Anyone tried EL34's in a 5E3 circuit?

[teletroy]

Apparently it is easy to replace the EL34's in a Marshall with 6V6's, as the bias requirements are similar. Has anyone tried to make a higher power 5E3 with EL34's? I'm wondering if you would get a similar gain structure at higher power (obviously you'd need to use a higher power PT and OT). Anyone?

YES AND IT KICKS BUTT! I did it in conjunction with Bruce's tonemod, and it's real pretty

[elpops]

It should be OK if it wired as a stock 6V6s amp but with the larger +25W OT.

The 6L6 wiring uses #1 pin/lug to hold the 1500 ohm grid stopper resistor and that very same lug/pin on an EL34 is a grid of sorts in the tube and needs to be at ground in the cathode biased 5E3. SO that means a complete rewiring of the power tube sockets.

So if I DON'T have the 1500 ohm grid stopper resistor going to pin 1 on the power tube socket, I am OK?

The first time I built it, it was just for 6V6. Then I did the 6L6 mod, but I don't remember changing the power tube wiring when I changed the resistors for 6L6s. I'll have to check over the weekend.

[Bruce / Mission Amps]

Well, when running 6L6s in the 5E3 it is not really necessary to change anything other then the cathode bias resistor (on the power tube sockets) to a 10 to 15 watt one.
I like to add ther 470 ohm resistor to the screens for a little safety's sake.

When you rewire for cathode biased EL34s, you need to ground lug/pin 1 and feed the signal to lug/pin 5.
What most builders do is run a 1K5W resistor from lug/pin 3 to lug/pin 6 and then feed the screen voltage to lug/pin 6.
After this mod the amp can use 6L6s or EL34s with no changes, just pop them in and out.

[elpops]

Nope, I'm pretty sure I have the 1K5 across pins 5 and 6, and 1 is unused. I'll double check, but if this is the case I should take the EL34s out and go back to 6V6s then. That's too bad, though. I hope I didn't damage my amp when I used EL34s in it.

[Bruce / Mission Amps]

It's OK to have 6 to 5 but you should ground lug 1, or at the least connect it to lug 8.

Bruce

[DC Bluez]

Tweed 5E3 6L6 and EL34s

Yes, I've done it!
You can do it too with the MA20 PT or new MA20/18 PT in the Mission Kits because both have filament windings with a +4a 6v3 secondary and a 3a 5v secondary.
Use a GZ30/5V4 rectifier or a Weber WR4 copper cap rectifier, a 10-15 watt 300 ohm cathode biasing resistor, a 5 watt, 2K2 first B+ node screen dropping resistor, install a min of a 1K-2W screen resistor on each power tube (like a black face Fender 6L6 amp or 50 watt Marshall) and if possible, use 4 ohm speaker load on the 8 ohm tap.

Hey Bruce, I have built up a dozen or so 5E3 Deluxes and modded to use 6L6GC and EL34s. Of coarse I changed the PTs and OTs out for the different tubes. I have also built up a 4 diode rectifier, Marshall style and used this for an EL34 output section, no tube rectifier and man this thing cranks. I also changed it to a fixed bias. The Tweed circuit using big bottles really delivers fixed bias. Dont get me wrong I like the tube rectified 6V6 and EL84 models also.

I have the inputs split using 2 volume pots and 2 tone pots and use 2 220K resistors to feed Pin 2 V2. I have the V2 pin 7 biased like a Plexi using 2.7K and .68uF. V2 cathode cap 4.7uF, changed from 22uF. Smooths out the low overtones. The 2 separate volume and tone controls are very easy to use on stage and really sounds fantastic. I do this for all of my 5E3 designs.

B+ running at 420vdc and V1 pin 1 runs at 147vdc. I like the balance of these voltages. It can run any pedal and sound great. Its a 50 watt Tweed 5E3 with mods basically but much easier to get a good tone and simplistic for stage or club use which is what I use it for.

So since the question was asked can you use EL34s I know you can use anything you want by changing PTs and OTs and a few components to get there.

EL34s like a little higher plate voltage so I did not use a tube rectifier. Can add the option of a switchable Tube/diode rectifier arrangement easy enough.

I also dont have it over filtered. 47uF mains, 16uF screens and 22uF preamp. I may try a 33uF on the screens but the amp is silent. With no negative feedback this 50 watt 5E3 EL34 head really sounds great for god old rock and roll and blues and also has enough bottomend to get up there very well. real punchy and cleans out nicely for smooth blues.