[Rockyhill]

Hi Garry,
 
I edited my post, probably while you were composing your reply. I primarily use this with speakers.
 
RH
 
Quote:

The stock tubes are NOS Shuguang 6J8P(6SJ7) from the 1970s. They are great tubes although not the best. May I know what headphone do you use?
 
The output of those new National Union 6SJ7GT is too strong. They required some burn-in period I think. I will try a couple of the RCA 6AC7 with my HD580 tonight. 
 


 

 

 

[gtube]

I used AKG 240M for reference when designing the amp. I also tried K701, HD580, LCD-2, T1 and HE-6. They all sound lovely.
 

Anyway, don't trust my comment. Hopefully, Skylab and other users can answer your question objectively.

 
Quote:

Anybody know if these might be able to drive the AKG-K701s? I mean, very few amps can, so do these fit the bill?

 

 

[gtube]

Hi Eclein,
Sure, please drop me an email with your name and address again.
 
 
Quote:

Thanks Garry for responding so quickly. Please send me the mini switch fix and I'll have someone local make the change or try to do the fix myself- I use mostly Grado's and very easy to drive cans.
Let me know if you need any other information from me to make that happen. 
 Thanks again.

 

 

[popa]

Okay everyone I looked over Garry's blog on his website and over a month ago he made this statement. "Latest update: Some users reported that the background hum is very noticeable when using low impedance headphones (<=32 ohm) such as Grado. If you are going to use low impedance headphones with the MP-301 MK2, please make a note to the order, so we will ship you the appropriate version. The stock version is optimized for 50-600 ohm headphones [...] I do not think very many people read this,myself included. Maybe Garry should have said more than once. Maybe I would have ordered the other version, I do not know. Anyway I still think this is a good amp.Just a few wrinkles to work out.

 

[dgcrane]

I think Garry mentioned that he just added this information, and in my book,  is doing a great job in making good for the problems that I had encountered.  
 
Darren

 
Quote:

Okay everyone I looked over Garry's blog on his website and over a month ago he made this statement. "Latest update: Some users reported that the background hum is very noticeable when using low impedance headphones (<=32 ohm) such as Grado. If you are going to use low impedance headphones with the MP-301 MK2, please make a note to the order, so we will ship you the appropriate version. The stock version is optimized for 50-600 ohm headphones [...] I do not think very many people read this,myself included. Maybe Garry should have said more than once. Maybe I would have ordered the other version, I do not know. Anyway I still think this is a good amp.Just a few wrinkles to work out.

 

 

[eclein]

I didn't know he had a blog, and I also think he's doing well to answer questions about issues and help us resolve them. Easy as pie to put something on the order page of his website "Please indicate what type headphones..."....done and no problem. I love his amps, I have the first and turned alot of people on to it, so many that when I got sick and ended up in the hospital for a month a bunch of them ordered this new version, on my word it would be good. I just hope this headphone thing doesn't sour any of them and they give the amp a chance. If I was too overbearing I apologize to Garry, Skylab and anyone else reading along but it just hit me wrong.
 
In the meantime my amp seems to be stuck in Il.somewhere???  LOL...........

 

[ETAHL]

My Sylvania 6SK7GT tubes came in. Plug them in for half a day. One is quiet, the other is average. They sound a bit thin in the mids with my system.
Plug the stock 6J8P back in. I must got a set quiet tubes, they are quieter than the Sylvania 6SK7GTs, Sylvania 6SD7GT and the GE 6SJ7. The stock tubes are the most well rounded of the tubes sound quality wise, doing everything well. The GE 6SJ7 is just a tad sweeter in the mids, but it is also the noisiest. So the stock tubes are still the ones to beat.

More tubes coming.

 

[Skylab]

The stock preamp tubes are really pretty decent sounding I agree. The Raytheon 6SJ7GT's I am using now are a little smoother in the treble, and just a little warmer overall. But given the difficulties in getting quiet NOS preamp tubes, I think my recommendation to people would be to upgrade the power tubes, leave the stock preamp tubes in there, and see how you like the sound, and if you like it, leave it! The stock preamp tubes with the NOS Tung-Sol 6L6WGB tubes I put in sounded very good.

 

[eclein]

Mine finally made it to my post office here, now we'll see if they bring it today or make me wait longer....aahhhhhhhh...LOL. I'm very easily pumped up and new toys always get me going. Will report back later...I do have some tubes coming-power tubes(Mullard EL34's) and RCA for the preamp sectin but the stock tubes will stay if it sounds good as is. I'm a firm believer in if it ain't broke then don't fix it!!!

 

[Greeni]

 
Quote:

My Sylvania 6SK7GT tubes came in. Plug them in for half a day. One is quiet, the other is average. They sound a bit thin in the mids with my system.
Plug the stock 6J8P back in. I must got a set quiet tubes, they are quieter than the Sylvania 6SK7GTs, Sylvania 6SD7GT and the GE 6SJ7. The stock tubes are the most well rounded of the tubes sound quality wise, doing everything well. The GE 6SJ7 is just a tad sweeter in the mids, but it is also the noisiest. So the stock tubes are still the ones to beat.

More tubes coming.

 
Have you tried the Jan-Philips ? Those are glass 6SJ7, others from RCA, Tung-Sol etc are metal tubes which may have a different signature.
 
 
 
Concering this new switch, would someone enlighten me how would it reduce the hum ? My wide guess, it does not reduce the hum of the tubes as such but changes the impedence interface with the headphones such that the hum was more faded into the background for the same volume. Would dynamics and other aspects not change too in the process ? My RSA P-51 Mustang has a high / med / low switch and they do not sound the same to me. This is not to say that it is becoming a Meier with different setting, but you don't just change the output level, many things get affected too. It is not a case of have your cake and eat it too, but still probably much better than spoiled by the hums. I guess the best thing is still to search for a set of quiet tubes.
 
Now if you are willing to trade-in your quiet tubes for my vintage matched pair of Tung-Sol....

 
 

 

[BmWr75]

My amp was picked up the Canada Post on April 24 and shipped out of Edmonton on April 26.  Still waiting for it to arrive.  Does anyone know if this will be coming by U.S. Post Office or another commercial carrier?  Will it require a signature?

 

[Monday]

bmwr75 -The tracking program will tell you when it clears customs and is handed off to the US postal service. Figure the US postal time from the port of entry.
 
Spent 3 hours with mine last night. Pretty much dead quiet with 702s.  Vocals are pretty fantastic.  Anxious to have the tube rolling pioneers zero in on the winning combination - I am too much of a toob noob to be much help there.  I know that my 702s need to break in some but I still feel like there is a lower octave of music that's there and just wants to be moved forward a bit.  Will changing the power tubes effect this?
 
 
 
 

 

[Rockyhill]

I appreciate everyone's feedback, especially Garry's.
 
I have a pair of 6P3S-E power tubes on order. Will try in conjunction with the 4 sets of input tubes I currently have.


 
Quote:

The stock preamp tubes are really pretty decent sounding I agree. The Raytheon 6SJ7GT's I am using now are a little smoother in the treble, and just a little warmer overall. But given the difficulties in getting quiet NOS preamp tubes, I think my recommendation to people would be to upgrade the power tubes, leave the stock preamp tubes in there, and see how you like the sound, and if you like it, leave it! The stock preamp tubes with the NOS Tung-Sol 6L6WGB tubes I put in sounded very good.

 

 

[ETAHL]

 
Quote:

 

 
Have you tried the Jan-Philips ? Those are glass 6SJ7, others from RCA, Tung-Sol etc are metal tubes which may have a different signature.
 
 
 
Concering this new switch, would someone enlighten me how would it reduce the hum ? My wide guess, it does not reduce the hum of the tubes as such but changes the impedence interface with the headphones such that the hum was more faded into the background for the same volume. Would dynamics and other aspects not change too in the process ? My RSA P-51 Mustang has a high / med / low switch and they do not sound the same to me. This is not to say that it is becoming a Meier with different setting, but you don't just change the output level, many things get affected too. It is not a case of have your cake and eat it too, but still probably much better than spoiled by the hums. I guess the best thing is still to search for a set of quiet tubes.
 
Now if you are willing to trade-in your quiet tubes for my vintage matched pair of Tung-Sol....

 
 

One set of the tubes to arrive is indeed a set of 6SJ7GT, the glass version.
As of right now, the amp has way too much gain at the headphone out. Listening level with my LCD-2 is at 9 O'clock of the volume knob, my Grado SR80 even less. The amp should be tuned to lower the gain to get more volume control range. The noise seem to be fixed, regardless of the volume level, so by lowering the gain, the noise will most likely faded as well.
From my DIY experience, the easiest is to use a resistive voltage divider at the output. However, the resistor has to be high quality to not affect the sound.
 
As right now, the hum level at the speaker output is very low with the stock tube, more of a tube hiss than a hum. I doubt that any tube change will help much. Fine tuning of the headphone out circuit is probably the best course of action to lower the hum.
 
 
 

 

[eclein]

GOT IT!!!!
Mine came US Postal service and I had a neighbor take it, she didn't have to sign for it.
 
Mine is dead quiet, like exceptionally quiet and you can hear the potential of this amp.
First off they are built like friggin tanks!!! No skimping here, heavy duty build and a first rate job is what mine is....the only beef I have so far is the speaker taps are so close together, and the plastic nuts are hard to tighten, my fingers are big but not too big and it was a contest to get speaker wire threaded in the post holes and then tighten down the nuts..but it works and is a minor nit pick. Stock tubes here and wishing I didn't buy a whole other set without first hearing these-they sound pretty good to me for stock items. All in all..I think it will be a sought after amp...and I'm only 30minutes into breakin!!!  Very nice Gary!! and Thank you so much Lee!!!!!!