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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 84

post #1246 of 8778
Quote:
Originally Posted by mordy View Post

Hi Gibosi,

 

LOL, firstly, let's keep up the high ethical standards of this forum dt880smile.png and not amputate or butcher tubes, just modify them for our needs.

 

To evaluate 5 new tubes takes a lot of mental energy, so I temporarily put aside this project in favor of evaluating a pair of RCA 6BY6 heptodes, which is an easier mental challenge. (Paid $5.25 total incl. shipping from a nice seller.) These only require the EF92 setting and nothing else (Plug and Play?).

 

At first I was not impressed by them. Nothing objectionable in the sound, but the treble was too bright and a little sibilant, and the bass was not very deep and a little weak. The mid range was pretty good but I thought that these tubes are not any better than a good 6AK5 tube.

 

However, you have to take your own advice and be patient. Tubes need to burn in, usually a minimum of 20 hours and some 50 hours (Voskhods need 120 hours). So I stuck in the 6BY6 tubes and left my system on, on low volume. These tubes do not get very hot, and I can easily touch them without worry.

 

{About my own advice: If you have trouble with a tube quitting on you suddenly, scrape the pins gently to get off the oxidation. I was going to practice cutting off the pins for the triodes, but could not think of a defective tube to cut. Then I remembered that one of the original LD 6N6P-i power tubes had stopped working. For some reason I had saved it around two years. Well, before doing the surgery I looked it over, looking at the pins. One pin looked greenish. Out came the pocket knife. Plugged in the tube. What??? It is working!! Couldn't believe it....}

 

Well, after supper I couldn't believe this either! The 6BY6 tubes had suddenly come to life after about 25 hours of use! The sound stage suddenly became huge with sound emanating from outside of the speakers on some recordings. The bass became much stronger. The mid range is sweet. The treble is still too bright, but can easily be adjusted with my tone control. I am hearing the same type of magic as from the 6AH6/6AU6 tubes. Not as detailed, not the same pin point imaging and clarity, but nevertheless a sweet, warm and engaging (tubey?) sound.

 

I feel that these still need more time - will keep you posted.

Hi mordy,

 

Re your comments on oxidised pins, I wonder how many people are getting below-par performance from their LD simply because of this inevitable consequence - eventually at least (my MKiv SE came with such crud on the Mullards 'twas a wonder the poor thing worked at all!

 

The solution? I got myself a silver-plating kit, and treat the pins to something lovely to behold...so hopefully no such worries in the future?...And the added bonus of improved conductivity - even the black silver oxide is better than (clean) copper. With any luck the sound will also be helped, especially following the principle of having similar metals , if possible, throughout the system - have pure silver interconnects and pure silver headphone cable (mainly because of the incredible difference I found after replacing rather good copper speaker cables, again with pure silver, and especially the INTERNAL wires of the Dynaudios).

 

So now, if only I could get to the socket holes...then any wire inside the LD...then...oh dear, getting rather carried away now. Had better say cheerio for now.

 

The moral? Look after your pins everyone!!

post #1247 of 8778

Hi hypnos 1,

 

Regarding cleaning the tube pins, there has been research done and my recommendation to scrape the pins lightly and gently is based on a 1945 study that I referenced a long time ago on this forum. Here is a much more recent quote that I just found from some electronic scientist:

 

" Folks, I am going to jump in here and I hope I do not upset any body with what I post. I work for a major computer company in a part of the business where we are very concerned with metal on metal electrical contacts. I have no idea how much money and how many hours we have poured into studying this, but it is a lot! The results of all of this research has shown beyond any doubt that the absolute best electrical contacts come from a metal on metal swiping action where at the atomic level the atoms of the one metal side are mechanically smeared into the atoms of the other metal side. If the mechanical smearing is good enough it actually seals out the oxygen and other molecules (to explain why takes some pretty heavy duty solid state physics and this is not the place for that). Any foreign substance no matter what it is only impedes the electrical contact. Now, if the metal surfaces are dirty or corroded in any way cleaning them back to pure metal is absolutely the right thing to do. However, the idea that some fluid (whether it is metal loaded or not) is going to improve the electrical contact by lubrication is just not supported by research in this field. "

 

About cleaning the the tube sockets: There are many posts about this and many methods. After reading through a lot of stuff, my opinion for now is that it takes very little contact area to make a good contact with the pins inserted into the tube socket (witness the tiny little thin gauge stranded wires in the 2-7 strap used successfully as reported on this forum). Following the old adage "If it ain't broke, don't fix it" sounds like a good idea.

However, if there is crackling etc and it is not the problem of the tube pins, and moving around the tube does not help, some people spray a little high temperature Gold Deoxit on tube pins and push the tube in and out 6-7 times. People warn not to use anything that does not evaporate quickly - gunk and residues are not what you want in the pin holes. (Some people say that you can using rubbing alcohol in a pinch.)

For mechanical cleaning thin pipe cleaners may work, as well as small tip cleaning brushes used to clean welding tips (available from welding supply stores). There may also be thin brushes used to clean guns and rifles available in sporting goods stores. A thin Dremel brush may work if used with your fingers only.

 

Here is a link to a tube cleaning kit:

http://www.musicdirect.com/p-1158-caig-vacuum-tube-survival-kit.aspx

 

And here is a video advertising this kit:

http://www.youtube.com/watch?v=n9r_ZPHxuIQ

 

Note that the Music Direct price is much less than that in the video.

 

What do I do myself? I just push the tube in and out of the socket a few times - so far so good....
 

post #1248 of 8778

I use a ladies fine nail file and sometimes Flitz.

 

The Gaig cleaners ere not effective from my experience but Deoxit Gold is excellent for pin preservation and better contact.

post #1249 of 8778

Thanks for suggestions. Looked up Flitz, but they make many different cleaning products. Could you specify which one you recommend? (Gun bore cleaner?)
 

post #1250 of 8778
Quote:
Originally Posted by mordy View Post

Hi hypnos 1,

 

Regarding cleaning the tube pins, there has been research done and my recommendation to scrape the pins lightly and gently is based on a 1945 study that I referenced a long time ago on this forum. Here is a much more recent quote that I just found from some electronic scientist:

 

" Folks, I am going to jump in here and I hope I do not upset any body with what I post. I work for a major computer company in a part of the business where we are very concerned with metal on metal electrical contacts. I have no idea how much money and how many hours we have poured into studying this, but it is a lot! The results of all of this research has shown beyond any doubt that the absolute best electrical contacts come from a metal on metal swiping action where at the atomic level the atoms of the one metal side are mechanically smeared into the atoms of the other metal side. If the mechanical smearing is good enough it actually seals out the oxygen and other molecules (to explain why takes some pretty heavy duty solid state physics and this is not the place for that). Any foreign substance no matter what it is only impedes the electrical contact. Now, if the metal surfaces are dirty or corroded in any way cleaning them back to pure metal is absolutely the right thing to do. However, the idea that some fluid (whether it is metal loaded or not) is going to improve the electrical contact by lubrication is just not supported by research in this field. "

 

About cleaning the the tube sockets: There are many posts about this and many methods. After reading through a lot of stuff, my opinion for now is that it takes very little contact area to make a good contact with the pins inserted into the tube socket (witness the tiny little thin gauge stranded wires in the 2-7 strap used successfully as reported on this forum). Following the old adage "If it ain't broke, don't fix it" sounds like a good idea.

However, if there is crackling etc and it is not the problem of the tube pins, and moving around the tube does not help, some people spray a little high temperature Gold Deoxit on tube pins and push the tube in and out 6-7 times. People warn not to use anything that does not evaporate quickly - gunk and residues are not what you want in the pin holes. (Some people say that you can using rubbing alcohol in a pinch.)

For mechanical cleaning thin pipe cleaners may work, as well as small tip cleaning brushes used to clean welding tips (available from welding supply stores). There may also be thin brushes used to clean guns and rifles available in sporting goods stores. A thin Dremel brush may work if used with your fingers only.

 

Here is a link to a tube cleaning kit:

http://www.musicdirect.com/p-1158-caig-vacuum-tube-survival-kit.aspx

 

And here is a video advertising this kit:

http://www.youtube.com/watch?v=n9r_ZPHxuIQ

 

Note that the Music Direct price is much less than that in the video.

 

What do I do myself? I just push the tube in and out of the socket a few times - so far so good....
 

Hi mordy,

 

Thanks for your very informative post - I am so glad I found this forum, especially this particular thread with such knowledgeable and helpful guys...(where are the gals I ask?!)...

 

The report you quoted was very interesting and has got me thinking further re my silver-plating viz 1. The maintenance of metal to metal contact through the inhibition of (bad) oxidation/corrosion - I am a firm believer in prevention rather than cure, and sound quality must surely be compromised well before any 'crackling'/tube failure...2. I may well be "up in the clouds" now, but I wonder if the softness of the silver coating might just help in the 'purity' of the contact between pin and socket, thereby assisting the possibility of the 'atom smearing' mentioned in the quote and thus the benefits of oxygen etc. reduction. Even if this is rather fanciful, the mental imagery of this taking place will almost certainly have me BELIEVING good things are happening! - the musical experience is in good measure a PSYCHOLOGICAL one...which is another reason why I do like to 'tweak' things, so long as it doesn't cost too much. And sometimes tweaks can result in definite empirical improvements.

 

Whatever, I shall continue to follow these wonderful posts with relish and look forward to even more words of wisdom from such a dedicated group of contributors - thanks to all of you.


Edited by hypnos1 - 5/14/13 at 9:06am
post #1251 of 8778
Quote:
Originally Posted by mordy View Post

Thanks for suggestions. Looked up Flitz, but they make many different cleaning products. Could you specify which one you recommend? (Gun bore cleaner?)
 

 

You are most welcome.

 

It's the Metal, Plastic and Fiverglass polish paste.

It also offers protection against corrosion.

 

http://www.flitz.com/p-16-flitz-polish-paste.aspx

post #1252 of 8778

Hi h1,

 

Welcome to the forum! The writer I quoted says mainly that liquids cannot improve metal to metal contact. I cannot see anything wrong with silver plating if it works for you. There are companies that gold plate the tube pins (Sylvania, Electro-Harmonix and others) so they must see a benefit in doing so.

 

I assume that the purpose of liquids is for cleaning purposes, and it seems that it is very important that no residue is left after the cleaning since it may interfere with the metal to metal contact.

 

IMHO the main thing is to enjoy listening to the music and not listening to the equipment (although I am told that there are people that mainly enjoy the latter).

 

When evaluating tubes I am forced to listen to the equipment. Sometimes the experience is such that you forget what you are doing and you just enjoy the music instead!

 

Cheers,

post #1253 of 8778

Hi All,

 

Remember the mention here about buying Little Dot MKIII amps for $10 + shipping?

 

Well, the dirt is hitting the fan already! If anybody bid on this, call up Ebay and ask for your money back right away.

 

Exhibit A:http://www.head-fi.org/t/663519/ebay-scam-auction-little-dot-iii-for-9-50-s-h

This is a new thread on this scam.

 

Exhibit B: http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback2&userid=qiangzhanghihi&&_trksid=p2047675.l2560&rt=nc&iid=171035236990&sspagename=VIP:feedback&ftab=FeedbackAsSeller

The feedback is starting from scammed people.

 

If it is too good to be true, it is too good to be true.....
 

post #1254 of 8778
Quote:
Originally Posted by mordy View Post

Hi Gibosi,

 

LOL, firstly, let's keep up the high ethical standards of this forum dt880smile.png and not amputate or butcher tubes, just modify them for our needs.

 

To evaluate 5 new tubes takes a lot of mental energy, so I temporarily put aside this project in favor of evaluating a pair of RCA 6BY6 heptodes, which is an easier mental challenge. (Paid $5.25 total incl. shipping from a nice seller.) These only require the EF92 setting and nothing else (Plug and Play?).

 

At first I was not impressed by them. Nothing objectionable in the sound, but the treble was too bright and a little sibilant, and the bass was not very deep and a little weak. The mid range was pretty good but I thought that these tubes are not any better than a good 6AK5 tube.

 

However, you have to take your own advice and be patient. Tubes need to burn in, usually a minimum of 20 hours and some 50 hours (Voskhods need 120 hours). So I stuck in the 6BY6 tubes and left my system on, on low volume. These tubes do not get very hot, and I can easily touch them without worry.

 

{About my own advice: If you have trouble with a tube quitting on you suddenly, scrape the pins gently to get off the oxidation. I was going to practice cutting off the pins for the triodes, but could not think of a defective tube to cut. Then I remembered that one of the original LD 6N6P-i power tubes had stopped working. For some reason I had saved it around two years. Well, before doing the surgery I looked it over, looking at the pins. One pin looked greenish. Out came the pocket knife. Plugged in the tube. What??? It is working!! Couldn't believe it....}

 

Well, after supper I couldn't believe this either! The 6BY6 tubes had suddenly come to life after about 25 hours of use! The sound stage suddenly became huge with sound emanating from outside of the speakers on some recordings. The bass became much stronger. The mid range is sweet. The treble is still too bright, but can easily be adjusted with my tone control. I am hearing the same type of magic as from the 6AH6/6AU6 tubes. Not as detailed, not the same pin point imaging and clarity, but nevertheless a sweet, warm and engaging (tubey?) sound.

 

I feel that these still need more time - will keep you posted.

 

Hi Mordy, good to see you tried some 6BY6! Interesting observation with the treble, I also felt it gets gentler over time with my 6BE6-type Sylvania JAN 5750 in which case I actually didn't appreciate it but tubes in these families seem to have different amounts of treble. If the treble after burn in still is too much for you, I would suggest to use the EF95-setting, which is likely to resolve that issue.

Interesting also you mention that large stage and sweet mids, my 6BE6 sound agrees with that. For the details. Hmm. Maybe they are not as detailed as the 6BE6? Possible. Or they need more burn in. I found that large stages can also lead easier to the impression of lesser details if imaging and resolution do not scale with the stage, then you will find less details per musician. In contrast, if the stage is small, especially not deep and the imaging is just OK you will still have the musician right in front of you and it may seem more detailed. My personal preference goes to larger stages and resolution in treble and mids because I find vocals, guitars, violins etc., space and reverb in recordings to match my fascination most. A good balance is a big plus of course. Got side-tracked... Would be interesting to hear your opinion on a Tung Sol 6BE6 if you cheaply come across one ;) I find them quite detailed to say the least...

 

Gibosi, exciting adventures with your butchered, mutilated, cut, modified, altered, adapted, compatibilised 6AV6 tubes. How are your impressions? Oh, and what is your opinion about the GE JG-5750/6BE6W after having had your cans for longer?

 

Mikelap, enjoy your 6AU6 and 6BE6 tubes. Congrats to those.

 

Hypnos1, good to see you around in this thread and congrats to your 6H30P-DRs :) I am still playing with the thought of getting a pair myself.

 

Oh, and of course I won't deny my roots: If not DRs, when you are rolling tubes, you may as well get a pair of power tubes you do not have (6H30P, 6N6P-IR) since you are at it wink.gif Power tubes make a difference, and more the better your gear gets smile.gif

 

 

 

LD I+/III/IV-Tube compatibility table: Page 77, post 1154


Edited by Acapella11 - 5/14/13 at 2:14pm
post #1255 of 8778

Regarding tube cleaning, I typically use the back of the tip of an Xacto knife. Using the flat side I scrape repeatedly all sides of the pins.

It's a bit laborious but all of the pins I do this with turn out quite shiny. This also helps with solder affinity. :)

 

So, I'll be the first to admit it. This is another reason I dislike clipping pins off of tubes...

I cut the wrong pins last night!!!

I looked at the diagram for the socket, not the tube, and ended up cutting pins 2 & 3 off of a pair of Sylvania 6AV6 tubes.

So annoyed with myself! At least they were only around $9 shipped for both.

post #1256 of 8778
Quote:
Originally Posted by inphu510n View Post

So, I'll be the first to admit it. This is another reason I dislike clipping pins off of tubes...

I cut the wrong pins last night!!!

I looked at the diagram for the socket, not the tube, and ended up cutting pins 2 & 3 off of a pair of Sylvania 6AV6 tubes.

So annoyed with myself! At least they were only around $9 shipped for both.

 

This is a bummer! But at least they were cheap tubes and I am quite sure you will never do this again... So get some more tubes and get cutting!! :)

post #1257 of 8778
Quote:
Originally Posted by Acapella11 View Post

Gibosi, exciting adventures with your butchered, mutilated, cut, modified, altered, adapted, compatibilised 6AV6 tubes. How are your impressions? Oh, and what is your opinion about the GE JG-5750/6BE6W after having had your cans for longer?

 

 

I haven't listened to the TS 6485 or any other tube requiring the 2-7 strapping since my sockets went flaky. And as a consequence, I haven't heard any of these reference tubes with my new headphones, only triodes. And thus, I can't compare any of the tubes I am currently using to the tubes the rest of you know well.  

 

My goal is to get a handle on all these triodes and then report back, comparing them to each other, with the hope that it might be somewhat useful.....

 

And then I need to send some time with the GE JG-5750/6BE6W and the RCA JRC 5915. But again, few if any of you know these tubes well either.....

 

I took my test sockets to a jeweler/goldsmith today, and she thinks she can do what I want, but won't be able to get to them until next week. If she is successful, then I will finally be able to listen to the TS 6485, and perhaps provide more meaningful comparisons.

 

In the meantime, I continue to cut pins and burn...  The GE 6AV6 are burning in as I write this... So far, first impressions, I like the GEs and the Mullards the best. The highs on Sylvania and RCA 6AV6s seem a bit to bright to me, but they all need to burn in more.... and perhaps my headphones also need to burn in more too.....

 

Cheers

post #1258 of 8778

Hey guys this is off topic but have a listen to this, singing is my sons girlfriend she has a very nice voice.  Thanks.  http://youtu.be/q0ZWG4NZDjo


Edited by MIKELAP - 5/15/13 at 12:02pm
post #1259 of 8778

Hi Mikelap . Yep, she has a lovely voice - and it's one of my favourite songs...it was nice to hear it again. I hope she goes far with her singing.

 

Many thanks to mordy and A11 for the welcome - much appreciated.

The 6N(H)30P-DRs replaced the 6H30P-EHs, which might well go back in for any further rolling. I did get some 6N6Ps (gold grid), but apparently David at LD said they were not suitable for the later MKiv SE - wish I knew why...

 

On the subject of rolling, the TS 6485s are proving to be so magical I cannot believe things could get any better - but never say die!! I have yet to try a pair of Sylvania Gold Brand 5750s - but A11, did you say the TS 5750s were better? Anyways I am looking forward to seeing how they compare to the 6485s. This rolling is somewhat addictive, but great fun and also very illuminating. And certainly FAR less expensive (and more convenient) than trying different combinations of source, amplifier, connector etc. etc.

But of course it's you guys, plus gibosi and audiofanboy who do all the real hard work - long may you prosper! All we lesser mortals owe you a debt of gratitude. Keep up the good work...

post #1260 of 8778
Quote:
Originally Posted by hypnos1 View Post

Hi Mikelap . Yep, she has a lovely voice - and it's one of my favourite songs...it was nice to hear it again. I hope she goes far with her singing.

 

Many thanks to mordy and A11 for the welcome - much appreciated.

The 6N(H)30P-DRs replaced the 6H30P-EHs, which might well go back in for any further rolling. I did get some 6N6Ps (gold grid), but apparently David at LD said they were not suitable for the later MKiv SE - wish I knew why...

 

On the subject of rolling, the TS 6485s are proving to be so magical I cannot believe things could get any better - but never say die!! I have yet to try a pair of Sylvania Gold Brand 5750s - but A11, did you say the TS 5750s were better? Anyways I am looking forward to seeing how they compare to the 6485s. This rolling is somewhat addictive, but great fun and also very illuminating. And certainly FAR less expensive (and more convenient) than trying different combinations of source, amplifier, connector etc. etc.

But of course it's you guys, plus gibosi and audiofanboy who do all the real hard work - long may you prosper! All we lesser mortals owe you a debt of gratitude. Keep up the good work...

 

 
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Re: Little Dot Mark IV SE tubes compatibility

Postby Chocki » Jul 7th, '12, 17:17

Well my 6N6P Gold grid power tubes arrived this morning, I've had them in all day circa 12 hrs playing while I've been working doing the kitchen up.
Impressions are very favorable, they are as good as the 6H30PI's but last a lot longer being military ruggedised. They start off completely silent at max volume with no imput (Remember my headphones are much lower resistance than sennheiser HD 650's so everything is much louder), but after 12 Hrs, they also exhibit some slight static noise but nothing like like the 6H30PI's, not that I ever listen at max output and it really is faint, while checking this out what I did notice though is that the LD DAC_1 suffers from crosstalk!. With IN2 playing, selecting any other input, you could still hear IN2 (RCA SPDIF) very faintly at max volume. Again not the slightest bit worried as I only intend to listening to one source.

Found this on Littledot site and its dated july 2012 did they change the model after that.

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