balanced phono stage?

[ericpeters]

Originally posted by djmiddelkoop
Ja, that's it.

Thinking of it, isn't it strange that most cartridges are connected unbalanced while there are two seperate floating (=not connected to ground) coils.
I mean technical speaking, an engineer designing something like this would connect it differential (balanced) to preserve the small signals from the coils.

And to avoid bad signals coming in!

I used to think that connecting all '- signals' to a shared ground was a cause for bad signal instead of a solution. I never understood why thee weren't a lot of designs trying to avoid this.

[Havoc]

I used to think that connecting all '- signals' to a shared ground was a cause for bad signal instead of a solution

Depends on the impedance of your ground. But with the limited separation of LP/cartridge it doesn't matter much.

The preamp is a bit more difficult and thus more expensive (just like the connectors). That is the only reason.

Forgot: there is a simple balanced head amp in the Jung book "IC audio opamp cookbook".

[ThorstenL]

Konnichiwa,

Originally posted by djmiddelkoop
Thinking of it, isn't it strange that most cartridges are connected unbalanced while there are two seperate floating (=not connected to ground) coils.

Not at all. Historically domestic audio systems where "single ended". In the pro area balanced connections have been around for ages.

Originally posted by djmiddelkoop
I mean technical speaking, an engineer designing something like this would connect it differential (balanced) to preserve the small signals from the coils.

Not neccesarily. The engineer may choose SE if the noise levels are important, as balanced systems have more input noise (theory says 3db averaged but up to 6db burst).

Sayonara

[zinsula]

Look at

http://www.ayre.com/products_detail.cfm?productid=11

Actually I saw a review in a German magazine about this, and they concluded that with MC input it is on the same level as a Pass XOno

Maybe Charles Hansen could tell you more?

Regards
Tino

[makinson1]

All pro recording equipment uses either Jensen or Lundahl transformers. Op Amps are for "Project Studio" amateur gear. Transformers have narly infinite CMRR.

[dcollins]

Originally posted by makinson1
All pro recording equipment uses either Jensen or Lundahl transformers. Op Amps are for "Project Studio" amateur gear. Transformers have narly infinite CMRR.

Unless you live under a bridge, you must know that 99% of pro gear is trafoless opamps.

Actually you can have better CMRR with those evil opamps, but transformers can adapt naturally to the interface in ways that the cross-coupled feedback wont....

I like and use transformers, but they aren't magic, and are frequently better bypassed. Even the good ones.

DC

[makinson1]

I was thinking of studios that still use analogue gear like tube condenser mics (Neumann U47, AKG C12), outboard effects (Manley, UREI, Pultec, API, Teletronics, Telefunken), tapes machines (Ampex ATR102 and Studer A-827), and consoles (Neve VR, Trident, etc.).

I would be interested in finding a music CD that was ever made without any transformer-coupled analogue gear in the precess. I'm just a student in these matters and must defer to my betters.

BTW, I think Mike Spitz still uses transformers in his ART 102:
http://recordist.com/ampex/jpg/atr-003.jpg

[dcollins]

Originally posted by makinson1
[B]I was thinking of studios that still use analogue gear like tube condenser mics (Neumann U47, AKG C12), outboard effects (Manley, UREI, Pultec, API, Teletronics, Telefunken), tapes machines (Ampex ATR102 and Studer A-827), and consoles (Neve VR, Trident, etc.).

Well, not all of those items use transformers, but I see what you are talking about.

I would be interested in finding a music CD that was ever made without any transformer-coupled analogue gear in the precess.

There are plenty!

BTW, I think Mike Spitz still uses transformers in his ART 102:

The original ATR-102 did have transformers, however many users (myself included) choose not to use them. Mike Spitz even sells a replacement module:

http://www.atrservice.com/products/i...d=66&dept_id=3

Other aftermarket repro electronics like the Aria are also transformerless...

DC

[makinson1]

Points all well taken. Geeks like me actually like the sound of transformers!

[tiefbassuebertr]

Originally Posted by SY

To realize the full benefits of running a phono stage balanced (and here I mean a balanced input- what you do with the output is much less important), you need to have each half tightly coupled in such a manner that the common-mode rejection is maximized. That means a high-quality differential amp at the input and/or a well-balanced input transformer. You'll also have to configure the tone-arm wiring and interconnect cable as a balanced configuration.

The upside is lowered noise pickup.

What about a circlotron input stage?
There are any few topologies for output stages, e. g.
Thorens TEM 3200 clone
Is this also to realize for an input stage?