[jimath-700]

Hello, I decided to start this thread because of the lack of info on tube rolling in the mp-301. This thread is open to all mp-301 owners. I'll note I do not yet have a mp-301mk3 but I'll buy one soon. In conclusion I hope this thread will be helpful and fun for all!

 

[jimath-700]

Bump

 

[jimath-700]

bump

 

[micmacmo]

I think the enthusiasm for this amp cooled after a number of users of the Mk 2 and Mk 3 reported problems with hum and buzz, regardless of the tubes. I have the original MP-301 and haven't suffered from noise. FYI, I've been happily using NOS RCA 6V6 tubes and NOS Mullard CV4010 tubes to drive my Hifiman HE-6 off of the MP-301's speaker taps.

 

[jimath-700]

Yeah I kinded noticed a lack of enthusiasm.
But, I'm glad you're having good results.

 

[DrKC]

I thought I would resurrect this thread and see if anyone has been tinkering with their 301.  I've had mine for about 2 years and have been experimenting with the tubes for the past 20 months.   I've seen where some folks have had noise or hum problems, but I've not experienced that.  While the amp is probably not suitable for IEM users, I have really enjoyed it with a variety of high impedance and planar headphones.
 
I saw a lot of posts talking about how the sound changed with different tubes.  My education/work experience is in electronic engineering, so I was pretty skeptical about these differences.  I really couldn't understand what specific mechanism was at work causing these differences.  So, I decided to hear for myself.  Instead of investing several hundred dollars in a set or two of primo NOS tubes, I went with current production Russian and Chinese tubes.  All the tubes have sold for $24 to $80 per matched pair.  (I got my winged Cs before the price went nutty last year).  To make a long story short, there was an audible difference.  Usually not extreme, but some of the tubes had a distinct profile.
 
Here is most of the tubes I've checked out
 

 
The Winged C 6L6GCs were the most neutral sounding tubes and the Valve Art 350Bs were the most musical sounding tubes albeit with some loss of detail.  I did 120 hours of break/burn-in on each set and then did some critical listening with the same set tunes each time.
So... what have you other 301 owners been up to with your amp?

 

[KobeeDog]

My favourite tubes in mine was the the 6L6 by a wide margin. I also tried EL34's as well as some Gold Lion KT88.
 
Here's a review I did of it awhile back if anyone is interested.
 
http://audioreview.ca/default.aspx?pagename=review&reviewID=7513

 

[Carson]

I have had mine now for around 8 months and so far so good. When i first got it the fuse would blow but Gerry instructed me to use a higher value and its been fine since.
I am running GL KT88's and RCA 5693 red tubes and so far i keep going back to them.  The sound stage is alot wider, instrument separation is very noticeable and clear. It is like listening to music in "3-D".  Nuances and little details i never noticed have come out.  This combo can seem a bit bright.
I have also tested the 6550 -seems good for low end but centers the sound stage some and the Syvlania 6sj7WGT does the same thing.
Certain music which is very bright i switch the lower sounding tubes. It doesnt seem to like music with a lot of heavy distortion. 
My TT is an Audio-Technica  AT-LP-120 usb. I jumped the wires from tone arm past the internal preamp directly  to the output. Even with the internal preamp bypassed switch set to External the signal still went through a circuit board. I wanted a clean sound.  Jumping it did help. I use a spare blue ray DVD to play CDs and i think it sounds just fine, less harsh.
My Preamp is a Little Bear Toroidal Transformer Little bear T10 Pro with Russian 6N2 tubes. Speakers are Fluance SX6-BK bookshelf (89db) and their subwoofer.  I can crank it up pretty loud.
So far thats all the tube rolling i have done with it.  I did alot of research and tried to use everyone's suggestions, but it is hard to find people who are tube rolling with this amp. I tried to buy the best of the lower priced gear because i am not rich. Being able to modify things helps build a better sounding system.
 
Hum and Buzz...I moved the amp away from the subwoofer and i turn off all the lights except an overhead LED. Dimmer switches are awful noisy when on. Plasma TV's too. Anything that causes EMF it will pick up, but not as bad as the tube preamp which i had to "fab" a grounded shield for.  Hum and buzz are acceptable now. I have to crank it to 2 o'clock to hear hum clearly. Careful for ground loops as well. Plug everything into one power strip.
Different tubes are more noisy as well. Cheap tubes means more noise. I did try the Chinese tubes that came with it-very noisy. 

 

 

[Carson]

Which are your "go to" set of tubes?

 

[Carson]

The Russian tubes on my preamp have burnt in nice.
I have a small scale for use with setting the weight on my tone arm. Its supposed to be 2. I followed the directions to balance then set the weight. It came out to 3.8. Using the scale i set it to 2 then added weight slowly and when i got to 2.5 it made a big big differance in sound. Now instead of the KT88;s i like the 6550's in my MP. Just a richer sound and not as high sounding as before.
I seem to have a slight buzz in my right speaker. changing speakers and tubes doesnt help. No difference when i change the source. Its slight and a upper mid volume levels. I cant hear it when music is playing, of course.

 

[DrKC]

  Which are your "go to" set of tubes?

For me, if I'm listening through speakers, I keep the Valve Art 350Bs in.
I like the glass Tungsols a little better than the metal RCAs in the preamp.
For headphones, it's hard to beat the Winged C 6L6Gs for a fairly balanced presentation.

 

[Carson]

I just ordered a pair of Tung-Sol 6L6GC-STR from Upscale. I will see how they sound. One issue i have is the music sounding way too bright.  So much so the highs will hurt my ears.
As for preamp tubes i am still fiddling around with those. My RCA Red cans with the 88s are way bright but have really good detail and wide sound stage. Depth is nice too and instrument separation.
If i could get that combination with less high it would be great. My 6550 sound good, richer some but the music closes in some.
My preamp is a little bear Tor. with Russian tubes.
 
I go to so many boards and they modify and improve their amps. I wonder if anyone has found out how to improve the MP Mk3?

 

[DrKC]

If bright is bothering you, I would give the Valve Art 350Bs a try.  A pair is pretty cheap.  After about 120 hours, these are some laid back, mellow tubes.

 

[Carson]

I just ordered a pair of Tung-Sol 6L6GC-STR , the Valve Art 350B's and a pair of 6SN7GTB - Tung Sol as well.
 
Changing to Russian ECC83 on my Little Bear preamp helped.  Also, i checked the weight for my tone arm on my Audio-Technica AT-LP120-USB. I followed the directions to balance and set the weight. Balancing the tone arm is very suggestive. It bounced around and kept swinging back to the rest. Once "balanced" i set the weight per the instructions.  I then got out my scale and was at 3.8grams instead of 2. So i set it at 2.5 and it sounds much better.  From now on i will always use a scale when setting my weight.
I like the sound of the 6550/ RCA red can 5693 combo.  Its full and detailed and nice and so far are my general use tubes. The KT88/5693 sound good, are really open and detailed the instrument separation is very good and has a more "3-d" sound. But they are just ear shredding bright. All of my tubes have a good years worth of burn in on them.
I think on my albums i will put a note saying which tubes sound the best for that album. Some records just sound better with certain tubes.

 

[DrKC]

  I just ordered a pair of Tung-Sol 6L6GC-STR , the Valve Art 350B's and a pair of 6SN7GTB - Tung Sol as well.
 
Changing to Russian ECC83 on my Little Bear preamp helped.  Also, i checked the weight for my tone arm on my Audio-Technica AT-LP120-USB. I followed the directions to balance and set the weight. Balancing the tone arm is very suggestive. It bounced around and kept swinging back to the rest. Once "balanced" i set the weight per the instructions.  I then got out my scale and was at 3.8grams instead of 2. So i set it at 2.5 and it sounds much better.  From now on i will always use a scale when setting my weight.
I like the sound of the 6550/ RCA red can 5693 combo.  Its full and detailed and nice and so far are my general use tubes. The KT88/5693 sound good, are really open and detailed the instrument separation is very good and has a more "3-d" sound. But they are just ear shredding bright. All of my tubes have a good years worth of burn in on them.
I think on my albums i will put a note saying which tubes sound the best for that album. Some records just sound better with certain tubes.

I think you'll like the 350b's if you're looking for "mellow".  I have a pair of Ting-Sol 6L6GCs - those are some crazy tall tubes - decent overall sound - haven't heard the STRs.
I've only tried KT-66s and did not like them - haven't tried any KT-88s.  Enjoy