6SJ7 Pentode 18 watt Lite...Formerly the ABSOLUTE Minimum
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Hmmmm??? Looks like it would work ... http://www.nj7p.org/Tube4.php?tube=6AC7
What's up with that heater business... battery ????
What's up with that heater business... battery ????
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Look at the date of the data sheet. In the early days tube circuits were powered by three batteries identified as A (filament heater), B (anode) and C (bias). The only one we retain in our vernacular is B, as in B+. Even though electronics had eliminated the need for batteries by 1941 the terminology and curriculum still persisted.What's up with that heater business... battery ????
I generally dislike wikipedia but this article has enough good information to enlighten the reader about battery powered triode circuits. http://en.wikipedia.org/wiki/Battery_(vacuum_tube) That's probably because it comes from a single source and hasn't yet been randomized by committee.
KennyO
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Upon the comments from DP, we experimented with OD pedal(s) in front the 6SJ7 ... With Omega>RFD > RFD> 6SJ7 ... The amp tone would go "Plastic" ... like a highly synthesized tone ... sustain for days , and lots of cool feedback (guitar) ... Strange but wonderful
I guess you can never have too much Gain eh ???
I guess you can never have too much Gain eh ???
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Recent changes to the Ab Min , include a .0047uf coupling cap , a 10-20uf cathode cap on the 6SJ7( bigger cap more gain ) , and a .015uf cap on the 6SJ7 screen .. All producing a much tighter Bass and a generous amount of “sparkle” ... Getting it tuned in to best fit playing with the band ...
Very happy with the Tone now, more chimey' and jangly' ...
Ps. After a lengthy time we discovered we had the Wrong Cathode cap on the 6SJ7 22uf , instead of the 2.2uf ... with the 22uf it was a fire breather... with the 2.2 it’s pretty tame ... (Clean) Choose what you like ...
Very happy with the Tone now, more chimey' and jangly' ...
Ps. After a lengthy time we discovered we had the Wrong Cathode cap on the 6SJ7 22uf , instead of the 2.2uf ... with the 22uf it was a fire breather... with the 2.2 it’s pretty tame ... (Clean) Choose what you like ...
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ZP, I much appreciate your help getting the PI in this amp sorted ... The amp as originally built was a bit too dark for my needs (leads) , with the 6V6s .. and the 22uf cathode bypass cap that was mistakenly installed on the 6SJ7 (instead of the 2.2uf on the schematic ), gave it a shed load of Gain .. on 3 Useable and quite good sounding over time , but I just couldn’t help keep tweaking on it to get it where it sounded just Right with the band .. It’s not overly Bright , like my Dog Sled, but now has enough sparkle to get right in the sonic territory I want to be with the band (used it at practice last night ... perfect !!! ) And that nice pentode chime to make the sound , for lack of a better word ... Pretty to the ear !!!
Insane , I think the screen cap change was most responsible for the extra bit of sparkle , but I can’t say for sure , because I changed the coupling cap at the same time .. My Dumb !!! But Hey , it works Great !!!
Insane , I think the screen cap change was most responsible for the extra bit of sparkle , but I can’t say for sure , because I changed the coupling cap at the same time .. My Dumb !!! But Hey , it works Great !!!
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Well, that was some time ago ... More time playing with the amp still leaves me with the desire for even more brightness , born of the newer harder Rock selections we’ve been asked to play ...
Just wondering if the 6SJ7 is inherently “dark” ??? It does really work Fine for our “Oldies” gigs , and some Jazz selections , but lacks the “cut” for some of the more “aggressive" music ...
Just wondering if the 6SJ7 is inherently “dark” ??? It does really work Fine for our “Oldies” gigs , and some Jazz selections , but lacks the “cut” for some of the more “aggressive" music ...
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