Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: NO_H2O on October 13, 2016, 06:55:34 pm

Title: Single ended EL34 guidance needed.
Post by: NO_H2O on October 13, 2016, 06:55:34 pm

I am thinking about another amp project. I would love to up cycle some old iron again but would not mind buying new iron. I have a couple pairs of NOS EL34s/6CA7s that I would love to put to work but already have a couple of 50 watt EL34 heads. Any more I think that they are a bit to big. A 10 to 20 watt combo is the sweet spot for me.
So I am looking for ideas for a SE EL34 1x12 combo. I heard a Reeves Custom 10 head that had a tone that I really like. Has anyone built or know of a build that would get close to that?

Title: Re: Single ended EL34 guidance needed.
Post by: shooter on October 13, 2016, 08:39:35 pm

Here's my last 2 builds;
HiFishII is a chimey, clean, nice tone, It's not a happy amp when overdriven, but likes it fine with pedals up front.  A bonus, you get a 2nd channel to plug in your digital, or vinyl, wire up a good bookshelf n listen, or play along.
LeGourmet5.4 is more a Champish sound, likes to be beaten on, plays rock well, likes pedals

Title: Re: Single ended EL34 guidance needed.
Post by: NO_H2O on October 13, 2016, 09:07:17 pm

The single ended Champish one looks interesting.
I found this schematic. Wish I could hear the finished amp. I do have the reverb transformer from the AO 43 sitting in a box.

Title: Re: Single ended EL34 guidance needed.
Post by: sluckey on October 13, 2016, 10:27:30 pm

Quote

I do have the reverb transformer from the AO 43 sitting in a box.

The AO-43 does not have a reverb transformer?

Title: Re: Single ended EL34 guidance needed.
Post by: NO_H2O on October 14, 2016, 12:03:11 am

My bad. I better look at the original schematic again.

Title: Re: Single ended EL34 guidance needed.
Post by: shooter on October 14, 2016, 08:54:21 am

You have the tube, now spec out your iron so you have an idea of B+, impedance, drive requirements for the 34, get the PA section drawn up, or copied, then you can stitch about any pre section to your PA.

Title: Re: Single ended EL34 guidance needed.
Post by: Auke Jolman on October 14, 2016, 04:03:06 pm

There are some nice examples over at ax84.com.

I've build the se lead amp and it turned out quite nice

Auke

Title: Re: Single ended EL34 guidance needed.
Post by: NO_H2O on October 15, 2016, 02:38:08 pm

I poked around on AX84 and looked at the Single Ended Lead projects. Lots of options there. I have not done a lot of searching there. The forum format seems a bit odd to me.

Title: Re: Single ended EL34 guidance needed.
Post by: TIMBO on October 15, 2016, 04:44:18 pm

Hey mate, This is a local built amp that I bought as a chassis only.
The circuit had me a bit confused as to why it was only 20w from a pair of el34s.
http://el34world.com/Forum/index.php?topic=18639.msg190688#msg190688 (http://el34world.com/Forum/index.php?topic=18639.msg190688#msg190688)
Great sounding amp not too loud.
(http://i761.photobucket.com/albums/xx254/Timbo-08/001%202_15.jpg) (http://s761.photobucket.com/user/Timbo-08/media/001%202_15.jpg.html)
(http://i761.photobucket.com/albums/xx254/Timbo-08/002%202_12.jpg) (http://s761.photobucket.com/user/Timbo-08/media/002%202_12.jpg.html)

Title: Re: Single ended EL34 guidance needed.
Post by: shooter on October 15, 2016, 05:04:09 pm

Quote

a bit confused as to why it was only 20w from a pair of el34s.

I'm running a pair of 34's in my cathode biased plexi-clubman, and it specs out at 26W.  Lot to do with B+, bias type, and how hot she runs(current).
but into a good 2X12 you bother EVERYBODY in the house, and some neighbors :laugh:

Title: Re: Single ended EL34 guidance needed.
Post by: TIMBO on October 15, 2016, 07:14:11 pm

AWESOME!!