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wavesoft wavesoft is offline
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Default Input transformer when needed ?

Hi

In MIC preamps and PHONO preamps sometimes an input transformer is added
that bridges the mic/phono to the first stage preamp.

But many times it is done wothout any transformer , so what is the rule ?
When input transformer is needed and when not ?

Thanks
ec


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Ian Bell[_2_] Ian Bell[_2_] is offline
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Default Input transformer when needed ?

wavesoft wrote:
Hi

In MIC preamps and PHONO preamps sometimes an input transformer is added
that bridges the mic/phono to the first stage preamp.

But many times it is done wothout any transformer , so what is the rule ?
When input transformer is needed and when not ?

Thanks
ec



Like most things in engineering it is a compromise. Both have their pros
and cons. Talking solely about tubes then I would say:

Transformers:

pros: galvanic isolation (no hum loops), gain at very low noise factor,
the 'iron' sound

cons: limited bandwidth, limited range of source impedances, cost,
distortion at high input levels

NO transformer:

Pros: wide bandwidth, wide range of input source impedance, low distortion

Cons: no galvanic isolation, difficult to get low noise

HTH

Cheers

Ian
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Phil Allison Phil Allison is offline
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Default Input transformer when needed ?


"wavesoft"

In MIC preamps and PHONO preamps sometimes an input transformer is added
that bridges the mic/phono to the first stage preamp.

But many times it is done wothout any transformer , so what is the rule ?
When input transformer is needed and when not ?



** Tubes are not well suited to low impedance, low level signal sources -
cos they inherently have too much voltage noise.

Using a step up transformer changes that situation by boosting both the
impedance and signal level of the source to one better suited to tube
amplification.

There is no one simple rule about using such transformers as there are so
many different possible circumstances and applications.

What you have just posted is just another, meaning free dumb TROLL.

Why don't you get real - PAL - ask the ACTUAL question you REALLY want
to know about.

I will not hold my breath waiting for any anonymous fool like you to
respond.




...... Phil


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RealInfo RealInfo is offline
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Default Input transformer when needed ?

Dear Phill ,

Do you have to poison this important group with your private frustraions ???

Be well




"Phil Allison" ëúá
...

"wavesoft"

In MIC preamps and PHONO preamps sometimes an input transformer is added
that bridges the mic/phono to the first stage preamp.

But many times it is done wothout any transformer , so what is the rule ?
When input transformer is needed and when not ?



** Tubes are not well suited to low impedance, low level signal sources -
cos they inherently have too much voltage noise.

Using a step up transformer changes that situation by boosting both the
impedance and signal level of the source to one better suited to tube
amplification.

There is no one simple rule about using such transformers as there are so
many different possible circumstances and applications.

What you have just posted is just another, meaning free dumb TROLL.

Why don't you get real - PAL - ask the ACTUAL question you REALLY
want to know about.

I will not hold my breath waiting for any anonymous fool like you to
respond.




..... Phil




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Phil Allison Phil Allison is offline
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Posts: 1,444
Default Input transformer when needed ?


"RealInfo"


** Dear Brain Dead TROLL -


kindly go drop ****ing dead.





..... Phil


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