[gibosi]

Quote:

A number of people have recommended that I try some Tung-Sol tubes in my LD 1+, so I ordered a pair each of JTL 6AK5s and 6AJ5s, 1950's vintage. Upon rolling them into my LD, both pairs exhibited a significant ground hum. It is the kind of hum that is of a constant level independent of the volume setting. Has anyone else experienced this? Has anyone found a credible explanation? And should I assume there is no remedy? Thanks in advance!

 
I tried cleaning the pins thoroughly, but heard absolutely no improvement and had given up. However, at a recent Head-Fi meetup, I met a guy with years of experience with tube amps. When I told him about these tubes, he suggested that I simply burn them in for several hours. And it worked! I ended up burning in the Tung-Sol 6AK5s for a total of 8 hours! But they are now very quiet and sounding exquisite! Thought I would pass this information along on the chance that it might help someone else.
 
Cheers!

 

[gibosi]

Quote:

anyone tried these tubes?
 
http://www.aloaudio.com/siemens-6ak5-w

It appears Alo is asking $29 for one tube? Well... If you would like to give them a try, they can be had on eBay for a bit more than $17 for a pair including shipping ($7.75 each plus $1.64 for shipping):
 
http://www.ebay.com/itm/300812726403?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

[thegreat682]

 
 
I bought these little guys a few weeks ago and after 50+hrs of burn in they have replaced Mullard CV131s as my default "go-to" tube.  I have not read much of anything about rolling with the 6CB6A series of tubes and they can currently be had VERY cheap.  I received both of these for $5 shipped.  I'd like to know more information about them as I have not found any information on dating GE tubes, and I very quickly fell in love with their sound signature.  I'd highly recommend giving these a shot.  They also light up brighter than any tube I currently have which sure does look pretty 

 

[Acapella11]

Quote:

I bought these little guys a few weeks ago and after 50+hrs of burn in they have replaced Mullard CV131s as my default "go-to" tube.

Would you state why? What is the tube's sound signature?

 

[thegreat682]

Quote:

Would you state why? What is the tube's sound signature?

Apologies.  I will try my best as I have never attempted anything like this before...
 
Compared to CV131s, the treble presented is much cleaner and detailed without much sibilance.  Vocals really shine through.  Bass is present and not muddy or overpowering.  I get a wider sense of space as well.  It has been really fun listening to the tubes mature and hearing new details in some of my favorite albums!
 
Edit:  I should really emphasize more how huge the space is presented in these, sounding similar the center of an auditorium.  I listen to a lot of live rock and blues and feel the 6CB6A tubes have added a ton of life to many of my favorite shows.

 

[gibosi]

Quote:

Apologies.  I will try my best as I have never attempted anything like this before...
 
Compared to CV131s, the treble presented is much cleaner and detailed without much sibilance.  Vocals really shine through.  Bass is present and not muddy or overpowering.  I get a wider sense of space as well.  It has been really fun listening to the tubes mature and hearing new details in some of my favorite albums!
 
Edit:  I should really emphasize more how huge the space is presented in these, sounding similar the center of an auditorium.  I listen to a lot of live rock and blues and feel the 6CB6A tubes have added a ton of life to many of my favorite shows.

Well, as you noted, these are pretty cheap, so I just ordered a pair of Tung-Sols and a pair of Sylvanias and am looking forward to auditioning them.

 

[mojorisin35]

Quote:

 
 
I bought these little guys a few weeks ago and after 50+hrs of burn in they have replaced Mullard CV131s as my default "go-to" tube.  I have not read much of anything about rolling with the 6CB6A series of tubes and they can currently be had VERY cheap.  I received both of these for $5 shipped.  I'd like to know more information about them as I have not found any information on dating GE tubes, and I very quickly fell in love with their sound signature.  I'd highly recommend giving these a shot.  They also light up brighter than any tube I currently have which sure does look pretty 

Very interesting! Yet another family of tubes to look at. I have a pair of ge m8083 mullard rebrands. Thanks for bringing these to my attention

 

[gibosi]

Re: 6CB6A tubes
 
These are also known as EF190.
 
http://www.radiomuseum.org/tubes/tube_6cb6a.html
 
Searching for EF190, you will find the old Soviet equivalents, 6J38P,and the Soviet military version, 6J38P-EV. These look pretty nice....

 

[Acapella11]

Quote:

Apologies.  I will try my best as I have never attempted anything like this before...
 
Compared to CV131s, the treble presented is much cleaner and detailed without much sibilance.  Vocals really shine through.  Bass is present and not muddy or overpowering.  I get a wider sense of space as well.  It has been really fun listening to the tubes mature and hearing new details in some of my favorite albums!
 
Edit:  I should really emphasize more how huge the space is presented in these, sounding similar the center of an auditorium.  I listen to a lot of live rock and blues and feel the 6CB6A tubes have added a ton of life to many of my favorite shows.

Thanks for the impressions. If I would roll tubes these days, I would surely be tempted =)

 

[gibosi]

Quote:

I just rolled my factory matched pair of Tesla 6f32 into my LD MKIII and my initial impressions are WOW!
Without even being completely being burnt in they are something special.



The most outstanding quality thus far is the Crystal clear sparkling highs, which present themselves with great extension without any hints of sibilance.
with these I find the Highs much more pleasant than the Tung sol 6AJ5 and the the highs of the Tesla's are way more resolved than the Voshkod 6ZH1P-EV.



I find the mids are very neutral they remind me of the Tung Sol 6aj5 mids perhaps a little less warm.
However they are nowhere near the luscious mids of the mullard ef92’s so if you find the mullards to colored you might want to look into a pair of these.

The Bass is deep accurate and clear and very close to the Bass of the Voshkod 6ZH1P-EV perhaps a touch more authoritative...

The soundstage is as wide and deep as any I have heard however it has the added dimensionality of height. I had not been able to discern this before with other tubes but with these tubes there it was.
Highly recommended! I cannot wait to see what they develop into after some burn in.



i will update as the tubes age

Gary
current tubes i own
Sylavania JAN5654
Tung Sol 6AJ5
Voshkod 6ZH1P-EV
Mullard EF92

Power
6n6p gold grid

on the way
Mullard M8083
Mullard M8161
Mullard M8100
CBS / HYTRON 6AK5W

 
My factory-matched Teslas in the funky box arrived yesterday. I haven't spent a lot of time with them, but doing some quick A/B-ing between these and the Voshkods, they sound very similar. Perhaps after they have burnt in and I have spent more time with them, I will be able to better discern how they differ. Except for the red paint, they look very similar to mojorisin35's. I can't quite make out what is written in red paint, but it looks like 3.? - perhaps this is a measurement used to certify that they are matched?
 
 

 
 
Yesterday, my Siemens 6AK5Ws arrived too. (It was a very good day!  I can easily distinguish female vocals, for example Norah Jones, from the Mullards and the Voshkods. They are not as lush as the Mullards and not quite as bright as the Voshkods. All in all the vocals seem very smooth to me and I quite like them.
 
 

 

[Audiofanboy]

Quote:

 
 
I bought these little guys a few weeks ago and after 50+hrs of burn in they have replaced Mullard CV131s as my default "go-to" tube.  I have not read much of anything about rolling with the 6CB6A series of tubes and they can currently be had VERY cheap.  I received both of these for $5 shipped.  I'd like to know more information about them as I have not found any information on dating GE tubes, and I very quickly fell in love with their sound signature.  I'd highly recommend giving these a shot.  They also light up brighter than any tube I currently have which sure does look pretty 

Nice, more tube families to try on my LD and less cash in my wallet... I obviously have to try this though, it just sounds too interesting to pass. That and the fact I'm looking for more high gain EF91-like tubes.
 
Could you possibly tell me who/where you bought these from (if you bought them on ebay and there's more from that seller)?

 

[thegreat682]

Quote:

Could you possibly tell me who/where you bought these from (if you bought them on ebay and there's more from that seller)?

 
Gladly 

.  I bought my tubes on ebay from desireme1979.  I just looked at his store and he currently does not have any more GE tubes, but does have a few Raytheon 6CB6A tubes.
 
Also, there is an interesting thread http://www.head-fi.org/t/572279/different-tubes-for-little-dot-mkiii-must-see-for-mk3-owners here where a user lists several different types tubes that he claims work in the MKIII with the EF92 jumper

 

[Audiofanboy]

Quote:

 
Gladly 

.  I bought my tubes on ebay from desireme1979.  I just looked at his store and he currently does not have any more GE tubes, but does have a few Raytheon 6CB6A tubes.
 
Also, there is an interesting thread http://www.head-fi.org/t/572279/different-tubes-for-little-dot-mkiii-must-see-for-mk3-owners here where a user lists several different types tubes that he claims work in the MKIII with the EF92 jumper

Thanks for the tip! That'll definitely keep me awake for a few nights...
 
After a bit of fact checking about all those tubes, and others I've read about, I decided to try a pair of Brimar 6BH6 I had lying around, since they seemed to have a compatible pin out and were similar to the 6BJ6 mentioned in that thread (150 mA current draw, so less than a 6AK5 and half of a EF91).
 
It didn't explode, actually it worked pretty well for a mystery tube. I was surprised by how airy and detailed it sounded, but the bass was crappy and it wasn't as musical as my favorite tubes. At least, I don't think I heard distortion but I could be wrong.
 
Ok, I'm convinced. I'll be rolling new families of tubes in my LD amp and reporting back. The families I'm most interested in are all the high current draw high gain ones, >300 mA. I see the guy in the other thread tested two or three tubes that draw 400 or 450 mA, I'd be curious to see if the amp can sustain that without massively overheating (as it is feels quite warm with EF91 in the winter as it is), and how it sounds.

 

[Acapella11]

Quote:

The families I'm most interested in are all the high current draw high gain ones, >300 mA. I see the guy in the other thread tested two or three tubes that draw 400 or 450 mA, I'd be curious to see if the amp can sustain that without massively overheating (as it is feels quite warm with EF91 in the winter as it is), and how it sounds.

 
I know what you are thinking and it is a great idea. Good luck! God knows what the MKIII / IV might drive after these experiments...

 

[gibosi]

Quote:

Nice, more tube families to try on my LD and less cash in my wallet... I obviously have to try this though, it just sounds too interesting to pass. That and the fact I'm looking for more high gain EF91-like tubes.
 
Could you possibly tell me who/where you bought these from (if you bought them on ebay and there's more from that seller)?

 
Today the Sylvania 6CB6As arrived:
 
 

 
I did a quick A/B with my GEC CV4014s and yes, these Sylvanias seem to have the same level of gain as the EF91s. I think the GEC's bass is a bit bigger, but not by much, and the GEC's upper midrange is a bit brighter. However, I find these Sylvanias very balanced and musical. I think it is great to finally have a good selection of cheap tubes available that can be used with the EF91/2 settings.
 
Oh.. The blue line you see on the tube is some kind of reflection. It is not on the tube itself.