Little Dot Tube Amps: Vacuum Tube Rolling Guide
Dec 1, 2020 at 11:53 AM Post #12,377 of 12,832

Whelkie D

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... so it seams that I'm the only one that instead of a magical unicorne bought a angry pitbull... strange... anyway, as said I opened the adapters ad discovered this simply incredible "quality" ... well high quality real rubbish... here are the pictures:

mini_mir_20201201_105451.jpg

mini_mir_20201201_105509.jpg

mini_mir_20201201_110240.jpg

mini_mir_20201201_110304.jpg

mini_mir_20201201_111603.jpg

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mini_mir_20201201_111948.jpg

ok, the name of the dealer in ebay is xulingmrs ... clearly problems could happen even to the best supplier and is correct to give him possibility to recover but, in this case, imho there is nothing to recover... the quality is simply absent at every degree


anyway, I've redone the solderings but nothing changed... the HUMMMM is still there even at gain 10... I'm have the idea the problems could come from couple of factors acting togheter... tollerances in the components inside tha LD (righ e left circuits slightly different) and a little to high power supply at home, here I have roughly 260Vac instead of nominal 230Vac so at the output of LD transformer the voltages are probably 10% higher than nominal and, togheter with components, that cause HUUMMMMMM
That's where I got my adapters from! Perhaps I ought to open mine up and see what they look like inside.
 
Dec 1, 2020 at 1:47 PM Post #12,378 of 12,832

lupoal

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I'm using an adapter for 6SN7 to 6N6P too and come from the same supplier... the only differenve is the housing, the second one plastic black with very different housing constuction, instead of the C3gblabla that is metal (in my case not completely shiny but with some spot of corrosion)... anyway, that one for 6SN7 works flowless, I'm not going to open it and check ... I'm quite scared the the inside could be horrible like the other one, I prefer to ignore and hope it is completely different... what is sure is that for C3g is pure rubbish (both pieces I have I mean)

in any case I think the problem is not only from the adapter but, as I wrote, also from C3g tubes that are much more critical then those we use to use with our LD... no problem, in the future I will look less for unicorns, these two now go into a bin and let's move on
 
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Dec 2, 2020 at 2:56 AM Post #12,380 of 12,832

lupoal

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no problem, I've spoken with the C3g seller and he decided to refund me the whole amount, shipment charge included (very gentle man)... the adapters are already in the condo bin basket... episode over, let's move on... two 6SN7 RCA should arrive from USA... and two Bad Boy (true or fake? we will see) from Canada
 
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Dec 5, 2020 at 2:54 PM Post #12,381 of 12,832

Arro

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The 6SJ7 octal pentodes work in both the I+ and the MK IV. I've been testing it out with a pair of Ken-Rad VT-116 while I wait for more tubes to arrive from America. To fit them in the I+ without modifying the amp I needed to use a pair of Pomona socket tester adaptors. Without this the pins on the 6SJ7 adaptor won't reach far enough into the socket. So far I've tested the VT-116 with 6N6P-IR and MELZ 6N8S as output tubes in the MK IV without problems. The effect on sound is similar to using 6SN7GT driver tubes. The sound just feels bigger and the sound stage is wider. Listening with HD650s it's as though the distance between instruments has been increased. Not bad for tubes that can be picked up for as little as £5 each.
 
Dec 5, 2020 at 6:30 PM Post #12,383 of 12,832

lupoal

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here inside there are two pages that summarise the info about tubes... the first one is the 77... the second one I can only remember is the 400+ area... I need help, where is the second one? I can’t find it :frowning2:
 
Dec 5, 2020 at 7:28 PM Post #12,384 of 12,832

triod750

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Could it be this? I have saved it as a document.

Posted by Acapella 2014, I think.
___________________________________________________________________________

Hi, Just for Christmas I have put together a table as a reminder for everyone in the thread and to help new arrivals. The table is now pretty much complete.

Please, let me know if you find any additions or anything that requires correction.

Little Dot I" / II/ III / IV Endgame Tube Table


Power Tube



Name
Adapter
Heater Current (A) / 6.3 V
Notes
5687/7044/7119(E182CC)
5687 Powersocket Adapter
0.9
easily usable substitutes, sound great
6AS7G/6080
Adapter + External Power Supply, see 1 and 2 and 3
2.5
this is probably the icing of the power tube cake
12AU7/12AT7/12AX7/7025/5751/ECC83/6057
Powersocket Adapter
0.35

6BL7/6BX7/6BQ7
Adapter + External Power Supply, see 1 and 2 and 3
1.5

6DJ8
not needed
0.365

6GU7/6CG7/6FQ7
not needed
0.6
not compatible with 12AX7 driver tubes
6N23P
not needed
0.31

6SL7*
6SN7 Powersocket Adapter
0.3
lower gain than 6SN7, not compatible with low impedance cans
6SN7*
6SN7 Powersocket Adapter
0.6
classic high end tube, not compatible with low impedance cans
6N6P-IR
not needed
0.9
high quality, long lasting version of the 6N6P-I and considered best sounding 6N6P before the very expensive 6N6P-DR




Maximum recommended heater current for power tubes is 1.0 A. Tubes exceeding this are highlighted in red.






Driver Tube



Name
Adapter
Heater Current (A) / 6.3 V
Notes
5687/7044/7119(E182CC)
External driver socket ^, external power supply
0.9
6.3 V / 12.6 V **
6350/6463/ECC813
External driver socket ^, external power supply
0.9
6.3 V / 12.6 V**
2C51 / 396A / 5670
External driver socket ^ + driver socket adapter
0.35

7AU7
External driver socket ^
0.6
3. 5 V / 7 V**
12AU7
External driver socket ^
0.3
6.3 V / 12.6 V**
12AU7/12AT7/12AX7/7025/5751/ECC83/6057*
External driver socket ^
0.3
One triode can be used besides a non-powered one, 6.3 or 12.6 V**
6BQ7A
Adapter
0.4

6DJ8
External driver socket ^
0.365
probably noisiest double triode, both triodes must be powered
6HM5
none
0.19
probably best standard AK5-type option
6N23P
none
0.31

6SL7*
6SL7 driver adapter
0.3

6SN7*
External driver socket ^, external power supply
0.6

C3G(S)* ^^
C3G AK5 Adapter
0.37
C3G(S) tubes sound great but they are produced with a fragile glass base. Widen the socket holes before inserting the tube to avoid breaking.
ECC81
External driver socket ^
0.3

ECC40
External driver socket ^, external power supply
0.6

E80CC/6085
External driver socket ^, external power supply
0.6
6.3 V / 12.6 V **




Maximum recommended heater current for driver tubes is 0.4 A. Tubes exceeding this are highlighted in red.



*: Requires socket extenders for LD MKIII
": For Little Dot I only driver tubes.


9 Pin power socket extender



7 Pin driver socket vector extender



**: Generally, when doubling the voltage, the apparent current is halved.


^: The external driver socket adaper uses a breadboard and allows the use of a single double triode to drive both channels.

^^ Hypnos1 (post 5670): How to remove the C3Gs metal shielding, this requires care to not break the fragile tubes.








Power Tube Requirements (Gibosi post #7937)


1) Double triode



2) Separate cathodes (there are some double triodes such as the E90CC where the triodes "share" a cathode. These will not work.)

3) Heater current 1.0A or less



4) 6.3 Volts







List of compatible tubes and 6DJ8, 6SL7, 6SN7, 12AX7 wiring instructions





For old school driver tubes operable without adapter, see page 77.

Driver Tube 7-Pin Vector Socket Adapter
[IMG]


Power Tube 9-Pin Socket Adapter


Revisions 1 & 2, 24/12/2014: Thanks for the input Gibosi and Mordy, thanks for sending the socket extender pictures Mordy, which are now included. Added a reference to Hypnos1 on how to remove the C3G(S) metal shielding.
Added ECC40 and E80CC/6085 as suggested by Gibosi, thanks.
Merry Christmas.
Revision 3, 09/01/2015: Added links to the implementation of 6AS7G/6080 power tubes, thanks Gibosi for finding the posts and suggesting the implementation and Mordy making it work. Added link to page 77 and 6N6P-IR.
Revision 4, 10/02/2015: Updated power tube links for 6080/6AS7G by Mordy's post 9059 on page 604 (3)
 
Dec 6, 2020 at 6:41 AM Post #12,386 of 12,832

Arro

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Images of the 6SJ7 in the I+ and the MK IV SE. The weather was much brighter this morning so I was able to take some pictures with my ancient digital camera.

IMG_6562.pngIMG_6577.png

I also tried solving the issue about reaching into the MK IV to get to the jumpers. I had the idea of attaching jumper wires to the internal pins which would then allow the jumpers to be changed externally. However the access holes on the bottom of the amp don't leave enough room for me to be able to fit the female end of the jumper wires to the internal pins with tweezers. I'll have to rethink that one.
Link if anyone is unsure what I mean by jumper wires
 
Dec 6, 2020 at 7:32 AM Post #12,387 of 12,832

johanchandy

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So I got the LD1+, installed the burson v6 classic opamp and the mullard m8100 tubes, and it sounds pretty decent but I find it fatiguing with my Grado hemp, I was hoping for a smoother more relaxed sound. I even find the stock tubes better in this regard. What is a nice warm bassy tube that would work for my setup? I'm using the modi 3 as a dac and the schiit heresy is amazing with the hemp for a live sound, I was hoping the LD1+ would give me a more relaxed alternative. Could this also be because it probably needs more burn-in as well?

I'm really loving the stock tubes soo much more paired with the burson v6c, really smooth and musical, but they're a tad noisy, what would be an upgrade to the stock tubes that share a similar sound?

Would the Sylvania 5654W 's be the tubes for me?
 
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Dec 6, 2020 at 9:41 AM Post #12,388 of 12,832

MIKELAP

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@triod750

exactly what I was looking for! thank you! :)

I'm waiting for my new printer, should be here middle next week... then I will print it too... precious info
Dont know if you have this .Its a list i made regarding interesting infos in this thread
LITTLEDOT TUBE ROLLING GUIDE STUFF.JPG
 
Dec 6, 2020 at 1:17 PM Post #12,389 of 12,832

mab1376

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Dec 6, 2020 at 4:00 PM Post #12,390 of 12,832

Arro

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what would be an upgrade to the stock tubes that share a similar sound?

Shanghai 6J1. They're an improvement over the stock Beijing 6J1 in every way while still keeping the soft treble that seems to be a characteristic of NOS Chinese tubes. You can tell them apart from the Beijing and Shuguang 6J1 by the atomic whirl logo.
Shanghai 6J1.jpg
The one problem you might have is finding them. There's very little information about the different Chinese tube factories available on the English speaking internet and Chinese sellers don't usually distinguish tubes by the factory that made them.
 

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