Wiring a Polarity Switch

[E-money]

I've looked through the Metas and done a search, but I'm having trouble finding info on the best way to implement a polarity switch. I'm building 2 channels of H-A-M-P-T-O-N-E preamp, and I'm kind of lost on how exactly to implement polarity switches, where in the circuit should they go, how should they be wired, etc.

Any advice, links to threads, schematics, etc would be greatly appreciated.

 

[fum]

Here's how I'd do it:

DPDT switch:

Regards

ju

 

[MikoKensington]

A far as circuit placement I throw the polarity switch after the input XLR. :thumb:

 

[DrFrankencopter]

My preference is at the output transformer (if you have one). I'd rather not have a switch in the mic level path.

Cheers,

Kris

 

[Kev]

[quote author="DrFrankencopter"]My preference is at the output transformer (if you have one). I'd rather not have a switch in the mic level path.[/quote]
YEP

unless
you have a circuit that you think responds differently in the pos transient to the neg transient ...
can't find the words to describe it better

errr
:roll:

a circuit that saturates ... or just operates normally in an asymmetrical manner

this was always going to be a subject for a Group DIY up-date ... but it never quite happened :sad:

 

[peter purpose]

This from Fletcher.....

"All amplifiers, even "class A" amplifiers amplify the top of the waveform differently from the bottom of the waveform. There are a whole lot of sounds (especially vocals) that are asymmetrical waveforms, so the manner in which they hit an amplifier can make a huge difference in the end result."

 

[Rossi]

Ever noticed that everything always makes a HUGE difference? :wink:

 

[Kev]

yep

there where some private email discussions back at TT about a unit that might emphasise .. perhaps even over emphasise this
... not sure as I've seen it here yet

both for mic-pre and line drivers ... say for mastering
the tonal qualities are something that just don't come from the usual methods

again ,
I had planed it for that update that never got written

 

[andre tchmil]

euh, do you mean "before" the output trafo, or "after" , thus at the output xlr ?

 

[Kev]

after a balanced output

that could be after the output TX for say a Project 2 / 312 sort of thing
or
straight on the output of the something like the Green Mk1 (see my pics)

yes ... before the output male XL3

 

[alk509]

[quote author="MikoKensington"]I throw the polarity switch after the input XLR.[/quote]

Uncle Miko,

It'll work, of course, but only on true balanced (e.g., transformer) inputs. Also, on Jakob's G9, for example, a polarity switch at the XLR input wouldn't affect signals going into the instrument input.

I make polarity switches the last thing before the output (i.e., between the output transformer and the output XLR).

Peace,
Al.

 

[E-money]

Thanks for all the answers/advice.

How about a situation with an unbalanced output?
Is the only option to add the polarity switch at the input transformer?

 

[gyraf]

yes, because you don't have output polarity to switch..

 

[smallbutfine]

:shock:
:razz: :wink:
Nice one Jakob :thumb: