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

Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 53

post #781 of 8778

I'm thrilled that so many of you are pleased with the 6CB6A tubes!  I'm happy that after a decade of forum lurking I was finally able to contribute something to such a great community!

 

After reading many posts here, I believe I'm going to break down and buy a few 6N6P tubes.  Is there a noticeable difference between the gold grid and the standard ones I'm seeing on eBay?  I'd love any feedback from those experienced with these tubes.

post #782 of 8778
Quote:
Originally Posted by gibosi View Post


Actually, I found these Sylvania JAN 6186 6AG5WAs pretty cheaply. And I just assumed that as these are military tubes, they might be more rugged and durable, as is typical of mil spec tubes, but of course, I do not know. Also I took your advice and ordered the Reflector 6J3P-E tubes. As I have a an LD1+, with an op amp (opa2107), I was unaware that Reflector made power tubes that sound like "heaven in a glass bottle". Thanks for the tip!

 

And just for grins, I am buying a couple pairs of 6BC5/6CE5s (GE and Sylvania), and a pair of Raytheon 6EW6s. (The 6EW6s require the EF92 setting? Someday I will sit down with the data sheets and your explanation above and figure this all out, but for now, it is much easier to ask the "Expert" :). Gosh, this thread is killing my wallet! ahaha... :)


I forgot you most likely live in the US, where you can US tubes shipped to you for peanuts, that explains how you got tubes shipped to you so fast lol, and why I'd been buying UK/Russian tubes so far.

 

Yup, EF92 jumpers for all these tubes except the 6BC5/6AG5/6J3P (and 6J38P).

 

About rolling power tubes, I'm actually not sure we'd get better performance with another family of tubes (on the LD MK II / III / IV, not 1). The amp is pretty flexible for driver tubes but calibrated for a pretty specific type of power tube, which, I have to say, offers tremendous sound qualities. The 6N6P/6N30P family has some pretty high upper limits which are essentially the 6N30P-DR, the so-called (and not without reason) supertube, which is expensive but not by that much more of a margin than the recent 6h30Pi once you factor in its lifetime ($60 for 5000 hours, $200-250 for 10000-20000 hours), extra quality control and sound quality. It's not that bad when you look at the prices of good driver tubes in the Schiit Lyr thread...

 

So, instead of spending another $100 rolling mystery power tubes (which I'm quite sure is possible if we investigate thoroughly) to get better performance, I would just get the DRs straight away and keep rolling cheap driver tubes.

 

Speaking of which (shameless plug), I *might* be selling some extra power tubes I bought a few months ago as spares in a week or two, as I realized I will obviously not be using them in the next 15 years, as my current power tubes will most likely outlast the amplifier they're in. I'm still not sure where I should try to sell them, and I hate selling on fleebay with commissions at every step, so I might make a classified here. A matched quad, or two matched pairs of NOS NIB 6N30P-DR from 1980, so extra rare and disappearing fast, which was why I bought them in the first place. Give me a nudge if you're *hypothetically* interested.

 

Apart from the 6N1P, no other different power tubes have been tried right?


Edited by Audiofanboy - 3/1/13 at 1:23am
post #783 of 8778

Dear682,

 

I have used the OEM 6N6P-i tubes that the amp came with, as well as the 6N6P and 6N6P gold grid power tubes.

 

The 6N6P-i tubes are only rated for 500 hours (which I did not know when I got them), and I was surprised when one of them gave out after not such a long time. I replaced them with 6N6P tubes which were OK, but found that the gold grid 6N6P tubes sounded better. I think that these 6N6P tubes are rated for 3000 hours. Presently I use the gold grid power tubes together with the Tung Sol 6AJ5 with very good and pleasant results.

 

I have my eyes on the 6N6P-IR tubes for around $30-40/pair. The R designation indicates extra long life, 10,000 hours. If I find a good deal on 80's tubes I may strike....
 

post #784 of 8778

My line of thoughts was that the total power output might be limited by the power tubes even if you get high gain driver tubes. Isn't it like a normal audio chain or computer, you upgrade one thing but the next one won't be able to handle all the juice it receives?

 

Yes, the 6n1p did not seem to be the flavour I was having in mind, considering they didn't power Grado 225is. And no, I don't think any other exotic power tubes were tried. I agree with putting the power tube a bit back, but depending on our experiences with the new driver tubes, we might need to look at other bottlenecks (power supply, lol ;) ).

 

My under dog suggestion for power tubes are the 6N6P-IRs. They have a quite different signature to the 6H30P-EV and a bit lower gain. In short: sub bass, large stage and sparkly treble are the strong points. The overall signature is slightly dark and they go well with the CV4015 if you like a neutral sound signature. Not much tubey warmth in this combination but rather tube-refined clarity. If you like a forward "in your face" sound, they are not for you. YMMV ;)


Edited by Acapella11 - 3/1/13 at 2:10pm
post #785 of 8778
Quote:
Originally Posted by Acapella11 View Post

My line of thoughts was that the total power output might be limited by the power tubes even if you get high gain driver tubes. Isn't it like a normal audio chain or computer, you upgrade one thing but the next one won't be able to handle all the juice it receives?

 

Yes, the 6n1p did not seem to be the flavour I was having in mind, considering they didn't power Grado 225is. And no, I don't think any other exotic power tubes were tried. I agree with putting the power tube a bit back, but depending on our experiences with the new driver tubes, we might need to look at other bottlenecks (power supply, lol ;) ).

 

My under dog suggestion for power tubes are the 6N6P-IRs. They have a quite different signature to the 6H30P-EV and a bit lower gain. In short: sub bass, large stage and sparkly treble are the strong points. The overall signature is slightly dark and they go well with the CV4015 if you like a neutral sound signature. Not much tubey warmth in this combination but rather tube-refined clarity. If you like a forward "in your face" sound, they are not for you. YMMV ;)


I'd say you're right about the "power limit" somewhere in the amp. I've read a few reports of DIY folks who got stuck changing driver tubes in circuits because if they used higher gain driver tubes, basically tubes with a higher 6.3V filament current draw, they had less 6.3V current left for the power tubes, assuming the 6.3V circuit is mounted in series in the amp for both driver and power tubes, which it should be.

 

As the 6h30p/6n30p draw more filament current than the 6N6p family as it is (825 vs 750mA I think...?), we're bound to find some kind of upper current draw limit in the amp, and that first limit might be on the 6.3V part. That and heat dissipation, which I'm already kind of worried about just using EF91 tubes.

 

This being said, find me a better, higher draw, power tube, and I'll still try it ;) . But I'll try messing around with those *new* driver tubes first. And now that I've figured out how the pin layout and jumper settings work, I've already found several new families of tubes that could be used with a small soldered wire between pins 2 and 7 on the 6AK5 jumper setting (a theory that I might very quickly put to the test, just because if will bother me if I don't). There's all sorts of new special quality tubes I envision testing with this scheme! I'll report back on that when I can actually confirm it, so we don't get all sorts of critical failures in the meantime...

post #786 of 8778

Hi all,

 

I've been lurking this thread for months now and have bought several tubes on recommendations left by members.
Thank you all so, so much for putting so much of yourselves and your time into playing around in this stuff. It's really a different world in here. I really appreciate the support and investigation and the tinkering you guys have done here.

 

I'll probably butcher some known audio terminology so forgive me now.

 

My setup is FLAC/MP3/Spotify HQ -> DAC Destroyer -> Little Dot MKII -> Sennheiser HD280Pro.

From what I've read the Senns are a darker headphone and therefore less prone to the brightness of say Beyerdynamics?

I'm itching to buy some DT770's or the new Fischer Audio cans. My Senns are 10+ years old now.

 

I'm not yet going to go into my impressions of tubes.

I just ordered a pair of RCA 6766/6CB6A tubes and a pair of G.E. 6GX8's. Definitely looking forward to these tubes.

 

I recently acquired a few Ultron "SQ" EF92 tubes and I'm wondering if you guys might be able to shed some light on what manufacturer they really came from. After some reading, I found that "Ultron" is a rebrand used by an audio store in West Germany quite a while ago and they would import and relabel tubes from different manufacturers.

Here's the tubes:

http://img.photobucket.com/albums/v96/inphu510n/Tubes/IMAG0478_zpsf15dd35b.jpg

(BTW how do you directly show images in posts here? I can't seem to get it right)

 

Any ideas?

There is some small lettering "50402" on the side of the tube but other than that nothing else.

My assumption is that they're a variant of the CV131 but none have the perforated shield these do.

That folded getter is really surprising. Not a lot of gas conversion was possible with that setup.

 

I'm loving these tubes! While they don't posses the analytical and excellent 3D imagery of the Voskhods the sub bass, bass and midrange are all so much sweeter and punchier. There's a slight roll off in the high end so it's not "sparkly" and exciting that way but overall every time I listen to these tubes I find myself tapping my toes and nodding my head.


Edited by inphu510n - 3/1/13 at 3:24pm
post #787 of 8778
Quote:
Originally Posted by inphu510n View Post

Hi all,

 

I've been lurking this thread for months now and have bought several tubes on recommendations left by members.
Thank you all so, so much for putting so much of yourselves and your time into playing around in this stuff. It's really a different world in here. I really appreciate the support and investigation and the tinkering you guys have done here.

 

I'll probably butcher some known audio terminology so forgive me now.

 

My setup is FLAC/MP3/Spotify HQ -> DAC Destroyer -> Little Dot MKII -> Sennheiser HD280Pro.

From what I've read the Senns are a darker headphone and therefore less prone to the brightness of say Beyerdynamics?

I'm itching to buy some DT770's or the new Fischer Audio cans. My Senns are 10+ years old now.

 

I'm not yet going to go into my impressions of tubes.

I just ordered a pair of RCA 6766/6CB6A tubes and a pair of G.E. 6GX8's. Definitely looking forward to these tubes.

 

I recently acquired a few Ultron "SQ" EF92 tubes and I'm wondering if you guys might be able to shed some light on what manufacturer they really came from. After some reading, I found that "Ultron" is a rebrand used by an audio store in West Germany quite a while ago and they would import and relabel tubes from different manufacturers.

Here's the tubes:

http://img.photobucket.com/albums/v96/inphu510n/Tubes/IMAG0478_zpsf15dd35b.jpg

(BTW how do you directly show images in posts here? I can't seem to get it right)

 

Any ideas?

There is some small lettering "50402" on the side of the tube but other than that nothing else.

My assumption is that they're a variant of the CV131 but none have the perforated shield these do.

That folded getter is really surprising. Not a lot of gas conversion was possible with that setup.

 

I'm loving these tubes! While they don't posses the analytical and excellent 3D imagery of the Voskhods the sub bass, bass and midrange are all so much sweeter and punchier. There's a slight roll off in the high end so it's not "sparkly" and exciting that way but overall every time I listen to these tubes I find myself tapping my toes and nodding my head.


Well, welcome here! Definitely don't hesitate to give impressions when you get you 6676/6CB6 and 6GX8 (6GX6?), we're all always looking for feedback, even in layman's terms.

 

About your EF92s, yes Ultron was apparently a rebrander, that would rebrand just about any brand of tubes it could get its hands on. Looking at the picture of your tube, and comparing with what I've seen on fleebay, it could be a Thorn/AEI EF92/CV131 tube, from its shield with holes and what I can see from its getter.

 

Like this one: http://www.ebay.fr/itm/2-x-EF92-CV131-6CQ6-WHITE-BOX-MADE-IN-ENGLAND-MESH-RECTANGLE-GETTER-/370751326625?pt=DE_TV_Video_Audio_Elektronenr%C3%B6hren_Valves&hash=item56528049a1

 

When you post a reply, there's a small picture-like symbol "Insert Image" on the right side of the menu, where you can upload any picture you have and select what size you would like it to appear in your reply.

 

Have fun rolling tubes!

post #788 of 8778

Yay, EF92 tube love =) and welcome to the thread.

Did you buy those from Cyprus via ebay? Or rather Germany ;)

 

For photos, there is an "Insert Image" button in the most right section of the control button row above the text box. Then, you just point to the file, which you want to upload and determine the displayed size. Should be easy =)
 

 

6.3 V, interesting finding Audiofanboy. So, this sets the max voltage. Curious to see what the max overall power handling of the LD MKIII /IV would be. Yes, the 6N6P are 750 mA. and the 6H30 825 mA (filament heater current, that is).

 

If you are interested in 6H30 tubes, I found a write up, which explains why this tube was chosen for a balanced pre-amp of a company, I wasn't aware of before. Of course, it is an advertisement type document, so it wouldn't show negatives, still a fun read.

http://www.balanced.com/products/line/Vk-50SE/6H30P.html

 

haha, I was writing my post meanwhile you were doing yours.


Edited by Acapella11 - 3/1/13 at 5:16pm
post #789 of 8778
Quote:
Originally Posted by Acapella11 View Post

Yay, EF92 tube love =) and welcome to the thread.

Did you buy those from Cyprus via ebay? Or rather Germany ;)

 

 

I bought them from Cyprus. ;)

Took their sweet time getting to me. Somewhere close to a month. I bought 5 so it was worth it.

 

One thing I've noticed in using the EF92's is that the power tubes get much, much hotter. Is that normal because of the extra current draw from the drivers?

post #790 of 8778

Yes, the EF92 draw more current, thereby burning more energy and generating more heat. Unfortunately, it seems, the efficiency did not improve between EF95 and EF92 tubes. I am convinced that this more of power allows us a potentially better listening experience. It should be interesting with the 'new' ( ;) ) driver tubes. Hope the LD won't melt down...

post #791 of 8778

Received a pair of Raytheon 6CB6As today.

 

 

 

While the recent Sylvania, Tung-Sol and RCA 6CB6As appear to be from the 1960s, judging from the box and the tube graphics, these Raytheons would appear to be newer. Like thegreat682, these are becoming my "go-to" tubes. I think I have already purchased too many of these? But I have yet to hear a 6CV6A I don't like and I have a pair of 1962 mil-spec GEs coming. These will be the last ones. lol :)  Unfortunately, with all these new tubes, I have not had time to compare them closely, but I can say they all have a very similar sound, which reminds me of the CV4015s.

 

As my headphones have a slight imbalance in the midrange, with the upper mids being a bit more forward, I find many 6AK5s to be too bright in the upper midrange (for example, female voices), and listening with any significant volume is sometimes uncomfortable. These 6CB6As, similiar to the CV4015s, complement my headphones very nicely. I should remind everyone that my ears can perhaps best be described as "rusty iron", as I am over 60, and my equipment is very modest, so I am looking forward to reading the impressions of those of you with "golden" ears and better equipment, especially how these 6CB6As compare to the Mullard CV4015s.

 

And soon, my mailbox will be graced with 6AG5s, 6BC5s, 6J38P-EVs, 6J3P-Es, 6GX6s and 6EW6s. And maybe I should take a look at some 8136s over the weekend? lol :)

post #792 of 8778

Finally got my 6N6P-IR tubes today, my initial impression is that they are much more transparent than my Electro-Harmonix 6H30Pi.

 

Listening to some Muse now though my Tung-Sol 6AJ5 tubes, very much liking this combo!

 

Also just ordered a pair of GEC CV4014 (EF91), which is my first EF91 tube! Can't wait based on some impressions I've read.

post #793 of 8778

gibosi, Thank you for sharing these impressions on the 6CB6A tubes. Given, the general signature is similar to the CV4015s and they are higher gain, they are listed on my short list now. If you compare the 6CB6As and CV4015, do you feel the higher power, at least in the sound being louder? This question goes also to thegreat682, comparing them to any EF92 tube in his stash :)

No need to call it "Rusty Iron", useful contribution is more precious than silver and gold ;)

 

 

Audiofanboy, There was an obvious question, I didn't ask you, specifically now since you are a HE-500 comrade: Comparing the 6H30P-EV and 6H30-DRs, which you fell in love with, with the CV4015s on the HE-500, how much and what difference is there to be noted?

 

mab1376, Exciting. Good to hear your impressions. Pleas keep us posted!


Edited by Acapella11 - 3/2/13 at 9:25am
post #794 of 8778
Quote:
Originally Posted by Acapella11 View Post

gibosi, Thank you for sharing these impressions on the 6CB6A tubes. Given, the general signature is similar to the CV4015s and they are higher gain, they are listed on my short list now. If you compare the 6CB6As and CV4015, do you feel the higher power, at least in the sound being louder?

 

Yes, the 6CB6As are louder than the CV4015. This is what makes it so difficult for me to make a detailed sound comparison as the volume control has to be adjusted back and forth somewhere between 1/4 and 1/5 of a turn every time I swap out tubes. These 6CV6As seem to have the same level of volume as the GEC CV4014s, but the bass is not quite as big and the upper mids are a bit more subdued.

post #795 of 8778
Quote:
Originally Posted by Acapella11 View Post

gibosi, Thank you for sharing these impressions on the 6CB6A tubes. Given, the general signature is similar to the CV4015s and they are higher gain, they are listed on my short list now. If you compare the 6CB6As and CV4015, do you feel the higher power, at least in the sound being louder? This question goes also to thegreat682, comparing them to any EF92 tube in his stash :)

No need to call it "Rusty Iron", useful contribution is more precious than silver and gold ;)

 

 

Audiofanboy, There was an obvious question, I didn't ask you, specifically now since you are a HE-500 comrade: Comparing the 6H30P-EV and 6H30-DRs, which you fell in love with, with the CV4015s on the HE-500, how much and what difference is there to be noted?

 

mab1376, Exciting. Good to hear your impressions. Pleas keep us posted!


Coming from the 6H30Pi (EH, so *theoretically* just a tad better than the Sovtek), the 6H30P-DR brought a truly holographic (3D) soundstage; that was the first immediately obvious improvement, even before burn-in. After burn-in, much better extension, especially in the bass department (200Hz downwards), flying detailed highs and great transients, and a naturalness of timbres and decay that I had not heard before. Not minute differences, but quite major, and that was before I upgraded a few more pieces of gear like my S/PDIF transport and battery power, which made another night and day difference that scaled extremely well with the -DR and CV4015, even moreso with the HE-500 and good CV4014 tubes with more power and thump.

 

I'll try my 6H30Pi again this week, just out of curiosity when I change my power tubes before shipping them. Just to anti-placebo myself again. I ought to sell my 6H30Pi too, it seems useless to keep them for no reason when they're definitely worth something and close to new...

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 Tube Amps: Vacuum Tube Rolling Guide