I'm about to build my first phono stage and there are some very interesting designs here on the forum. On other forums I also read about Balanced phono stages but I've never seen any schematic of even a commercial balanced phono stage.
Is this a completely different design or is it possible to take 2 stereo phono stages and have one side of each stereos connected "out of phase" to the same channel?
any suggestions are appreciated.
Eric
Is this a completely different design or is it possible to take 2 stereo phono stages and have one side of each stereos connected "out of phase" to the same channel?
any suggestions are appreciated.
Eric
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.
The upside is lowered noise pickup.
Eric,
here is one, for example:
http://www.vacuumstate.com/images/RTP5_rev_1.GIF
There is more to find at vacuumstate.com.
I have build something like this and it works very well, It is even the most noiseless Phono stage I ever build, or found on a commercial product.
Dick
here is one, for example:
http://www.vacuumstate.com/images/RTP5_rev_1.GIF
There is more to find at vacuumstate.com.
I have build something like this and it works very well, It is even the most noiseless Phono stage I ever build, or found on a commercial product.
Dick
Try finding the Barry Porter design from ETI. It comes from the februari 1987 issue, with an update in march 1989. I'm running this for a couple of years now and it is very good. Based on a couple of LM394H for each channel with NE5532/34 further on. Added a DC servo myself, and an extra psu for the front end. It likes the mains psu to be in a separate case far away from the preamp.
If you decide to go this way, you must be sure that your wiring is balanced up to the cartridge. So if it uses a coax inside the arm or at the interconnect, you will need to re-wire the arm with a twisted pair. You can keep the earth wire. Or -like I did- run a twisted pair outside the arm. At the moment I use 0.1mm magnet wire twisted, straight from the cartridge pins to the input of the preamp.
If you decide to go this way, you must be sure that your wiring is balanced up to the cartridge. So if it uses a coax inside the arm or at the interconnect, you will need to re-wire the arm with a twisted pair. You can keep the earth wire. Or -like I did- run a twisted pair outside the arm. At the moment I use 0.1mm magnet wire twisted, straight from the cartridge pins to the input of the preamp.
balanced phono stage
Hi Eric,
Just see:
http://www.diyaudio.com/forums/showthread.php?postid=378122#post378122
Hi Eric,
Just see:
http://www.diyaudio.com/forums/showthread.php?postid=378122#post378122
http://www.klaus-boening.de/html/revised_headamp.html
Klaus Böning is also a memeber here.
http://www.diyaudio.com/forums/member.php?s=&action=getinfo&userid=9994
Klaus Böning is also a memeber here.
http://www.diyaudio.com/forums/member.php?s=&action=getinfo&userid=9994
Ja, that's it.
What SY and the others mean, is that you have to remove the (unbalanced) interconnect cable and replace it with a balanced, and connect as you say.
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.
Dick
What SY and the others mean, is that you have to remove the (unbalanced) interconnect cable and replace it with a balanced, and connect as you say.
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.
Dick
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".
Konnichiwa,
Not at all. Historically domestic audio systems where "single ended". In the pro area balanced connections have been around for ages.
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
djmiddelkoop said:
Not at all. Historically domestic audio systems where "single ended". In the pro area balanced connections have been around for ages.
djmiddelkoop said:
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
commercial balanced phono stage
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
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 said:
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
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
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
makinson1 said:
Well, not all of those items use transformers, but I see what you are talking about.
There are plenty!
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/item_details.php?item_id=66&dept_id=3
Other aftermarket repro electronics like the Aria are also transformerless...
DC
What about a circlotron input stage?
There are any few topologies for output stages, e. g.
http://www.diyaudio.com/forums/tubes-valves/213159-thorens-tem-3200-clone.html
Is this also to realize for an input stage?
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