Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: rake on March 18, 2018, 01:53:23 pm

Title: Single ended EL84
Post by: rake on March 18, 2018, 01:53:23 pm

Any good schematics foe a single ended EL84 practice amp?

Or, has any of y'all built one?

Title: Re: Single ended EL84
Post by: sluckey on March 18, 2018, 02:02:40 pm

Schedule 40. Read about it here...

     http://el34world.com/projects/Schedule40.htm

Here's the schematic...

(http://el34world.com/projects/images/Schedule40GA-5.jpg)

Title: Re: Single ended EL84
Post by: sluckey on March 18, 2018, 02:07:38 pm

And here's another...

     http://www.ax84.com/static/p1/AX84_P1_101004.pdf

Title: Re: Single ended EL84
Post by: shooter on March 18, 2018, 02:24:02 pm

here's a couple I've built

Title: Re: Single ended EL84
Post by: rake on March 18, 2018, 02:29:32 pm

Thanks guys!

Title: Re: Single ended EL84
Post by: TIMBO on March 19, 2018, 02:29:21 am

This one rocks!
(https://i.imgur.com/TkQyvLD.jpg)

(https://i.imgur.com/RwclNeQ.jpg)
This is the schematic for the above amp.

Title: Re: Single ended EL84
Post by: rake on March 19, 2018, 07:56:46 am

That gives me a lot to work with.
Thinking one of them with a reverb circuit
would make a great mic'ed up small club rig.

Let the little amp make great tone and
let all that Crown and JBL stuff make it really loud!  LOL!  :l2:

Title: Re: Single ended EL84
Post by: Menryk on April 01, 2018, 01:46:52 pm

Which of these all schematics (SE EL84) show amp with clean and good sound without distortions?

Title: Re: Single ended EL84
Post by: kagliostro on April 02, 2018, 03:01:37 pm

I think a 6V6 SE will be more adapt for your necessity

Franco

Title: Re: Single ended EL84
Post by: DummyLoad on April 02, 2018, 06:54:06 pm

as K states - 6V6/6F6. etc.. EL84 is a high gm tube. very easy to overdrive.



--pete

Title: Re: Single ended EL84
Post by: shooter on April 02, 2018, 08:36:23 pm

Quote

as K states

you really need to tweak to keep from distorting, although I did do a mono-block using a quad of 84's
2 great speakers and she trended favorable with most of my deaf audio friends  :laugh:

Title: Re: Single ended EL84
Post by: Menryk on April 03, 2018, 04:24:26 pm

Thanks guys,

sorry but I didn't tell you that I need stereo amp but not for quitar.
To amplifing signal from tuner or gramophon (without tone correction).
Usually I use EL84 in all my amps. Because of that I asked about EL84.
From many months I tried to find good schematic to my purpose and to this time I don't find ready to applying schematic.

Every time when I see some schematic It means that I need change it to my purpose.
Now I work with amp (this time to the quitar) and I need change many things.

So do you have the best example of SE with ECC83 (12AX7) and EL84, Hi-Fi amp in your opinion?

Title: Re: Single ended EL84
Post by: shooter on April 03, 2018, 08:57:02 pm

here's 2 HIFIsh builds, both sounded good within the "clean" range, the PSE was clean to about 70% volume
the QSE has no controls, simply driver PA.  the QSE I drove 2 Audio Nirvana 8" full range.  the QSE schematic is only a "guideline" I know it was tweaked n not documented  :think1:

Title: Re: Single ended EL84
Post by: galtjunk on April 04, 2018, 04:11:04 am

I built a Decware  stereo single ended sv83 amp.
You can use EL-84's if you like but I prefer the russian 6p15.

You can get a circuit board from them or you can build it point to point.
I built mine without the board.
http://www.decware.com/newsite/SE84CDIY.htm

All of the info you need can be found at http://www.decware.com/newsite/SE84CDIY.htm

It is bridgeable so you can build 2 and double the power.
It sounds great.
I may still have a visio layout if you need one.

Title: Re: Single ended EL84
Post by: Menryk on April 04, 2018, 07:51:44 am

Thanks guys very much,

I will check all your suggestions.

Shooter - interesting, especially preamp.
I don't see volume potentiometer.

Galtjunk - very interesting proposal.
What is voltage in point B.
In A point is 346V - I'm not sure that my transformer has this high voltage.

Title: Re: Single ended EL84
Post by: shooter on April 04, 2018, 08:53:14 am

Quote

don't see volume potentiometer.

none to see, it's built as a PA amp, vol n tone happen in whatever you jack in

Title: Re: Single ended EL84
Post by: Ed_Chambley on April 04, 2018, 03:10:50 pm

Sorry, late to the party.  I have built this and played it, but it was for a freind's son.  Great practice amp and has all the bells needed IMO.

Title: Re: Single ended EL84
Post by: galtjunk on April 06, 2018, 04:15:07 am

Quote from: Menryk on April 04, 2018, 07:51:44 am

Thanks guys very much,

I will check all your suggestions.

Shooter - interesting, especially preamp.
I don't see volume potentiometer.

Galtjunk - very interesting proposal.
What is voltage in point B.
In A point is 346V - I'm not sure that my transformer has this high voltage.

I built it with the suggested Edcor transformers.
I think A shows 328 volts but I don't have a reading for B.

There is a set of videos on youtube showing the construction process.
Search for DIY Zen Triode tube amplifier.
There should be 12 videos.

Title: Re: Single ended EL84
Post by: Menryk on April 06, 2018, 01:37:19 pm

Thanks galtjunk,

I will try to check.

M.