Reverse polarity output pre amp

lightman1

Why? I have the Rogue 66 Magnum pre that I stole from Sketchy Craig. In my research of this fine piece of this gear, it is noted that it is a reverse signal path to the outputs. Thus requiring you to reverse the polarities of the speaker outputs of the amplifier.....- is +...+ is -.
What is the reason for this in the tube pre circuits to justify this?
Curious minds want to know.

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lightman1

Off to a flying start! I have been known to unknowingly switch polarities at the speakers and curse the audio gods for lacking low end response.
My terminology was not right.
It's an inverting pre amp.

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kharp1

IF what I understand is correct, it's because each step in the circuit inverts it and they leave the last circuit out to improve sonics. Better to have to switch the polarity at the binding posts then an added circuit. At least that's the philosophy according to Joule from what I read.

mhardy6647

^^^ I think that's the crux of the biscuit (as Mr. Zappa would've put it).

I don't know, though.

It is kind of arbitrary (especially since there's no guarantee that the master recording manifests "correct" polarity).

Remember, the convention of electricity dates back to Benjamin Franklin, who had a 50/50 chance of guessing correctly the "true nature" of electricity. He guessed wrong, and so we were stuck with electrons being "negative".





or not

http://www.austincc.edu/wkibbe/truth.htm

mhardy6647

... and what, I hear you ask, does the nature of electricity have to do with the polarity of a sound wave?

Well... nothing... but I have a reputation to maintain!

Back, sort of, on topic. The cool little gizmo I just got (Galaxy Cricket) can, it appears, be used to check the polarity through an active component (e.g., an amplifier) -- although I haven't tried it for that yet.

It could be a little tricky to use in a typical home hifi, though, as the gizmo's designed primarily for balanced connection to everything except loudspeakers

http://www.galaxyaudio.com/products/cpts

pkquat

It's so people have to buy ULTRA expensive polarity reversion cables of course.
Or is it polarity inversion cables. I get them confused.

I'd go with @kharp1 's answer.

I use Phil Collins synth bass drum on the extended version of "Take Me Home" from 12"ers to verify polarity. The woofer visibly extends out first.

FTGV

If you are one the "golden ears" that can actually perceive absolute phase then reversing the polarity of the speaker connections will be sonically benificial.

lightman1

FTGV wrote: »

If you are one the "golden ears" that can actually perceive absolute phase then reversing the polarity of the speaker connections will be sonically benificial.

Thanks, FreddyJimBob. I am not a golden ear. But I know what I like.

lightman1

Why would the Rouge build this pre?


And to say this pre doesn't give towards

JuanR

I own the 66 and I never reversed it, guess I should try it since it makes a world of difference on my Joule -150... BIG SOUND DIFFERENCE! not just a subtle one...

Dennis Gardner

You have to think of it as a bass drum facing backwards. You can tell the difference, but you don't know why. I think that a lot of recordings that sound lean are due to absolute phase issues.

When that kickdrum hits and your woofer is sucked in instead of pushing out on that first attack, there is a difference in how that wave exits the speaker.

I have always thought that absolute phase was why certain tracks sounded so much better with SDA than others, but who knows.

pitdogg2

Pffft i just push the absolute phase 180* button on my carver c16 .....

[Deleted User]

And to add even more to worry about some record companies suggest that their records sound better when absolute polarity is reversed at the speakers.

geppy1

Is this like the phase invert function on the old NAD 1700 and Yamaha CX 800 preamps?. If it is, I thought things sounded more natural and for sure on the Yamaha.

dhart86

Russ ..thanks for posting this thread. I got the Joule 150 MK II pre ....oops I meant MII (sorry) and i connected everything the traditional way, forgetting that it was an inverting pre,

So I just reversed the polarity connections at the binding post and I am pretty sure that I got a better, clearer and cleaner sound stage....or maybe Juan just suggested it?

Anyway, I'll be leaving it this way!

BlueMDPicker

KennethSwauger wrote: »

And to add even more to worry about some record companies suggest that their records sound better when absolute polarity is reversed at the speakers.

Hi Ken,

Would there be an issue with reversing polarity at the speakers with SDA's due to the need for a common ground?

Additionally, I have a Joule Electra LA-100MkIII connected traditionally (+ to +, - to -) as are the rest of that system's components. This thread caused me to question my memory when I setup the turntable so I played by setup LP again yesterday. I have correct phase from turntable to speakers. With the Joule being phase inverting, I'm surprised by my results.

I use SDA 2B Studio speakers in this system - Music Hall MMF-5, Bottlehead Seduction, Joule LA-100MkIII, DCM 75+75 and SDA's. I'm apprehensive with experimentation at the amp or speaker binding posts due to the SDA cable. Thoughts?

lightman1

That's part of the reason for my query. If the SDA are a phase sensetive type of crossover, will it have an effect the sound or throw off the crossovers?

Dennis Gardner

The answer to the SDA absolute phase issue is to swap the phase between the preamp and amp. This leaves the amp/speaker in good relation to each other with absolute phase in tact. Have a set of ICs inverted and marked just for this purpose.

lightman1

Now we're cookin'! Thanks Dennis.

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pitdogg2

Yep I'm deaf in both eye's

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MrBuhl

My Audible Illusions Modulus is phase inverting. I have used it with SDA's set up both ways, speaker cables reversed, and not. I let my ears be my guide, I liked it best reversed as intended. YMMV.

lightman1

Dig it. IF I ever get home, I'll be setting up the goods and letting it settle in.

[Deleted User]

I don't believe you can reverse the polarity between the preamp and power amp via the interconnect cable. You have to do that either at a balanced connection (most phono cartridges are balanced, for example) or at the speaker.

lightman1

I don't want to cook anything in the tube amps by using SDA 3.1 in reversed polarity. Maybe I'll just buy some better speakers..........

pitdogg2

KennethSwauger wrote: »

I don't believe you can reverse the polarity between the preamp and power amp via the interconnect cable. You have to do that either at a balanced connection (most phono cartridges are balanced, for example) or at the speaker.

I believe your reversing phase not polarity

lightman1

Therein lies the confusion between terminology and topography, Ivan.

[Deleted User]

"Would there be an issue with reversing polarity at the speakers with SDA's due to the need for a common ground?"

Yes, the concern is to not short out the amplifier with the SDA connection. If the left and right SDA speaker negative's were connected to the amplifier's positive terminals and this was a pair of twin/blade SDA speakers then the amplifier would be shorted. If it were a pair of pin/blade SDA speakers there wouldn't be any SDA information created but the amp wouldn't be shorted.

One of the real early audiophile tweaks was to reverse the polarity on one channel of the phono cartridge and reverse the polarity on the speaker connections of the same channel. Supposedly this made life easier for the amplifier's power supply.