• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Very Basic EL84 or EL34 DIY Amp

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
H

haziz

Member
Joined 2007
What is a basic DIY EL84 or EL34 amp design? It should sound good, preferably in ultralinear mode (with possibly a triode option). Output preferably in the 16-50 W range though since I have a number of speakers may be somewhat flexible there; I would like to be able however to preferably drive 88 dB/W/m speakers. Using commercial made amps I have found that I actually prefer UL EL84 or EL34 amps (Manley Stingray and Snappers) to SETs (at least 1 amp with 2 parallel 300B tubes).

My ability to read schematics is very limited and my patience for extensive bodywork is very limited (I also don't own anything more sophisticated than a very basic drill). I did briefly start the Bottlehead Paramour kit but never finished it.

I know I am throwing out a lot of caveats but I am confident the ingenuity of the DIY gurus here should be able to accommodate.

Thanks.

Sincerely,

Hany.
 
K

Kent Smith

Member
Joined 2004
My suggestions:

You might want to finish the 2A3 SET amp first before you tackle a more complicated PP circuit. Two reasons: first, the experience will be invaluable on later efforts. Second, those few Watts of SET will actually play at a good moderate level on 88dB speakers.... great for jazz, acoustic, etc. I find that about 15 to 20 Watts of tube power is plenty for loud concert passages. (I used to have 88dB efficient speakers). You might look up SY's Red Light EL84 circuit here on the forum, it looks good to me. But I would finish the kit before starting something from scratch, which takes a lot more effort and patience!

Good Luck,
Kent
 
jduffy

jduffy

Member
Joined 2006
haziz said:
I did briefly start the Bottlehead Paramour kit but never finished it.

I know I am throwing out a lot of caveats but I am confident the ingenuity of the DIY gurus here should be able to accommodate.
Click to expand...

Just curious to know why you weren't able to finish the Bottlehead kit? I did one of their kits and thought it was very well laid out. It took about two nights to complete it and was my first kit.

Doing something from scratch and using just a schematic is a very different experience. I recently finished a preamp which came out perfectly but it took a lot more time and energy than say the Bottlehead kit.

I'm the reverse of you in that I like SET much more than PP. My next amp will be the Abdellah KT88 (you can do a search here) which appears to be a simple build, but I'll probably substitute the tube and use the EL34. Different strokes for folks and all that.

Good luck with your search.
 
ray_moth

ray_moth

Ex-Moderator
Joined 2004
my patience for extensive bodywork is very limited
Click to expand...
Same here!

A way around that problem, apart from buying a kit, could be to buy a used amp (e.g. from ebay) and cannibalize it for the chassis and transformers and, possibly, the tubes if they're still OK. You would probably want to replace most of the other stuff in there, especially the capacitors, pots and resistors. The layouts of most PP amps will lend themselves to implementing other designs, within reason.
 
S

Simpleton

Member
Joined 2005
You can always go for the DIY Paradise Simple EL84. Can't beat that for simplicity in PP configuration.

http://www.diyparadise.com/simpleel84.html

I'm waiting for the prices of the transformer set from my custom winder company to start building one.

I know it's an overkill, but you can always use a 19" rack case, or another commercialyl available box, you just have to drill for the tubes (or leave them inside the box with some vent holes) and the volume pot and other connectors. Say, 4 driliings max, 3 of 6mm for the RCAs and pwoer cord and one of 10 for the pot.
 
gofar99

gofar99

Member
Joined 2007
oddwattaudio.com
Greetings, I suspect that this is off topic, but maybe. The issue would be bias complications. Transmitters often run in class C and audio gear in variations of A and B. It could be very difficult to bias the tubes in the configuration of the simple el84 to run class C. I would be interested to see how it could be done. Anyone out there have thoughts on this?

Good listening
gofar99
 
C

chrisb

Member
Joined 2002
Gold_xyz said:
A beautiful amplifier is the velleman kit K4040
http://www.vellemanusa.com/us/enu/product/view/?id=350535

also the Jolida SJ502 is a very good schematics (I think)
http://www.drtube.com/schematics/jolida/sj-502a.gif

Triode mode switch can be easy added... :)
Click to expand...


I have a SJ302 (EL34 version) of this design, slightly modified ( Triode, no feedback) and as my first tube component, there's still a soft spot in my heart for her.

However after several DIY/kit projects, she's been retired to the "needs major upgrade" pile. In my system with Fostex single driver based speakers, the several amps that have replace the Jolida, in rotation and depending on my mood are:

-for P/P, the Eli Duttman /Jim McShane "El Cheapo" design (mine based on recycled Scott 222 integrated, with EL84's - but probably a great circuit to rebuild a sickly SCA35 or Stereo 70)

- Bottlehead Paramour II
- RH84 (Alex Kitic's design - modified for EF86 driver/EL84 parafeed output)
 
A

Audio_idiot

Member
Joined 2006
haziz said:


I know I am throwing out a lot of caveats but I am confident the ingenuity of the DIY gurus here should be able to accommodate.

Thanks.

Sincerely,

Hany.
Click to expand...


Hi Hany,

No offence, but DIY gurus can only help only if you can really DIY...

IMHO, if you have no patient to assemble a kit, you are better of saving your mony on any scratch built for your beer money.

And, AFTER you had completed your kit, you can start with the Simple EL84 from diyparadise.

Cheers

Ken
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom