29GK6 heater current?

[bst]

I've just purchased a large quantity of new 29GK6's, but cannot find the filament current for these tubes. I've tried the usual sources -- the sites sponsored by Frank Phillipse, Duncan Amps, NJ7P, and Franz Hamberger --, and even a few old ARRL handbooks, but have drawn a blank.

Can anyone provide this data? Thanks in advance.

 

[45]

I guess it is 165mA for 29V.
Not sure because I never heard of it until now... however looking at the GK6 family the filament VA is always 4.8 VA.

45

 

[Mickeystan]

Hello BST,

I do not have the heater current specs to share with you. I think if you were to set up one of the tubes and measure the current you would find it is on the order of 0.165 amps or 165 ma at 29 volts. The reasoning behind this estimate is the 6GK6 heater voltage is 6.3v at 760ma. or 4.78 watts. The 29GK6 will likely require the same heater power in watts to properly heat it. Thus, 29 * 0.165 = 4.785 watts. Just an estimate but it is likely very close to reality.

Mickeystan

 

[smoking-amp]

The GE Essential Characteristics manual lists the 29GK6 as:
28.6 V, 0.15 A

By the way, do the tubes look like they have Beam plates rather than suppressors? I have an annotation on the listing that says RCA may be non-beam.

Don

 

[Eli Duttman]

4X 28.6 = 114.4, which is within 10% of 125 V. Wire sets of 4 tube heaters in series and connect (via switch and fuse) to the AC mains.

Those tubes were used in 150 mA. series heater strings installed in TV receivers. IMO, it's follow the leader time.

 

[bst]

Thanks to all for your detailed replies!

I have an 'orphan' 1-amp constant-voltage transformer which I haven't previously been able to utilize. My line voltage fluctuates between 122 and 127 volts, and this transformer stabilizes inputs from 112 - 132 volts to a nominal 115 volt output.

This will be just the ticket for a series heater string with 4 x 29gk6s in a push-pull stereo amp.

Thanks again!

 

[TerrySmith]

The 29GK6 and the rest of the *GK6 family are identical to the EL84/6BQ5 except for heater voltages and pinout. I have about 50 or so 29GK6's, most are GE made, 5 Philco branded ones are Japanese made. All the GE's use innards that are European- they look (and sound) like Amperex EL84 tubes.

Here's an amp I built a while back with 29GK6's then later changed to use 10GK6 tubes. diytube.com :: View topic - ST-35 with Compactrons