Need tube help please

[basstracker1970]

I need to know what tubes will cross with a 6L6GC tube. That is the tube in my dak ix and it is suppose to be a 6DG6GT. Will those tubes cross or has the radio been modded to take the 6L6GC tube. Thank you....

 

[Shockwave]

I need to know what tubes will cross with a 6L6GC tube. That is the tube in my dak ix and it is suppose to be a 6DG6GT. Will those tubes cross or has the radio been modded to take the 6L6GC tube. Thank you....

Many tubes used the same pinout as the smaller 6DG6 tube. They include the 6L6GC, 8417, 6550 and probably some others I'm forgetting right now. There is nothing wrong with placing a 6L6GC tube in a 6DG6GT socket.

No rewiring is required. This tube does have more plate dissipation. It would need to be reloaded and tuned because of the different plate capacitance. The bias and neutralization may need tweaking to optimize performance too.

 

[basstracker1970]

So the 6L6GC tube and the factory 6DG6GT tube are the same so i could use either one with no problems? Also are you saying the 6L6 tube has more power than the 6DG6GT tube. The radio right now is keying 9-10 watts and swings pass 20watts. I need to get the DK down to around 3-4 watts. Would putting back the factory tube 6DG6GT tube bring that down? Many thanks for your help.....

 

[Shockwave]

It's not that the 6L6 automatically has more power or will make more power. The added plate dissipation simply means the tube could be driven harder to make more power without overloading it or make the same power with much more headroom.

What determines if a tube swap alone will make a difference in power output is the gain of the tube used. Many times smaller sized tubes have more gain than their larger counterparts.

For example, when Tram switched from the 6L6 RF tube in the D-201 to the 6DG6 in the D-201A, they also had to install a 10 ohm resistor in the cathode circuit to knock the gain down and maintain the 4 watt carrier.

 

[basstracker1970]

What tube would cross with a 12by7 tube ? thanks for all your help

 

[The Mad Scientist]

It's not that the 6L6 automatically has more power or will make more power. The added plate dissipation simply means the tube could be driven harder to make more power without overloading it or make the same power with much more headroom.

What determines if a tube swap alone will make a difference in power output is the gain of the tube used. Many times smaller sized tubes have more gain than their larger counterparts.

For example, when Tram switched from the 6L6 RF tube in the D-201 to the 6DG6 in the D-201A, they also had to install a 10 ohm resistor in the cathode circuit to knock the gain down and maintain the 4 watt carrier.

Or the tube could be driven with the same power and add to the longevity of it.

 

[basstracker1970]

Ok guys thanks for all the help here but I am so very confused now. My dak 9 has two tubes VT-701 and VT-702. Now in the VT-701 socket my dak has a 6L6GC tube and in the VT-702 socket it has a 6W6GT tube. Can someone explane to me what each tube is for and if these are the right tubes for this radio. Is one tube for modulation and the other for rf power out???

The radio is dead keying 9-10 watts and swings 20+ watts. I need to get it down to 2-3 watt dead key so i can run my box with it. Any help here is very much appreciated..... Thank you all

 

[basstracker1970]

Ok I found a wire that was added under the tube board to a resistor that bypassed the resistor. I took it out and the dead key dropped to 6 watts better and is still swinging 15+ watts. I just need to get it down a bit more.