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HAMPAMP TUBE AMP SERVICES · 06-21-2009, 08:42 PM

[QUOTE=American Viking;46127]yeah, my jaw dropped at the very first post. Why did you go about changing all that stuff right off the get-go? One thing you gotta know about tubes is that if the socket fits, it's interchangeable. 6550/KT88/EL34/5881/KT66 no matter what anyone tells you they will all work in the same amp as long as they can fit side by side. All the sockets are the same.

Just because a tube fits in the socket does not mean it is interchangeable electrically. A 6V6, 6SN7, 5U4G, 5V3A will fit into the same socket as the 6L6, EL34, 6550, KT-88, etc. But you better not power up your 900 with a set of 6V6's or 5U4G rectifier tubes in it. Any tube that shares design parameters that are close or over-rated can be made to work but the pin-out must match or some socket rewiring would have to be done. Be careful and check specs and pin-outs before converting to any tubes besides what is in there to begin with. True, 6550's, KT-88, EL34's, 5881's, KT-66's and even 6L6's are somewhat interchangeable but, and don't get me wrong, not trying to be an ass, the way you worded that might lead some to believe that "if it fits-it will work" Sorry, I don't mean to be offensive, just want to clarify.

06-21-2009, 08:42 PM	#13 (permalink)
HAMPAMP TUBE AMP SERVICES Senior Member Join Date: Apr 2009 Location: Myrtle Beach S.C. Posts: 133	Re: JCM 900 6l6 to EL34 Conversion problems [QUOTE=American Viking;46127]yeah, my jaw dropped at the very first post. Why did you go about changing all that stuff right off the get-go? One thing you gotta know about tubes is that if the socket fits, it's interchangeable. 6550/KT88/EL34/5881/KT66 no matter what anyone tells you they will all work in the same amp as long as they can fit side by side. All the sockets are the same. Just because a tube fits in the socket does not mean it is interchangeable electrically. A 6V6, 6SN7, 5U4G, 5V3A will fit into the same socket as the 6L6, EL34, 6550, KT-88, etc. But you better not power up your 900 with a set of 6V6's or 5U4G rectifier tubes in it. Any tube that shares design parameters that are close or over-rated can be made to work but the pin-out must match or some socket rewiring would have to be done. Be careful and check specs and pin-outs before converting to any tubes besides what is in there to begin with. True, 6550's, KT-88, EL34's, 5881's, KT-66's and even 6L6's are somewhat interchangeable but, and don't get me wrong, not trying to be an ass, the way you worded that might lead some to believe that "if it fits-it will work" Sorry, I don't mean to be offensive, just want to clarify. __________________ Pie are not squared, Pie are round Due to inflation, I can no longer afford to put in my 2 cents worth. '81 Gibson SG jr '97 Gibson SG Special '82 Gibson Explorer '63 Fender Strat '00 Fender Strat '76 Ibanez Doubleneck (Gibson copy) '08 PRS Paul Allender Kramer (parts box) V Peavey Vandenburg (parts box) Marshall 1959 Marshall VS100R Marshall 1960/A x 2 Line 6 Flextone III Peavey Triumph 60 Gibson GA-5 Danelectro Cadet Model 122