[jyc327]

ohhhhh like rust....yeah its suppose to be an even coat of blackish grey
 

 

[novak]

So the power tubes on my Mk. 3 are starting to die on me so I thought I'd go ahead and order a new pair and while I'm at it, upgrade the driver tubes aswell. So far I've been using the stock tubes, but they're a little too light on the lower end and I'd want a pair that offers a little more bass and perhaps a little wider staging aswell. Any recommendations? I'd preferably want to stay under 60€  for everything so nothing too crazy (the cheaper, the better honestly!). I use the LD with my HD 650's, if that matters.

 

[mordy]

I have done a little bit of tube rolling and research. This is still a work in progress, but I am convinced that you can buy excellent tubes for under $8 each (including shipping!), and many times one pair for that price. You have to be patient and follow Ebay postings.
Since the power tubes only account for some 15% of the sound, I would stay with stock tubes. Here is a link to a current Ebay offer:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260578750645&ssPageName=STRK:MEWAX:IT
You could look for a pair of 6N30P-DR or 6H30Pi-DR tubes. These will be better than stock, but will cost $100-200/pair or more. On the upside, they should last 10,000 hours, but personally I can't see spending so much on a $224 amp.
 
 
As far as driver tubes are concerned, I have tried 8-9 different ones that were recommended in previous posts on this site. So far I am most impressed by RCA, Sylvania and Mullard tubes. Look on Ebay for 6AK5W/5654 RCA and Sylvania tubes from the late 50s and 60s. You can get them for $3-4 with a little patience.
David of little Dot likes the Mullard M8100/CV4010 tubes. Here is a link to what I think are Mullard tubes made for the Australian army-navy in 1961. (Next to impossible to decode the date codes on the tube!) that sound great and cost less than $8 each with shipping:
http://cgi.ebay.com/5654-6AK5-6096-CV4010-TUBE-/150258062878?pt=LH_DefaultDomain_0&hash=item22fc14161e
Good luck!

 

[novak]

Thanks for the info! I nabbed a pair of stock power tubes locally earlier today.
 
I also found a link to some [size=12.0pt]6Sh1P-EV's in this thread so I went ahead and ordered those aswell. I think I'll wait 'till they arrive before I test out anything else. I'll definitely keep an eye out for affordable examples of the tubes you listed aswell.

[/size]

 

[mordy]

[size=12pt]I also have the 6Sh1P-EV's which are quite good and have a strong bass.[/size]
[size=12pt]I have a source for this type of tube for $38.00/100, but I can't use so many. Maybe some people want to split this deal?[/size]

 

[jyc327]

man i just got 16 of these for 17 bucks. i cant help you on that bundle. but they do sound good. some of the ones i got i noticed microphonics. i have some cheap rings i put on and it helped. but not all are like that. oh mine batch came in two flavours. some had this "rib" that ran down its length (3 in total) and some dont.

 

[mordy]

I haven't really had any problems with microphonics. My MkIII is sitting on a shelf with plenty of space around it for ventilation. In addition I have three old aluminum cones (feet) that I put under it so that there is more airflow around it. Even after an extended time on it does not get very hot.
In any case, always wanted to know where to get inexpensive rings to put around the tubes to see if the sound improves. Maybe you could could describe what you are using and where to find them cheap.
The main thing is to have fun playing with the MkIII. Trying different tubes, burning them in, listening to critical recordings to see how the sound stage and bass works out with a specific set of tubes and comparing different sets of tubes.
So far my conclusions are that antique tubes from the 40's aren't necessarily better than stuff from the late 70's, and that inexpensive US made tubes can hold their own very well against more expensive British tubes. And tube matching is good for the economy but doesn't make much of a difference in listening. Read somewhere that tubes were made with 5-10% tolerances so the matching is not crucial.
I also have a theory that tubes designed for longer life have stronger bass, but that may just be a totally mistaken notion.
I wish that you could look at a tube and how it is made and make predictions about how it sounds, sound stage, bass etc, but no such luck!  It is just trial and error.
What do you think?

 

[AlexRoma]

Hi guys. Last week my LittleDot MK III has arrived , so , I guess I'm gona join the tube rollers club

. 

   I've got only one headphone - BeyerDynamic DT990 250ohm Premium . I had read last 30 pages and decided to upgrade the drive tubes since I am really not happy with the stock
 
I like all kinds of music but this cans are somehow too sibilant and upfront sounding (no complaining for the bass  

). I was expecting from a tube-amp to enlarge the sound stage, bring more air and instrument separation, smooth the highs and bring the mids a little forward . But.. The stock tubes are nothing special in my case.. Even after 30 hours burn-in MK III sounds nothing better than my Audinst HUD-mx1 DAC/ss-amp, no lush, no smooth upgrade, the bass is even more uncontrolled and boomy (Gain setting =10) .. So I'm quite disappointed at the moment...
 
Guys, unfortunately at the moment I may afford only one pair of tubes.. Which one are a better match in my case ? 
 
1. Tung-Sol Mil-Spec 6AK5 5654 EF95    (quite old and expensive, 50$ pair on ebay, most had been used

.. Are they really much better in my case, then half the price M8100 mullards ? )
2. Mullard M8100  EF95
3. Mullard M8161  EF92
4. Mullard M8083  EF91    (most controversial tubes so far.. Some guys find them super warm and spacey , other super boring and harsh

)
5. Russion 6Sh1P-EV / 6J1P-EV   
6. ... ... ... something else
 
Remember, they must cure DT-990 claustrophobia and ultra-brighness !  No bass burst needed, only lush, warmth, space, air ...

 

[mordy]

I have a set of NOS Mullard EF91 tubes that I broke in for about 100 hours on my MkIII. I did not like them; to me they sounded too harsh.
Maybe it is worth trying for you - I paid $9.25 for them, and for another $3 I could send them to a US address.
If anybody is interested, the cost would be $12.25 including shipping in the US.
 
The Mullard CV4010(M8100) tubes are very well balanced, with a beautiful midrange and not too powerful bass. If you look on Ebay for CV4010 you will find somebody who sells them for $5 each +shipping.
 
Again, I can only guess how something would sound because I do not know which tubes would sound good with your headphones.

 

[AlexRoma]

Thank you mordy for replay.  I live in east Europe, so in my case the shipment price is an issure.. In most cases it is equal or twice the price of the tubes

..
 
Ok.. Any  other suggestions, ideas ? Come on, guys, the must be a lot of DT990 owners here..

 

[Katun]

Alright, I'm completely new to tube amps (go easy on me), so I had a question about the MK III.
 
The two small tubes in the front are the ones people tube roll? And the large ones in the back be left alone as they are power tubes?
 
I thought this whole tube rolling thing would be super complex, but if it's just the front 2 tubes, it makes it that much easier.
 
(I'm a few clicks away from getting this paired with a DT990/600. Tube rolling is looking promising.)

 

[mordy]

I am also new to tube rolling, but to change the tubes is not much different than putting a plug in a wall outlet and pulling it out. You take the tube between your fingers and gently rock it slightly sideways back and forth (hence tube rolling) while you pull upwards. Just make sure to insert the new tube with the pins aligned with the holes.
The other thing is to wait for the tube to cool off if you have been using the amp - maybe 5-10 minutes before you make a change.
The smaller tubes ("peanut tubes") are the driver tubes and the ones to change. They account for about 85% of the sound of the amp. The larger power tubes in the back are quite good as stock, and to get a little better sound you have to spend big bucks which does not make it worth it for me.

 

[mordy]

Here is a current offering of great US made Sylvania tubes from 1967 for $2.50 each. These tubes are my sound stage champions so far. On a good recording the sound stretches outside my speakers maybe a foot or two. Better sound stage and detail than the Mullard CV4010. Bass, bass slam, highs are great, but the CV4010 maybe has a little sweeter midrange and overall balance. However, the ability to separate out the instruments and locate the players in depth as well as in width wins me over. Even old mono recordings get a little bit of a soundstage.
 
http://cgi.ebay.com/1-NIB-Sylvania-5654-6AK5-Tube-75-available-/270656236668?pt=LH_DefaultDomain_0&hash=item3f045e6c7c

 

[Katun]

Quote:

Here is a current offering of great US made Sylvania tubes from 1967 for $2.50 each. These tubes are my sound stage champions so far. On a good recording the sound stretches outside my speakers maybe a foot or two. Better sound stage and detail than the Mullard CV4010. Bass, bass slam, highs are great, but the CV4010 maybe has a little sweeter midrange and overall balance. However, the ability to separate out the instruments and locate the players in depth as well as in width wins me over. Even old mono recordings get a little bit of a soundstage.
 
http://cgi.ebay.com/1-NIB-Sylvania-5654-6AK5-Tube-75-available-/270656236668?pt=LH_DefaultDomain_0&hash=item3f045e6c7c

Thanks for the link! I was hoping someone could point me in the right direction in terms of which tubes to buy.
 
So, those are superior to the stock tubes, correct? I might buy a couple right now, even though my amp is not coming for another month...

 

[mordy]

I personally found these tubes superior to the stock tubes, but it is possible that each individual equipment set-up reacts differently. In any case, after having tried some ten different tubes that came recommended I find these among the best and with the widest sound stage. The beauty is that you don't have to spend $50 for a set of great tubes to experiment with.
Would like to hear from you once you got your amp and tried these out. It is definitively worth it to buy the tubes when they are available at this price.