[Rockyhill]

Quote:

I've listened to this amp  99% thru 600 ohm headphones.  I got no hum with the stock driver tubes or Phillips JAN 6SJ7WGT.

Would you be able to spend some time listening through speakers and report your experience? That would be appreciated.
 
Thanks,
 
RH

 

[Skylab]

Using B&W DM601 bookshelf speakers, and with Raytheon 6SJ7GT driver tubes, I can't hear any hum through the speakers unless I have my head very close to the speakers. From a 2M listening position, I hear no hum.

Again, though, I do not think there is anything magical about the Raytheons - I don't advise people run out and try to find a pair (and the odds of your finding these specific Raytheon "Bantal" tubes is very, very unlikely). I just think it happens that the MP301 "liked" this particular pair, versus the other ones I tried.

And again, with the stock preamp tubes, I had absolutely zero hum, even with headphones. My review is almost done, and in it I will be recommending to NOT try to roll the preamp tubes. There are lots of rolling options for the power tubes, and the hum does not seem to be related at all to the power tubes. The MP301 Mk 2 is a bit finicky relating to the driver tubes, but since the stock tubes were quiet, I think the best move is not to change them.

 

[BmWr75]

Quote:

Would you be able to spend some time listening through speakers and report your experience? That would be appreciated.
 
Thanks,
 
RH

Your question just reminded me that I listened to this amp via JBL L112 speakers yesterday for a while....there was no hum (was using the JAN drivers and reissue Genalex KT-66 power tubes).  
 
Did listen to the amp via Klipsch KLF-20s (100 dB efficient) for a while the day I got the amp, still had the stock tubes in it.  It sounded fine from the start.  I had to pause the source while I was messing with another system, when I came back in the room a weird (more static than hum) sound could be heard coming from the speakers.  Immediately turned the amp off.  Restarted it and the source and the noise problem did not happen again.
 

 

[gtube]

Hi Rocky,
I just randomly took one MP-301 MK2 out of the shelf. I also found a pair of RCA 6AC7 and RCA 6SJ7Y in my warehouse. They are brand new tubes. I compared them to the stock 6J8P thru my 32 ohm headphone, 300ohm HD580 headphone and my B&W speakers (88db). The 6AC7 and 6SJ7Y are just a liitle bit noisier than the 6J8P thru the 32 ohm headphone. Through the HD580 and the speakers, they are very much the same. I cannot hear any difference. The tiny hum can only be noticable when my ear is 20 cm away from the grill of my B&W.
 
If you cannot get this result, you can ship it back to me for inspection/exchange or refund.
 
Thanks,
Garry
 
Quote:

Garry,
 
I would think the focus would be on resolving the issues reported with speaker use as this is (primarily) a speaker amp. The product description lists the following replacement tubes: 6SJ7, 5693, 6AC7, 6SK7, 6SD7, 6J4P, 6*4, 6*8
 
Speaking for myself, the 6SD7 and 6SJ7 have significant hum. Other owners report similar experience. I do not have noisy ground in my house. No other appliances/electronics in my house exhibit hum like this.
 
Skylab,
 
Regarding this post below, what tubes are you using and is the amp quiet with speakers?

 


 

 

 

[jeust0999]

I just wanted to mention that the new design of this amp was improved on every single aspect over the previous generation. It is neither function over form, or vice versa. Instead, it is simply progression from all angles. Really good looking amp, regardless of price/competition.
 
For those who own these amps, keep posting more pictures!
 
Thanks.

 

[ETAHL]

Rockyhill,
It is a bummer, but looks like you amp is not working properly, maybe a lemon.

It is the best to send it back to Garry for a replacement for a tested and impedance fixed unit. Much less headache for you down the road.

 

[Rodz]

hi Garry.
 
 the hum really seems to be related to the particular tubes on hand..as i type this i am using some GE 6ac7 with zero hum,the supplied tubes and a set of tung-sol 6sd7gt's were also absolutely quiet from the get go.a pair of sylvania 6sk7gt's on the other hand?...hummed badly.if what i experienced was the same as what others have,this is not a slight hum,it's a heavy 60 hz hum that's easily heard,it sounds much like a bad filter cap...but as i said only one of four sets of tubes I've tried has done this,all are NOS and while that doesn't exclude the possibility of the sylvania's being at fault...given the multitude of other posts about this.i think it's fair to say that there IS an issue...but for me at least it really seems to defy logic beyond thinking it's the particular tubes being used...i believe someone else posted that the sylvania tubes i have actually were the only ones that didn't hum for them,which is why i picked them up,but the hum was really that bad that i took them out in less than 5 minutes...this at about 2 meters from my b&w cm1's [only 84db!]
 
my stock output tubes are also redplating slightly,but having switched them side to side,the worst of the two remains so,leading me to believe this is a tube issue,so while they appear to work ok for now, I'll also be trying replacements for them shortly

 

[Raul]

Quote:

Hi Raul,
There are two fuses in the IEC power socket (one for spare). The power cord coming with the amp is a quality one. It is not soft at all. Other users can confirm. Could you email me a picture? Since it was the power cord problem, the fuse didn't blow for sure. The home power breaker should be cut off immediately if the power cord goes wrong. As I rememer, you are from Italy, the MP-301 MK2 only comes with a US plug power cord only. The defective one should not be the one we supply. Did you use an adapter?
 
 


 

Hi Garry,
yes I am from Italy and I got the amp directly from the China warehouse. Mine didn't come with a US plug power cord, but with a schuko plug power cord, so I didn't use any adapter. As you can see from the pics below the cord was very thin (and also very soft) when compared with conventional power cords. Maybe your guys in china are less careful to quality than you are

 

 

[gtube]

That is very strange. I have never ordered this type of power cord. They should be all high quality US plugs. I am going to ask the staff in China to see if they substitute the US plug cord for a EU plug when shipping to Europe.

 
Quote:

 

 

[gtube]

I like your CM1. I have the B&W 805 Matrix. It is very hard to drive. With MP-301 MK2, the old B&W DM200 sounds better than the 805 Matrix. The B&W 805 Matrix must be driven by the MP-401 to get the best performance. The 600 series is more suitable for the MP-301 MK2. It is a bit out of topic here in a headphone forum. I should stop now. 
 
Quote:

hi Garry.
 
"my b&w cm1's [only 84db!]"
 
 

 

 

[Raul]

Quote:

That is very strange. I have never ordered this type of power cord. They should be all high quality US plugs. I am going to ask the staff in China to see if they substitute the US plug cord for a EU plug when shipping to Europe.
 

I don't know if it's strange, but I can assure you that this one was the power cord that came with my amp, and the fact that it shorted after a few hours confirm it wasn't high quality. Now I am happy with a thick PC power cord, but maybe you were right to fire the QC guy over there.
 

 

[Raul]

About the hum affaire, I was the first to affirm to have no hum in my amp.
I tried it for less than an hour with stock tubes and I found the sound a bit "thin" (but no hum anyway) so I replaced them with other tubes I had at hand without waiting the burning of the stock ones. I put two used metal 6SJ7 RCA and two russian 6P3S-E, and the sound quality decisely improved. And still absolutely no hum.
I have to say that I am using the amp with Dynaco A-25 speakers that should have a rather low sensitivity (about 86dB I think) but without signal and the volume at maximum there is absolutely no hum, even with your ear very close to the speaker.
Yesterday I made another test by replacing the RCA's with a pair of NOS Fivre (vintage italian tube brand) 6SJ7-GT. Great sound and still no hum.
So I took my Superlux HD-681 (32 ohm 98dB, sorry but but I haven't great quality cans) and tested the amp with these for noise. With no signal and max volume there is absolutely no hum, only a slight "hiss" in the background, noticeable but very slight. Then the shorted power cord prevented me to test some other headphones, but I hope to have time to do it tomorrow.
 
And about the "running very hot" thing, after how much time your became so hot? With mine I can easily keep a hand on the trannies cap (but I never ran it for several hours in a row). Garry, maybe the 230V option can have something to do with this? 

 

[Raul]

Quote:

 
The B+ and P wires were reversed on the right channel.  Guess that is why it was louder and distorting at higher volumes.
 

Garry and Scott - so which are the correct positions of the three wires of the OPT connectors? Both mine have black on B+, red on U and white on P, but from ETAHL pic here http://www.head-fi.org/forum/thread/536681/new-info-musical-paradise-mp-301-mk2/315#post_7454553 it seems that his CN1 has black on the P (while it seems to have white on CN2).
 

 

[Rodz]

 
Quote:

I like your CM1. I have the B&W 805 Matrix. It is very hard to drive. With MP-301 MK2, the old B&W DM200 sounds better than the 805 Matrix. The B&W 805 Matrix must be driven by the MP-401 to get the best performance. The 600 series is more suitable for the MP-301 MK2. It is a bit out of topic here in a headphone forum. I should stop now. 
 


 

 i like the CM1's too, i had to try them with this amp,but i didn't really buy it to replace the Bryston that normally drives them, tho my results also hold when driving the small monitors on my desktop...which IS what this amp was bought for i fully understand your experience Garry,it is mine as well,for the most part my amp is very quiet...but not with every tube i've tried,and apparently not for many others here with any tube..i can offer no reasons why,but everybody can't have dodgy tubes,even tho it might look like they do[from my perspective as well!]there has to be some reason and i just wanted to give a specific example that was outside what you seemed to be thinking people were saying....if what i heard is what others are dealing with,it's really not mild residual noise..this amp is capable of some serious HUMMM
 
i came home tonight to find yet another package of goodies in my mailbox,while typing this i am listening to a set of nos GE 6SJ7's...and again...there is NO hum,even at this very close distance[about 2ft] ,these are shiny new and have literally about five minutes on them,they're as quiet as can be...these show some promise and i think are going to be keepers....thats four different sets for me that have no audible hum at all...and only one set that does

 

[gtube]

Hi Rual,
The black wire goes to the B+, red one to U and white one to P. Same on both channel. If B+ and P are switched, the sound is at least 30% smaller on that channel. Don't worry about it if both channels are balanced.
 
Thanks,
Garry
 
Quote:

Garry and Scott - so which are the correct positions of the three wires of the OPT connectors? Both mine have black on B+, red on U and white on P, but from ETAHL pic here http://www.head-fi.org/forum/thread/536681/new-info-musical-paradise-mp-301-mk2/315#post_7454553 it seems that his CN1 has black on the P (while it seems to have white on CN2).