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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 306

post #4576 of 6858
Quote:
Originally Posted by mojorisin35 View Post
 

 

 I have been auditioning the Amprex 1968 OG 6DJ8 I received from Audiofanboy with Mikelap's amazing adapter and my mind is Blown! Wow !

 

Gary

 

Nice! Good timing, seeing as I was about to PM you to know if you had gotten the package...

 

Yup, the OG are pretty amazing tubes and really do give you that "holy Schiit" moment!

 

Now wait until you get the urge to get the even more premium types lol... Mind may be blown a few more times!

post #4577 of 6858
Quote:
Originally Posted by MIKELAP View Post
 

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                                                                                                                         

I wonder what would happen if you guys started selling modified Little Dots, I would be the first to buy one!

post #4578 of 6858
Quote:
Originally Posted by Sony Slave View Post

I wonder what would happen if you guys started selling modified Little Dots, I would be the first to buy one!
Then they would be called DarkVoice or BottleHead... biggrin.gif
post #4579 of 6858
Quote:
Originally Posted by TrollDragon View Post


Then they would be called DarkVoice or BottleHead... biggrin.gif

I wouldn't be surprised if it has the sound of the dark voice, but at a lower cost.

 

On topic, it seems like members are taking the Little Dot to uncharted territory. As a matter of fact, do you or anyone else know how the best heavily modified Little Dot 1+, MKIII, or MKIV  setup sounds compared to other "high end" tube amps?


Edited by Sony Slave - 1/3/14 at 12:35pm
post #4580 of 6858
Quote:
Originally Posted by Audiofanboy View Post
 

 

Nice! Good timing, seeing as I was about to PM you to know if you had gotten the package...

 

Yup, the OG are pretty amazing tubes and really do give you that "holy Schiit" moment!

 

Now wait until you get the urge to get the even more premium types lol... Mind may be blown a few more times!

 You dont want that happening to often its not a pretty sight  !                                                                                                                                    CREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 100

post #4581 of 6858

To my surprise my LD 1+ did not HUM with the Fleetwood 6CB6 and Westinghouse Premium 6BA6.

post #4582 of 6858

So just an update guys,

 

I took Mike and Mordy's advice and my 6HM5's came in today. Apparently my other tubes were not in fact lost in the mail, they were just horribly late, so I got some Electro-Harmonix 6H30pi's running as well.

 

After plugging them in, my first thought is... HOLY CRAP!

I'm not sure how to describe this. The 6HM5's really bring out the sound.. everywhere really. The music has more "pop"; it seems richer.. if that makes sense. Only down side is that one of the 6HM5's seems to be an exceptionally sensitive tube. I can touch any of the other ones and get no hum, but with this one.. if I even touch it lightly it'll hum. It was humming all the time at first, but I switched its position and wrapped it in tin foil; so now it's fine.

But yeah.. holy crap. I think I'll test out my voshkod's next, and see if I can tell the difference since both are supposed to be great.

Thanks again everyone :-D


Edited by sam6350 - 1/3/14 at 8:10pm
post #4583 of 6858

Well a bit of an update on my copper tube adapter, each one of my 6DJ8's hum, the 6N23P or 6N2P not so much hum but there was a faint bit of tube rush in those. The Siemens 6DJ8 was the absolute worst the hum on it was exceptionally bad and would NOT go away.

 

So I build a test adapter with a little bit of Mogami Star Quad and a twisted pair of 18 AWG heater wires. I kept the heater wires away from the A/G/K wires as much as possible and all the hum is gone, even the tube rush from the Soviets. So I am going to have to re-engineer my tube adapter.

 

1) Heater wires brought outside through a hole in the bottom and top at the back of the adapter.

2) Run new heater wires in the pipe using shielded wire, attaching each end of the shield to the pipe.

3) Create a new adapter out of lexan, with the Tube rings removed so it is only as thick as an octal socket and plugs right in over top of the B7G sockets. (<- Leaning this way.)

 

So much fun we go through with this hobby, the BreadBoard option would most likely work the best but would not have the WAF where my amp is situated.

 

Here is the totally silent test adapter with a 6N23P installed and my new German Maestro GMP 8.300 D Professionals...

:beerchug: 

post #4584 of 6858

I had the same issue and regardless of what I tried it never went away... UNTIL I added an external DC regulator of the heater circuits AND grounded the - lead to the chassis as per Gibosi... hope that helps.

 

Disregard this lol I need to learn to read better when I'm sleep deprived (yay hr 34!)


Edited by kvtaco17 - 1/3/14 at 9:13pm
post #4585 of 6858
Quote:
Originally Posted by kvtaco17 View Post
 

I had the same issue and regardless of what I tried it never went away... UNTIL I added an external DC regulator of the heater circuits AND grounded the - lead to the chassis as per Gibosi... hope that helps.

 

Disregard this lol I need to learn to read better when I'm sleep deprived (yay hr 34!)


Get some sleep good sir, It's not good for the system to go without!

:beerchug:

post #4586 of 6858

I will in a bit... I've had pretty nasty bouts with insomnia lately... nothing helps... my doctor suggested taking a mild sleep aid... that was hours ago and I'm still making an amp enclosure design in autocad...

post #4587 of 6858

Well good luck to you in your battle with the insomnia, I can't imagine what it would be like having never suffered from it myself.

:beerchug:

post #4588 of 6858

Its just been lately... I assume its stress related with, work and the passing holiday, things will calm down and it'll subside.

post #4589 of 6858
Quote:
Originally Posted by mordy View Post

 

Need an answer to the following:

 

With the 6CG7 tubes the octal driver tube I am using runs much hotter than with the IR tubes. The plate voltage is 173V, which is higher than what I measured in the past with the IR tubes - around 147V.

 

Could it be that such a high voltage is detrimental to the tube? (Heater voltage is 6.3V and grid voltage is 1.33V).

 

Mordy,

 

Perhaps Ctritical Bill (CB) will weigh in on this.... However, from one of his earlier posts, it would seem that this is not good....

 

http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/4125#post_10027162

 

If I understand CB correctly, a plate voltage of 173 V on your 6SL7 driver tube may be close to over driving your 6CG7 output tubes. Again, if I understand correctly, the 6SL7 works best with a plate voltage around 200 V and the LD simply cannot provide a driver tube with voltage this high. So even though it sounds good, it is probably not advisable....

 

But again, if I understand correctly, this is more an indication of the unsuitability of the 6SL7 as a driver tube in the LD, than it is a problem with using the 6CG7 as an output tube. Once you get an external heater, using a 6SN7 or 6CG7 as a driver could well be better.

post #4590 of 6858

I finally did my first 9pin(Driver Tubes) adapter for LD 1+ and LD MK III i've used a 12AU7/12AU7A(Rogers,Electro- Harmonix,JJ Electronics and  Chinese made)those are the only tubes i have.They all hum on both amps i doubble checked all my solder joints and pin connections to the amp(unplug/plug it back)still humming.Could it be the Tubes?

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