EL84hrm

[10thTx]

IF I were to try it again, this is what I would attempt. The FX would add an additional gain stage.

To get a slightly more clean tone, I might have V2a be switched in and out much as Hoffman's "hotswitch" mod on Marshalls.

OR, I might use DaGeezers dual pot idea on the volume between V1a and V1b and the FX level pot. In other words, use dual relays that switch between pot settings simultaneously faking a more clean to more overdriven switching.

I attached a SCH file that is editable if someone wants to offer other considerations around this idea.

With respect, 10thtx

[rp]

It's interesting to note on this thread the repeated negative comments made WRT the AX84 P1, HO, etc., as they have been pretty popular with DIY amp builders over the years...

My complaint isn't so much with the circuit but that when it comes to little SEs the mojo is in the wild abandon - you can run them full out w/o bringing on, door pounding neighbors, cops, tinnitus, banishment, etc. IME tone stacks here kill the wide open mojo, and MVs are tits on a bull too. Once you squash a little amp the mojo's dead and gone, and you can get the exact same attenuated bedroom sound from any $100 SS amp or just stick a distortion pedal in front of a stock Champ circuit. I tried out the AX84 as I had a gutted small Marshall SS combo to fill and wanted to keep the faceplate so I need to occupy 5 holes with V TMB M. Neither the bud I built it for nor I liked it much - just not dynamic enough nor enough volume. I should have stuck a Champ in there and just plugged up the holes. That P1 is far from me now, it occurred to me later I could try a tonestack lift to see if that might wake it up.

[jazbo8]

My complaint isn't so much with the circuit but that when it comes to little SEs the mojo is in the wild abandon - you can run them full out w/o bringing on, door pounding neighbors, cops, tinnitus, banishment, etc. IME tone stacks here kill the wide open mojo, and MVs are tits on a bull too. Once you squash a little amp the mojo's dead and gone, and you can get the exact same attenuated bedroom sound from any $100 SS amp or just stick a distortion pedal in front of a stock Champ circuit. I tried out the AX84 as I had a gutted small Marshall SS combo to fill and wanted to keep the faceplate so I need to occupy 5 holes with V TMB M. Neither I not the bud I built it for liked it much - just not dynamic enough nor enough volume. I should have stuck a Champ in there and just plugged up the holes. That P1 is far from me now, it occurred to me later I could try a tonestack lift to see if that might wake it up.

I too recycled the SEL for the same reason - I even had VVR installed in it yet could not get a decent enough tone at low volume, oh well...

I attached a SCH file that is editable if someone wants to offer other considerations around this idea.

With respect, 10thtx

IMO, this is straying away from the "D"HRM theme, I like what you had before but just tune the output stage to suit the larger octal tubes. What do you think?

[10thTx]

IMO, this is straying away from the "D"HRM theme, I like what you had before but just tune the output stage to suit the larger octal tubes. What do you think?

Yes, it's straying waaay off & I think it would sound pretty good. And perhaps it would offer a solution to driving the 5881/6L6? It should be noted that Mat's success already was coloring way outside the lines given Dumble didn't make SE OD amps (as far as I know).



Having said that, I am not a big fan of SE amps. IF I need a lowered volume amp, I'll probably use ECL84's like in the SoLow Watt (or 6K6 or 6BM8's).

And having said that .............. I think Mat got this amp "right" from the start using an EL84.

With respect, 10thtx

[sixstringer]

Has anyone actually built the duet version of the 86 Special? Are there photos?

[rp]

Occurs to me, all of you trying to build this as a bigger SE using KT88, 6V6, 6L6 etc, maybe 7591? Supposedly it's an easier tube to drive, closer to an EL84 than a 6L6. Just what I remember reading, not sure if true, or how useful it would be here. Can't hurt to throw it out there.

[sixstringer]

Ciao RP, grazie per la risposta.

I'm thinking that Mat's 86 Special preamp with a double single-ended EL84 power section would be cool. I see reference to a "Super SE" power section but I've not been able to find any info on it, or the 86 Special Duet, other than the purposed Duet schematic with a PP power section.
Can anyone direct me to the Super SE amp or more info on the Duet?
Thanks

[mat]

Has anyone actually built the duet version of the 86 Special? Are there photos?

Hi there,
I havent played my build for a while. I converted the little brother back to dumble style overdrive channel. The bigger 2 EL84 version sounds good but is different from d-style sound. With more gain it closes to fuzz face style sound and playing feel. The build is still little noisy, have to get back to that some day. I might try 10thx' suggestion for 5879 tube.

One gut pick before I redid some of the wiring. https://www.flickr.com/photos/89060375@ ... /lightbox/

Not so good iphone clip: https://soundcloud.com/ef86special/reco ... ecording-2

Double single ended might be cool option. Just havent got enough time to try all these cool things. When I'm retiring, I know just what to do

[sixstringer]

Thanks for the reply and photo. I'm working on the chassis now!

[Harald.Nowak]

Any reason why you went back from ef86 to 12ax7, mat?
I am right now tweaking a double el84 86 special inspired build; went down with the anode load of the ef86 to 86k only and added the triode pentode blend control from merlin blencowe, both to get the gain into controlleable levels. What i still don't like is the squishy attack (less so when fully in triode mode but still); it seems the ef86 simply compresses too much thereby overly accenting the attack sounds - would like to get rid of those overly blownup attack sounds, while still retaining the added sustain.
Or i also go back to 12ax7 - therefor my question about your motivation, mat.
Cheers,