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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 87

post #1291 of 7488

 

GE 6BE6W/JG-5750 manufactured in 1959. I can't help but notice how similar these look to the black plate GE 6AU6/6136....

 

After burning these in for over 20 hours, I have come to the conclusion that these are very nice tubes. Again, as I am not able to listen to my 6AH6/6485 and/or 6AU6/8425/6136 at this time, I am feeling a bit handicapped.... 

 
But the show must go on....  and actually, this is quite easy as it seems that I am hearing virtually everything in these GE 6BE6 that A11 has noted regarding his TS and Sylvania 6BE6
 
"Airy, open, spacious representation, neutral.
Treble: Extended, refined, not bright. Well resolved. 
Mids: Quite sweet, round, clean.
Bass: The bass quality is very good, well articulated and punchy.
Stage: Large and wide
Great detail against a black background."  (My apologies to A11. :)
 
But seriously, these are very nice tubes, and it seems that there is a strong sonic resemblance among the various brands of 6BE6. Further, I believe am hearing some of the same "amazingness" I remember hearing with the GE and TS 6AH6/6485 and the GE 6AU6/8425/6136 tubes.  
 
I hope someone will decide to purchase both the GE and TS and do a shoot out! :)
 
And now, I am burning in a pair of RCA 6BY6/JRC-5915 manufactured in 1963.....
post #1292 of 7488
Quote:
Originally Posted by hypnos1 View Post

Hi J,

 

Glad you were able to source the 6485s at such a good price - and to have someone match a pair is even better!

I cannot wait until you try them, given your findings re the Voskhods...mine have done about 50 hours now, and combined with about 40 hours on a pair of early 6N30P-DRs I cannot believe what my ears  - and brain - are experiencing. I can only hope your setup (and you!) are  treated to something similar...

 

Thanks to Gibosi for the info re EF95 setting.

 

Your comments re soldering were interesting - just might have a go sometime. Methinks the complex alloys used in the pins - possibly manganese/zinc/nickel/copper/cobalt - would contribute to the very careful preparation needed before getting anywhere near with the iron. I, and others on this forum I am sure, look forward to your outcomes in this feat!

 

Regards, CJ

Hi CJ, Gibosi, and many thanks to all for the accelerated (and free) course on  tube rolling ¡¡  I received my TS 6485s yesterday, nice NOS american tubes, I guess very old ones, looks like sixties stock.   After all my chat about matching, soldering, etc. I arrived late from work and simply could not wait and did the 2/7 jumper trick. It is true that this has to be done with twisted wire, but I felt that 26 AWG was a bit too thick, including the insulation,  so I rolled my own from bare copper filaments (¡¡) arriving at something a little thinner.  After some artistic work with little pieces of insulating tape, I got my custom jumpers,  perfect and tight fit with the tubes inserted.  I should sell them for $20 a piece.  Of course, we have to be patient and wait for a good burn in before any opinion about sound quality.  These tubes have been sitting for around 50 years, so at the minimun lets them awake and tell us what they can do. However, from the start it is obvious that the 6485s are good ones. To begin with, there is no background noise or microphonics, the detail is very good and have plenty of bass. Very promising...      

 .        

post #1293 of 7488
So I'm beginning to think that my MKII doesn't like triode tubes. The two pairs I've tried had a slightly audible buzz/clicking on the right channel. Also I've noticed more microphonics and (I have no idea what the word is) proximity sensitivity. If I put my fingers near the right channel tube I hear a very audible buzzing/interference noise.
I switched in some older EF92's and there was no buzzing in the right channel.
I've tried both 6AV6 and 8532 tubes and they both exhibit some form of buzzing in the right channel.

I guess I'll have to upgrade to the MKIVSE. *sigh*
Edited by inphu510n - 5/18/13 at 12:30pm
post #1294 of 7488

 

Quote:
Great detail against a black background."  (My apologies to A11. :)

 

Gibosi, I feel honoured you are citing my words to reflect your own impressions ;) Seems the GE JG-5750 6BEW is a good one as well. Please, let me know which your favourite 6BE6/6BY6 tube(s) is (are) once you had the opportunity to listen to all of them. Just out of curiosity, which power tubes are you using?
 

Inphu510n, I used your triode experience with the MKII in the tube guide table on page 77 and acknowledged you. Useful for every MKII tube roller. With respect to the potential upgrade: Look at it as a long term investment and you will be able to roll power tubes as well! Or sink all your money straight into DRs ;)

post #1295 of 7488
Quote:
Originally Posted by Acapella11 View Post

Just out of curiosity, which power tubes are you using?

 

Inphu510n, I used your triode experience with the MKII in the tube guide table on page 77 and acknowledged you. Useful for every MKII tube roller. With respect to the potential upgrade: Look at it as a long term investment and you will be able to roll power tubes as well! Or sink all your money straight into DRs ;)

 

I have the LD 1+. This is a hybrid amp, which uses tubes to "flavor" the sound and a solid-state op-amp for power. As the op-amp can be "rolled' as well, I guess my current "power tube" is an OPA2107. :)

 

The 1+ is a rather different kind of beast compared to the LD II, III and IV....

 

Imphus510n. I seriously doubt that upgrading to a MKIVSE will "solve" this problem, as the problem is most likely just some faulty tubes. Any one who has rolled tubes for any length of time experiences this on occasion....

 

(Now that said, if you really want to upgrade to a MKIVSE, this is as good an excuse as any! ;)

post #1296 of 7488
Quote:
Originally Posted by gibosi View Post

 

(Now that said, if you really want to upgrade to a MKIVSE, this is as good an excuse as any! ;)

 

Definitely where I'm leaning. :D

It's also high time I upgraded my cans too. I just put in a Schiit Modi DAC and that helped smooth things out a bit though I know changing headphones is definitely going to change things dramatically.

 

I have another set of Sylvania 8532's on the way and will give them a try.

Indeed, one of the RCA 8532's that I was trialing last night was definitely less present than the other. It was as if parts of the song were missing from which ever channel the tube was placed in.

Another thing I should note, the 8532's I tried last night did not have amazing pin contact. They slid into the socket much more easily than other tubes. I'm wondering if slightly bending or tweaking the pins might improve their connection. I'd already scraped the pins with an Xacto knife so it's not that.

I have a pair of Ultron SQ 6AV6's and they had a similar issue with the right channel however less so than the 8532's.

I'm definitely looking forward to the Sylvania 8532's. There were things I really loved about the Sylvania 6AU6WC tubes but the GE 8425's just took the cake. I still really love the 8425's. It doesn't hurt that Tektronix was/is located a few miles from where I live.

 

I'm looking forward to re-trying some of the tubes I've collected once I get new headphones. Leaning towards Fischer FA-003ti's or Beyer 770 600ohm right now. We'll see. I was using this setup primarily at work where closed cans were necessary. I'm thinking I might just get a Fiio and some UE triple.fi 10's for work use. The MKII is definitely a conversation piece though I keep rolling so many tubes through it, it would get distracting at work.

 

Anyhow, thank you all for your continued "hard work" and diligence in pushing the boundaries of this amp.
I think once the eBay tube adapters arrive I'm going to walk into ALO Audio's store here in town with the adapters and a set of 8425's and see what their amp can really do. They're primarily pushing Voskhods with their tube amp but hehe, that tube can't compete.


Edited by inphu510n - 5/18/13 at 3:11pm
post #1297 of 7488
Quote:
Originally Posted by gibosi View Post

 

I have the LD 1+. This is a hybrid amp, which uses tubes to "flavor" the sound and a solid-state op-amp for power. As the op-amp can be "rolled' as well, I guess my current "power tube" is an OPA2107. :)

 

The 1+ is a rather different kind of beast compared to the LD II, III and IV....

 

Yes, should have checked your profile and of course you mentioned it before. My default thought goes to MKIII / MKIV(SE).

 

Quote:

Imphus510n. I seriously doubt that upgrading to a MKIVSE will "solve" this problem, as the problem is most likely just some faulty tubes. Any one who has rolled tubes for any length of time experiences this on occasion....

I have kept everything in the table with respect to I+, MKII and III / IV compatibility. Let's see whether MKII triode issues come up again.

post #1298 of 7488

become my go to tubes L3000.gif Good stuff, and so far, (even) more impressive than the GE 8425 (6AU6 type). Tube code is 3227106-3, which I interpret as Tung Sol (thanks Mordy :) ) and 6th week of 1971.

 

Hi Acapella, still burning in the TS 6485s, but after a few hours I have to agree with you 100%,  excellent sounding tubes.  Clean, clear, detailed, open, great stage, nice bass.  Mine have a Tube code 322PW-1, no idea what it means... 

post #1299 of 7488

Hi JS,

 

I have tried to get a decoding sheet for the letter coding on the Tung Sol tubes, but no luck. The only thing I found was that these letter codes pre-date the numerical codes, meaning that these tubes probably are from the 50's and 60's. The last digit, which could be 1, 3 or 7, based on my experience, is a factory code.

One of the reasons why so many tubes have obscure date codes is for business purposes. As you point out, tubes that are fifty years old and more, can perform like new. However, psychologically, the manufacturers figured that many people when buying tubes wanted fresh ones that were newly manufactured, thinking that they are better. So in order to allow the old stock to move off the shelves, they obscured the dates.

Don't know myself why I just have to know when a tube was made. Perhaps the knowledge that some of the US made late 70's/early 80's tubes were poorer quality (for Russian tubes after the fall of communism in the 90's) is the reason.

 

Just got a RCA 6J4 tube, which is the same type as the 8532 tube. The RCA date code is (I think, hard to read) MI, which means July 1961.

 

Have not been able decode Sylvania letter date codes. Does anybody know?
 

post #1300 of 7488

So, I had a listen to the Sylvania JAN 6AH6WA and compared them to the Tung Sol 6485 (6AH6 type), mainly because quite a few people have them already, they are great tubes and I do not have to change jumpers :)

 

Treble: The Sylvania has a well extended treble, non-fatiguing. In comparison to the TS 6485 it is not as clean though. The TS plays opener, airier, which makes the treble more engaging and fun. Importantly, the TS sounds also cleaner in the treble, which makes it more interesting.

Mids: Round and sweet, this is probably where the Sylvania comes closer to the Tung Sol.

Bass: More bass weight than the TS and also goes deeper. If your taste goes more towards bass, the Sylvania may be interesting. However, I find the TS bass tighter, better defined but this could be a result of the general signature difference with the TS sounding cleaner than the Sylvania.

 

The Tung Sol sounds opener, more revealing, cleaner and has a deeper stage, which goes along with wetter sound. Also, I find the TS 6485 imaging is better. It is more neutral, where the Sylvania is sweeter and tubier.

 

My vote goes for the TS 6485 between these two tubes.

 

Then, I stuck in the TS 6BE6, for curiosity. Still, I am trying to figure out differences but it is often inhibited by the effort to switch two jumpers between every passage you want to compare. I think the general difference between these TS tubes is that the 6BE6 is more mid centric. Both tubes are neutral but the 6BE6 sounds somewhat rounder. The 6485 is brighter and harder (in comparison). This gives crunchier riffs, tighter bass, sharper treble. The 6BE6 is in comparison a more subtle imaging instrument with its strength in resolution and details using a larger stage than the 6485. I think if you can appreciate and hear all the "purity" of details over the clean background, if the gentler presentation suits your system and taste, the 6BE6 wins. If you like the sparkly 6485 sound and are not too much fussed about all these micro details or simply don't have the system to hear them, then the 6485 wins. I might revise some of this later again. But this my impression at the moment.


Edited by Acapella11 - 5/19/13 at 10:50am
post #1301 of 7488

 

RCA 6BY6/JRC-5915 manufactured in 1963/64. Mordy, do these look like your RCA 6BY6?

 
After 20 hours plus of burn-in, the sonic resemblence of these to the GE 6EB6 is immediately apparent.  Like the 6EB6, these are very quiet tubes, revealing "great detail against a black background". 
 
I would guess that as these tubes were often used to modulate and/or demodulate two separate signal streams, they would have to have very low noise and be very clean and neutral by design. And as these heptodes were often used to demodulate an FM radio signal down to audio, it is not unreasonable to conclude that they were also designed to faithfully process audio frequencies. 
 
These heptodes are a great find, I think.
 
Again, borrowing from A11's description of the 6EB6:
 
Airy, open, spacious representation, neutral.
 
Check.
 
Treble: Extended, refined, not bright. Well resolved. 
 
Check. But I think the RCA is a just a tiny bit brighter...
 
Mids: Quite sweet, round, clean.
 
Check. For both, vocals, horns and other acoustic and percussive instruments sound very natural
 
Bass: The bass quality is very good, well articulated and punchy.
 
Check. Both of these tubes have very good bass, strong, deep and punchy.
 
Stage: Large and wide
 
Check. Both of these tubes have a large, wide and deep sound stage, very realistic to me.
 
After spending a couple hours A/B-ing these tubes, I am a bit  embarrassed to say that my old ears could not reliably differentiate between these tubes. I am quite sure there are differences, but I believe they are very subtle.... 
 
Again, "great detail against a black background". What really stands out in my mind for both of these is the amount of low-level detail revealed in my favorite recordings. It is kind of mesmerizing....
 
And perhaps it is not so bad that I can't pick a clear winner in that I can recommend both of these tubes without reservation. :)

Edited by gibosi - 5/19/13 at 11:06am
post #1302 of 7488

Gibosi, Sounds very interesting. Thanks for the detailed description and it is good to read that you have similar impressions. Sometimes, if you keep comparing too much, I find, differences start to blurr. Fresh ears are a plus and also being actually in the right mood, because then, at least I, remember differences better. From your write up it seems the RCA 6BY6 would be brighter, but only a little. "A little brighter" sounds good to me. Should hear some 6BY6 tubes.
 

post #1303 of 7488

Hi Johnnysound,

Glad you're discovering how good the TS6485s are - just wait 'til further burn-in! I can't thank the guys here enough for extolling their virtues, especially audiofanboy for placing them at the top of his list some while back. To my mind they are producing a coherence of sound that transcends a merely good 'balance', plus of course an amazing clarity.  It creates an experience that,as mordy states, is one of sitting back and just enjoying the music, rather than analysing/evaluating what is producing it. This has hit me especially with some (nay most) of the tracks on ELOs 'Out of the Blue' album, where in the past my equipment - and my ears - had great difficulty 'disentangling' some rather complex sound creations in said album. Now I can with great glee appreciate the incredible feat of mixing the engineer achieved, some years ago now...WOW!!!

 

Mordy, I am wondering how things are coming along with your 6DK6s. Have acquired some RCAs, and as you mentioned the Sylvanias being bright I hope I haven't wasted my money on a brand that could be even brighter - although it appears sometimes RCAs can really come up with the goodies?

 

Re. the socket savers what a marvellous achievement guys. I look forward to hearing whether adding another link into the signal chain causes any degradation at all - am the eternal pessimist, I'm afraid! But it does look like they are a good outfit...BTW, I emailed them for dimensions and apparently the diameter is about 1.7cm.

post #1304 of 7488

Hi G and all,

 

Here is my pair of RCA 6BY6 from Oct 1966. They have Gray plate and thus look different from your 5915 tubes.

 

 

Here is a picture of my newly acquired RCA 6J4 tube. There is a beautiful orange glow reflection from the heater at the bottom of the tube. I am running it together with the Sylvania 8532 tube, and they seems quite compatible with similar sound signature.

Somebody had complained that they had problems with microphonics with the 6J4 tube, but even tapping it directly with my finger their is no untoward noise.

 

Somebody had mentioned microphonics. Here is a definition from Wikipedia:

Microphonics or microphony describes the phenomenon wherein certain components in electronic devices transform mechanical vibrations into an undesired electrical signal (noise). The term comes from analogy with a microphone, which is intentionally designed to convert vibrations to electrical signals.
When electronic equipment was built using vacuum tubes, microphonics were often a serious design problem. The charged elements in the vacuum tubes can mechanically vibrate, changing the distance between the elements, producing charge flows in and out of the tube in a manner identical to a capacitor microphone. A system sufficiently susceptible to microphonics could experience audio feedback, and make noises if jarred or bumped. Certain vacuum tubes were made with thicker internal insulating plates and more supports to minimize these effects

 

The 6J4/8532 tubes sound great. It is true that there is no sibilance, but I have the luxury of having tone controls, and even it seems that Sylvania tubes may have a family trait of being bright, it is easy for me to moderate it with the treble control.

 

About the difference between the Little Dot MkIII and MkIV I believe that it is minimal and mainly cosmetic. When I asked David Zhe Zhe he did not seem to think that the MkIV had a sonic advantage over the MkIII.

post #1305 of 7488

Dont know if this is of interest related to Sylvania tubes                     http://pax-comm.com/pa01039.htm                                                 http://www.audioasylum.com/cgi/vt.mpl?f=tubes&m=242045


Edited by MIKELAP - 5/19/13 at 2:18pm
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