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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 388

post #5806 of 10500
Quote:
Originally Posted by i luvmusic 2 View Post
 

As long as we use External Power Supply we should be fine i think.I have used 6AS7 and the LD 1 get a little warmer than usual that is all so IMO it is safe to use 6AS7 i did run mine for 6 hours straight to see how long the LD 1 can handle the 6AS7 and my amp still functioning properly.It depends on how comfortable you are using 6AS7.LD 1 can handle that tube no doubt in my mind.

 

This is great news! We are all indebted to you for going out on a limb and trying these tubes as drivers. Thanks! :)

post #5807 of 10500
Quote:
Originally Posted by hypnos1 View Post
 


Thanks gibosi...but that means a voltage regulator as well - was hoping to find something "all-in" (6V approx.) to keep things neat...you know I like things 'neat and tidy!'

 

Cheers.

I don't know in your area if you can go to your local recycling yard(City owned yard not privately owned) and asked for Desktop Power supply it should be FREE of charged because they will distroy them anyway so you should be able to get them for FREE.What i did is went to my Town recycling yard and asked for old computer then they asked me why i need a junk computer and i told them i just need the power supply for my electronic project and they let me in and told me take as much as i want so i grabed 2 PS unfortunately 1 it does not work so now i got 12V-15A Power Supply for free and i  used a 12A voltage regulator.

post #5808 of 10500

USED 6AS7 as a driver for your LD at YOUR OWN RISK i'am not responsible for ANY DAMAGED occured using 6AS7.:wink:

I used my LD 1 as a guinea pig for all of us so PLEASE use yours with your own risk.

post #5809 of 10500
Quote:
Originally Posted by i luvmusic 2 View Post
 

I don't know in your area if you can go to your local recycling yard(City owned yard not privately owned) and asked for Desktop Power supply it should be FREE of charged because they will distroy them anyway so you should be able to get them for FREE.What i did is went to my Town recycling yard and asked for old computer then they asked me why i need a junk computer and i told them i just need the power supply for my electronic project and they let me in and told me take as much as i want so i grabed 2 PS unfortunately 1 it does not work so now i got 12V-15A Power Supply for free and i  used a 12A voltage regulator.

 

Geez, man...I don't know about "going green"...more like canary yellow...'cheep cheep' - sorry for the pun!

Got to admire your resourcefulness. Well done...good idea...but we're back to that regulator!

 

Glad to hear you've had no problems with the 6AS7 as driver...wish I could feel 100% safe with them as powers, though...time will tell (don't know how long resistors can take punishment before throwing in the towel!).

 

Keep up the good work...

post #5810 of 10500
Quote:
Originally Posted by hypnos1 View Post
 

 

Geez, man...I don't know about "going green"...more like canary yellow...'cheep cheep' - sorry for the pun!

Got to admire your resourcefulness. Well done...good idea...but we're back to that regulator!

 

Glad to hear you've had no problems with the 6AS7 as driver...wish I could feel 100% safe with them as powers, though...time will tell (don't know how long resistors can take punishment before throwing in the towel!).

 

Keep up the good work...

For power i would not push my luck on that with my experienced for driver it makes the LD a bit warmer than usual(i don't know much when it comes to Electronics or Electrical) i'am just imagining 2 6AS7 pushing or pulling that current from LD maybe the LD would not stand the heat that long maybe.But i'am willing to try it for a short period of time.

post #5811 of 10500
Quote:
Originally Posted by i luvmusic 2 View Post
 

For power i would not push my luck on that with my experienced for driver it makes the LD a bit warmer than usual(i don't know much when it comes to Electronics or Electrical) i'am just imagining 2 6AS7 pushing or pulling that current from LD maybe the LD would not stand the heat that long maybe.But i'am willing to try it for a short period of time.

 

For sure ilm2, we're gonna have to be extremely careful, lol!

 

Ah well, time for bed...

post #5812 of 10500

Folks, the word is not cheap (or cheep), but FRUGAL. I'll bet you have a friend with an old outdated laptop who can give you the old power supply ....

 

I discovered that the power supply I am using comes from an old label printer. 50W and 8A at 6.3V. Another source for a power supply would be an old credit card machine or an old scanner etc etc.

post #5813 of 10500

More plug-and-play fun:

 

Went to my box of 6SL7 tubes. Found a near pair of two Sylvania 6SL7GTW from the 50's. One has a beige base and one a brown base. For reasons that are not fully explained this near pair was chosen to do the duty of power tubes.

Then I picked a tall National Union 6SL7 with tinted glass (late 40's early 50's ?) as the driver tube. Somehow I have the notion that the driver tube should be tall. After all, it is in charge. Had to adjust the voltage down a little; 6.39V reads 6.3V at the tube pins.

 

FIrst impression: Plays louder than the 6SN7. Then, sweet and fleet presentation with excellent treble and good, not overwhelming bass. Very musical - and I thought that I did not like 6SL7 tubes.....Not the utmost detail, but a very cohesive and beautiful sound stage.

 

This all 6SL7 lineup is quite nice....

 

 

 

If you think my set up is awkward, watch this giraffe drinking water from a fountain in the desert....

Giraffe-Drinking-Water-Images.jpg 


Edited by mordy - 4/9/14 at 6:21pm
post #5814 of 10500
Quote:
Originally Posted by hypnos1 View Post
 

Will certainly have to keep a very close eye on those resistors...wish I knew exactly where they would be located inside the unit, though...

This is my MK IV board, the SE should be the same except for upgraded capacitors and jacks.

The two resistors circled in red are the 150Ω cathode resistors that Artsi spoke of, these resistors are 1 Watt. The two White Square resistors on the right edge of the board are 5 Watt sized just for reference.

 

If running the 6AS7's as power tubes with the 1W resistors draws too much current, the most that would likely happen is you would just burn out those two resistors. The heat / flame generated when these resistors burn would cause much stress to the two caps on either side. If it doesn't cause any trouble to the circuit board underneath as well.

 

This is a 1/4 Watt resistor with too much power through it, the bigger the wattage the better the burn. :)

 

So What Do?

 

New resistors come with long legs, you could put 5 Watt or 10 Watt resistors in place of these 1 Watt's for a few dollars each. Bend the legs and the resistor would have to be mounted in the air a little as it would not fit in the other resistors space.

 

Then the resistors would not burn out, the transformer would... :wink_face:

post #5815 of 10500

hi guys, would these tubes be rollable for the Mk III ?

 

http://www.ebay.com/itm/3C22S-EF95-6F32-Tube-lamp-USSR-Lot-of-2-pcs-/131045114396?pt=LH_DefaultDomain_0&hash=item1e82e5c21c

post #5816 of 10500

No!

 

It's a rectifier, not even close to EF95. That substitution "information" is positively retarded.

post #5817 of 10500

Many thanks, Oskari! I searched around the net and couldn't find info to state whether it was a direct replacement or not. Thank goodness for this thread and you fine people :)

post #5818 of 10500
Quote:
Originally Posted by mordy View Post
 

Folks, the word is not cheap (or cheep), but FRUGAL. I'll bet you have a friend with an old outdated laptop who can give you the old power supply ....

 

I discovered that the power supply I am using comes from an old label printer. 50W and 8A at 6.3V. Another source for a power supply would be an old credit card machine or an old scanner etc etc.

 

Yes indeed mordy, frugal is a MUCH nicer word....but "cheap" has an extra dimension - naughty AND (possibly!) nice - when used amongst friends, that is!!

 

And as in all probability - ref TDs doomsday scenario below! - that power supply will be in operation for a very short while, I would be silly not to take the ch...oops, sorry...FRUGAL option, n'est-ce-pas? So on the hunt I shall go (IF my nerve holds out, that is! :eek:).

 

Quote:
Originally Posted by TrollDragon View Post
 

This is my MK IV board, the SE should be the same except for upgraded capacitors and jacks.

The two resistors circled in red are the 150Ω cathode resistors that Artsi spoke of, these resistors are 1 Watt. The two White Square resistors on the right edge of the board are 5 Watt sized just for reference.

 

If running the 6AS7's as power tubes with the 1W resistors draws too much current, the most that would likely happen is you would just burn out those two resistors. The heat / flame generated when these resistors burn would cause much stress to the two caps on either side. If it doesn't cause any trouble to the circuit board underneath as well.

 

This is a 1/4 Watt resistor with too much power through it, the bigger the wattage the better the burn. :)

 

So What Do?

 

New resistors come with long legs, you could put 5 Watt or 10 Watt resistors in place of these 1 Watt's for a few dollars each. Bend the legs and the resistor would have to be mounted in the air a little as it would not fit in the other resistors space.

 

Then the resistors would not burn out, the transformer would... :wink_face:

 

Many, many thanks TD for showing where I need to stick my finger...no, THERMOMETER!...so as to back off before things get too scary - or should it be DISASTROUS! And burning out the transformer is NOT an option...

 

Excuse my ignorance, but where does anode resistance come in, as opposed to cathode resistance?...Would appreciate your enlightenment.:confused_face(1):

post #5819 of 10500
Quote:
Originally Posted by TrollDragon View Post
 

This is my MK IV board, the SE should be the same except for upgraded capacitors and jacks.

The two resistors circled in red are the 150Ω cathode resistors that Artsi spoke of, these resistors are 1 Watt. The two White Square resistors on the right edge of the board are 5 Watt sized just for reference.

 

If running the 6AS7's as power tubes with the 1W resistors draws too much current, the most that would likely happen is you would just burn out those two resistors. The heat / flame generated when these resistors burn would cause much stress to the two caps on either side. If it doesn't cause any trouble to the circuit board underneath as well.

 

This is a 1/4 Watt resistor with too much power through it, the bigger the wattage the better the burn. :)

 

So What Do?

 

New resistors come with long legs, you could put 5 Watt or 10 Watt resistors in place of these 1 Watt's for a few dollars each. Bend the legs and the resistor would have to be mounted in the air a little as it would not fit in the other resistors space.

 

Then the resistors would not burn out, the transformer would... :wink_face:

Hi TD,

       If repalced those resistors with say 10W and used a external power supply would it be still put alot of stress on the transformer?

post #5820 of 10500
Quote:
Originally Posted by Rossliew View Post
 

Many thanks, Oskari! I searched around the net and couldn't find info to state whether it was a direct replacement or not. Thank goodness for this thread and you fine people :)

Did you have a look at page 77 those are tubes that are compatible with the Littledot for the most part but some have to be modified like the 6AV6 tubes that you need to cut  pins 5 and 6 off and cover those up with electrical tape , or the 6AU6 tubes which need an adapter or a socket wire mod 2-7 which means you link pin holes 2 and 7 with a very small wire and insert in socket holes on Littledot and insert tubes after  


Edited by MIKELAP - 4/10/14 at 3:27pm
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