Cathode Biased EL84 Amp vs Fixed Bias

[SongsForTheDeaf]

Just curious what the difference would be tonally between a cathode biased 30 watt 1x12 EL84 amp with 3 12ax7s and 4 EL84s vs a 4x10 EL84 amp with 5 12ax7s and 4 EL84s fixed bias also 30 watts

I never really realized how important high headroom was for my sound till I started bringing my own amps to rehearsals!

 

[Edgecrusher]

Re: Cathode Biased EL84 Amp vs Fixed Bias

Depends more on the circuit itself than the tube compliment trying to compare 2 amps by bias type is like trying to describe the driving performance of 2 cars only using the kind of tires each has. You wont be able to guess an amps headroom completely by spec alone as many things interact to determine it. Is one tube rectified? Does one have a choke? What are the specs on the output transformer all these things (and more) can have an effect on the headroom.

 

[GuitarStv]

Re: Cathode Biased EL84 Amp vs Fixed Bias

Speakers and efficiency can also play a big role in volume. A speaker that's 6 dB more efficient puts out twice the sound pressure.

 

[misterwhizzy]

Re: Cathode Biased EL84 Amp vs Fixed Bias

I wouldn't trust any answer in this thread until you say, "I'm comparing make and model A to make and model B. What are the differences?"

 

[SongsForTheDeaf]

Re: Cathode Biased EL84 Amp vs Fixed Bias

well the models I'm comparing are a Traynor YGL2 30 watt cathode biased 1x12 with celestion vintage 30 vs a Mesa Boogie Lonestar Special 30 watt fixed bias with 2 Jensen speakers and 2 mesa speakers...The mesa does have a tube rectifier but only uses it on the 15 or 5 watt mode, on the full 30 watt mode it uses a solid state rectifier

 

[James Rock]

Re: Cathode Biased EL84 Amp vs Fixed Bias

If it is any help my Pro Junior didnt have as much headroom (or should I say doesnt sound anywhere as clean at similar volumes and didnt get as loud) as my current amp through the same speakers. The pro junior has a negative feedback loop and is fixed bias 2xEl84 and my amp I use with no negative feedback and is cathode biased 2xEL84, the preamp is higher gain as well (not high gain alot less then your amps your comparing). With those amps I would expect the MESA to be louder depending on the rating of those speakers but havent compared them.