Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: lego4040 on April 16, 2014, 01:35:07 pm

Title: EL84 For Fender amps?
Post by: lego4040 on April 16, 2014, 01:35:07 pm
So I double ordered matching JJ EL84's for the Vox, no biggy but could I use them in a 5e9-A? With proper pin changes of coarse? If not I'll be posting them for trade for 6v6's
Title: Re: EL84 For Fender amps?
Post by: HotBluePlates on April 16, 2014, 04:51:28 pm
You can use an EL84 wherever you see a 6V6. (See disclaimers below)

Both are 12w tubes, and will use the same OT load for the same power output at the same supply voltages. The EL84 will need less bias voltage to hit the same idle current, and therefore a smaller cathode resistor if you're cathode biasing. This is due to the EL84's higher Gm, and as a result it will take less drive signal to reach full output power (your amp will seem "hotter" and break up earlier on the volume control).

Because there is a long history of over-volting 6V6's (going well beyond published maximum voltages), you may wish to evaluate whether the EL84 will sound good and give adequate service life when choosing an amp to use the EL84 in place of the 6V6.
Title: Re: EL84 For Fender amps?
Post by: EL34 on April 16, 2014, 05:02:07 pm
I have used EL84's in a Princeton Reverb and it sounded great
Title: Re: EL84 For Fender amps?
Post by: lego4040 on April 16, 2014, 06:18:26 pm
Good to hear that
Title: Re: EL84 For Fender amps?
Post by: P Batty on April 17, 2014, 10:18:02 pm
The 6G9 Tremolux actually used EL84s (6BQ5), with a GZ34 rectifier, no less! The Wikipedia article on the EL84 has a lot of info:

https://en.wikipedia.org/wiki/EL84
Title: Re: EL84 For Fender amps?
Post by: lego4040 on April 18, 2014, 09:18:56 am
Oh yeah, thanks for the heads up. I will read that later
Title: Re: EL84 For Fender amps?
Post by: Stankfut on April 18, 2014, 10:21:30 am
PBatty....ya beat me to it.....I knew there was one Fender that did use them, couldn't remember the model though :laugh:
Title: Re: EL84 For Fender amps?
Post by: phsyconoodler on April 19, 2014, 11:16:10 am
I built a Deluxe Reverb single channel amp recently and the guy who bought it requested EL84's. I did the necessary adjustments and it turned out to be a killer sounding amp! Crank it up and you've got a marshally overdrive that melts faces! Still has a nice chimey clean as well. Love it!

  It was fixed bias and I had to adjust the bias to about -17v to make the tubes thrive,upped the PI bias resistor to 820 from 470. Sweet amp!

Title: Re: EL84 For Fender amps?
Post by: lego4040 on April 19, 2014, 12:22:15 pm
On my bucket list of amp builds is the fender 5E9-A. In my search of similiar amps I found the Gibson GA16T and 18T, which both use the EL84's. Review's on these amps are great and like the Fenders now command $$$$. I might have found a home or these EL84's. I see the difference is the Gibson is a single channel amp as Fender is two. Now to find info on trannies, etc.... for this