Turntable Stylus/Pickup Question

[scott2000]

I was wondering how a turntable stylus/pickup handles the signal in regards to inversion. I've been reading that with single tube pre amps with no inversion stage, the thing recommended is to flip the speaker wires. I guess this makes sense to me because the driver is actually going in reverse of the wave form.?? Swapping positive and negative at the interconnects wouldn't be the same thing as this. Correct?

Another thing I read was a suggestion to swap the terminals at the cartridge. Is this how this works? I just thought it was a single ended type thing with the negative being the ground reference. Suggesting to swap the leads at the cartridge is making it sound as if the stylus/pickup works similar to a transformer in this regard.

I haven't researched far into it yet but was hoping someone would have some insight. I hope this makes sense.

 

[Gold]

Another thing I read was a suggestion to swap the terminals at the cartridge. Is this how this works? I just thought it was a single ended type thing with the negative being the ground reference. Suggesting to swap the leads at the cartridge is making it sound as if the stylus/pickup works similar to a transformer in this regard.

A phono cartridge is like a dynamic microphone. In the case of an moving magnet cartridge the stylus sits inside a coil and modulates the magnetic field. Phono cartridges are well suited for a balanced connection to a preampbut this isn't common practice. . It's just two ends of a coil, twice.  Wayne Kirkwood's Phono Transfer System uses a Cohen type front end for this. I can't recommend this enough. Most noise that isn't surface noise is interface noise. Phono preamp specs generally have no connection to reality. Shorting the input or a resistive source impedance and measuring noise is pretty close to lying.

I think the confusion is that records are recorded in sum/difference or vertical lateral. To make that into left right some lead swapping needs to happen.

 

[scott2000]

Thanks.....

I'm still confused as to what happens when swapping positive and negative leads of a cartridge but there is enough here for me to look into and then some///.....seems it would yield something other than inverting the signal..... ??? Can't wait to try later.......

I need to process this but now I'm turning my focus on the Kirkwood setup atm...

Interesting to see JR having a part in this. I knew he had some designs  but hadn't realized parts of them were still in use today...

 

[JohnRoberts]

Carts are generally like transformer windings so to flip polarity you just reverse the leads.... BUT some carts have straps on one leg to ground that can complicate the flip if not floating. 

I actually designed one phono preamp with a polarity switch to electronically reverse polarity (back last century).

JR

 

[scott2000]

Ok. I will try when I get home. Thanks....

I guess I'm overthinking / confusing it by comparing it to a single ended stage ... . .

Phono cartridges are well suited for a balanced connection to a preampbut this isn't common practice. .

wow....

This is actually pretty incredible..... better finding out late than never I guess

 

[JohnRoberts]

Ok. I will try when I get home. Thanks....

I guess I'm overthinking / confusing it by comparing it to a single ended stage ... . .

Most are single ended...for cost/complexity reasons.

wow....

This is actually pretty incredible..... better finding out late than never I guess

Back in the 80s I published a phono preamp kit with balanced inputs and got a desist letter from somebody who managed to patent the concept. Some guy from Texas found a wet behind the ears patent examiner who had never heard of balanced inputs and who thought it was a new concept.  :

I used to put a lot of time and effort into designing the next, best, phono preamp, now not so much.

JR

 

[scott2000]

I used to put a lot of time and effort into designing the next, best, phono preamp, now not so much.

JR

Ok.  Yours and Paul's time and efforts seem to have helped in part setting the bar way up there
where things must sound quite nice....

Thanks for the help guys! It  makes complete sense to me now...