balanced input stage

[sonix]

hi,
i need a balanced input stage, like this:

An externally hosted image should be here but it was not working when we last tested it.

, for a 300b se amp like this:

An externally hosted image should be here but it was not working when we last tested it.

.
is this possible?
thanks
sonix

 

[Steve Eddy]

What's your goal? Do you just want a balanced input or do you want additional voltage gain as well? If you just want a balanced input and don't need any additional voltage gain, why not use a good quality input transformer?

se

 

[sonix]

i would like to have an ballanced input. examples of one input transformer?

 

[jam]

Why not use an input transformer....

That's our Steve.............

 

[SY]

Re: Why not use an input transformer....

That's our Steve.............

Somehow, one of those migrated to the input of my amp, too.

 

[jam]

SY,

I am waiting for Steve to come up with the self powered transformer only amplifier..............

But kidding aside what transformer are you using and have you tried to use a transformer as a phase inverter to bridge an amplifier.

Regards,
Jam

 

[Sch3mat1c]

WTF, that first schematic has an unbalanced input...but no way to balance the signal when using it... omgHUH?? Anyways, yes an input transformer will work. You can build a differential amp to balun the signal before feeding the power amp. You could redesign it to be balanced all up to the output tube.

Tim

 

[sonix]

thanks for all answers!! can anyone do a redesign of the second circuit? PLZ !! I'm a beginner on this field

thanx
sonix

 

[Steve Eddy]

thanks for all answers!! can anyone do a redesign of the second circuit? PLZ !! I'm a beginner on this field

Not a problem. Just put the transformer between the input jack and the attenuator like this (note the new value of the attenuator):

 

[SY]

...what transformer are you using and have you tried to use a transformer as a phase inverter to bridge an amplifier.

Regards,
Jam

JT11-P1 and yes. I posted a schematic of my input stage a few months back. I'm quite happy with the result.

 

[sonix]

like this?

 

[sonix]

picture:

An externally hosted image should be here but it was not working when we last tested it.

 

[Steve Eddy]

Don't know. The link doesn't work for me.

se

 

[SY]

Me neither. I get a German error message.

Hey, Steve, what are you doing up this early?

 

[fdegrove]

Hi,

Cheers,

 

[Steve Eddy]

Thanks, Frank.

Yup, like that.

se

 

[jam]

Frank,
...............but it is still going to end up looking like this.

 

[Steve Eddy]

Hey, Steve, what are you doing up this early?

Simple. I went to bed earlier than usual.

se

 

[fdegrove]

IRONMAN...

Hi,

Jam,

You want iron? Lots of it?

Don't even think about asking for the price of any of those unless you happen to be the owner of a certain Swedish furniture company....

AUDIOTEKNE

Cheers,

Where are da tubes?

 

[sonix]

another experiment

An externally hosted image should be here but it was not working when we last tested it.