5881 wxt versus 6l6gc in a MM HD 150 combo?

woody96

I just picked up (posted here) a 1980 MM 2x10 HD 150 combo in excellent condition....love it....sounds very, very good, but not great..... Looked inside...and it has been tubed with Sovtek 5881wxt's sometime in its past.....does not red plate at all in either high or low power settings....they seem to glow very normal and all is well as the amp functions and all....BUT, again, does not seem to my ear to have the headroom it ought and sounds just a bit sterile....(I know this could be because of a lot of things....)

Is this a problem having 5881 wxt's in here? Is this why it maybe sounds a bit sterile or has some less headroom? Should I get some 6l6gc's in there ASAP and rebiased because 5881's should not be in there due to high plate voltage of this amp?

Any help would be appreciated....

Woody

Full Name
Keith Wilkes
Music Man Equipment
Music Man 2x12 HD 130; also a fender super reverb and a vintage peavey classic.

Member for

11 years 2 months

woody96 Thu, 09/03/2015 - 14:03

I know, great info, just wanted to make sure 5881 wit's won't damage the amp. I don't have funds right now for some new 6L6gc's and want to play it until I do.....
5881 wxt's OK until I can replace?

Full Name
Lars Verholt
Music Man Equipment
HD-130 head, 210X cab, 210RH cab, RD-50 110 combo, Sixty-Five 112 combo, RP65-112

Member for

11 years 2 months

lmv Fri, 09/04/2015 - 06:20

The Sovtek 5881WXT is in reality a thick base version of the soviet military 6Π3C-E tube. It has similar, but not identical, ratings to the old American 5881 (Tung Sol) and 6L6 (RCA) tubes. The fact that you have been able to play the amp, and the previous owner too, with good results, confirms that these tubes are safe to use.

I agree - an actual old 5881 spec tube will not work in Music Man amps as the maximum ratings are far less than what is required.

Sincerely,
Lars Verholt

Music Man Equipment
MM 2-10-65

Member for

11 years 2 months
Profile picture for user mm210

mm210 Fri, 09/04/2015 - 14:24

The 5881 wxt should be fine in there since it's working this far but I will have to say, that is one of the worst SOUNDING tubes I have ever installed. I even put a set in a 62 concert and they sounded like crap. Very brittle sounding. I'm not going to say they are bad tubes, just not MY cup of rum (oops, tea!). Mike.

Full Name
Mike Griffin
Music Man Equipment
MM 112-RD-65

Member for

11 years 2 months

mgriffin155 Fri, 09/04/2015 - 15:50

Hi Woody, There you got it from the two smart guys in the room. Go ahead and use as is until you can afford 6L6GC's It looks like a matched quad of 6L6GC's will be around $70-80 in the USA. In the mean time, rock on. mgriffin

Full Name
Keith Wilkes
Music Man Equipment
Music Man 2x12 HD 130; also a fender super reverb and a vintage peavey classic.

Member for

11 years 2 months

woody96 Sat, 09/05/2015 - 19:51

Thanks all. GREAT information....!