Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Little Dot MKIII Tube Rolling
New Posts  All Forums:Forum Nav:

Little Dot MKIII Tube Rolling - Page 177

post #2641 of 3194
Originally Posted by maxdot View Post

Oooooooooohhhhhh !!!!! Now it works :D haha, awesome!! I just had to switch the ef92 switches to on (they're in the holes beneath), that's it. No more crackling bass or strange volume. 


Infinity, you're my hero! ;)


I actually broke one of my M8161's by not changing the jumper on the left channel.





post #2642 of 3194



just received 4 Raytheon JAN-CRP 5654W tubes. Right now they're burning in on my MK IV SE. Just bought them on spec and haven't read about them so far. Experiences? Thoughts? Opinions?


Will compare with my other 5654 / 6AK5 tubes like the Mullard M8100, some Voskhods, RCA black plates, GE 5654W JAN...

post #2643 of 3194

The early 50's Raytheon tubes with the small mica discs (not touching the glass envelope, and the entire plate assembly being supported by the bottom pins) are among my favorites.

Later Raytheons don't sound good to me.

post #2644 of 3194

Mine have been produced in 1955. Having them "burned in" for about 6 hours with pink noise they sound quiet nice. Seem to have a lot of "air" for a EF95 tube. Haven't heard enough and burn in will last couple of days to make a nearly final statement.

Edited by infinity650 - 2/22/12 at 2:36pm
post #2645 of 3194



It's my first post here! I bought the LD MkIII with CV4010 and have been enjoying it for about 2 weeks and decided to jump on the rolling bandwagon with Voshkod 6ZH1P-EV and EH 6H30Pi! I was pleased with CV4010, but I'm now on the slippery slope of rolling heh (rolling down hill.. I'm sure there are more rolling/slope metaphors :) )


I have a few questions about the whole tubes thing.. why does the manual and everyone recommend only using the amp for 8 hours a time and then leaving for 30-45 mins? If it's a heat issue, can I just point a fan on it to keep the temp down? Coz that's what I'm doing at the moment :)


When a tube dies, how will I know which one it is? power or driver? I guess now I have the stock power tubes and the CV4010 tubes as spares I can use some trial and error to find this out..


Once either the left or right tube dies, does that mean I have to throw them both away, since it's unlikely to find a matching single tube?


What's the best/greenest way to dispose of a dead tube?



post #2646 of 3194

Hi Keyser,


I also wondered about why you cannot leave on the amp for more than 8 hours at a time, especially since it might take over 100 hours to burn in certain tubes. Don't know if I can recommend this to anyone, but I put my amp on three 1" high aluminum cones (big in Hi Fi in the 80's), and there is adequate airflow around the amp. Different tubes generate different amounts of heat, but the ones I use don't make the amp too hot, and it is only warm to the touch even after being on for a day or two. I once tried some EF92 tubes which made the amp too hot to touch - perhaps that could be cured with a fan; how hot the amp gets also depends on the room temperature where you live.

So far I have not noticed anything untoward by leaving the amp on for long periods of time when I burn in tubes; otherwise I shut it off after use.

It is important to let it sit in the off position a few minutes when changing tubes to allow the capacitors to discharge.


How do you know when a tube dies? In the driver tubes they usually go silent.  (First try to clean the oxidation off the pins.) If the vacuum goes, the silver coating turns white. Sometimes the tube crackles excessively. Main thing is that the sound diminishes or is absent in that channel.  Many times the power tubes start to sound less loud, and this is how you can tell if the power tubes are going bad as well. It should be very easy to detect if a tube is bad by noticing the change or absence of sound in one channel.


Personally, I don't put too much importance to matching. If one tube goes bad, just replace that one with one that is burnt in. I don't think that you will hear any difference. You can even use different (but similar) tubes in each channel, since each side of the amp is completely independent of the other side.


Regarding disposing of old tubes, I don't think that the very small quantities of chemicals/metals in the tubes are too harmful to the environment, and I would just toss them the way you dispose of glass. In my experience not too many driver tubes went bad, but I broke a few by dropping them. More problems with power tubes - please note that the stock 6N6P-i tubes are only rated for 500 hours (as compared to 3000 hours for the 6N6P tubes), although these ratings may apply more to the harsh environment in military applications rather than the TLC of an audiophile.

post #2647 of 3194

Regarding the heat issue, if you are worried about it one thing you could do is get something like a USB powered fan to blow across the tubes and amp. As an example: http://www.thermaltakeusa.com/Product.aspx?S=1295&ID=1801  - that one even has a knob to control the speed. Probably lots of other ones out there too.

Edited by kabes - 2/28/12 at 5:59pm
post #2648 of 3194

Maybe someone can help me with this .My question is related to the jumpers. if i am running tubes in the ef-95 family  where do i put the jumpers which pins theres 3  is it on the 2 first pins from right like on picture and when i see jumpers off what does that mean .do i remove the jumpers  can somebody explain this Thanks . 010.JPG

post #2649 of 3194

The EF-95 is the same as the m8100 setting which you already have on.

post #2650 of 3194
Originally Posted by mab1376 View Post

I actually broke one of my M8161's by not changing the jumper on the left channel.





Oh really, guess I was lucky then!


Anyways I've tried the m8100 and the Voskhods now for some time (after using the m8161).




I was after more bass in sound when watching movies and also music, and wasn't satisfied with what m8161 had to offer.

I use the sennheiser hd650 and a xonard dx soundcard which delivers excellent sound imo.




So which of all these tubes gave the best bass?

The answer is ironically also the one which is the cheapest of all, the Voskhods.Without a doubt this one has the best bass.

The problem with the other tubes, especially the m8161, was that the bass was too slow basically. What I mean by that is that the Voskhods tube is able to deliver faster moving bass, almost creating wind inside your earphones, and thus it gives you more punchy and alive bass experience.


I tried all tubes very extensively. At the beginning I thought the bass of the m8100 was worse than the Voskhods. Then I preferred the m8100 had a bit fuller bass than the Voskhods. But then I tried a particular punchy bass scene in the movie Transformers (at 44 min where the plane uses 105 shells against the ground target). I realised then that the air moves faster in the Voskhods than the other tubes and gives a much more rich bass experience.

The problem with the m8100 and more so the m8161 is not that they don't provide deep bass. It is that the bass is more deep and slowish instead of deep and punchy. The m8100 is about 70% of the Voskhods in terms of fast moving bass sound I would say. And the m8161 is about 45-50% of the Voskhods fast bass.


Conclusion: Which tube you want for providing best bass of these 3 tubes depends upon what you are going to use them for and what bass type you like. If you like the bass to be deep and don't care about it being fast, then the m8161 might be the way to go. I actually prefer the m8161 in some cases, such as when a male sings hoarsly, this tube really creates a superb vibrating deep bass and the sound of the voice is incredible. A good example of this is the song  Wishing Well by Terence Trent. Ofcourse the treble in the m8161 is better too than atleast the Voskhods.

If you want punchy bass then I would go with the Voskhods. Song that have this faster bass like Michael Jackson or in movies, this is definately your pick. The m8100 does provide nice bass too, it is not slow bass but it is not really fast either. So basically if you go with the m8100 you get more deep bass kind of like the m8161 but with faster bass than the m8161, although you don't get quite the deep slow full bass like the m8161.

The treble and soundstage of m8161 is far superior the Voskhods and a good amount better than the m8100. That said I did not like the m8161 because it had too much treble. You couldn't turn up music without the treble cutting into your ears. The tubes are so strong the ones I'm using that the equaliser really does not change much at all, I can turn down treble to 0 in my xonar dx equaliser and it doesn't change much.

The Voskhods still has really nice treble, there is nothing wrong with it. For example in Watchmen the glass is breaking in the beginning when a man is thrown out a window and you hear the glass breaking so freakin clearly it's sick (with great punchy bass at the same time!!). The Voskhods is just not as clear sounding and exact as the m8161. But having more exact treble at cost of not being able to turn up sound in movies nor music without that punchy bass is not a good trade off in my book. For anyone interested I can post my AC3 filter settings (in k lite codec pack older verion) for being able to turn up sound extensively in movies without it hurting your ears so you get max volume at action scenes aswell as having the speech in a high volume and the treble at a nice level (this took me 2 days to set so it sounded good at max volume). I actually have the mk iii at MAX and the equaliser in my computer at MAX and the AC3 filter at more than default max volume level, so you can imagine the things I've turned up in the filter, it just sounds Awesome now. You can hear things in movies you never could with speakers I believe =)



Hope this helped someone =)




post #2651 of 3194

Hello. All, does anyone think the 8 hour issue of leaving it on could have anything to do with the big 250v 220uf caps. I noticed the life span of these caps to be between 1 to 5 thousand hours of life. almost the same as tubes. The reason why i wonder is because i upgraded the 220uf caps for a friends mkIII and found the readings on the old caps to be on the low side 190uf witch is beyond the 20% tolerance. Could this be one of the reasons for the 8 hr issue.


post #2652 of 3194
Originally Posted by jsvilla93 View Post

Hello. All, does anyone think the 8 hour issue of leaving it on could have anything to do with the big 250v 220uf caps. I noticed the life span of these caps to be between 1 to 5 thousand hours of life. almost the same as tubes. The reason why i wonder is because i upgraded the 220uf caps for a friends mkIII and found the readings on the old caps to be on the low side 190uf witch is beyond the 20% tolerance. Could this be one of the reasons for the 8 hr issue.


Heat is one factor. Heat can dry out or breakdown the caps in time. When changing the caps one thing that can help is to use caps with a higher temperature ratings when possible. Also heat can effect the carbon resistors and the value can raise over long periods of time. Wireround resistors are more stable for long periods of time in the heat as compared to carbon resistors. Heat can also casue some sagging on parts in the tube. There is also contamination in the tube if left on for long periods of time with no signal.



post #2653 of 3194

Regarding running the amp longer than 8 hours at a time:


I would only do this when burning in new tubes. I would plug in my headphones and set my iTunes program to play continuously. Usually the amp, which is well ventilated, would not feel hot at all to the touch; if it did feel very hot I would shut it off to cool off (happened with some EF92 tubes).


During regular listening sessions I would always shut off the amp after use, and I would never leave it on for extended periods of time.


If it is correct that some of the parts in the amp have a limited life span of only 1000-5000 hours it would be very bothersome to me since I do not have the knowledge of how to change any of the internal parts.


So far I have used the LD MkIII almost two years and I cannot hear any diminishing of the sound quality .

post #2654 of 3194
Hi all,
Contacted David Zhe Zhe of Little Dot and asked the following questions (His answers are underlined and in italics)
What is the life expectancy of the Little Dot MkIII preamp assuming it is being used 3 hours daily? Are there internal parts that wear out or deteriorate over time similar to vacuum tubes having a finite life expectancy?

No.  Lifespan would be pretty much the same as any other consumer electronics ~10 years or so.
What is the reason for your recommendation of not keeping the amp on longer than 8 hours each time?

Possible heat buildup if placed in an area with low ventilation.


So just keep on enjoying the the Little Dot MkIII and don't worry about nothin'!

post #2655 of 3194

Hi everyone,


I am looking to purchase a pair of decent headphones for myself... I am just getting started in the audiophile hobby, so if anyone has any reccomendations please let me know.  For now I am leaning towards the audio technica ath m50s.


I've ripped all my cds onto itunes using the alac encoder, and i plan to do most of my listening from my computer.  I think the best way to go is hooking up an external dac to my pc to bypass the internal soundcard, and then hooking that up to a dedicated tube amp, such as the mkiii.  I don't want to spend too much on dacs or amps, though, because the ath m50 can only do so much. 


So I'm wondering if that setup would be better for me, or if I should just buy a hifiman ef2a and use that as the dac and amp?  Would that be a better bang for my buck or is there really that much of a difference in quality that I should opt for the first setup?


Thanks for your help



New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Little Dot MKIII Tube Rolling