[IYAshike]

Thanks a lot for the quick and informative response MIKELAP.
 
Here the link in case someone else is interested. 
 
IMO, the 6N6P-IR seems to be 'the way to go' (price/performance ratio)... l might get it for Christmas so that l have time to get more familiar with the sound of the MKIII with the stock power tubes 

 

[HamyAntti]

Wow what a difference between old (600+ hours) Mullards compared to new (~25h) Mullards. 
Still a bit crispy sound, but it's smoothening. Bass is deeper and more balanced. 
I just love this amp.

 

[richdytch]

Hi folks. Apologies if this has been touched on before - I've had a look around for previous answers on the forums, but didn't see anything. 
 
I've been rolling power tubes in my mkiii on and off. I notice a fairly profound difference in headphones between the stock tubes, 6H30-PI, and 6N6P-IR. I particularly find that the 6N6P-IR sound extremely linear and clean - almost not tubey, compared to the stock tubes, which seem slightly warmer in character. 
 
My question relates to the fact that I now use my mkiii as a preamp. Chain is mkiiii pre -> Marantz pm7001ki as power amp -> PMC twenty.22 and an old Yamaha sub (does an amazing job for £40, believe it or not). 

Does anyone know if the power tubes of the mkiii contribute to the sound of the unit when used as a preamp, or are they completely bypassed and is only the output of the driver tubes sent to the preamp out? I've had a look at a schematic I found on the web, which would suggest that the power tubes DO contribute to the preamp out, but I'm no expert in interpreting these things. 
 
At the moment, I *think* I can hear the difference over my speakers, but am wary of my own confirmation bias. If the difference is there, it's certainly less apparent over speakers. Would be good to know what's going on. Cheers!
 
Rich. 

 

[HamyAntti]

There was a clear difference in sound when I changed power tubes in my mkIII. Old ones where over 3 years in daily use. Now sound has more air to it and isn't forced out* (don't know how to describe it bettetr).

IF you hear difference. Then there is difference.

 

[mordy]

Hi richdytch,
 
The power tubes contribute to the entire presentation in a way of supplying the foundation for the music, especially the bass - think rhythm section in a band.
 
When I was using the MKIII I was able to switch on and off the power tubes while playing (using an external power supply for 2.5A power tubes), and I could instantly hear the difference.
 
The various 6N6P iterations have a more subtle difference (the IR the best for the money), but once you use 6SN7 tubes (just plug and play with an adapter) there is a marked difference; even more with 2.5A tubes.
 
Think about the difference between a lukewarm soda pop and a cold sparkling one! The 6080 family 2.5A power tubes - think Champagne....

 

[richdytch]

HamyAntti, Mordy, thanks very much for your replies. 

If I may be so bold, I'll take it as a yes that the power tubes DO affect the sound when using the mkiii as a preamplifier. 

And Mordy, all this talk of 6080 2.5A power tubes is news to me - I've not stopped by this thread for a long time. Now I sense some expenditure coming on, although I'll have to find out exactly what I'm buying first. Would you say they're a match for the 6H30-DR? Not that I'd ever be particularly comfortable with forking out the sums involved for the DRs. 

5 years or so, and I'm still loving the mkiii. It's almost a hobby in itself. I've got some nice RCA blackplates in at the moment. Really enjoying them. 
 
Rich, 

 

[mordy]

Hi richdytch,
 
I only used the MKIII as a preamp and power tubes make a big difference.
 
Never bought the 6H30-DR because I felt that they way too expensive and hyped up. For those who compared them to the IR tubes, the general opinion was that the improvement was only incremental and not worth the cost.
 
That was when they cost $50-100 each - just checked now, and the prices have doubled to $400/pair. or more.
 
The easiest way to upgrade is to get inexpensive 6SN7 tubes and buy the octal to 9pin adapters - then it is just plug-and-play.
 
IMHO the results will surpass the so called 6H30-DR "super tubes."

 

[i luvmusic 2]

It's like sticking a F1 engine into CIVIC.............

 

[mordy]

 

[richdytch]

Thanks Mordy
 
I feel an early Christmas present to myself coming on!

 

[richdytch]

Well, I ordered some random cheap 6SN7 tubes on ebay, for $6 each, which turned out to be 1980 Sylvanias. Or so the sticker on one of them says. Also ordered some socket adapters, and some 6HM5 tubes from Yugoslavia, the tall bottle ones. Obviously it's early days, but at this stage I'm really enjoying the combo in my mkiii. I'd say that the most notable aspect is a certain silkiness to the mids and treble, where before there was maybe a little more grain. I tried a very nice recording of Stravinsky's Firebird suite and they handled that very very well indeed. They definitely do 'scale' well. I'd previously listened to the same recording, also using the mkiii as a preamp, but with the stock 6N6P tubes, and with the LD turned up far enough to handle the full dynamic range of the piece, I was experiencing distortion when the big bass drums kick in. No hint of that now, which is very pleasing. Overall the setup is brighter than it was with my previous combination of Mullard m8100/6N6P-IR, but the smoothness of it makes up.

 

[mordy]

Hi richdytch,
 
Glad that you enjoy the new tubes. The 6HM5 is considered to the best of the plug and play types. Different 6SN7 tubes will sound different, but the point is that overall they sound better than the most expensive 6H30 tubes in the MKIII.
 
If the tubes are new, you may want to give them some 50 hours of burn in to reach their full potential.
 
Cheers,
 
PS: When you are ready to upgrade, the next step is C3g drivers and 2.5A power tubes, but these require special adapters, power supplies and voltage regulators - a totally different ball game.
 
And should you want to upgrade further, the next (and maybe ultimate step), is the Feliks Elise.
 
I have the Elise, and there is no going back......

 

[richdytch]

  Hi richdytch,
 
Glad that you enjoy the new tubes. The 6HM5 is considered to the best of the plug and play types. Different 6SN7 tubes will sound different, but the point is that overall they sound better than the most expensive 6H30 tubes in the MKIII.
 
If the tubes are new, you may want to give them some 50 hours of burn in to reach their full potential.
 
Cheers,
 
PS: When you are ready to upgrade, the next step is C3g drivers and 2.5A power tubes, but these require special adapters, power supplies and voltage regulators - a totally different ball game.
 
And should you want to upgrade further, the next (and maybe ultimate step), is the Feliks Elise.
 
I have the Elise, and there is no going back......

 
Wow - well I'm a compulsive tinkerer, so you never know Thanks Mordy, for your advice and tips for the future!

 

[MIKELAP]

Dont know if you ever checked out the Littledot tube rolling guide if you like to  roll tubes or tinker youll love that thread i suggest starting from the end                                                                                                                                                                          http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/10020#post_12170683

 

[richdytch]

Hi Mikelap... I've been a silent lurker on that thread for 5 years or so, but I'd not been there for over a year until recently - when I started using the mkiii as a preamp for my hifi (I generally use a solid state amp for my HE400 these days) and started getting itchy tweaking fingers. That's when I first heard talk about 6SN7s being used as power tubes in the LD. Mordy's recommendation spurred me into action. My choice of the 6HM5 was less well informed, having just seen a few people say they really liked them - since then I've realised the reputation they have for being pretty much the best plug and play driver for the mkiii. 
 
Yesterday I was suffering from listening overdose. Everything I listened to sounded harsh and congested, so I packed it in. It's still early days for my 6SN7/6HM5 combo, but it's already sounding very nice. The first time using my LD as a preamp where it's sounded undeniably superior to the preamp built into my Marantz PM7001KI. Objective met, and I only have about 15 hours' of burn-in time. I'm going to take frequent breaks from listening and continue to let them burn in. 
 
At the moment the nature of the improvement is a better sense of space, an unobtrusive warmth, but most of all, smoothness - definitely lower levels of distortion in the mids and treble.