Little Dot Tube Amps: Vacuum Tube Rolling Guide
Jan 1, 2014 at 7:06 PM Post #4,546 of 13,432
Started to listen to some octals so far the black glass Tung Sol seems to be superiour to the vt-229 and 6SUL7 bass with the  hd800 is pretty nice                                                                                                                         
 
Jan 1, 2014 at 8:40 PM Post #4,547 of 13,432
I am concerned in my move to put 6cg7 to 6sn7 adapters in place of power tubes.
I didn't receive them yet, but I read that I need a seperate power supply to run 6sn7's.
Is that right or does it only apply for driver tube section?
I'm afraid that I can't use the adapters plug and play...
(BTW, do 12ax7 tubes have more potential than yugo 6hm5's?)

 
You definitely need an external power supply to use 6CG7/6SN7 as driver tubes. However, you do not need an external power supply to run these as power tubes. The power tube circuit in an LD can provide up to 1.25 amps, I believe. For example, the 6NP draws .75amps, the 6H30-EH draws .85amps, whereas, the 6CG7/6SN7 draws only .6amps, so no problem. And the 6CG7 does not need an adapter. It is 9-pin plug and play.
 
The 12AX7 is a dual triode, whereas, the 6HM5 is a single triode, so you will need a dual triode adapter to use it. And if you are going to use a dual triode adapter, the 6DJ8 has much more potential than 12AX7 or 6HM5, IMHO.
 
Jan 1, 2014 at 10:08 PM Post #4,548 of 13,432
  Hi mab 1376,
 
here is post #2078 p. 139 (happy to see that you agree with the reviewer):
 
Hi All,
 
Here is a review of the IBM 1680 (6BE6) tube made by Sylvania: (please read until end or skip to summary)
 
EF95 1/7 Strap setting (used for burn in): The first impression was the signature heptode sound of wide expansive sound stage, clarity and abundant detail. Then some shortcomings became apparent: soft flabby bass, cool mid range, lack of dynamics, and sibilant treble.
 
These deficiencies disappeared slowly, and after significant burn in they almost all disappeared to a certain extent. After being burnt in for 50-60 hours the tubes had improved markedly. The bass is acceptable but lacks slam and attack. The mid range became warmer. The highs are still sibilant and sharp. Good bye (and good riddance) EF95 1/7 setting.
 
EF95 NS (no strap): This setting yields better sound than the one previously described. Firmer, more distinct bass, mid range regular warm, highs still sharp but no sibilance, good detail. Yep, much better, but no wow factor. A certain lack of micro dynamics, rhythm and pacing. A good simulation of my solid state receiver with better bass. Bye Bye EF95 NS.
 
EF95 2/7 strap: Wow! Multi layered 3D heptode magic! Bold, powerful bass, full of details and micro dynamics, great highs. Involuntarily toe tapping - a 4 on a scale of 5.
Cons: Bass does not go down to the deepest levels, and there is a minor mid range coolness and hollowness.
Very good presentation overall with tons of detail and musicality. EF95 2/7 - you are welcome any time.
 
EF92 setting (using EF95 6/7 strap setting): Treble excellent with great detail and power but some sibilance; mid range good, bass is a bit boomy. Overall quite good, grows on you. Perhaps this setting would match certain types of equipment.  EF92 - nice to see you, bye.
 
 
SUMMARY OF THE IBM 1680 TUBE:
As mentioned before, the differences between heptodes are much more subtle than between 6AK5 tubes, and thus harder to describe.
Using the EF95 2/7 strap setting this tube is very good performer, albeit not on the level of the very best heptodes.
 
The EF92 setting may be a good choice if you like a very detailed treble presentation.
 
EF95 NS is OK. 
 
EF95 1/7 is not recommended.
 
Price wise, the 1680 is a winner with a cost of less than $8 for a pair shipped.
 
As they say in a prominent consumer magazine: Recommended, Best Buy.
 
Edit 7/27/13: Listening to the EF92 simulated setting now. Don't know if the tubes stabilized or my perception changed, but these tubes sound excellent now on this setting. Bass is firm but not in your face, almost no sibilance. Detail, detail. Simply beautiful.

 

Will try this setting once my DT770 pro 80 ohm arrive.
 
Jan 2, 2014 at 12:18 AM Post #4,549 of 13,432
Hi Gibosi,
 
"The 6CG7 does not need an adapter. It is 9-pin plug and play." Did not think of that - thanks Gibosi!
 
So what we have for the first time is a native US made power tube for the little Dot MKIII!  Been waiting for this a long time. First impression of how the 6CG7 sounds is very promising but need to wait for burn in to complete.
 
Here are pictures: These tubes were sold by Sears and made by Sylvania - paid less than $2.00 each.
 

Silk Screen text: Sears: We guarantee that this tube will give perfect satisfaction for one year

Night view - the glow is very modest

 
The 6CG7/6FQ7 tube is said to be a development of the octal 6SN7 tube. The transformer housing on the LDIII is barely warm, but the 6CG7 runs VERY hot and I almost burnt my finger now touching it. OK, the 6N6P-IR power tubes run very hot as well.
 
The driver tube is my best octal so far, a Tung Sol 6SL7GT from 1957. Will see how a shoot out will come out with the Russians. Kind of like the idea of $2.00 power tubes.....
 
In this lot I also got GE tubes, one RCA tube and a tube that says Cornell. The Cornell has an unusual print on it: New or Used. Judging from the bent pins it probably is a pull out and used.
 
When do you think the Sears warranty goes into effect? From the time of purchase in the 60's or 70's, or from the first time it is being used 40-50 years later? LOL
 
Jan 2, 2014 at 12:25 PM Post #4,550 of 13,432
Mordy,
 
It's great that someone tried these as power tubes! And if they turn out to be acceptable, as cheap as they are, you will be able to indulge in the luxury of rolling through the various brands and choosing the one that matches up best with your favorite driver tube of the day.
 
~~~~~~~~~~~~~~~~~
 
Received a 1945 RCA 6SN7GT (equivalent to the RCA VT-231) in today's mail. Grey smoked glass with two rectangular mica ‘ears’ on either side of the round top mica.  From what I have read, RCA manufactured these tubes from 1942 through 1956, but the earliest ones are considered to be the best.
 

 

 
A huge spacious sound stage with a very lush and warm mid-range and strong bass. This is a very musical tube with superb tonality, instruments simply sound natural and correct, but as one reviewer put it (abeit a bit more crudely), it is something like a very beautiful and voluptuous woman with just a little too much around the middle. No, she's not perfect, but you just can't let her go. lol :) 
 
As the Sylvania VT-231 is leaner with less bass, using it as a power tube, and using this warm and bassy RCA as a driver, might be a good match.
 
Jan 2, 2014 at 1:37 PM Post #4,551 of 13,432
I was checking out the 6CG7 tubes at  $2.00 each you were really lucky i didnt see anything below $7.00 approx. and usually   there about $15.00 each ill keep looking .
 
Jan 2, 2014 at 2:21 PM Post #4,552 of 13,432
SO I've been working on putting together a Lyr VS LD1+ 6DJ8 shootout and instead of going nuts I'm just gonna post my impressions thus far.
 
 
75 Voskhod
 
Lyr:
 
Slightly bright and slightly warm... very detailed, big sound stage (trumped only by the Tesla) Good impact and bass quantity without any odd wooliness. Close to neutral with a tube flair.
 
LD MK1+
 
Slightly less neutral then above (mids slightly recessed), similar detail, slightly smaller sense of space, slightly less dynamic... so damn close its not funny. (obviously with low impedance cans) S
 
 
 
Amperex 70's OG A Frame
 
Lyr:
 
Warm, lush, detailed and impactful... very musical!
 
LD MK1+
 
Detailed, bassy, very dynamic... lush, enjoyable!
 
 
 
Amperex Bugle Boys (tubes too worn to get a date)
 
Lyr:
 
Warm, thick and syrupy... liquid... good bass and mids... somewhat slower then the above tubes, treble is pulled back but pleasant, a good pair to tame a bright headphone OR for someone who likes a very tube-y sound.
 
LD MK1+
 
Pleasant and warm almost the same as the Lyr...
 
Tesla E88CC
 
Lyr:
 
Very extended treble, neutral in the mids and bass... GIANT sound stage! Brutally honest... especially with hot or poorly recorded audio... sometimes sibilant.
 
LD MK1+
 
Bright... very detailed... occasionally painful... Similar Huge sound stage to the lyr... Less dynamic... no longer as punchy...
 
 
 
Amperex 68/69 OG 6DJ8
 
Lyr:
 
Similar to the A frame, but warmer... very musical but occasionally diffuse...
 
LD MK1+
 
Warm, lust, detailed... might be missing some of the dynamics from the lyr, but not much.
 
 
 
RCA 6DJ8
 
Lyr:
 
On the warm side... good treble extension, though occasionally sibilant... not bad nor great...
 
LD MK1+
 
Same deal, on the LD this tube losses out on some dynamics.
 
 
 
Mullard 6DJ8
 
Lyr:
 
Soupy, muddy... diffuse... and warm... imagine what the classic tube-y “round” or “rolled off” sound brings to mind and multiply it by 2... Some people with probably love this this BUT its too mushy for me... even with my HD800.
 
LD MK1+
 
Same as above BUT with LESS bass control...
 
SO far its very close, with the Lyr having better dynamics and slightly better bass control (probably because of all that power on tap)
 
Jan 2, 2014 at 3:21 PM Post #4,553 of 13,432
  SO I've been working on putting together a Lyr VS LD1+ 6DJ8 shootout and instead of going nuts I'm just gonna post my impressions thus far.
 
..............
 
SO far its very close, with the Lyr having better dynamics and slightly better bass control (probably because of all that power on tap)

 
Fascinating! And this reinforces my hunch that a tricked-out LD1+ comes quite close to the Lyr for a lot less money. :)
 
And I have been wondering... since both the LD1+ and the Lyr are hybrids, how much of this difference is due to the way the Lyr configures these tubes and how much is due to a very different solid state output stage.... 
 
Jan 2, 2014 at 3:38 PM Post #4,554 of 13,432
Its close depending on tubes and opamp its 75-80% of the way there... The Lyr is very thick sounding on its own... Whereas the LD has a more graceful way of present music... Both are awesome though!
 
Jan 2, 2014 at 3:55 PM Post #4,555 of 13,432
Its close depending on tubes and opamp its 75-80% of the way there... The Lyr is very thick sounding on its own... Whereas the LD has a more graceful way of present music... Both are awesome though!

 
Fascinating comparison, I've been waiting for this kind of review ever since we started using 6DJ8 types on our LDs!
 
But, the comparison I would be even more interested in would be between a Lyr and a maxed-out MK III or MK IV.
 
As a MK IV SE owner - which would be pretty close to the Lyr price range without the premium tubes it come with (~$360 shipped w/o tubes) - I would love a shootout between a 6N30P-DR + Philips E88CC/E188CC MK IV SE and a Lyr with the same driver tubes! I'm pretty sure the results would come out as "surprising" between the two units!
 
Anyone have both a Lyr, a MK IV and spare cash to buy a the god-tier tubes lol?
 
Jan 2, 2014 at 4:08 PM Post #4,556 of 13,432
   
Fascinating comparison, I've been waiting for this kind of review ever since we started using 6DJ8 types on our LDs!
 
But, the comparison I would be even more interested in would be between a Lyr and a maxed-out MK III or MK IV.
 
As a MK IV SE owner - which would be pretty close to the Lyr price range without the premium tubes it come with (~$360 shipped w/o tubes) - I would love a shootout between a 6N30P-DR + Philips E88CC/E188CC MK IV SE and a Lyr with the same driver tubes! I'm pretty sure the results would come out as "surprising" between the two units!
 
Anyone have both a Lyr, a MK IV and spare cash to buy a the god-tier tubes lol?

 
In the interests of LD research, might I humbly suggest that YOU buy a Lyr? lol :)
 
Jan 2, 2014 at 4:18 PM Post #4,557 of 13,432
   
In the interests of LD research, might I humbly suggest that YOU buy a Lyr? lol :)

here here i second the motion! lol :)
 
Jan 2, 2014 at 4:42 PM Post #4,558 of 13,432
Sweet now I'm off the hook and don't have to buy an mkiii
 
Jan 2, 2014 at 4:54 PM Post #4,559 of 13,432
   
In the interests of LD research, might I humbly suggest that YOU buy a Lyr? lol :)

 
Think of my poor wallet after Xmas and buying all those premium 6922 tubes lol!
 
All jokes aside, I keep coming back to the idea of getting a Lyr for my HE-500; but every time I do, I wonder whether it would really be an improvement over the MK IV SE and end up not getting one...
 
Let's put it this way lol: if someone can compare both a rigged Lyr and a maxed out MK IV, I might be willing to lend him/her/it (you never know who you're talking to these days...) my single pinched waist 6922! How's that for some incentive huh?
 
Or, I could import a Lyr to Europe for twice its US price... True...
 
So many amps to test, so little money...
 
Jan 2, 2014 at 4:58 PM Post #4,560 of 13,432
If someone wants to give up their amp for a week I'll compare the mkiii or iv to my lyr.
 

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