Triode connected 6146s as modulators?

[KE6DF]

Has anyone tried to run 6146s triode connected as modulators?

The spec sheets show triode connection data for G2 connected to the plate.

But, I'm talking about driving G2 with a resistor connected to G1.

807s work well that way, so one would think 6146s would do OK also.

Saves having a screen and bias supply.

Dave

[Opcom]

It's said that it will work like 807's. I've never done it.

[KL7OF]

see the triode connection diagrams for 813s as well..   some have the screen grounded and others have the screens grounded thru a resistor....I've tried both ways and could not tell the difference....using an old cell phone type spec analyzer...and on the air subjective reports

[kb3ouk]

http://amwindow.org/tech/htm/813/813.htm
uses triode connected 813s in the modulator, grid and screen tied together, then ground the supressor.

[KL7OF]

http://amwindow.org/tech/htm/813/813.htm
uses triode connected 813s in the modulator, grid and screen tied together, then ground the supressor.

There is also the one with the suppressor screen and grid all tied together

[W2PFY]

I have heard knowledgeable people say that 6146 tubes do not make good modulators. If I remember correctly, it was something about a feedback issue. So I am also curious how well they'll work too.

[KL7OF]

B and W 5100 is 6146s...a pair modulating a pair.....Northern radio made a commercial TX with a pair modulating a triple..

[KC4VWU]

Doesn't the Junkston Valiant use them also?

[The Slab Bacon]

But..........the Valiant and Barkin Willie 5100 didn't have them triode connected.

[K3YA]

By using 6146 triode connected with the grids tied together you are trading the complexity of the G1 and G2 supplies for the more complex, low impedance driver that is needed with class B operation.

My recollection from long ago is that 6146's connected as high mu triodes don't work as well as 807's in a similar configuration. 

Used as tetrodes, 6146 can be operated AB1 and  R-C coupled to the driver tubes thus eliminating the driver transformer.  Run this way it is practical to employ a little negative feedback around the modulator to clean up the higher order distortion products that most tetrode modulators seem to have.  I did this in my Viking 1 which I consider the a pretty decent sounding rig.

[VK7ZL]

Dave

The modulator for my 40M transmitter uses a pair of QE05/40's (6146's) triode connected. It was orginally from a Pye base station and they were limited to 50W in commercial service driving a single QE06/40 on the low VHF band.
I home brewed an RF deck using a pair of 1625's which give a comfortable 55W output - limited by the size of the mod. tranny.

Modulator circuit below.

Bob