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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 450

post #6736 of 10500

Cut one RED and one BLACK from 20/24 PIN Connector and splice/solder the ceramic resistor on those pair of wires and you are in business just make sure that the resistor  does not touch anything else the resistor can get hot.

post #6737 of 10500
Quote:
Originally Posted by hypnos1 View Post
 

Hey guys...

 

A cheap laptop power supply/charger is sooo much easier lol! Not to mention neater...but then, y'all know I love neat and tidy!

 

Cheers.

Iv'e got some PS for FREE....:biggrin: ZERO NADA $ for me:wink:

post #6738 of 10500
Quote:
Originally Posted by i luvmusic 2 View Post
 

Iv'e got some PS for FREE....:biggrin: ZERO NADA $ for me:wink:

 

Hi ilm2.

 

The best things in life are free?...I feel a song coming on, lol!

 

I, too, try to be cheap - er, sorry, FRUGAL - but sometimes the hassle that can ensue has me reaching for the wallet, especially if we're not talking big bucks...:p

 

mordy...as gibosi has found, I don't think we have to worry too much about over- provision of power handling...my set-up has been on and off numerous times, and still all is OK. Actually, as you guys have easy access to your pins/sockets, why don't you use the meter to see just what happens on start-up? On second thoughts, easier just to measure at the regulator, no? Just a thought....

post #6739 of 10500
Quote:
Originally Posted by hypnos1 View Post
 
Quote:
Originally Posted by i luvmusic 2 View Post
 

Iv'e got some PS for FREE....:biggrin: ZERO NADA $ for me:wink:

 

Hi ilm2.

 

The best things in life are free?...I feel a song coming on, lol!

 

I, too, try to be cheap - er, sorry, FRUGAL - but sometimes the hassle that can ensue has me reaching for the wallet, especially if we're not talking big bucks...:p

 

mordy...as gibosi has found, I don't think we have to worry too much about over- provision of power handling...my set-up has been on and off numerous times, and still all is OK. Actually, as you guys have easy access to your pins/sockets, why don't you use the meter to see just what happens on start-up? On second thoughts, easier just to measure at the regulator, no? Just a thought....

I agree with you the free stuff is good if you like screwing around with stuff like me.I feel bad that he is having trouble with his PS i do have a few desktop PS and some of them are the older model they do not work that well the out put voltage is lower compared to the newer model the older PS are unstable. 


Edited by i luvmusic 2 - 7/4/14 at 12:33pm
post #6740 of 10500

Success!

 

Decided to use my new back up spare PS for my PC - a Thermaltake TR2 430 which is (you guessed it) a 430W PS. Can't decide what is worse, the LD MKIII not working or the PC not working - in any case I had to preserve the PS just in case, so no cutting.

 

Found the right size wires to push into the right plugs, hooked everything up, and voila! Everything works just fine!

 

There is a difference: The bass got considerable stronger and better defined compared to the old laptop PS so there must be something to the power output of different power supplies. Many of the high end audio  manufacturers are selling upgraded power supplies for their products.

 

The other difference is that at the indicated 6.3 volts at the tube pins the voltage regulator reads 6.6V instead of 7V with the previous PS.

 

This PS has dual fans (front and back) and seems a tad quieter as far as hum goes, but there is a whine at very high volume settings which I normally don't use. Have to figure out how to eliminate it.

 

Esthetically, you could probable say that my configuration changed from spider web to snake pit - don't know why the braiding of all the wires looks like snake skin color.

 

Again, I want to thank everybody who helped me in figuring out how to use the computer PC - thanks!


Edited by mordy - 7/4/14 at 2:10pm
post #6741 of 10500

  Good for you Mordy:beerchug: as i said before the output varries from PS to PS newer power PS works better without any MOD(dummy load).

My Desktop PS with the 12A regulator to get 6.3V on the tube pin i need to set the regulator at 6.39V if i'am using the laptop PS(19V-8A) the regulator is set to 6 to 7V to get 6.3V on tube pin.  

post #6742 of 10500

What do you guys do with your none working tubes?

post #6743 of 10500
Garbage, or cut the bottom off of them to make adapters. smily_headphones1.gif

Unhealthy schiit inside them, so don't playing with the bits and licking your fingers... biggrin.gif
Edited by TrollDragon - 7/4/14 at 2:51pm
post #6744 of 10500

Too late i just did...:biggrin:

Mine are not garbage yet see.

 

Sorry i don't mean to be childish i was just bored packing all my stuff to send back home my work here is done time to go back home(CANADA).I put a red LED inside the tube.


Edited by i luvmusic 2 - 7/4/14 at 3:31pm
post #6745 of 10500
Quote:
Originally Posted by mordy View Post
 

Decided to use my new back up spare PS for my PC - a Thermaltake TR2 430 .........................

 

There is a difference: The bass got considerable stronger and better defined compared to the old laptop PS so there must be something to the power output of different power supplies. Many of the high end audio  manufacturers are selling upgraded power supplies for their products.

 

Frankly, this surprises me.... The upgraded power supplies in high end gear are designed to actually run the amp itself, that is, provide clean DC power to the cathodes, grids and plates. They do not provide power to the heaters. Heater power supplies are typically separate and making them more powerful than necessary shouldn't make any difference.... ????

post #6746 of 10500

Surprised me too. At this stage I am running a sub mini 6832 as driver, a 12SL7GT as one power tube with a separate power supply, and the RCA 6AS7 with the 430W PC PS. My guess is that there is some kind of synergistic effect between the channels, even though they are supposed to be completely separate.

 

Don't have any explanation, and maybe it doesn't make sense logically; I am only reporting what I am hearing. A new 500W PS can be bought on sale at Newegg for around $30 with rebates. Over the years I have saved a couple of PCs by installing new PS when the old one gave out, and I like to have a spare on hand.

post #6747 of 10500
Well my take on the PS issue is that the heaters are probably getting a proper current now where they were underpowered before.

Driving the regulator from a 12V 4A supply will only ever give you 4A of output, dropping the voltage to 6 will not give you 8A of power... The regulator is converting the voltage, it still only has the rated supply amps to work with.

Which is why I have always recommended a 8A or higher supply for a 5A draw...

The easiest way to test this is to actually measure the current draw on the heaters, something I suggested with a diagram some 100 or more pages back... wink.gif

If you do use your meter to measure the current on the 6AS7's or any other tube for that matter, hook up your meter power up the tubes and take your reading, leaving a meter on the 10A current measurement too long will burn it out as it does get warm inside.

1. Set the meter for 10A scale and double check it.
2. Move your probes to the 10A connections double check them.
3. Connect the meter in series with the heater wires + or Red to the positive on your regulator, - or Black to the tube.
4. Power up the LD and observe the current draw as the tube heats up no more than 30 seconds.

If you get a brief reading after you turn on the amplifier then nothing, it is possible that the in rush current has popped the 10A fuse in your meter and you will need to replace it.

Expensive meters and Amprobe's are a different story but I don't think anyone has those except for "Mr. Fluke" who we havn't seen in a while... biggrin.gif
post #6748 of 10500

Anyone of you guys used this TEAC - UD-H01 DAC?Thanks!

post #6749 of 10500
Quote:
Originally Posted by TrollDragon View Post

Well my take on the PS issue is that the heaters are probably getting a proper current now where they were underpowered before.

Driving the regulator from a 12V 4A supply will only ever give you 4A of output, dropping the voltage to 6 will not give you 8A of power... The regulator is converting the voltage, it still only has the rated supply amps to work with.

Which is why I have always recommended a 8A or higher supply for a 5A draw...

 

Boy am I surprised! I have always assumed that when using these regulators, it was the wattage that remained constant. And therefore, as we reduced the voltage, amperage would accordingly increase. And now I learn that the amperage can never increase! Well, I learn something new everyday! lol

 

And so, as TD recommends, if someone intends to run two 6AS7's, it is necessary to use a power supply that can provide significantly more than 5A. The 19V 4.74A AC Adapter / Charger I recommended above is not suitable....

 

Edit: And I should add... If you are running 6SN7's as drivers, check your power supply. For best results, it should be rated at 1A or higher.


Edited by gibosi - 7/4/14 at 7:29pm
post #6750 of 10500

All this power supply talk... As I go to turn on my computer tonight, the LEDs light then go out. Pull the power cord, wait 10 seconds and try again, same deal lights go on then out.

Take it all apart, yank the supply out and down to the workshop I go to find the blown capacitor on the board. A 3300uF @ 10V on the 12V crowbar side was all puffed and the electrolyte was cooked and oozing out of it.

Of course no one has an exact match in the parts bin so I swapped the one from the 5V side and put a 2200uF @ 16V in its place, all up and running again. smily_headphones1.gif

Old Enermax's can take a beating for sure.



Edited by TrollDragon - 7/4/14 at 10:14pm
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