5879 tube in place of an EF86

[jcat5503]

Im planning on building up one of the 18/36 watt marshall style amps with four el84's in the output section and the EF86 tube on the vox style side like the Ceriatone 18/36 EF86. Thing is i want to use a 5879 tube in place of the EF86. I believe its possible, they're both 9-pin tubes. I own a /13 with that uses a 5879 on the "click" channel and it's an amazing sound.

No one seems to know much about these tubes at all... any help would be much appreciated

Thanks!!

 

[Ben S.]

From what I can see, you would need to make a few adjustments. The 5879 has a slightly lower heater current, lower amplification factor, lower plate current, etc; similar impedances. Not huge differences though. Looks like a fairly linear tube to me, could be nice. Never used it myself. Good luck.

5879 - http://www.pmillett.com/tubedata/HB-3/Receiving_Tubes_Part_2/5879.PDF
EF86 - http://tdsl.duncanamps.com/sheets/ef86/ef86_01.pdf

 

[schmidlin]

An excellent choice. The EF86s have a legacy, which includes being microphonic. The 5879 is a premium audio grade tube and if you find a microphonic one you are a better man than I. They sound great and are pretty much a direct swap with a different pin-out. Cheap and available, too.

I use only the 5879 in my preamp pentode builds for these reasons, FWIW.

Enjoy!

 

[jcat5503]

Yeah there are indeed some differences.

Do you really? Have you used any in a 18 watt marshall type buildup?

Yes they're amazing tubes, i love the tone of them.

Have you used them in place of an ef86? (with different pin out)

 

[Prairie Dawg]

Yeah there are indeed some differences.

Do you really? Have you used any in a 18 watt marshall type buildup?

Yes they're amazing tubes, i love the tone of them.

Have you used them in place of an ef86? (with different pin out)

Neither of them are particularly easy to find. How about using 6SJ7s?

 

[jcat5503]

6SJ7s? Never heard of them. does anyone use them from the factory?

have you used them in place of an EF86? How about the tonal qualities?

 

[Chrome Dinette]

I don't know of anyone currently using 6SJ7's(though Siegmund uses a similar, older tube with grid cap) from the factory, but they aren't hard to come by for a decent price.

Also, if you are willing to put a 7pin mini socket in there, there are countless tubes you could try.

 

[jcat5503]

okay from what i have read they were used in some vintage fenders, correct?

 

[jcat5503]

yes indeed. Tons of tube options.

I just really like the tone of the 5879 . I'd really like to build up an 18 TMB with a 5879 in place of the EF86 on the "Vox" side.

 

[Chrome Dinette]

The schematic labelled "old bassman" shows 6SJ7's as the input stage tubes.

Very old Champs used it as well, grid leak biased.

I think there are some Ted Weber amps using these.

Most of these I have seen are metal, though I have one glass one.

There is a (metal) "special red" version as well.

 

[jcat5503]

Yeah i remember seeing a red iron that used a red metal 6SJ7. Sounded great

 

[jcat5503]

Still. Has any one people experimented with replacing the EF86 in the 18 watt marshall style amps?

 

[plexi67]

go on you tube and type 5879 amp, and you should see some 18 watt stuff pop up. Gibson GA 40 used them, divide by 13 uses them.
And People have used the octal preamp tubes too in amp builds.
Depends on what your after or like.

 

[jcat5503]

I'll certainly do it

Thanks!

 

[darkbluemurder]

The pinout of the 5879 is slightly different than that of the EF86. I have heard that the 5879 has a bit lower gain. Even if I have not personally tried it in an 18W Marshall circuit I believe it should work fine.

 

[wyatt]

Yeah i remember seeing a red iron that used a red metal 6SJ7. Sounded great

The RCA 5693 is the top of the line 6SJ7 designed to run for 10,000 hours with minimum noise. I run a couple in my Gibson GA-20 and in the driver section of a tube hi-fi. Most of the 569* series were red.

The 6J7 and 6SJ7 was used a little by Fender, but a lot by Gibson and Valco in the old RCA and Western Digital designs all the companies used as their starting point.

Looks ike current Red Iron uses 6SL7's, which are dual triodes. But have no fear RCA made the 5691 ($$$$) for 6SL7's.

 

[thom_rees]

This has peaked my interest, I never really thought about swapping a EF86 for a 5879 but it sounds like something I would like to try. I have one question though pins 2 + 7 on a EF86 are the shield and grounded to the chassis where as the 5879 has no connection on pins 2 + 6, so would these pins would just be lifted ie not grounded to the chassis.

The other pins are pretty obvious just swap plate for plate (6 on EF86 goes to 8 on 5879), cathode for cathode and grids for grids.

Are there any other changes that I should be aware of before making the swap??

 

[jcat5503]

Yeah. I'd like to know pretty much the same thing

 

[schmidlin]

Yes, just ignore the internal shielding for the 5879. Rely on your external shield, if needed.

 

[tyru007]

You can check out a few custom built 5879 based amps over at the Hoffman Forums. The HOSO56 and the 56T.

http://www.el34world.com/Forum/index.php?topic=8243.0