6L6 spitfire/creme brulee variant : phase inverter question
Moderators: pompeiisneaks, Colossal
Re: 6L6 spitfire/creme brulee variant : phase inverter question
I am curious myself about all the people just changing the output tubes in EL84 amps to 6V6 & 6L6 outputs. Aren't EL84s much easier to drive? Wouldn't the switch to 6V6s etc require some redesign to the PI and/or pre?
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airfrankenstein
- Posts: 9
- Joined: Wed Sep 21, 2011 2:47 pm
Re: 6L6 spitfire/creme brulee variant : phase inverter question
Yes the EL84's are easier to drive. I built an ac15 to specs without the vibrato channel using EL84's. As for the current build I picked up some cheap mono hifi amps with 6L6 and ef86 tubes and corresponding transformers and just decided to experiment. The most logical thing would have been a bassman type circuit I suppose.
Going back to the PI question, I noticed that dr z's route 66 uses a vox PI to drive 2 6L6 power tubes. I'm switching back and forth between the two to see which sounds best and I tend to lean towards the fender values. My concern now is to get the voltage swing "right" for the preamp section :
I'm having a hard time getting plate voltages to rise.
I've reduced my B+ supply resistors to 1K whereas the original spitfire schematic listed 22k ! Despite that my voltages are still a tad low if the rule of thumb states that plate voltages should be about 50% of the B+ node feeding them.
Going back to the PI question, I noticed that dr z's route 66 uses a vox PI to drive 2 6L6 power tubes. I'm switching back and forth between the two to see which sounds best and I tend to lean towards the fender values. My concern now is to get the voltage swing "right" for the preamp section :
I'm having a hard time getting plate voltages to rise.
I've reduced my B+ supply resistors to 1K whereas the original spitfire schematic listed 22k ! Despite that my voltages are still a tad low if the rule of thumb states that plate voltages should be about 50% of the B+ node feeding them.