cans that are around 25 to 50 ohms. But even with those, it sounded very good. But after being hum free(as well as hiss free) with my previous cans, I just couldn't bear hearing any hum. I was also itching to go balanced. But one day I will own this amp again(If I ever get anymore higher impedance cans which I'm sure I will). I only hope that the masses still hadn't caught own to this amp and push the price way up. Well it still would be worth it. There are several tube amps that I've listened to that were way.....more expensive that I didn't like as much as this one. It also sounds pretty good as a speaker amp. I'm also interested in it's brother. It's a dedicated headphone amp instead of an intergrated speaker/headphone amp. Low and behold, it's a transformer coupled amp that's also point to point. So many times I read about people commenting that the cheapest point to point transformer coupled amp is the woo 6. So apparently not so many people know about it either. So it might be next on my list.

 

[SP Wild]

What about this MC84C 07 - I assumed it was transfomer coupled amp... is it OTL instead?

I think this secret amp is safe with us ... and we'll keep it that way, until your return. SSSHHHH!

 

[moodyrn]

Yes the mc84C 07 is an OTL amp. That's why it's been known to hum with low impedance phones. The amp I was speaking of really isn't a secret. There was actually a comparison with some other amps a few years ago, but it somehow got lost and forgotten really quickly. As far as I know only a very few have owned it. It's the MC66-AE. It doesn't look as nice as the mc84 c07, but it is transformer coupled and a dedicated headphone amp. I've been thinking on pulling the trigger because it can be used for both low impedance and high impedance cans. But since there isn't a lot of info on it, I feel I would be taking a risk. But hey, it is a ming da, so it couldn't be too bad. They make a ton of high end products. The mc84 and mc66 are the cheapest products they make.

 

[SP Wild]

Wow - OTL. This may be why it sounds so different to my OT coupled Cayin. moodyrn, the Cayin has an impedance selector switch - but at the 0-33 ohm it hums with my Denons more that the Ming Da OTL. In fact, only my K701's do not hum with the Cayin. The HD650's still exhibit a little hum.

Whereas the HD650 and K701 does not hum with the Ming Da. The Denons hum less with the OTL than with the Cayin "low impedance ready" OT coupled. My point being - I think you may have to travel further up the valve amp ladder to eradicate low z hum. However given the low price of Ming Da - It's worth a shot. Please let us all know if it is what we are after.

Ok that explains why they are the best match with HD650 - good with K701 (I suspect there is lesser control that may add to "tone density" but the K701 is a speedy phone) - fairly uncontrolled with the D7000 (which I didn't ponder too much as they will never be used together because of the hum).

 

[moodyrn]

That is a little bizarre. I auditioned the cayin at a shop in Hollywood, FL with some hd580s I had. It didn't hum at all. The owner had a pair of grado 325s and they didn't hum either. This was with the stock tubes that come on the amp.

 

[SP Wild]

Strange indeed as this is my 2nd Cayin that hummed exactly the same as the first. The first one the potentiometer failed and I was sent a brand new black one. My one is the HA1A not that other Cayin tube Dac with headphone out.

 

[BmWr75]

Quote:

Originally Posted by moodyrn /img/forum/go_quote.gif Yeah, this thing excels at powering high impedance, power hungry cans. It's hums a bit with low impedance cans. I have however had good success with using a 300 ohm adapter with *some* of my low impedance cans. But it sounds beautiful with cans that are at least 250ohms.

moodryn,

I'm curious about the 300 ohm adapter, please share more info.

Thanks.
BMWR75

 

[moodyrn]

Well the results vary depending on the phones. The thing it does with all low impedance phones is remove the hum. But on some phones it slightly rolled off the highs, and on some I couldn't hear a difference. On some headphones it made the sound more balanced without rolling off the highs. For example, it made the sound more balanced on the audio technica ad1000s I used to own. These can sound harsh because of the hot treble. I still had the same extension, but without the harshness. On the shure srh840s, it rolled off the highs. This wasn't a good match because they are already slightly laid back. It made my er4p sound like er4s. So that was an improvement. So it's really hit or miss. But it does completely do away with the hum on all of them.

 

[SP Wild]

Quote:

Originally Posted by SP Wild /img/forum/go_quote.gif Finally received this amp two days ago. It took a month and a half but it is here. What can I say, for $300 shipped on ebay to Australia, I have no complaints. The volume knob worked its way loose - but a quick nip with the right allen key solved that. When I first got it there was a major channel imbalance with everything coming from the right side. I tried swapping tubes left to right and there was no change. Before I threw it in the bin I thought I'd try "burning" it in. Not a huge believer in burn in - but alas that is what was needed. It is now balanced at the center. Burn in it did, as now it sounds so much more refined than before after several days of burning in on and off. It was not a sound I have ever heard or expected. The only other valve amp I have is the Cayin HA-01. So this is what a "tubey" sound is, as the Cayin is reputed to have a SS tube sound. Like a midrange bubble where the midrange is the most dominant attribute over treble or bass extension. Where the Cayin reproduced the "fuzz" of a distorted electric guitar perfectly, this amp reproduces the "twang" of an undistorted electric guitar perfectly. I have once declared the K701 unsuited to valve amps - in hindsight, a fool I am, for with one tube amp was my experience. Any blandness targeted at the K701 will be alleviated with this amplifier. Richness of tone density is abundant. The 62 ohm impedance of the K701 should really be considered 600 ohm for all practical purposes - whereas the Cayin will hum with my 300 ohm HD650 the 62 ohm K701 suffers no such ill fate. And what of the HD650? Some said the HD650 is no match with the Cayin - for which I could not agree, for the pleasures this match gave me were real. With each step deeper into this horrible abyss I emerge wiser and now agree that indeed they are a poor match. No seriously its great - have yet to roll tubes. I'd pay a LOT more to have this sound now that I have heard it.

Had a chance to re-evaluate both these tube amps and feel I must back track on these comments. One may interpret the previous post as meaning the Ming-Da is better than the Cayin. This is not so. The Cayin seems to be a full league ahead of the Ming-Da. Both "stock", Cayin is more detailed, dynamic, and extended on both extremes - with all my phones. The Ming-Da is smoother, that is it. It is smoother because of the less detail, dynamics and extension - the midrange bubble contains the sound and hence it always feels inhibited. Tube rolling may turn the tables. Must refrain from making remarks about a component until the "new toy" syndrome passes.

 

[mlantinen]

Quote:

A lot of people are surprised when they listen to this amp for the first time. I really do miss mine. It really can't be beat for the price.

Quote:

No doubt - it is a very sweet amp, and an incredible bargain for the $$$.

I've had mine now since last November, I think, and I still am really enjoying it. Yes, there's some hiss with lower impedance cans (which all of mine are at the moment), but I simply adjust the gain (my computer volume to around 50%) and most of the hiss goes away when adjusting the volume on the unit.

Looking into a solid state amp combo like the audio gd compass and panther. Getting upgrade-itis. Time will tell if I can let go of this little baby.

 

[Linyanti]

I have owned this amp for several months. I have Mullard EL84's and RCA 12AX7's. I am listening and playing games with a Beyerdynamic MMX300 headset with a 75 Ohm headphone adapter.

I got the amp pretty quiet but there was still a little hum. I made a ground cheater plug to work out a hum on another piece of equipment and just tried it on this amp and it really helped.

For a long term solution the cheater plug is not the best. The biggest risk for getting shocked is if the wiring of the building is wrong. But I check all of my outlets and they are fine however the cheater plug does not look elegant.

I then purchased an Ebtech HumX and installed it. The end result is much quieter than it was before.

Here is the Ebtech HumX website

Ebtech - Audio Solutions

Here is the type of plug adapter where you break off the grounding connector. Obviously I am not endorsing violating electrical codes but this can be used as a test.

Leviton 15Amp 125V 2-Pole 3-Wire to 2-Pole 3-Wire Grounding U-Ground Plug-In Adapter - Leviton 274 - LevitonProducts.com

 

[BmWr75]

I've got a new pair of Beyer HD-880/600 ohm cans burning in on my PC. Am looking forward to hearing these on the Ming Da..........stay tuned.

 

[SP Wild]

OK this is my final verdict of this amp.  My headphones are K701, HD650 (my low impedance models not counted due to humming).  Other amps include XcanV3, Lehmann BCL, Cayin HA-1.  All tube components are standard on all amps.
 
First up we must eliminate the XcanV3 as they are one tier below the BCL, Cayin, and Ming Da - all three which I now clump together as somewhat in the same league.
 
My HD650's are at its best plugged to the Ming Da - due to the forward midrange nature of the amp - no trace of veil can be heard - almost neutral in fact.  This now is my favorite combination of all possible combinations of phones and amps.
 
The K701 still sounds very nice with the Ming Da - but I prefer them served by the Cayin in SET mode to add warmth and intimacy.
 
The HD650 being my favorite phone is driven best by the Ming-Da - So there is no way in the world I am going to toss this amp in the bin (which I was going to when I first got it).  Therefore HD650 + Ming Da = Synergy to my ears.
 

 

[moodyrn]

I loved the senn/ming da combination as well; great synergy. My previous 600/ohm beyers were even better synergy. If someone is looking for an all-rounder, this isn't it. But for someone looking just to power high impedance cans, it's up there with amps at twice the price.