using line level impedance transformer/balun?

[Ruediger]

This is also my experience with my Tube preamp that has a impedance transformer, it sound way more lively and dynamic than the one without and i've grown quite found of it.
That's why i'd really like to replicate this device.

Transformers will not soften Your sound. They will produce distortions when overdriven but that would take away the freedom to adjust the volume for the right loudness.

Look for products which do TSE (Tape Saturation Emulation) or products from www.soundperformancelab.de. They give You that Vodoo sound. Some of them use DSPs

Ruediger

[Beowulf57]

This is also my experience with my Tube preamp that has a impedance transformer, it sound way more lively and dynamic than the one without and i've grown quite found of it.
That's why i'd really like to replicate this device.

Are these two tube preamps identical except that one uses an input transformer ( not a step-up transformer I assume: 1:1?) and the other does not? What are the input impedances of the two preamps? Just want to be sure we're talking about a transformer effect. Also, the output voltage capability of your source and the gain of the preamp will affect the "dynamics." Are the gains of the two preamps identical?

We are getting a bit far from the forum's content area...

[Eaulive]

We are getting a bit far from the forum's content area...

This thread was in the wrong forum since the beginning anyways

[Chas]

Back in the eighties, I remember Ed Meitner was advocating the use of transformers between pre and power amps. I think Museatex (where he worked in Montreal, at the time) even sold them for a while.

Of course, this was well before balanced lines came into vogue in consumer systems. Not that the two things are related. Or maybe they are with regard to CMRR?

[Eaulive]

Of course, this was well before balanced lines came into vogue in consumer systems. Not that the two things are related. Or maybe they are with regard to CMRR?

I don't think transformers and CMRR are related in any way. A transformer can sometimes reduce noise due to its isolating properties but not because it provides any common mode rejection.

CMR is provided by having signal or opposite polarities travel the same path through the same cable-interconnect-field of interference so the similarities of the noises picked up are easy to cancel at the receiving end. The path may or may not include transformers.

[jcrobso]

If you go back to the first post and go the link the unit has RCA jacks, not balanced!

[Ruediger]

I don't think transformers and CMRR are related in any way. A transformer can sometimes reduce noise due to its isolating properties but not because it provides any common mode rejection.

CMR is provided by having signal or opposite polarities travel the same path through the same cable-interconnect-field of interference so the similarities of the noises picked up are easy to cancel at the receiving end. The path may or may not include transformers.

The purpose of (input) transformers is a high CMRR, that's what they are good for. See the technical papers at Jensen transformers.

Ruediger

[jcrobso]

The purpose of (input) transformers is a high CMRR, that's what they are good for. See the technical papers at Jensen transformers.

Ruediger

They can be hooked up balanced or unbalanced, CMRR only happens in the balanced configuration.

I find it interesting, one of the goals over the years in amp design to get the "straight wire with gain" was to eliminate transformers from the signal path.
I have a mixer board at the station that is around 20 years old it has transformers on the inputs and outputs to keep things balanced.
I also have a new state of the art computerized DSP digital mixing board the has balanced ins and outs, no transformers! This board sounds great, cost $50,000 so it should.
My take on transformers is that if you NEED them use them.

[Eaulive]

The purpose of (input) transformers is a high CMRR, that's what they are good for. See the technical papers at Jensen transformers.

Ruediger

Here we go again.

No, input transformers have no influence on CMRR. Common mode rejection is made possible by the transmission line configuration, the processing at the receiving end may or may not be a transformer.
Modern equipment have a very high CMRR and do not use transformers.

If you use standard unbalanced RCA cable, your equipment's input stage can have the highest CMMR and all the transformers in the world, no common mode rejection will occur.

I suggest you read too

[Eaulive]

They can be hooked up balanced or unbalanced, CMRR only happens in the balanced configuration.

Exactly, assuming the line is balanced as well of course.

[Ruediger]

Here we go again.

No, input transformers have no influence on CMRR. Common mode rejection is made possible by the transmission line configuration, the processing at the receiving end may or may not be a transformer.
Modern equipment have a very high CMRR and do not use transformers.

If you use standard unbalanced RCA cable, your equipment's input stage can have the highest CMMR and all the transformers in the world, no common mode rejection will occur.

I suggest you read too

This gets silly.

http://www.jensen-transformers.com/an/ingenaes.pdf

http://www.dself.dsl.pipex.com/ampin...d/balanced.htm

In the latter paper look for "impedance balanced output".

Ruediger

[Eaulive]

This gets silly.

http://www.jensen-transformers.com/an/ingenaes.pdf

http://www.dself.dsl.pipex.com/ampin...d/balanced.htm

In the latter paper look for "impedance balanced output".

Ruediger

So, where did I say this was not true?
I agree that english is not my mother tongue but still...

[alessa]

Cool, i opened the tube preamp that sounded good, and got the transformer spec:
it's a OEP A262CAN SCRN (screening can)
http://www.canford.co.uk/ProductResources/ig/2739.pdf
I can't really understand what it does..
but as it is cheap, maybe it's worth a buy to test it with power amps, or other preamps..?

[Ruediger]

Cool, i opened the tube preamp that sounded good, and got the transformer spec:
it's a OEP A262CAN SCRN (screening can)
http://www.canford.co.uk/ProductResources/ig/2739.pdf
I can't really understand what it does..
but as it is cheap, maybe it's worth a buy to test it with power amps, or other preamps..?

What kind of input connector does the preamp have? What do You connect to it and how is that wired?

Ruediger

[alessa]

What kind of input connector does the preamp have? What do You connect to it and how is that wired?

Ruediger

It's got XLR input, i connect the balanced output of my Soundcard RME fireface 800, it is wired in balanced stereo jack to XLR..