[TrollDragon]

Oh yeah!!! this week is my 5th anniversary of " totally free from analog cigarette or cigar""


Cheers

 
Much Congrats!
 
The new ones you posted are nice, and thanks for the PM I'll check into them.

 

[TrollDragon]

 I'm not into vamping, but I really enjoy the decadence of a Cuban cigar with a single malt scotch, on occasion...

 
A fine listening session was had here...
 

 

[mordy]

Hi electroshock,
 
If you use the search option on top of the page you will find a lot of material on the 6DT6 ("Detox") tube. Here is an excerpt from post #3056:
 
Started out with the EF95 1/7, but now I use EF92 setting without a strap, and I am happy with this ( but I liked the EF85 1/7 setting as well) . My 6DTA6 tubes in use at this time are Japanese made, either by Hitachi or Toshiba and perhaps they come from the same factory as the (demystified?) Siemens Foreign and Haltron tubes.
IMHO the 6DT6 tubes require 30-50 hours burn in to enter their prime.
 
Changing the strap settings has a big effect on the sound, and it is usually easy to pick out the best combination. I admire your work on making the adapter - wish I had those skills. In the past I found that grounding the amp chassis helped to reduce hum. Don't overlook RF sources such as portable phones etc in close proximity to the amp.
 
 

 

[gibosi]

  Will the 5687WA modification with the external heater work with the LD 1+ (I assume yes as gibosi has advocated for this mod).  Also is there a wiring diagram for this mod? I found the parts list that gibosi made but I have not found a diagram. I am hoping I may be able to salvage my box by using it with this mod.  

 
Not exactly sure what kind of wiring diagram you are asking for....
 
If you are asking how to wire up an external DC heater PS, this might help:
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/4410#post_10076232
 
If you are asking how to wire your 9-pin socket to the LD's two 7-pin sockets in order to run an 5687WA, this might help:
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/6885#post_10722910

 

[electroshock]

  Excellent work on the Adapter box it looks great.
 
Possibly your heater wires are running too close to the other pins? Heater wires need to be twisted and separated a fair distance from other wires or run at 90 degrees across the other wires if you don't have the room. The heater wires will induce AC hum into the circuit.

Thanks for the tip I will give that a try as the inside of the box looks like a birds nest...

 

[electroshock]

   
Not exactly sure what kind of wiring diagram you are asking for....
 
If you are asking how to wire up an external DC heater PS, this might help:
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/4410#post_10076232
 
If you are asking how to wire your 9-pin socket to the LD's two 7-pin sockets in order to run an 5687WA, this might help:
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/6885#post_10722910

Wow thanks gibosi both of these links are exactly what I was looking for.  I am going to order the components and start playing around. Thanks also for your earlier post on the 6DJ8. I tried moving the wires inside the box as TrollDragon suggested but it did not seem to make a difference with this setup.  I think I am going to just concentrate on 6TD6 strap options and getting the 5687 setup as I was able to get a Sylvania 5687WA with a mfg date of 9-64 that I am excited to try. I post again when I get everything setup.

 

[electroshock]

  Hi electroshock,
 
If you use the search option on top of the page you will find a lot of material on the 6DT6 ("Detox") tube. Here is an excerpt from post #3056:
 
Started out with the EF95 1/7, but now I use EF92 setting without a strap, and I am happy with this ( but I liked the EF85 1/7 setting as well) . My 6DTA6 tubes in use at this time are Japanese made, either by Hitachi or Toshiba and perhaps they come from the same factory as the (demystified?) Siemens Foreign and Haltron tubes.
IMHO the 6DT6 tubes require 30-50 hours burn in to enter their prime.
 
Changing the strap settings has a big effect on the sound, and it is usually easy to pick out the best combination. I admire your work on making the adapter - wish I had those skills. In the past I found that grounding the amp chassis helped to reduce hum. Don't overlook RF sources such as portable phones etc in close proximity to the amp.
 
 

Thanks mordy for the kind words and the info. I like the idea of being able to plug the 6DTA tubes directly into the board with the EF92 setting.  I am going to play around with the strap settings while I am waiting for the external voltage components.  

 

[bbmiller]

Originally Posted by TrollDragon /img/forum/go_quote.gif
 
Get the tall 6HM5,'s from this seller, most of the users of this thread has bought them from him.
http://www.ebay.com/itm/6HM5-6HA5-EC900-export-quality-audio-triode-tube-NOS-FREE-SHIPPING-/300879467071

Are these the tall ones as well? 
 

6HM5 EC900 - lot 10 pcs EI Yugoslavia

 

[Uncle AL]

Awhile back, there was a photo of a large collection of vacuum tubes stored neatly in drawers. May I suggest, that along with useful discussion of tube rolling and adapting, that head-fiers post photos of how they maintain their inventory of vacuum tubes?

 

[Rossliew]

  Are these the tall ones as well?
 

6HM5 EC900 - lot 10 pcs EI Yugoslavia

Yes, these will do.

 

[MIKELAP]

  Yes, these will do.

bbmiller those are the ones i bought just remind the guy to pack them well ,because when i got mine 2 of them were broken the guy says i put them in a foam box yes he did but they were bouncing around in there Hmm..tell him you know somebody that happened to recently maybe he will do a better job this time dont think he'd like negative feedback i am waiting for replacements .

 

[MIKELAP]

  Yes, these will do.

 

[bbmiller]

 

  Yes, these will do.

bbmiller those are the ones i bought just remind the guy to pack them well ,because when i got mine 2 of them were broken the guy says i put them in a foam box yes he did but they were bouncing around in there Hmm..tell him you know somebody that happened to recently maybe he will do a better job this time dont think he'd like negative feedback i am waiting for replacements .

Thanks MIKELAP. I just sent the message to eBay they, Say it can take two days for him to reply.

 

[TrollDragon]

Well I did a little playing on the weekend between feeds of Turkey...

 

 
These are the tubes I ran in the MK IV for a little listen, from left to right are the modified Octal Drivers, Regular Drivers and Output's. They are placed in the order of what I enjoyed best to least. Various music genre's were listened to and I was using the modded DBV3 style Fostex T50RP's. The house was full of family from near and far so there was absolutely no chance to listen with the beyerdynamic DT880 Pro's.

 

Spoiler: DBV3 Fostex T50RP terminated with mini XLR & Toxic Cables 6.5mm

 
Groups Left to Right:

• Sylvania JAN 5751, Raytheon 6832, Sylvania JAN CHS 6SL7GT
• EI Yugoslavian 6HM5, GE JAN 5654
• Electro-Harmonix 6H30Pi-EH, OE NEC Japan 6GU7, RCA Cleartop 6CG7

 
The output tubes in group 3 don't really offer a major change to the sound of the amplifier. The 6H30Pi's do have the best sound of the three types I tried, they have the best range and deliver the highest output level, they are very smooth with great detail. The 6GU7's are a nice inexpensive solution for a replacement to the 6H30Pi's, they have a little more amplification but don't really deliver the same level of output. This is understandable as the LD's circuit was NOT designed around the 6GU7 so one cannot expect the same level of performance. The 6CG7's... Well I just don't like them at all, it seems to me that there is something a little "Off" in the sound that is hard to describe. It could very well be the ones I have (3 different makes) but I would not choose them as a replacement output tube. As with any tube review it is all subjective, my gears & my ears so your mileage will vary.
 
The regular drivers in group 2 were really no competition when it comes to sound, just like switching from AM radio (5654) over to FM radio (6HM5) the difference is a very welcome upgrade to the quality of sound over the stock 5654's.  The first thing you notice on the 6HM5's is where did that nice bass come from? The bass is far from overpowering, the tube is very musical and easy to listen to. The EI 6HM5 is one of the quickest and most cost effective upgrades you can to for your Little Dot, but order 3 or 4 as you will want a spare or two.
 
Modifying your Little Dot to accept dual triodes like the ones in group 1 is an upgrade that will be Head and Tails above even the best 6HM5 type drivers when it comes to overall sound quality and presentation. There are SO MANY choices and options to be experimented with when you decide to take your first step down that rabbit hole that is Dual Triode Land, you will seriously have to do some research first as to which path you want to take.  Now you will be looking for tubes on eBay that 90% of the world searches for so the prices ramp up consideribly, also the chance of getting taken by shady sellers increases as a lot of these tubes are in much higher demand. You really need to be an informed buyer to know what you are looking for and what it is that the seller is actually selling. There are many great deals that come along when looking for 6DJ8 / 6SN7 type tubes but you might have to camp out on eBay for a time and that is a discussion that those who know how to work the eBay system can help with.
 
I am not going to describe the sound of the group 1 tubes as there are so many variations of them and they do change from manufacturer to manufacturer even year to year. When you do make an adapter for the Little Dot you can change tubes and sound at whim without jumper or switch settings coming into play. Just shut down, change tubes and in a minute or two you are good to go again with a whole new sound.
 
 
The Westinghouse CWL-6BQ7A is one of my absolute favorites when it comes to the 6DJ8 style of tubes. I listen to this tube a lot and really enjoy it, the 6BQ7A is a very musical and euphonic tube.

 
Considering the tubes in group 1, the one with the most detail and upper presence is the 5751 which is an update to the 12AX7 tube. They have lowered the µ to 70 on it and increased the current/bandwidth. This is the reason the 5751 is very popular as a preamp tube, the pair I have came from a Jolida phono stage after a friend upgraded his tubes. The sub miniature Raytheon 6832 is another great tube that is on par with a lot of the 6DJ8 tubes on the market but it does require a custom made adapter to use it conveniently with plug and play. Lastly the 6SL7GT is another driver option that does not require an external power source to use. There are literally 100's of different 6SL7's out there to choose from, I don't have a large selection of these but out of the ones I do have this one is the best sounding to my ears. I have one that is very microphonic that does have a better sound than the one pictured but the noise from it is more annoying than the sound benefit so it does not get much use. This is apparently a common trait of 6S?7 tubes, they might or might not be microphonic so you take a chance when purchasing them.
 
 
Well I don't know if this will be an informative post to those new to our fun little game of rolling tubes in the Little Dot amplifier. It is all subjective and without a way to volume match the output of each of these tubes all reviews will have to be taken on what the reviewer hears with their ears and gears. To actually compare the output of the tubes properly, it does require some sort of SPL meter. You are not able to match volume by ear since audio memory is very short and each tube will have a different gain that reflects in the level of the output volume.

 

 

[sssboa]

 
OK, thx
Just ordered a pair of c3g and 6SN7 with all adapters.
I took 6SN7 vintage Sylvania nice looking black plate, chrome top, moderately priced, I doubt they affect quality really so want them to be lookers

So the tubes arrived.
C3G do not much my Beyerdynamic DT880 headphones at all, bass is bloated and poorly controlled, Voshod perform much better, also they (c3g) don't sound much off some bassy ef95 tubes. it's my problem with beyerdynamic DT770/880/990 cans that most tubes make them sound too warm and with overwhelming bass, so after months of testing very wide array of tubes I singled out Soviet EF95 Voshod and EF92 Mullard as best sounding with my phones, still very warm but not too (I use M8081 but I think all EF92 sound very similar if not the same as opposed to EF95 that differ a lot from brand to brand, all EF91 sounded too warm to me and also similar too each other but clearly Mullard had best highs, with military model having a slight edge maybe) . 
6SN7 look cool when off, when on they do not glow much and do not think they add anything to the sound over my default type of power tubes (Soviet 6N6P), not sure if they (6SN7) do not add some very subtle humming in the background though and crackling when the amp is touched, I also bought 6SN7 Tung-sols with black plates, normally very expensive, they look like piece of art and it's probably waste to use them as power tubes.
C3G and their adaptors will be for sale probably.