[gibosi]

  Little Dot makes a model that seems to have the specs I want - the MK9. However, I cannot find much of reviews or user information on this amp, and it seems that there is no English manual for it yet.  Does anybody have any information?

 
As I have also been looking at something similar, that is, two 6AS7 for power and a single double-triode driver, I have considered the MK9. However, I am slightly put-off by the fact that the amp is designed for 6N9P/6SL7 rather than the 6SN7. I have read that 6SN7's will work, but as the MK9 is not optimized for these tubes, I do not know if they would sound as good as they might in an amp designed for them. Further, I do not know about the 5687 in the MK9. As the 6N9P has .3A heaters compared to the .9A for the 5687, it is not clear if the LD9 can run tubes drawing 3X the heater current. Another limitation I see is no provision for 12V tubes. But of course, there is no reason why an external heater PS couldn't be slapped on as we are now doing. But for only $500, even with these reservations, it just might be good enough..... or not.....

 

[i luvmusic 2]

Would it be nice if the S.E.X. can be modified to run 6AS7's or 6SN7's this will be my next amp in the near future.

 

[MMMan]

As I have also been looking at something similar, that is, two 6AS7 for power and a single double-triode driver, I have considered the MK9. However, I am slightly put-off by the fact that the amp is designed for 6N9P/6SL7 rather than the 6SN7. I have read that 6SN7's will work, but as the MK9 is not optimized for these tubes, I do not know if they would sound as good as they might in an amp designed for them. Further, I do not know about the 5687 in the MK9. As the 6N9P has .3A heaters compared to the .9A for the 5687, it is not clear if the LD9 can run tubes drawing 3X the heater current. Another limitation I see is no provision for 12V tubes. But of course, there is no reason why an external heater PS couldn't be slapped on as we are now doing. But for only $500, even with these reservations, it just might be good enough..... or not.....

I've looked too.... And the Mk 9 has the best price for the feature set required. However, right now I am happy with nice 6SN7s in the Mk IV.

BTW, the LD Mk VI owners threads seem to like the 6SN7 as a driver, despite the lower gain.

 

[TrollDragon]

Hey mordy,

Upon smelling an acrid smell, I would guess that you have some resistors on the board that are partially cooked or have been overheated enough to turn the paint on then black. You really should pop the amp apart and investigate, as those resistors won't last.

 

[mordy]

Hi TD,
 
I'm afraid that if I open up the amp and take it apart I'll won't be able to put it together correctly again. Meanwhile, everything is working as it should.
 
There is a post somewhere that a person who had a problem with a MKIII contacted David Zhe Zhe and was advised to send it to a repair place in California. Apparently, the parts and labor on the Little Dot amps are covered, except for the shipping.

 

[hypnos1]

Right guys, here goes...
 
First, the BAD news...I'm a first class idiot (which some may have gathered by now lol!).

 
Second, the GOOD news...my LD hasn't been nuked after all!!! (I am fairly sure).
 
Before carting her off to the repair man, I decided to do just one last complete check. This time, it occurred to me to use the meter and confirm there was no signal at the headphone connection inside the amp...lo and behold, THERE WAS!

 So I unplug at the 'phone, test the plug and...yes, you've got it...NO READING...doh...! I pull it apart and..

..both (thin) silver wires (+) detached...
 
The one thing I hadn't really considered, as I was SO careful when putting it together...sealed with resin, and generously covered in insulating tape - those tiny plugs (on the HD650) are the devil to work with.
 
So, folks, although I haven't re-soldered yet - after dinner project! - that's 99% sure to be the culprit, no?!! Will confirm later this evening.
 
But even if all is well, from mordy's near-miss, it would appear mods ARE needed so I shall go ahead and see what my local valve/tube man suggests.
 
Sorry to have been premature, but at least it has been a wake-up call to stop taking such a big risk and try to get it sorted...something I'm sure mordy now agrees with, lol!

 

[hypnos1]

  Hi,
 
Yesterday I was using my 6080s planning to do a comparison test with the 6832, 7963 and 5687 tubes. As you may recall my fans draw air away from the amp. Suddenly I smelled a whiff of acrid smell. Mindful of all the warnings from Gibosi and TD about running 2.5A tubes I immediately shut off my Little Dot and the rest of the system. The faint smell went away, and I switched the 6080s for 6SN7 tubes.
 
Plugged in everything - all is OK, but I decided against taking a chance of running 6AS7/6080 tubes again in the LD MKIII. Problem is that I love the sound of these tubes - the bass is so much better. The 6SN7 tubes are OK, but they lack the heft and authority of their big brothers.
 
So what is the next step? Should I try the 5687 tubes as power tubes? Will they have enough power to give me the bass I like? Would they be an improvement over the 6SN7s?  In addition, I would have to buy two special adapters.
 
Or should I go the way of the other members on this forum who bought other amps? I think I know what I want: An amp that uses 6080/6AS7 tubes or similar as power tubes, and uses dual triodes as drivers. It has to be able to be used as a pre-amp as well as headphone amp. In addition, I want a protective circuit that allows me to use a DC coupled amp. (My old Sony ss amp has a protective circuit, but I can't use my Outlaw RR2150 receiver.)
 
Little Dot makes a model that seems to have the specs I want - the MK9. However, I cannot find much of reviews or user information on this amp, and it seems that there is no English manual for it yet.  Does anybody have any information?
 
I am open to suggestions for an upgrade, but I am not ready to build something myself. I realize that I could get whatever I want if you spend enough, but I am looking for the biggest bang for the buck (the LD MKIII certainly fits this criterion).
 
The MK9 is around $500. It seems to me that some of the amps mentioned here like the Glenn and the Woo 2 are much more expensive, and the Crack is DIY.
 
Any advice is appreciated.

 
Hi mordy.
 
Sorry to see your amp appears to have said "enough is enough", lol!. But all is not yet lost...perhaps some easy and not too expensive mods may just do the job (as per lemonjelly). Will know for sure soon, when my local repair man has done his stuff...and of course I'll let everyone know straight away.
 
As you may have seen from my previous post, it does actually look like my baby may well be OK after all...silly me!!
 
As for a replacement, I may well now not need the Little Bear, but it will certainly be a very interesting project...and who knows, with the 5687s as drivers it just might be a real winner - for peanuts!

 
Good luck, whatever course you eventually take...it looks like we are both somewhat in limbo at present. And all because we can't/won't give up our wonderful 6AS7G/6080 tubes...I for one could NEVER go back...

 

[mordy]

Well, well, maybe I shouldn't be worried after all. I have a set of Chatham 6AS7 tubes on the way, with a current draw of 0.84A each. There is the possibility of the acrid whiff coming from somewhere else - my 1980s Sony 110W amp or one of the three voltage regulators on hand, or the PC 12V PS, or one of the two wall warts.....
 
Maybe my wife's pear pie spilled over in the oven and caused the smell? Me thinks that I shouldn't be paranoid and just go for it!
 
When my DC coupled receiver blew up I was able to smell it by sticking my nose by the amp, but this time I forgot to do this test. Tried the smell test now - no smell. Stay tuned....
 
Hypnos 1, you made my day!

 

[i luvmusic 2]

So you guys are going back to 2  6AS7G driver tube?

 

[mordy]

"And all because we can't/won't give up our wonderful 6AS7G/6080 tubes...I for one could NEVER go back..."
 
I feel exactly the same way, so in some way, manner or shape I just have to use those tubes. As mentioned, I have Chatham 6AS7 tubes on the way. I may wait for them arrive to plug into my amp just in case.....The 6AS7/6080 I only intend to use as power tubes.
 
The 6SN7 are very nice, and a big step above the 6N6P family, but the 2.5A tubes is still much better. Meanwhile, I am using a pair of 1960's RCA 6SN7GTB as power tubes and am trying to compare the two sub miniature dual triode tubes I have (6932/7963). This got to be the most difficult comparison so far - they are that similar, but there are differences; I just have to find ways to describe the differences. In addition, I realize that they need time to warm up to sound their best (don't know if this depends on the sub miniature tube, the 6SN7 tubes or both together, but I have to wait some 20-30 min after turning them on to get the best sound).
 
These tubes were the ultimate development of vacuum tube tube technology at the end of the tube era. Perhaps their intended use in missile warheads dictated very tight tolerances and thus the similarities.

 

[hypnos1]

  Well, well, maybe I shouldn't be worried after all. I have a set of Chatham 6AS7 tubes on the way, with a current draw of 0.84A each. There is the possibility of the acrid whiff coming from somewhere else - my 1980s Sony 110W amp or one of the three voltage regulators on hand, or the PC 12V PS, or one of the two wall warts.....
 
Maybe my wife's pear pie spilled over in the oven and caused the smell? Me thinks that I shouldn't be paranoid and just go for it!
 
When my DC coupled receiver blew up I was able to smell it by sticking my nose by the amp, but this time I forgot to do this test. Tried the smell test now - no smell. Stay tuned....
 
Hypnos 1, you made my day!

 
SCOOBY-DOOBY-DOO....OH HAPPY DAY!...
 
Yep, mordy...made my day too lol....MY LD LIVES!!   
 
I cannot believe it - 'twas that darned plug all along

. Normally, when a plug like that is going, there's some kind of early warning...not this time, obviously!
 
Don't know how much longer I could have gone without my fix

.
 
However, m, methinks it still rather risky to continue without any mods...but tonight..TO HELL WITH IT - I'm getting my fix, lol!
 
Cheers!

 
 
 

  So you guys are going back to 2  6AS7G driver tube?

 
No ilm2...POWER tubes - for me at least, there is nothing to compare with my C3GSs as drivers for the GEC 6AS7Gs...PURE HEAVEN!!

 

[superdux]

New gear is costing me, so i want to hand over my 12AX7 adapter that MIKELAP had made and sent me. It comes with a 12AX7 to 6SL7 adapter for octals to use. There is also a brand new 1 russian octal and a tung sol 6SL7GT that goes with it if you like. I have also put some extra socket savers onto the adapter to keep the strain from plugging and unplugging off of the adapter plugs. This adapter has worked fine for me in my LD MKIII but i have come to love my C3G's more over the time. Please send me a message for further info and price.
 

 

 

 

 
EDIT: gibosi gave me some tips on more tubes to roll with this adapter, so for the while i will be keeping it but you still can ask if you're interested.

 

[i luvmusic 2]

 

  Well, well, maybe I shouldn't be worried after all. I have a set of Chatham 6AS7 tubes on the way, with a current draw of 0.84A each. There is the possibility of the acrid whiff coming from somewhere else - my 1980s Sony 110W amp or one of the three voltage regulators on hand, or the PC 12V PS, or one of the two wall warts.....
 
Maybe my wife's pear pie spilled over in the oven and caused the smell? Me thinks that I shouldn't be paranoid and just go for it!
 
When my DC coupled receiver blew up I was able to smell it by sticking my nose by the amp, but this time I forgot to do this test. Tried the smell test now - no smell. Stay tuned....
 
Hypnos 1, you made my day!

 
SCOOBY-DOOBY-DOO....OH HAPPY DAY!...
 
Yep, mordy...made my day too lol....MY LD LIVES!!   
 
I cannot believe it - 'twas that darned plug all along

. Normally, when a plug like that is going, there's some kind of early warning...not this time, obviously!
 
Don't know how much longer I could have gone without my fix

.
 
However, m, methinks it still rather risky to continue without any mods...but tonight..TO HELL WITH IT - I'm getting my fix, lol!
 
Cheers!

 
 
 

  So you guys are going back to 2  6AS7G driver tube?

 
No ilm2...POWER tubes - for me at least, there is nothing to compare with my C3GSs as drivers for the GEC 6AS7Gs...PURE HEAVEN!!

Sorry my bad i mean POWER TUBES not DRIVER LOL,i always mixed up the two.

 

[gibosi]

  Well, well, maybe I shouldn't be worried after all. I have a set of Chatham 6AS7 tubes on the way, with a current draw of 0.84A each. There is the possibility of the acrid whiff coming from somewhere else - my 1980s Sony 110W amp or one of the three voltage regulators on hand, or the PC 12V PS, or one of the two wall warts.....

 
Given lemonjelly's description of the "melted" resisters in his amp, I think you should still be concerned:
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/7170#post_10808730
 
On the other hand, no one else has reported a similar failure and you may well be able to run 6AS7/6080 in your LD indefinitely. The fact that you, hypnos1 and ilm2 have yet to have a failure of any kind due to these output tubes is one more example of the value and quality inherent in LD products. These cheap little amps are simply amazing!
 
Nonetheless, I think everyone here understands the risks very well so I will be quiet now.... (says the guy with an LD1+ which doesn't even have output tubes! lol
 
Cheers

 

[mordy]

Hi Gibosi et al,
 
Thanks for the encouraging words. Something strange happened....
 
I let my amp play with the 7963 as driver and the the two RCA 6SN7GTB as power tubes. As mentioned, I found it hard to distinguish the 7963 from the 6832. One sounded better here, the other better there, but almost the same. Suddenly I paid attention to the sound - what's going on?
 
It sounded like I put back the 6080s in the power seat! A full, weighty, satisfying bass, a delicate, detailed shimmering treble; sweet midrange. Really don't know what happened, but suddenly the 7963 took flight and left the others behind. Maybe 48 hours wasn't enough for burn in - maybe it needs 60 hours.
 
Here is a size comparison between the 7963 and a Coke bottle style tube:
 

 
I am afraid to move everything around again; this is too good to change. Hope I am not imagining all this. Let's see how it sounds tomorrow.
 
What others are saying:
 
"The 7963, while claiming no octal forerunners (as there were no frame grid octal twin triodes), can trace its ancestry to the 6DJ8 family. In fact, with regard to audio applications, the 7963 offers performance in low level audio applications that is superior to all 6DJ8 variants, and to all other subminiature twin triodes as well."

Absolutely SUPERB"
 
"It has totally blown my ears away the past few days (big style)"
 
Maybe some promoter will arrange a match between the C3g and the 7963 to see who is the reigning champion....