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Which power tubes for BF Bassman?

3/7/2000 6:00 AM
Don Which power tubes for BF Bassman?
Hello. I also have a bman head converted to AA864 specs. Its still kind of hard and brittle. Which power tubes or simple mods would you suggest to let it compress a little? It's a '67. 5881's maybe?  
3/7/2000 6:52 AM
Steve A.

    I think that the 5881's have a nice round tone compared to the 6L6's. If the tube clamps don't hold them very well try a dab of high temp silicone on each side.  
    BTW what B+ is going to the plates of the power tubes?  
Steve Ahola
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3/7/2000 4:46 PM

Hi Don and Steve!  
Steve,wouldn't you loose some of the fender clarity with 5881?  
I used EL34 in my boogie for a while(sovtek ones)  
and i preffer it with 6L6.  
As for my bassman,i'd like to make it creamier,but more like changing the circuit,than the tubes(i just love the 6L6,I don't know why thought.  
Best regards.  
3/7/2000 4:49 PM

ifyou are using the bassman for clan, going to 5881's would lose some sparkle, but for overdriving it, 5881's or el34's would actually smooth thins out a LOT
3/7/2000 5:37 PM

There is a 6L6 taste test in the latest issue of Vacuum Tube Valley magazine. The test was performed using both single coil and hunbucking pickups, and an Allen amplifier which has a "fender type" circuit.  
Surprisingly, to me anyway, the Sovtek 5881WXT+ got high marks. Did they actually improve this tube from the 5881WXT version?  
Also, they liked the surplus Philips 6L6WGB.  
Check out the article, if you get a chance. The nice thing is that both of these tube types are affordable and readily available.
3/7/2000 5:38 PM
If your Bassman with it's modified to a864 circuit is 'hard and gritty' then I suggest that there is something seriously wrong. My (original)a864 is very smooth&clear but never hard and gritty. Am using NOS tubes tho.. all of them. Perhaps you should double check your wiring and use decent NOS tubes as well.
3/7/2000 9:02 PM
Jim S.

Maybe your power tubes are fine, but are just biased too cold. They should idle at around 35 milliamps per 6L6. Less than 30 ma is definitely too cold.
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