[Nirvana Woman]

Quote:

To all,
     I'm new to this game, still waiting for my LD MK III to arrive so please excuse my ignorance.  Why is all the conversation is on rolling the driver tubes and not the power tubes?  or am I missing that in the long thread? 
Thanks, Jon

Because the ones that come stock with the Little Dot are great and the differences between them are much smaller than between drivers.
Also, it's much more lucrative to roll driver tubes because power tubes tend to be much more expensive.
 
Also you are not forgiven for your ignorance because there wasn't any .

 

[Acapella11]

Quote:

To all,
     I'm new to this game, still waiting for my LD MK III to arrive so please excuse my ignorance.  Why is all the conversation is on rolling the driver tubes and not the power tubes?  or am I missing that in the long thread? 
Thanks, Jon

There was not much of a discussion, but sadly there was not. Differences between power tubes do exist and I think it is worth to try other power tubes because you might be surprised about synergistic and non-synergistic effects. Just because most people do not roll power tubes doesn't mean you shouldn't.

Also, there is a reason why LD MK IV has 6H30P and why I am using 6N6P-IR power tubes. Enjoy the tubes and welcome to the club =)

 

[mojorisin35]

It is very interesting that power tubes are starting to be discussed . My 6N6P gold grid arrived from Russia in record time. I rolled them into my ld mkii with the stock driver tubes and two things became immediately clear:
1. There is more volume available.
2. There is a considerable improvement in the bass. it is more coherent and clear. with the stock tubes it was a "thub thub" whereas with the 6N6P gold grid's it is a more resolved  "thup thup" and the sub bass is more pronounced. the whole spectrum seems more coherent as well but that may be the newness of the tube rolling for me and not a real artifact of the tubes. your results may vary.
 
I enjoy listening to a couple of tracks for reference's Jane's Addiction "splash a little water on it" and "Dancing Flute & Drum" from chesky's Dr. Chesky's Sensational, Fantastic, and Simply Amazing Binaural Sound Show!
with the new tubes the deep bass in "splash a little water on it" was good with the stock tubes however with the new  gold grid's it nearly rumbled my beyerdynamic dt 1350's of my head. when i listened to the dancing flute and drum the overall effect with the gold grid's was even more impact full and impressive than it was with the original tubes.
If this is a 15% improvement which is often quoted as being the improvement of rolling new power tubes then I am on the edge of my seat for the driver tubes i ordered to arrive! which are supposed to make the most dramatic difference to the SQ.
as well on that note if anybody has some amperex EF92 6CQ6 they would like to sell at a reasonable price please contact me.
For those in the know is the jump in price to the eh 6H30pi a 15% jump in sq  from the gold grids or just "different"?
Gary

 

[Audiofanboy]

About power tubes (on the MK IV SE mind you), I can say they make much more of a difference than what I've been reading most of the time. In my case, going from the 6h30pi-EB (an upgrade in and of itself) to the 6n30p-dr (the most expensive and rare alternative), I'd say the jump in performance was closer to 30-40% in sound quality, with much better extension in the bass and treble, a huge improvement in resolution and separation, and mostly a true holographic (3D) presentation that I just couldn't exactly get with the 6h30pi (enjoyment can't be graded on a linear scale though, but I'd still a 30% improvement in toe-tapping and fun factor just for the power tubes).
 
Still, if I use just decent driver tubes, a crappy DAC and transport, I don't get that much improvement, it's still garbage in garbage out at every step, including driver to power tubes. But combined with great driver tubes, power tubes make a huge difference in these LD amps. The reason I ended being so picky about driver tubes (and everything in the music chain before that for that matter) is because the power tubes scale very well with other upgrades. My original 6h30pi, while very revealing, just didn't scale with other improvements that well. I used to love the m8100 with the 6h30pi, now they seem a bit too cartoonish (still great and toe-tapping though) with the 6n30p-dr that reveals just how boomy the bass could be and how the treble was quite rolled-off. I suspect it is the same with the 6n6p family of tubes, more transparent power tubes allow for better tuning of the rest of the elements, and end up amounting to much more than the accepted 15%; in my humble opinion of course .
 
And as Acapella pointed out a few times, there also the synergy between driver and power tubes that needs to be accounted for, like my example with the 6n30p-dr and m8100...

 

[Acapella11]

For those in the know is the jump in price to the eh 6H30pi a 15% jump in sq  from the gold grids or just "different"? Gary

 
It is worth it, I'd say - but because most people here use HD650s and you are using Beyerdynamic DT 1350s, which are supposed to sound cooler and more monitoring, I would be tempted to prioritize a pair of 6N6P-IR, which are also cheaper. If you are then really hooked, get the 6H30P tubes, although you might find in the end that only EF95 tubes will fit (and not the - in my ears - superior CV4015). YMMV as usual.

 

[thegreat682]

Any opinions on 6CB6A tubes?  I just got a deal on 2 GE NOS tubes that was too good to pass up and am curious if anyone had any experiences.  Been using Mullard CV131's for a couple of years now and am thinking it is time for a change...

 

[Audiofanboy]

More EF91 reviews! I just got a package filled exclusively with CV4014 of three different brands. This time I took pictures, which makes it a lot easier to understand tube construction and getter shapes (and shop on ebay thereafter).
 

 
Mullard CV4014 KB/DC, made in the Whyteleafe factory (so quite rare) in 1959. Blue glass, rectangle D getter above a cage element, metal cage thingies between the anodes around the tube (seen on the left of the picture behind the writings.
These have an extremely large 3D soundstage that sounds like a huge cave (not in a bad way) with the opposite of an "in your face" presentation. Bass is loose and dry (not fat), somewhat piano like with a slow decay. treble is airy and non sibilant, a bit elevated, again the instruments are presented in a very spacious way and very well separated (more like far apart). Mids and vocals are fine, not under-emphasized and musical. You could say these tubes have a fairly u-shaped signature but not overly so. For some reason, they aren't as loud as other EF91s, but closer to the my CV4015 in terms of volume.
Overall, these are great CV4014 tubes (what did you expect?), at least as good as their Mitcham counterparts made in the same time period if not better, and much more spacious. While not quite as detailed as  the CV4015 (hard to dethrone), this is a top tier tube, a laid back, balanced and easy to listen to CV4014, great for alternative and casual styles of music.
 

 
GEC CV4014 KB/Z, made in 1960 (MO Valve Company in Hammersmith). Square getter on top of a hollow dark grey box, silver all around the glass. I got 8 of these, all identical, but two have an extra "GEC" sticker like on the picture, I tested two others with only the military markings.
Now there's an interesting tube. More weighty and dense than the Mullards, guitars have more impact and fell heavier, vocals are fatter (or less thin than most EF91 tubes). Soundstage is large but feels very natural, like the CV4015. There's a typical emphasis on highs but also on mids, which is unusual for EF91s, no U-shaped sound here, more of a swoosh curve. Mids and mid-bass are really liquid (think tubey but in a good way, not harmonic distortion) and have a nice weight to them. Bass is neutral and tight and you hear it when it's in the music, it's not overdone but punchy and well controlled, closer to an EF92 tube. These tubes are quite resolving without feeling over detailed and too bright; the micro details are presented in a discrete but adequate way (you don't hear really loud brassy sounds a foot away from your head like it's the only instrument there, too much "air" kills the music). The vocals really have a fluidity and naturalness that is unusual for EF91s.
Overall, excellent CV4014, probably one of the best I've heard. Great balance, punchy and meaty "just detailed enough to not be annoying". Great mids for an EF91 and even in general, tight thumpy bass. Only caveat would be that like most EF91/92s, these feel a tad bright, but that's compensated by the liquid midrange!
 

 
Brimar CV4014 KB/FB (doesn't say Brimar, but everything goes that direction; previous CV138 KB/FB I'd tested were also Brimar), made in 1957 in STC, Footscray. Folded D getter and silver glass all around, only military markings and 6064 on the tube.
First impression is the great clarity of this tube when played, details stand out in a natural way in an average size soundstage (read large, this is an EF91). Treble isn't overemphasized yet it is quite pleasant and detailed, mids are pretty good and make vocals sound natural but not brilliant. Bass has that special "Brimar" flavor to it, but in a tighter/drier variety than the Brimar CV4014 with no military markings (see two picture below) I'd tried earlier. I happen to quite enjoy that bass, even though I wouldn't want it everyday.
Overall, very enjoyable CV4014, not the most detailed but natural, balanced and resolving, with toe-tapping peculiar bass!
 

 
Brimar CV4014 KB/FB, can't quite read the date markings, but they should be from 1959. Same characteristics and factory as above, only difference is the large O getter, the rest of the construction is identical.
These sound almost the same as the folded D getter ones, maybe just a bit tamer, but still balanced, natural and with peculiar bass.
 

 
These are the original Brimar CV4014 I'd reviewed, they have the same construction as the two above but with a small O getter. In terms of sound, they are similar but the bass is fatter (not as tight). All Brimar CV4014 tubes are great to try though.
 
In any case, these 4 pairs of tubes were a cool set of CV4014 to test and give feedback on. But, as usual, I'm sure when I put the CV4015 back in and "recalibrate" my brain and ears, I'll remember why I keep going back to them...
 
A few more pics of the other tubes I'd reviewed (I'll try and update my previous post too).
 

 
These are the later "flashing" Mullard CV4014, I have years '66 '68 & '72, all identical, see the O getter with no cage like element underneath and the open structure between the anodes.
 

 
The late 50s Mitcham-made Mullard CV4014 I'd reviewed, see the cage below the D getter and the metal thing between anodes.
 

 
The 50's Mullard CV138 I don't like (that sounds spiky like old basic EF91 tubes with the same flying copper leads with a black rectangle suspended on top).
 

 
The 50's Mullard CV138 6AM6 that I do like and could live with, with a much more solid construction than the ones I don't like.
 

 
And while I'm at it, my Mullard CV4015 that I keep going back to.
 
Voila, that's it
 
(Btw, no I'm not trying to impose a subliminal message to buy "Sony" products lol. I just realized I have the logo on all my pictures... Sorry about that )

 

[Acapella11]

Thank you for all the EF91 goodness!
 
The GEC CV4014 KB/Z sound interesting. They are made by General Electric? Are they higher gain than the CV4015s?
 
Great review on these tubes. I think, it gives us all a better insight in the variety of the normally under-represented EF91 family.

 

[Audiofanboy]

It's not General Electric as in GE but some other specific UK company though. I'd found the story on a couple of websites but I forgot the specifics... I think I had to look up the MOV or MO-V company or group to understand the history behind GEC.
 
Yes, it has higher gain than the CV4015, I need a good quarter less volume on the knob with these (same as most EF91 basically). I does seem to help drive my HE-400 a bit (bass sounds more powerful regardless of amount).
 
They're easily available on ebay apparently, but expensive... If someone else wants to try them.
 
I might update my review of these tube a bit though. Upon further testing, one of the two tubes I'd selected kind of just killed itself (happened when I unplugged and replugged headphones, I heard a slight glassy noise and bam no sound in the left channel, I'll be careful with that from now on). And the two other tubes I tried *and* the two GEC labeled ones sound even better than the ones I originally reviewed (more space, deeper bass, no brightness). So, to be continued!

 

[john57]

GE is generally American made and GEC is generally UK made. The GEC are a brighter sound tube but does not quite last as long. I also have the GEC 6080 tube.

 

[Audiofanboy]

Quote:

GE is generally American made and GEC is generally UK made. The GEC are a brighter sound tube but does not quite last as long. I also have the GEC 6080 tube.

I think you'd tried and commented on the GEC CV4014 back towards the beginning of the thread right? Which version of these tubes did you try out of curiosity (military date code, GEC label, getter...)?
 
Here's the link I'd found about GEC btw
 
http://en.wikipedia.org/wiki/General_Electric_Company_plc

 

[john57]

My GEC tubes have the GEC sticker on them and came with the pin savers attached and wrap in a cigar tube in brown paper and in a old white box. My GEC CV4014 KB/Z looks exactly like the pictures above except with the tube at the far left with the up arrow that shows SK mine shows XF. All the other numbers are the same including the 6064 at the bottom. I am trying a new set of headphones and I already have return one set. I post a link when the review is done. I am also enjoying my LD Mk6+

 

[Audiofanboy]

Quote:

My GEC tubes have the GEC sticker on them and came with the pin savers attached and wrap in a cigar tube in brown paper and in a old white box. My GEC CV4014 KB/Z looks exactly like the pictures above except with the tube at the far left with the up arrow that shows SK mine shows XF. All the other numbers are the same including the 6064 at the bottom. I am trying a new set of headphones and I already have return one set. I post a link when the review is done. I am also enjoying my LD Mk6+

Thanks for the information, the pair I'm now using is quite similar.
 
Two tubes with a GEC sticker (the two one the right of the picture), one with a WM code, the other one with XB, stamped by the UK military two months apart from each other, 4 and 6 months before yours, so they should be quite similar. They sound and look fine, but probably aren't NOS.
 
I swear these sound different from the 5 or 6 SK (4 years older) otherwise exactly identical tubes I also got. The GEC labeled ones are airier with a larger soundstage, sound just a bit less liquid and more balanced, and have bass that is tighter and goes deeper (and less of a mid-bass thump than the "SK" ones). I must say these are even better than the ones I originally reviewed.

 

[Bee inthe Attic]

Hey, I'm new to tubes and have a question:
 
Are Mullard tubes supposed to have the name "Mullard" printed on them. I bought the Mullard M8100/CV4010 from ebay. Here is a link with a picture.
 
http://www.ebay.ca/itm/M8100-CV4010-6AK5W-MULLARD-NOS-MATCHED-PAIR-/310282214423?pt=UK_Sound_Vision_Valves_Vacuum_Tubes&hash=item483e42dc17
 
I don;t know much of anything yet about tubes. So what's the difference between M8100 & CV4010... and are these genuine Mullard if it's not printed on the tube?

 

[Acapella11]

Yes, they are fine. There are different types of basically the same tube. CV is the military name. As with the EF91 tubes above, sound can vary between different years and factories, which can also be reflected in the labeling. I prefer my M8100 with Mullard label (the one that looks like a larger shield) but, I just checked, they aren't offered at the moment on ebay. They look like these (sorry for the long link):

 

https://www.google.co.uk/search?q=mullard+m8100&hl=en&client=firefox-a&hs=oGk&tbo=u&rls=org.mozilla:en-USfficial&tbm=isch&source=univ&sa=X&ei=Sv4KUZeyJYOd0AX81oGoDg&ved=0CD0QsAQ&biw=1920&bih=906#imgrc=djfpMDwJfO3e4M%3A%3BGR_IHJkfvnH3bM%3Bhttp%253A%252F%252Fi.ebayimg.com%252Ft%252FM8100-MULLARD-6AK5-EF95-E-MATCH-PAIR-NEW-VALVE-TUBE-%252F00%252F%2524%28KGrHqMOKp!E3tTlFCYqBO!04Bethg~~_35.JPG%3Bhttp%253A%252F%252Fwww.ebay.co.uk%252Fitm%252FM8100-MULLARD-6AK5-EF95-E-MATCH-PAIR-NEW-VALVE-TUBE-%252F390429216735%3B300%3B225