Looking for EL34 PP Schematic Amp ? at least 35Watt

[calico88]

I'm looking for a schematic for Tube AMp using EL34 PP, which can create at least 35 Watt.

does anyone can reccomend me which Schematic ?
I'm looking for a simple Schematic less component to be use...

I done search but coudnl't found one.


regards
cal

[SY]

Work on those search skills- there's probably a hundred or two out there.

For low component count, it's hard to beat a Dynaco ST-70.

[kevinkr]

Take a look at my ST-70 mods page, configured for Ultralinear operation this circuit can do 40Wrms per channel with the right iron. Use the stock dyna power supply circuit design or upgrade choke and capacitors for a stiffer supply.

http://www.kta-hifi.net/projects/amp...0amp/st70.html

The schematics are in the old pcx format (I'll eventually get everything back up in pdf)

Use this great free graphics program to view, edit and print pcx, jpg, etc.

http://www.faststone.org/FSViewerDetail.htm

Note I have no affiliation with Faststone - just a happy user.

edit

[richwalters]

As a start....... the standard Mullard 20 Watt amp with EL34's as it stands can be squeezed to give 30watts at 0.5% thd.

richj

[AKN]

Hi,

Lundahl, well known maker of audiotransformers has one PP EL34 design presented on the companys web here.

[calico88]

Kevin,
thanks for pointing the Dynaco, yes I agree this brand is my first look and the only simplest schematic I found.

I only download and see the schematic only not the power supply schematic.. I miss something ?

I wonder how to configure in linear and triode mode ?

actually I'm looking for the Triode mode that can do 35Watt at least.

I don't think I can found the Dynaco Output transformer here, can I use other like lundahl or tango ? which model ?

or what's the specification of that Output transformer ?

other questions, how can I modify the bias into auto bias ? possible ?

Kevin, I don;t think I can modify the schematic my self, all I can do is build base on the schematic, if you can show me the final schematic like Triode mode (can you modify to 35W plus ?), auto bias and PSU Schematic.

regards
Cal

[Eli Duttman]

I'm looking for the Triode mode that can do 35Watt at least.

Cal,

No way are you going to get 35 W. from a PP pair of triode wired EL34s. You'll be hard pressed to get 35 W. from a PP pair of triode wired KT88s. A near Class "B" operating point is necessary.

What sort of speakers are you planning on using? Honest 91 dB. efficient speakers need only 15 WPC, in most rooms.

[ray_moth]

As Eli said. Even two pairs of EL34 in triode mode parallel PP probably wouldn't quite make it. 6550 or KT88 in triode mode parallel PP could do it, though.

[calico88]

thanks guys,
I will use regular speaker like 80 Db sensitifity.

I guess I should look the schematic using 6550, KT88 is more expensive.

ok, ELI or anyone can suggest me TRIODE PP using 6550 at lest 35W ?

cal

[refference]

Hi Calico88 ,

If you are looking for a simple , cheap and good quality
unit ,and an excellent cost / benefit ratio , try the following :

1st option : DYNACO STEREO 70
Uses one 7199 and two EL34 per channel and can
deliver 35 W / ch .

2nd option : If you don’t want to use the expensive and
hard to find 7199 tube , I suggest the DYNACO MARK II
Uses one 6AN8 and two EL34 per channel and can
deliver 35 W / ch .

3rd option : The MULLARD’S 520
Uses one EF86 ( hard to find , only Svetlana manufactures
it nowadays ) , BUT with “minor” changes in the resistors
values you can use the 6AU6 ( cheap and easy to find ) ,
yet uses one ECC83 (12AX7) and two EL34 per channel
and can deliver ( squeezed ) 30 W / ch of good quality sound .

Obviously , there is many , many more circuits that can
attend your previously specified characteristics , BUT the
3 examples above are simple , relatively cheap , the TRANS-
FORMERS are very , very easy to find , easy to build , and the
final result will surprise you .
NOTE : The 3 options above are ULTRALINEAR circuits , that
means , they are a good compromise between the pentode
power and the triode linearity , exactly what you are looking for .

Regards ,

Carlos