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Post by mrholmes on Sept 11, 2020 3:27:45 GMT -6
RGOs
I hope this is a good question. For the Delta 200 I had to study the diagrams and I saw the OT option. www.sowter.co.uk/specs/9540.phpRemoving the elctronical balanced section vs. the OT - BUT WHY?
Why do those two options exist in the audio world?
I don't understand the technical idea between those two options except that they may influence the sound. Doing this mod for the whole console is not going to happen soon.
But I could do it for two subgroups. The big question is, does it affect the sound at all?
Hope you guys are all save.
THX in advance. Cheers Holmes
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Post by Ward on Sept 11, 2020 5:41:11 GMT -6
Transformers provide a variety of electrical functions that are simulated or equivalently duplicated in a transformless circuit (calling jsteiger audioscape wave and others to explain better) but in our field we're mostly concerned with sound. Transformers add weight, tonal depth, but also smear and distortion to the sound. The transformerless designs are cleaner do not impart a significant effect on the tone. The clearest example many of us have been able to cite is a microphone comparison of Neumann U89 (transfo) versus a Neumann TLM170 (no tranny here).
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Post by matt@IAA on Sept 11, 2020 5:57:01 GMT -6
Balanced means there are two audio cables carrying the signal, hot and cold, with the cold being inverted polarity (positive to negative on the voltage wave).
You can do this with a transformer by taking the signal out of the secondary winding. Or with electronic components (for example, one op amp drives the hot, another inverting amp drives the cold).
Transformers provide DC isolation and if they are well made they can be near invisible. Electronics can have situations they don’t work so well, but are also transparent.
People like using transformers for subtle distortion / frequency response change / phase shift effects.
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Post by EmRR on Sept 11, 2020 9:23:16 GMT -6
The purely technical reason for transformers is isolation. They will probably be beneficial with runs through harsh electrical environments and between drastically different ground potentials. Like....radio station control room across 5 miles of Telco to the transmitter site.
We generally like the sound. Is installing them in a console the best way? Maybe not.
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Post by markfouxman on Sept 17, 2020 0:06:29 GMT -6
Other important benefits of the transformers are their ease of converting unbalanced lines into balanced and ability of perfectly symmetrical cable drive and thus very high noise rejection.
Best, M
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Post by mrholmes on Sept 17, 2020 5:23:43 GMT -6
Other important benefits of the transformers are their ease of converting unbalanced lines into balanced and ability of perfectly symmetrical cable drive and thus very high noise rejection. Best, M . Original question was if OTs make sense in a console? What's your opinion?
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Post by mrholmes on Sept 17, 2020 5:24:07 GMT -6
Erased double post.
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Post by johneppstein on Sept 17, 2020 12:52:00 GMT -6
Other important benefits of the transformers are their ease of converting unbalanced lines into balanced and ability of perfectly symmetrical cable drive and thus very high noise rejection. Best, M . Original question was if OTs make sense in a console? What's your opinion? Yes, of course.
Superior isolation (electronic output has none), Arguably better balancing on the output (not all "electronically balanced" outputs are actually balanced), lower noise (any stage with an amplifier in it generates some noise), different and possibly lower distortion (depending on quality), much less susceptibility to ground loops (tranformers provide isolation, electronic circuits don't), much better reliability (active circuits often fail, transformers seldom do unless thery're badly abused), etc, etc, etc.
Electronic balancing came in because it's significantly cheaper.
Not "opinion" - FACT.
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Post by mrholmes on Sept 17, 2020 13:39:58 GMT -6
. Original question was if OTs make sense in a console? What's your opinion? Yes, of course.
Superior isolation (electronic output has none), Arguably better balancing on the output (not all "electronically balanced" outputs are actually balanced), lower noise (any stage with an amplifier in it generates some noise), different and possibly lower distortion (depending on quality), much less susceptibility to ground loops (tranformers provide isolation, electronic circuits don't), much better reliability (active circuits often fail, transformers seldom do unless thery're badly abused), etc, etc, etc.
Electronic balancing came in because it's significantly cheaper.
Not "opinion" - FACT.
For a layman this fact is interesting I always thought my 1073 sounds best if I try to avoid the transformer artifacts as good as I can, meaning not driving to hot in or out.
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Post by svart on Sept 17, 2020 13:41:16 GMT -6
Balanced means there are two audio cables carrying the signal, hot and cold, with the cold being inverted polarity (positive to negative on the voltage wave). You can do this with a transformer by taking the signal out of the secondary winding. Or with electronic components (for example, one op amp drives the hot, another inverting amp drives the cold). Transformers provide DC isolation and if they are well made they can be near invisible. Electronics can have situations they don’t work so well, but are also transparent. People like using transformers for subtle distortion / frequency response change / phase shift effects. Not to nitpick your post in particular, but it does bring up something that warrants specific distinction.. What you describe, two signals out of polarity to be summed at the receiver to nullify common-mode noise ingress, is differential-mode transmission. The main advantage is that it doubles the voltage when inverting and summing the signals, which increases SNR by 6dB, but also makes the receiver immune to ground noise currents as a ground return is not required. "Balanced" is short for impedance balanced. Balanced transmission just needs a single hot signal with a matched impedance current return at the receiver to nullify common noise but does not increase SNR and still requires a ground return that can lead to ground loops. Differential-mode transmission is almost always inherently impedance balanced anyway, but balanced-mode transmission does not need to be differential although the same type of receiver is used so there is almost zero compelling reason to use balanced signals rather than differential signals.
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Post by matt@IAA on Sept 17, 2020 14:25:33 GMT -6
Yes, thanks for correcting and clarifying. 👍👍
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Post by johneppstein on Sept 17, 2020 23:01:14 GMT -6
Yes, of course.
Superior isolation (electronic output has none), Arguably better balancing on the output (not all "electronically balanced" outputs are actually balanced), lower noise (any stage with an amplifier in it generates some noise), different and possibly lower distortion (depending on quality), much less susceptibility to ground loops (tranformers provide isolation, electronic circuits don't), much better reliability (active circuits often fail, transformers seldom do unless thery're badly abused), etc, etc, etc.
Electronic balancing came in because it's significantly cheaper.
Not "opinion" - FACT.
For a layman this fact is interesting I always thought my 1073 sounds best if I try to avoid the transformer artifacts as good as I can, meaning not driving to hot in or out.
Sure. You want something really bad sounding? Try overdriving a typical transformerless output.
But some people seem to like that, I guess....
Understand, most console (or preamp) outputs were not intended to be overdriven by the designers. IMO the thing about overdriving transformer outs was largely the influence of guitar players used to guitar amps. YMMV.
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Post by johneppstein on Sept 18, 2020 1:47:53 GMT -6
Balanced means there are two audio cables carrying the signal, hot and cold, with the cold being inverted polarity (positive to negative on the voltage wave). You can do this with a transformer by taking the signal out of the secondary winding. Or with electronic components (for example, one op amp drives the hot, another inverting amp drives the cold). Transformers provide DC isolation and if they are well made they can be near invisible. Electronics can have situations they don’t work so well, but are also transparent. People like using transformers for subtle distortion / frequency response change / phase shift effects. Not to nitpick your post in particular, but it does bring up something that warrants specific distinction.. What you describe, two signals out of polarity to be summed at the receiver to nullify common-mode noise ingress, is differential-mode transmission. The main advantage is that it doubles the voltage when inverting and summing the signals, which increases SNR by 6dB, but also makes the receiver immune to ground noise currents as a ground return is not required. "Balanced" is short for impedance balanced. Balanced transmission just needs a single hot signal with a matched impedance current return at the receiver to nullify common noise but does not increase SNR and still requires a ground return that can lead to ground loops. Differential-mode transmission is almost always inherently impedance balanced anyway, but balanced-mode transmission does not need to be differential although the same type of receiver is used so there is almost zero compelling reason to use balanced signals rather than differential signals. That's actually a somewhat bogus description used by companies too damn cheap to do a real electronically balanced connection. A truly balanced connection cancels noise on both lines coming in. Your "balanced mode" connection (also known more accurately as "pseudo-balanced") does not do this, as there is no noise on the minus line to null noise on the hot. ( since the minus line is grounded on one end there is no noise to cancel.)
Usually there's no or little discernable difference UNLESS you're in a high noise environment, as many in residential studios are. That's why REAL pro gear does not use that, but "prosumer" gear often does.
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Post by Ward on Sept 18, 2020 4:56:07 GMT -6
Balanced means there are two audio cables carrying the signal, hot and cold, with the cold being inverted polarity (positive to negative on the voltage wave). You can do this with a transformer by taking the signal out of the secondary winding. Or with electronic components (for example, one op amp drives the hot, another inverting amp drives the cold). Transformers provide DC isolation and if they are well made they can be near invisible. Electronics can have situations they don’t work so well, but are also transparent. People like using transformers for subtle distortion / frequency response change / phase shift effects. Not to nitpick your post in particular, but it does bring up something that warrants specific distinction.. What you describe, two signals out of polarity to be summed at the receiver to nullify common-mode noise ingress, is differential-mode transmission. The main advantage is that it doubles the voltage when inverting and summing the signals, which increases SNR by 6dB, but also makes the receiver immune to ground noise currents as a ground return is not required. "Balanced" is short for impedance balanced. Balanced transmission just needs a single hot signal with a matched impedance current return at the receiver to nullify common noise but does not increase SNR and still requires a ground return that can lead to ground loops. Differential-mode transmission is almost always inherently impedance balanced anyway, but balanced-mode transmission does not need to be differential although the same type of receiver is used so there is almost zero compelling reason to use balanced signals rather than differential signals. Hey svart and matt@IAA, this makes my burning question burn even harder in my brain . . . why are console inserts unblanaced? They don't balance at the sends and returns and then run unbalanced (normal operation) internally. They send unbalanced, they process balanced? and then they return unbalanced. Always bothered me.
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ericn
Temp
Balance Engineer
Posts: 14,817
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Post by ericn on Sept 18, 2020 10:35:35 GMT -6
It’s not about weather you should add transformers to a console, it’s about is the particular transformer going to improve the sound? Example the little Neutrik’s that DDA and many others use as an option , no headroom, nice big Jensens mounted outside the board yummy!
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Post by Michael O. on Sept 18, 2020 13:04:02 GMT -6
Not to nitpick your post in particular, but it does bring up something that warrants specific distinction.. What you describe, two signals out of polarity to be summed at the receiver to nullify common-mode noise ingress, is differential-mode transmission. The main advantage is that it doubles the voltage when inverting and summing the signals, which increases SNR by 6dB, but also makes the receiver immune to ground noise currents as a ground return is not required. "Balanced" is short for impedance balanced. Balanced transmission just needs a single hot signal with a matched impedance current return at the receiver to nullify common noise but does not increase SNR and still requires a ground return that can lead to ground loops. Differential-mode transmission is almost always inherently impedance balanced anyway, but balanced-mode transmission does not need to be differential although the same type of receiver is used so there is almost zero compelling reason to use balanced signals rather than differential signals. Hey svart and matt@IAA , this makes my burning question burn even harder in my brain . . . why are console inserts unblanaced? They don't balance at the sends and returns and then run unbalanced (normal operation) internally. They send unbalanced, they process balanced? and then they return unbalanced. Always bothered me. I think, like so much else in the gear world, that it ultimately comes down to modern cost cutting measure. I’ve used old consoles where the inserts were transformer balanced (and some where the insert couldn’t be switched out of circuit), so it’s not the case that all console inserts are unbalanced.
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Post by svart on Sept 18, 2020 13:23:43 GMT -6
Not to nitpick your post in particular, but it does bring up something that warrants specific distinction.. What you describe, two signals out of polarity to be summed at the receiver to nullify common-mode noise ingress, is differential-mode transmission. The main advantage is that it doubles the voltage when inverting and summing the signals, which increases SNR by 6dB, but also makes the receiver immune to ground noise currents as a ground return is not required. "Balanced" is short for impedance balanced. Balanced transmission just needs a single hot signal with a matched impedance current return at the receiver to nullify common noise but does not increase SNR and still requires a ground return that can lead to ground loops. Differential-mode transmission is almost always inherently impedance balanced anyway, but balanced-mode transmission does not need to be differential although the same type of receiver is used so there is almost zero compelling reason to use balanced signals rather than differential signals. Hey svart and matt@IAA , this makes my burning question burn even harder in my brain . . . why are console inserts unblanaced? They don't balance at the sends and returns and then run unbalanced (normal operation) internally. They send unbalanced, they process balanced? and then they return unbalanced. Always bothered me. I thought some are? Didn't SSL use differential inserts on the 4k, 6k and 9k? I think the need for differential signals is mostly overrated unless the noise ingress is high. I'd think that room auditory noise is much higher than electrical EMI that might get on mic cables, so having mic cables with crazy "star-quad" and double shields and such seems like overkill, especially when you have highly sensitive coils mostly exposed at their ends.. Just sayin'. I guess that unless you have an environment full of EMI/RFI noise, plain unbalanced shielding is fine. Nobody is clamoring for differential guitar cables, although humbuckers to work on a similar principle. Anyway, on a related note, one thing that JohnE is overlooking in his opinionated "nothing is ever as good as the old things that I understand" diatribe is that transformers are inherently poor at rejection of EMI. The shields are typically only good for about 20dB of isolation, but large coils are nothing but antennas. Electrical interfaces are far less likely to pick up EMI than transformers. Besides being lighter, cheaper, smaller and having much better impedance flatness and frequency bandwidths, their supposed drawbacks are much smaller than most unfairly claim. A lot of modern amplifiers can have noisefigures only a few times higher than the resistors used to set their feedbacks, which means they aren't appreciable sources for "noise". Large format mixers full of thousands of amplifiers can have noise floors lower than the ambient stage noise during a quiet violin solo at the orchestra but folks like JohnE would have you think that one amplifier's noise would drown out jet engines given half the chance..
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Post by mrholmes on Sept 18, 2020 16:55:13 GMT -6
It’s not about weather you should add transformers to a console, it’s about is the particular transformer going to improve the sound? Example the little Neutrik’s that DDA and many others use as an option , no headroom, nice big Jensens mounted outside the board yummy! I understand this right I could use two external output transformers optional? www.facebook.com/51xAudio/photos/a.1061200047225566/2868696493142570/?type=3
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Post by johneppstein on Sept 18, 2020 19:42:11 GMT -6
Not to nitpick your post in particular, but it does bring up something that warrants specific distinction.. What you describe, two signals out of polarity to be summed at the receiver to nullify common-mode noise ingress, is differential-mode transmission. The main advantage is that it doubles the voltage when inverting and summing the signals, which increases SNR by 6dB, but also makes the receiver immune to ground noise currents as a ground return is not required. "Balanced" is short for impedance balanced. Balanced transmission just needs a single hot signal with a matched impedance current return at the receiver to nullify common noise but does not increase SNR and still requires a ground return that can lead to ground loops. Differential-mode transmission is almost always inherently impedance balanced anyway, but balanced-mode transmission does not need to be differential although the same type of receiver is used so there is almost zero compelling reason to use balanced signals rather than differential signals. Hey svart and matt@IAA , this makes my burning question burn even harder in my brain . . . why are console inserts unblanaced? They don't balance at the sends and returns and then run unbalanced (normal operation) internally. They send unbalanced, they process balanced? and then they return unbalanced. Always bothered me. Some consoles do have balanced inserts. The thing is, it requires separate jacks for input and output. Nearly all less costly consoles use one TRS for both - saves a lot of money and room. So the answer, as with a lot of things, comes down to $$$. And the unbalanced circuitry itself is cheaper, so again $$$.
And most consoles do not process balanced internally.
One other thing - in most cases if something is Class A circuitry it's internally unbalanced.
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Post by johneppstein on Sept 18, 2020 20:21:03 GMT -6
Hey svart and matt@IAA , this makes my burning question burn even harder in my brain . . . why are console inserts unblanaced? They don't balance at the sends and returns and then run unbalanced (normal operation) internally. They send unbalanced, they process balanced? and then they return unbalanced. Always bothered me. I thought some are? Didn't SSL use differential inserts on the 4k, 6k and 9k? I think the need for differential signals is mostly overrated unless the noise ingress is high. I'd think that room auditory noise is much higher than electrical EMI that might get on mic cables, so having mic cables with crazy "star-quad" and double shields and such seems like overkill, especially when you have highly sensitive coils mostly exposed at their ends.. Just sayin'. I guess that unless you have an environment full of EMI/RFI noise, plain unbalanced shielding is fine. Nobody is clamoring for differential guitar cables, although humbuckers to work on a similar principle. Anyway, on a related note, one thing that JohnE is overlooking in his opinionated "nothing is ever as good as the old things that I understand" diatribe is that transformers are inherently poor at rejection of EMI. The shields are typically only good for about 20dB of isolation, but large coils are nothing but antennas. Electrical interfaces are far less likely to pick up EMI than transformers. Besides being lighter, cheaper, smaller and having much better impedance flatness and frequency bandwidths, their supposed drawbacks are much smaller than most unfairly claim. A lot of modern amplifiers can have noisefigures only a few times higher than the resistors used to set their feedbacks, which means they aren't appreciable sources for "noise". Large format mixers full of thousands of amplifiers can have noise floors lower than the ambient stage noise during a quiet violin solo at the orchestra but folks like JohnE would have you think that one amplifier's noise would drown out jet engines given half the chance.. Well, it depends on the quality of the trannie. If your transformers have double mu-metal shields that are correctly designed and configured their noise rejection can be pretty damn good. But that's expensive. And remember, transformers themselves do not generate noise unless they're broken in some way. And if we're going to talk about outliers (as you are at least verging on) I've heard solid state circuits that would make pretty good transistor radios. Every active circuit produces at least some noise. And you are grossly exaggerating my position in the sentence where you (mis)used my name.
What it all comes down to is quality. And remember, noise is cumulative.
One more point - we are discussing EXTERNAL CONNECTIONS, not internal circuitry. External connections are far more likely to pick up environmental noise that well designed internal circuits, be they part of the console or in a outboard chassis. And, BTW, most external processors are, in fact, internally unbalanced. But I'm sure you actually know that, you're just being deliberately confusing.
One more point about inserts - usually the cable runs are relatively short, at least compared to long runs from mics or to a machine room.
Somehow I doubt that you actually bothered to read my preceding post before slagging me.
And I understand new gear just as well as older gear. Nothing has really changed in (analog) audio in a very long time - it's just smaller.
BTW - do YOU use transformers with only 20 dB of rejection in your builds?
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Post by Ward on Sept 19, 2020 13:57:26 GMT -6
Thanks matt@IAA, svart and johneppstein. I should have written "why are SOME console inserts unbalanced". I think you're right about the 4K and 6K SSLs, but were all the 9K balanced inserts? I remember the Sony/Oxfords were, because the patchbays on the console were a BITCH. But I digress. Anyhow, if all outboard gear is balanced, all LFAC inserts should be balanced too. JMHO.
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