Bottlehead Forum

General Category => General Discussion => Topic started by: John Roman on August 04, 2011, 06:57:22 AM

Title: EL-84
Post by: John Roman on August 04, 2011, 06:57:22 AM

I'm interested in building an EL-84 based amp and am wondering what the  forum may suggest as to designs to check out. I've assembled several Bottlehead kits along the way but this amp I'm thinking  would be more of a " from scratch" build. I'm not opposed to a kit or even starting with an amp sourced from Ebay or the like but I would like to get my hands dirty on this one. The Bottlehead experience has been great but I'm hoping to learn more about the circuits and achieve perhaps greater satisfaction thereby. I guess I'm just looking for more of a challenge, no offense intended! So please, suggest ideas or provide links. I've begun looking but of course wanted to ask this group there thoughts.
Kind regards,
John

Title: Re: EL-84
Post by: 2wo on August 04, 2011, 03:31:36 PM

For P-P look at the aforementioned Red light district or baby huey or el cheepo

Title: Re: EL-84
Post by: John Roman on August 05, 2011, 09:12:15 AM

I've been looking at the Red Light District and will check the others.
Kind regards,
John

Title: Re: EL-84
Post by: Lee Hankins on August 05, 2011, 11:09:45 AM

John, check out DiyTube.com, another great site similiar to the Bottlehead forum.  Shannon has a Stereo 35 board based on the Dynaco Stereo 35 amplifier.  I have built this amp and it sounds excellent, I just like the sound of Single Ended over any push-pull amplifier.  I have also built an amp based on his Eiclone board (EL34 p-p amp) and Get-Set-Go board (6B4G, 6A3 SE amp).

Title: Re: EL-84
Post by: braubeat on August 05, 2011, 11:28:10 AM

I put in a vote for single ended. They sound way better(to me). Also much simpler to design and build for your first attempt. Not any cheaper though. Particularly if you go with parafeed. Check out these.
http://diyaudioprojects.com/Schematics/Mullard-SE-EL84-Tube-Amp-Schematic.htm
http://sarris.info/main/set-el84-tube-amp-diy-project
There are more like these. They could be easily converted to parafeed.

Michael

Title: Re: EL-84
Post by: RayP on August 05, 2011, 02:24:21 PM

It would help us to give you ideas if you let us know the speakers you intend to use, size of room, music tastes etc so that we can get a sense of how much power you need. It might help to know what kits you have built.

Is there a reason why you picked the EL84?

ray

Title: Re: EL-84
Post by: rock4016 on August 05, 2011, 03:00:13 PM

I've built the Red Light District amp, and it sounds better than the 2 other EL84 single ended amps I have built, and my Decware Select, FYI.

Title: Re: EL-84
Post by: corndog71 on August 05, 2011, 04:52:03 PM

I 2nd the DIY tube ST35 design but upgraded with Dave Gillespie's EFB circuit.  It sounds better than my Mk IV monoblocks.

Title: Re: EL-84
Post by: Jim R. on August 07, 2011, 05:27:33 AM

Without knowing all the particulars about the new s.e.x. amp kit, if the power transformer has enough oomph, it is possible that ths could be a good platform on which to build an SE el84 amp.  I don't offhand know what the operating point would be with the 4k transformer, but 4k should be fine for an el84.  Given that the opts don't have UL taps though, you'd have to run in triode or pure pentode mode, and they may not have enough current handling capacity for pentode mode.

Regarding thee Mullard circuit above (I'm assuming it's the Mullard 3-3), that amp was designed in the era of very high output ceramic cartridges and thus has an awful lot of gain and hence noise.

In terms of PP, the diytube board is nice, as is the Triode electronics one, and you can also check out the tube lab pp el84 amp.

-- Jim