I'm sorry that none of you guys understand balanced lines and cannot read a schematic. The TDM electronically balanced output was designed to behave just like a transformer. It has 1/4" TRS balanced inputs and outputs and you can plug in unbalanced 1/4" TR plugs and the gain doesn't change. This is exactly how a transformer would behave.
I see what djk is talking about.
The output of the inverting phase amplifier gets summed into the + input of the non-inverting amplifier. (and visa-versa) The amplifiers must have extra gain because you take away some gain by adding an inverted signal. Turn it up so you can take it away.
If you insert a TR plug into a TRS jack, the ring connector on the jack gets shorted to the Sheild/Ground. This shorts the output of the amp through the output resistor, and thus takes away the inverted sum input of the other amplifier. That is how you can short one of the pins and not loose gain.
A clever arrangement to be sure. The TR plug functions as a switch that changes the gain.
I would not bother to do a design such as this. In all pro and semi-pro audio chains, you have so many gain stages, pan pots, faders, trims and sends, you would never know notice the "low" signal.
For Hi-Fi applications, this design conatins too many extra resistors, caps and nodes in the signal path. Delete R144, R145, C118, C119, C122, C123, R149 and R150 you have something like a textbook unbalanced to balanced circuit.
I would not use pin 3 and turn up my volume control a few more clicks.
I stand by my original warning. Do not short outputs.
Aud_Mot
Ps: As for not being able to read schematics... djk, can you please explain to the class how this "behave just like a transformer"
The output of the inverting phase amplifier gets summed into the + input of the non-inverting amplifier. (and visa-versa) The amplifiers must have extra gain because you take away some gain by adding an inverted signal. Turn it up so you can take it away.
If you insert a TR plug into a TRS jack, the ring connector on the jack gets shorted to the Sheild/Ground. This shorts the output of the amp through the output resistor, and thus takes away the inverted sum input of the other amplifier. That is how you can short one of the pins and not loose gain.
A clever arrangement to be sure. The TR plug functions as a switch that changes the gain.
I would not bother to do a design such as this. In all pro and semi-pro audio chains, you have so many gain stages, pan pots, faders, trims and sends, you would never know notice the "low" signal.
For Hi-Fi applications, this design conatins too many extra resistors, caps and nodes in the signal path. Delete R144, R145, C118, C119, C122, C123, R149 and R150 you have something like a textbook unbalanced to balanced circuit.
I would not use pin 3 and turn up my volume control a few more clicks.
I stand by my original warning. Do not short outputs.
Aud_Mot
Ps: As for not being able to read schematics... djk, can you please explain to the class how this "behave just like a transformer"
This might be interesting for all of you:
HB.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
HB.
XLR connections
If you go to the www.aes.org website you can download the AES standard for XLR + some background info for free, doc is AES14-1992 (r1998)
Jan Didden
If you go to the www.aes.org website you can download the AES standard for XLR + some background info for free, doc is AES14-1992 (r1998)
Jan Didden
Different Pin Outs in different Countries!!!
JuNA - i see you live in Europe so it is important to know that the pin outs on XLR connects differ in N. America. The examples given previously are not the same in Europe.
Pins 2 & 3 are swapped - i've had to contend with this problem on my balanced CD player as it's a European/Asian standard mixing with a US design balanced pre-amp.
BQ
JuNA - i see you live in Europe so it is important to know that the pin outs on XLR connects differ in N. America. The examples given previously are not the same in Europe.
Pins 2 & 3 are swapped - i've had to contend with this problem on my balanced CD player as it's a European/Asian standard mixing with a US design balanced pre-amp.
BQ
Balanced Zen Line Stage XLR and RCA Connections
Greetings to all,
I am trying to build the Balanced Zen Line Stage. At the moment I am trying to figure out how to connect an RCA and Balanced Input to the PCB board published on the passdiy.com site. The same goes for the output stage (RCA and Balanced output).
I have come to the following conclusion. Please read through it and post your replies if you think that I have made any mistakes.
RCA Input for one channel:
Centre on RCA plug connects to the IN+ point on the PCB.
Shield of RCA connects to the GND point on the PCB
Point IN- on PCB board should be shorted to the GND point on the PCB (!)
(are all the GND points on the PCB the same?)
BALANCED Input for one channel:
Pin 1 of the Balanced plug connects to the GND point on the PCB
Pin 2 of the Balanced plug connects to the IN+ point on the PCB
Pin 3 of the Balanced plug connects to the IN- point on the PCB
RCA output for one channel:
Centre on RCA plug connects to the OUT+ point on the PCB.
Shield of RCA connects to the GND point on the PCB
Point OUT- on PCB board should NOT be shorted to the GND point on the PCB (!)
(are all the GND points on the PCB the same?)
BALANCED output for one channel:
Pin 1 of the Balanced plug connects to the GND point on the PCB
Pin 2 of the Balanced plug connects to the OUT+ point on the PCB
Pin 3 of the Balanced plug connects to the OUT- point on the PCB
Thank you all, unfortunately we are not all electricians!
George
Athens Greece
gchrist@in.gr
Greetings to all,
I am trying to build the Balanced Zen Line Stage. At the moment I am trying to figure out how to connect an RCA and Balanced Input to the PCB board published on the passdiy.com site. The same goes for the output stage (RCA and Balanced output).
I have come to the following conclusion. Please read through it and post your replies if you think that I have made any mistakes.
RCA Input for one channel:
Centre on RCA plug connects to the IN+ point on the PCB.
Shield of RCA connects to the GND point on the PCB
Point IN- on PCB board should be shorted to the GND point on the PCB (!)
(are all the GND points on the PCB the same?)
BALANCED Input for one channel:
Pin 1 of the Balanced plug connects to the GND point on the PCB
Pin 2 of the Balanced plug connects to the IN+ point on the PCB
Pin 3 of the Balanced plug connects to the IN- point on the PCB
RCA output for one channel:
Centre on RCA plug connects to the OUT+ point on the PCB.
Shield of RCA connects to the GND point on the PCB
Point OUT- on PCB board should NOT be shorted to the GND point on the PCB (!)
(are all the GND points on the PCB the same?)
BALANCED output for one channel:
Pin 1 of the Balanced plug connects to the GND point on the PCB
Pin 2 of the Balanced plug connects to the OUT+ point on the PCB
Pin 3 of the Balanced plug connects to the OUT- point on the PCB
Thank you all, unfortunately we are not all electricians!
George
Athens Greece
gchrist@in.gr
Hugo,
Your illustration of a "balanced XLR Y cable" seems to be wrong.
BQ,
I do not think there is any difference between the balanced XLR pins used in Europe and N. America.
In Europe we use 1=Shield, 2=Line, 3=Return.
We do use different colours, which can lead to confusion in absolute phase when leads are re-made.
Cheers,
Your illustration of a "balanced XLR Y cable" seems to be wrong.
BQ,
I do not think there is any difference between the balanced XLR pins used in Europe and N. America.
In Europe we use 1=Shield, 2=Line, 3=Return.
We do use different colours, which can lead to confusion in absolute phase when leads are re-made.
Cheers,
XLR Pinouts in different countries
John,
I've came across this problem many times where manufacturers are NOT consistent in keeping pins 2 (hot) and 3 (cold). That is why the majority of pro-gear label the connections which is hot or cold.
For some equipment it doesn't really matter. Many higher-end studio equipment use coupled transformers and servo connectors that and automatically switch if the polarity is backwards.
Nevertheless, i've came across many users manuals that specifically say pins 2 & 3 for N. American units are different than pin outs for Asia/European units.
I've also found export models made and designed in the US continue to keep the same pinouts on their XLR connectors (in order to save confusion for bands that perform concerts all around the world. If a rackmount unit breaks down while setting up a concert in Germany, they can go down to a local music shop and buy the same unit knowing that the pinouts are the same.
BQ
John,
I've came across this problem many times where manufacturers are NOT consistent in keeping pins 2 (hot) and 3 (cold). That is why the majority of pro-gear label the connections which is hot or cold.
For some equipment it doesn't really matter. Many higher-end studio equipment use coupled transformers and servo connectors that and automatically switch if the polarity is backwards.
Nevertheless, i've came across many users manuals that specifically say pins 2 & 3 for N. American units are different than pin outs for Asia/European units.
I've also found export models made and designed in the US continue to keep the same pinouts on their XLR connectors (in order to save confusion for bands that perform concerts all around the world. If a rackmount unit breaks down while setting up a concert in Germany, they can go down to a local music shop and buy the same unit knowing that the pinouts are the same.
BQ
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.