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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 425

post #6361 of 10575

 As i mentioned before my end game tubes are the 6AS7G/6080  and Raytheon 6832 IMO these tubes are nice Driver tubes.

Few weeks ago when a lot of the topic here are the C3g i nearly pulled the trigger for C3g but then i thought about getting the CRACK so i decided to get those RCA,SYLVANIA and the mysterious GTC 6AS7's  and some RCA,GE and SYLVANIA 6080's some day i might get C3g if i can be sure that it will work with the Crack so now i will wait until i get the Crack.Few more months and i will be back home then crack time and also i need to shipped out all my gears can't be flying with these amps(LD 1+ and LD MK III plus the crappy adapter and power supplies that i build)so i'am hoping that my boss will allow me to go home in a few months and be working in my hometown for good.

Or i may sale my gears and start a new LD setup. 


Edited by i luvmusic 2 - 6/3/14 at 3:32pm
post #6362 of 10575
Quote:
Originally Posted by hypnos1 View Post
 
 And as I believe you have managed to make your own adapters in the past, the mod needed to provide these tubes with 2.5A each is a piece of cake...and it can be done using the From what to 6SN7 Adapter adapter, 

From what (tube NO.) to 6SN7 Adapter adapter?

post #6363 of 10575

How pure does heater current and voltage have to be? Pictured below are two pictures from this and another thread showing what I think are linear regulators attached to two different types of 12V  DC power supplies one being a laptop and the other being the 12 all rail of a PC power supply. In both pictures the 12V is sent to what the responders called a regulator, but I believe may be a linear regulator to be morearrow-10x10.png precise about it. I thought linear regulators have to waste away a little voltage so if you were to put linear regulators on 12 V to regulate 12 V they would not work. Am I making correct assumptions?

 

Also I believe I do see slight stroboscopic effects from incandescent light bulbs which aren't strobe lights. I believe this is due to slight fluctuations in the light due to slight cooling between AC cycles with the voltage goes to zero between sine waves. But if we are talking about even slider fluctuations less than 100% pure DC power supply could that affect our audio if used for heater current and not for cathode or anode voltage? 

 

So in summary is slightly DC impure heater current nonetheless as pure as we will ever need because it is heater current and not cathode or anode voltage and current? And if we do need pure regulated DC from a linear regulator do we have to start out with morearrow-10x10.png than 12V to get a voltage regulated to 12V ?

 

post #6364 of 10575
Quote:
Originally Posted by bbmiller View Post
 

From what (tube NO.) to 6SN7 Adapter adapter?

 

To run 6AS7's in the LD:

 

The stock tube in the LD, 6H6PI/6H6n, has the same pinout as the 6DJ8, 6GC7 and 6FQ7. And the 6AS7 has the same pinout as the 6SN7. So you need an adapter with 6SN7 on top and 6DJ8 or similar on the bottom. These are common and plentiful on eBay.

 

Next you will need to cut off pins 4 and 5 on the bottom of this adapter which disconnects the tube from the LD's internal heater supply. And then, connect your external heater power supply to pins 7 and 8 on top.

post #6365 of 10575
Quote:
 

Whoops I misread. Sorry!


Edited by bbmiller - 6/4/14 at 7:37am
post #6366 of 10575
Quote:
Originally Posted by bbmiller View Post
 

How pure does heater current and voltage have to be? Pictured below are two pictures from this and another thread showing what I think are linear regulators attached to two different types of 12V  DC power supplies one being a laptop and the other being the 12 all rail of a PC power supply. In both pictures the 12V is sent to what the responders called a regulator, but I believe may be a linear regulator to be morearrow-10x10.png precise about it. I thought linear regulators have to waste away a little voltage so if you were to put linear regulators on 12 V to regulate 12 V they would not work. Am I making correct assumptions?

 

Also I believe I do see slight stroboscopic effects from incandescent light bulbs which aren't strobe lights. I believe this is due to slight fluctuations in the light due to slight cooling between AC cycles with the voltage goes to zero between sine waves. But if we are talking about even slider fluctuations less than 100% pure DC power supply could that affect our audio if used for heater current and not for cathode or anode voltage? 

 

So in summary is slightly DC impure heater current nonetheless as pure as we will ever need because it is heater current and not cathode or anode voltage and current? And if we do need pure regulated DC from a linear regulator do we have to start out with morearrow-10x10.png than 12V to get a voltage regulated to 12V ?

 

I don't think the voltage has to be all that pure just to run heaters. Collectively, we are successfully using battery chargers, laptop power supplies, virtually anything that can provide adequate voltage and amperage. The cheap regulators we are using allow us to adjust the voltage as our power suppliers might be putting out 30 volts, 24 volts, 15 volts, or whatever. And yes, the regulators do "waste" a little voltage, so if you want to run 12.6 volt tubes, you will need a power supply that can output around 15 volts, or higher.

 

For drivers, I recommend a 30 volt power supply as this will allow the use of 6.3, 8.4, 12.6, 20 and 25 volt tubes. In order to run 6SN7's as drivers, you will need about 5 watts (6.3V x .6A = 3.78W). If you want to run 6AS7's as drivers, you will need at around 20 watts (6.3V x 2.5A = 15.75W). For power tubes, specifically 6AS7's, which run at 6.3 volts / 2.5 amps, you will need a power supply that can handle both tubes, around 40 watts (6.3V x 5.0A = 31.5W).

 

Regarding voltage regulators, the limiting factor is usually amperage. Most of what you see on eBay are limited to about 2 amps. These are fine for the vast majority of driver tubes. But if you want to run 6AS7's as drivers, you need a regulator that can comfortably handle 2.5 amps. An inexpensive 5 amp regulator, like the one I have, works well. If you want to run a pair of 6AS7's as power tubes, you will need a regulator that can comfortably handle 5 amps. I personally do not trust my cheap 5 amp regulator to actually handle 5 amps, so if I wanted to run 6AS7's as power tubes, I would purchase one of the cheap 8 amp units, similar to the one that Hypnos1 uses.

post #6367 of 10575
Quote:
Originally Posted by bbmiller View Post
 
  • Driver Tubes: 2x JAN 5654 (MK IV) or 2x M8100/CV4010 (MK IV SE)
  • Power Tubes: 2x Soviet 6H30EH (MK IV) or 2x 6H30PI Gold-Pin (MK IV SE)

OK the stock tubes for the LD are 6H6PI/6H6n, well the above is straight from little dot IV specification page and you must obviously be talking about other models of little dot so if you offhand know how it would relate to my little dot IV se model I would appreciate you make it very easy for me and related to my model, though your response as is very much appreciated.

 

The pinout is the same for the 6H30-types and the 6H6-types. You could roll a 6H6PI in your se if you wanted. And therefore, the same adapter can be used for the II, III and IV.


Edited by gibosi - 6/4/14 at 7:34am
post #6368 of 10575
Quote:

Regarding voltage regulators, the limiting factor is usually amperage. Most of what you see on eBay are limited to about 2 amps. These are fine for the vast majority of driver tubes. But if you want to run 6AS7's as driversarrow-10x10.png, you need a regulator that can comfortably handle 2.5 amps. An inexpensive 5 amp regulator, like the one I have, works well. If you want to run a pair of 6AS7's as power tubes, you will need a regulator that can comfortably handle 5 amps. I personally do not trust my cheap 5 amp regulator to actually handle 5 amps, so if I wanted to run 6AS7's as power tubes, I would purchase one of the cheap 8 amp units, similar to the one that Hypnos1 uses.

OK so let me see if I am perceiving things right here. You are saying to get voltage regulation you do have to drop a little voltage. But if you were to run 6AS7 as power tubes you would use this regulator you recommend, even though people here have claimed spectacular results with regulators with less than adequate voltage inputs to regulate or put another way they are essentially running unregulated, but you think running 6AS7 as power tubes with heater supply regulators would be of benefit. I suppose because you think you may be able to get even better results than the people here have gotten with essentially unregulated power that they perceived as being regulated?

post #6369 of 10575
Quote:
Originally Posted by bbmiller View Post
 

OK so let me see if I am perceiving things right here. You are saying to get voltage regulation you do have to drop a little voltage. But if you were to run 6AS7 as power tubes you would use this regulator you recommend, even though people here have claimed spectacular results with regulators with less than adequate voltage inputs to regulate or put another way they are essentially running unregulated, but you think running 6AS7 as power tubes with heater supply regulators would be of benefit. I suppose because you think you may be able to get even better results than the people here have gotten with essentially unregulated power that they perceived as being regulated?

 

I am not sure I completely understand...  But perhaps this will help. The LD can provide, at most, 1.25 amps per power tube. (The stock tubes draw about .9 amps.) However, the 6AS7 requires 2.5 amps per tube, which is far more than the LD can deliver, hence an external power supply is absolutely required to use these tubes.

post #6370 of 10575
Quote:
Originally Posted by bbmiller View Post
 

From what (tube NO.) to 6SN7 Adapter adapter?

 

Hi bb.

 

The adapters you need are 6SN7 to 6CG7...available from xulingmrs on ebay.com. I notice as well as the standard one at $19.90 ea. (free shipping) there is now another with copper cover and a lead for connecting to ground or chassis, for the same price but with $5 shipping - looks very good!

 

If you go for running the heater wires into the top of the 6CG7 adapter (cutting bottom pins 4&5 completely), instead of from shortened pins 4&5 at the bottom, please remember (hope I'm not insulting you, lol!) that as you look at the adapter from above, the pins run ANTI-clockwise from the 1-8 indent, #1 being to the right of the indent as you look from above...and you need pins (holes) 7&8, of course. Doing this, I should think you would need stranded wire for both this and the pins to fit in the socket (again, hope I'm not insulting you!).

 

Good luck!


Edited by hypnos1 - 6/4/14 at 9:07am
post #6371 of 10575
Quote:
Originally Posted by gibosi View Post
 
Quote:
Originally Posted by bbmiller View Post
 

OK so let me see if I am perceiving things right here. You are saying to get voltage regulation you do have to drop a little voltage. But if you were to run 6AS7 as power tubes you would use this regulator you recommend, even though people here have claimed spectacular results with regulators with less than adequate voltage inputs to regulate or put another way they are essentially running unregulated, but you think running 6AS7 as power tubes with heater supply regulators would be of benefit. I suppose because you think you may be able to get even better results than the people here have gotten with essentially unregulated power that they perceived as being regulated?

 

I am not sure I completely understand...  But perhaps this will help. The LD can provide, at most, 1.25 amps per power tube. (The stock tubes draw about .9 amps.) However, the 6AS7 requires 2.5 amps per tube, which is far more than the LD can deliver, hence an external power supply is absolutely required to use these tubes.

OK am I right in perceiving we are not talking about cathode anode power but he the voltage power. And at least in the case of the person shown in my pictures using the 12 vote PC power supply rail that wasn't adequate voltage to get regulation from his regulator because you do have to drop some voltage. And perhaps I am mix perceiving Hypnos1 said and his posting on this little dot IV se appreciation thread which can be found here, but I thought he said he was using a 12 V laptop power supply which would not give him sufficient voltage drop in his regulator to be running regulated. So if I am perceiving things correctly Hypnos1 was running his power tubes with sufficient amperage, but on insufficient voltage to be running regulated but still getting what sound to him as spectacular results.

post #6372 of 10575
Quote:
Originally Posted by bbmiller View Post
 

OK am I right in perceiving we are not talking about cathode anode power but he the voltage power. And at least in the case of the person shown in my pictures using the 12 vote PC power supply rail that wasn't adequate voltage to get regulation from his regulator because you do have to drop some voltage. And perhaps I am mix perceiving Hypnos1 said and his posting on this little dot IV se appreciation thread which can be found here, but I thought he said he was using a 12 V laptop power supply which would not give him sufficient voltage drop in his regulator to be running regulated. So if I am perceiving things correctly Hypnos1 was running his power tubes with sufficient amperage, but on insufficient voltage to be running regulated but still getting what sound to him as spectacular results.

 

There are essentially two power supplies, one for the heaters alone and the other for the amp. In this case we are talking about the heater supply only. Power to run the amp itself is not affected in any way.

 

The 6AS7 is a 6.3 volt tube, and therefore, a 12 volt power supply is more than adequate, providing it can provide enough amperage.

post #6373 of 10575
Quote:
Originally Posted by gibosi View Post

 

There are essentially two power supplies, one for the heaters alone and the other for the amp. In this case we are talking about the heater supply only. Power to run the amp itself is not affected in any way.

 

The 6AS7 is a 6.3 volt tube, and therefore, a 12 volt power supply is more than adequate, providing it can provide enough amperage.

Whoops I guess if I had studied the tube numbering system a little better I would've known that. So this that mean if you set up one of these tubes with the regulator in series the 12 V output from one of my many old PC power supplies the regulator would be set to 6.3 V the spot on or would you do something like temporarily put amperage meter in series with the tube and power supply and regulator to adjusted to certain current weather that current was achieved at 6.3 V or something a little higher?

post #6374 of 10575
Quote:
Originally Posted by bbmiller View Post
 

Whoops I guess if I had studied the tube numbering system a little better I would've known that. So this that mean if you set up one of these tubes with the regulator in series the 12 V output from one of my many old PC power supplies the regulator would be set to 6.3 V the spot on or would you do something like temporarily put amperage meter in series with the tube and power supply and regulator to adjusted to certain current weather that current was achieved at 6.3 V or something a little higher?

 

I would assume that any of your old 12 volt PC power supplies can supply the necessary amperage, in this case, 5.0 amps to run two 6AS7's. If you choose a regulator that can provide 5 amps comfortably, you would use the small brass screw to adjust the voltage down to 6.3 volts, and you would be good to go. It is not necessary to adjust the amperage. The tubes will draw only what they need, 5 amps for the two of them, no more and no less.

post #6375 of 10575
Now if one were to run the heaters in series you could use the 12 volts from the PC power supply and no regulators would be required... biggrin.gif
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