08-07-2013, 06:12 PM
Picked up a 38-7 and it has one 6L6. Haven't seen a schematic with a 6L6. Has anyone see this before ?
Larry
Larry
38-7 with 6L6
08-07-2013, 06:12 PM
Picked up a 38-7 and it has one 6L6. Haven't seen a schematic with a 6L6. Has anyone see this before ?
Larry
08-07-2013, 06:53 PM
Which one do you have - the floor, chairside or the tabletop version?
It is possible that to drive a larger speaker with more power they simply used 6L6 as it is the same pinout.
08-07-2013, 08:46 PM
I have the tabletop version with the concentric tuning dial. Wondering if I have a revised model with the 6l6. Wouldn't the 6l6 put a heavier load on the transformer than the original tube?
08-07-2013, 09:19 PM
A tube does not "put a load" on the transformer. The transformer (or rather the load, that is the speaker's voice coil, reflected by transformer) loads the tube.
The tube is the source and the load is, well, the load.
08-07-2013, 09:28 PM
So the 6l6 was just substitued for the 6f6 output tube that was original to the set and shouldn't create any problems?
Larry
08-07-2013, 09:57 PM
Sub is probably OK if power transformer is not marginal. 6F6 or even 6V6 is neither rare or expensive and would be better for the long run. No noticable difference in sound for the average two legger.
08-07-2013, 10:57 PM
You really do want to replace the 6L6 with the correct 6F6
At -14 V grid bias, the 6L6 will draw 72 mA from the power supply while the 6F6 at the same grid bias only draws 45 mA, so the 6L6 puts an additional load of 20 to 30 mA on the supply and power transformer. Not good for long term reliability and the extra current through the bias resistor will also throw off the other bias voltages.
08-07-2013, 11:26 PM
have pulled the 6l6 and replaced it with the 6f6. as soon as the speaker repairs dry, am goiing to crank it up.
thanks to everyone for taking the time to respond to my question. have been at this for a couple of years and still a novice. thanks again Larry
08-08-2013, 11:20 AM
Replaced the 6L6 with the correct 6F6and it seems to play as well as it did with the 6L6.
However....found that the 1st audio had been changed from a 6K5 to a 6R7, and that set wouldn't play with a 6K5 in place. Put the 6R7 back in and it played like a champ. This radio had a very good recap in the not too distant past (before me) and even the 6k5 socket doesn't appear to have had the wiring changed. Could this have been a factory modification ?
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