I have'nt had much to say about valve amps for the last many months , but the braincell is at work all the time trying to come up with something novel , Pause , back in 94/95 I came up with a design for a 50 watt head with 6 EL84's in Push-Pull at the behest of a guitarist friend in Co Cork ( now emigrated from our shores ) . I believe it was a first , a Hex84 cct. . The EL84 valve is my favourite valve , if you use one in single ended Class A say 4 to 5 watts , you've got an ideal practise/ recording amp , without being too loud . 2 EL84's in Push-Pull can give you 10 to 15watts of lovely guitar tone depending on type of cct employed .and of course 4 EL84's are the classic power stage of many an amp. notably the AC30 arguably the best guitar amp ever ! I took it a stage further in 94/95 with 6 EL84's , it put out a clean 50 watts thru' a self designed output transformer that took a day to wind all the bifilar windings , I say it myself that was a good amp , wonder if it's still somewhere in Co Cork ? . Which brings me back to the current time . The autumn months were'nt wasted , I was working on a new development which appears to be fruitful , A Dual output mode amp which uses a common pre-amp. voicing But is selected to 2 different output stages using a common output transformer with only minor trade off's as regards optimum matching .
So far I've built a 100/30w valve head EL34's (4) and EL84's (4) to give the respective 100watts and 30watts , also a lesser powered 15" combo amp using 2 5881's (30watts) and 2 EL84's (15watts) and they both sound great . They are complicated beasts and it cannot be used in channel switching modes , But actually deciding which power or tone you want to play with , ie , the larger power suiting a larger venue , the smaller power for a smaller place , this is assuming sensible pairing with appropriate spkr cabs , ideally a 4x12" for larger venues (100w) and 2x12" for lesser places (30w) . I dread the the thought of single 12" large power cabs being used , as some major manufacturers do " Infinate Sustain Boxes " I call them , eg , turn the contols up and hold the note and three days later the same guitar note is still feeding back . Powers in the region of a 100 watts need to breathe thru' multiple 12" spkrs such as 4x12" cabs , long live " Marshalls" . I personally cannot see the logic in making these very small 300watt speaker loaded 100watt valve amps (which also belie their weight) .
This is all assuming you are lucky enough to be playing large venues where you can turn it up ! That's ROCK N ROLL !!! .
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