Q: unbalanced Dir O/P on the ATB

[Kris]

Would it be ok to just use balanced cable for these?

[Kris]

To answer my own q... yes... :)

[Alan Hyatt]

Yes, as they are self compensating circuits you can use what you want to use...Sorry for the delay in answering.

[McNeilis]

Alan... why did you actually choose to use unbalanced direct outs?

I'm not clued up on the balanced/unbalanced situation but... I'd primarily be using this board for tracking and taking into Nuendo, and so would be using the direct outs for each track right? Would it have cost much more for balanced connections and does it affect the sound much?

Thanks,

Michael.

[hargerst]

I guess nobody else is gonna answer your question, so I'll take a whack at it.

Balanced electronics are good for a couple of things: mainly, running long low-impedance lines (for microphones, for example), and using the balanced circuit to cancel out any noise that's picked up along the way.

But most audio electronics, in general, aren't built that way. Most of the electronic stuff you use is actually unbalanced inside. Yeah, it may go into a piece of gear balanced, or come out balanced, but that's not its natural state. If you look at a preamp, eq, compressor, or power amp, you'll see that the first thing that happens to the balanced signal is the manufacturer unbalances it. What? All that work to keep the signal balanced, and most manufacturers immediately unbalance it?

Yup, cuz the signal's a whole lot easier to work on when it's unbalanced. And the unbalanced signal is contained inside a metal case, so not much hum and noise can get in there.

Now, induced hum and the need for low impedance aren't as much of a problem when you're talking about higher line level signals, high impedance, and short cable runs. Mic impedances are generally in the few millivolts output ranges at 50 to 600 ohm impedances, while line level impedances are generally in the 1 Volt output range at 10,000 to 20,000 ohms. Lots harder for a little noise to sneak in there when you're running a volt of signal.

By leaving the signal unbalanced when connecting between different gear with short cables, you can eliminate a balancing stage on the inputs and outputs. That's two less stages that can add noise and distortion.

Coming out of a mic preamp at line level into an eq into a compressor into the line in on your board into your recorder can eliminate 8 unnecessary balancing circuits. That's bypassing a lot of crap you don't need to be running thru.

Plus, it allows the manufacturer to eliminate some of the extra circuits, reducing costs, keeping out potential sources of distortion, and you pay a little less at the store. A lot of well respected designers and engineers feel that overuse of balanced circuits can reduce the sound quality significantly.

You use balanced circuits where you absolutely hafta use them, but there are a lot of us that use unbalanced ins and outs as much as possible, when it makes good sense from a sonic standpoint.

Hopefully, that answers your question.

[Alan Hyatt]

Sorry guys, I have been away and not checking the site on a regular basis.

Harvey hit it pretty much on the nose. While many outputs of the console are balanced, Malcolm decided on which ones he wanted to have balanced. Malcolm has been building consoles for 34 years and no one has ever complained.

What Harvey says is correct, and in 99.99% of any studio, wire length runs are no long so there is no audible difference. What there is is a 3dB difference between balanced and unbalanced signals which is why Malcolm uses self compensation circuits to keep everything at the proper gain levels throught the console and maintatin the correct voltage at +4

[pianodano]

Hello,

I am not complaining either but I hope someone will help me with a couple of questions . I cannot find the associated voltages. Being kinda old school I expected to find them at the i/o's on the signal flow charts. I plan to use my 32 channel ATB for 16 track tape + DA78's + daw. My tape recorder is definitely balanced and setup at +4dBm = 1.23v. I assume I am ok on the input side of the mixer. But the direct outs on the ATB I am concerned about. I do see a 0dB symbol but a voltage at 0dB is not given. I hope it is 0dB=1v and will not require the use of bump boxes. The only maker I ever knew of that made one of any quality and was adjustable was Tascam but they are long since discontinued. Probably because they where over $500.00 for 8 channels each direction.

I also need to order the studio isolation transformer and need to know the current draw of the mixer power supply.

Thanks in advance.

Danny

[rachel]

Please tell me more about the studio isolation transformer - I take it this is
one of those magic boxes that helps ground the power in the studio?

I have been doing all my reading on star grounding as per Alan Hyatt's
advice and since I am now convinced that domestic power is a hit and miss
affair, I am interested in one of these as a solution. Are these isolation
transformers worth it? How much do they cost...?


rachel

[Ausrock]

Rachel,

If you are able to run all your studio gear, instruments, etc., off their own circuit you probably won't need to worry too much as general opinion is that "in general" the mains supplies here in Aust., are usually more stable than those o/seas. Numerous "establishments" have tried balanced mains power units, etc., with mixed results..........and they ain't cheap.

:cool:

[pianodano]

Hi Rachel,

Isolation transformers are tough to live without nowadays in hi fidelity audio.
For one thing, all power lines are really gigantic antenas.

An isolation tranformer totally isolates its secondary from the outside world by means of transformer windings. They are expensive (even small ones) and used everywhere. Hospitals, broadcast stations and anywhere it is critical that unadulterated power is provided.
More info.http://en.wikipedia.org/wiki/Isolation_transformer

Additionally, even if you have dedicated circuits feeding your studio, whenever something else connected to your electrical service such as, your air conditioner cuts in or a refrigerator or for that matter any kind of motor even at your neighbors house it induces a high current draw upon startup. This is called "Locked Rotor" current. Some isolation transformers also provide a voltage regulator to compensate for over/ under voltages but more often than not this is a separate device.


Here is a couple.

http://www.sweetwater.com/store/detail/IT20/

http://www.sweetwater.com/store/detail/PRO7000/

Danny

[Alan Hyatt]

Danny,

I agree..In fact, we just had to go out to the first 32 input buyer in Los Angeles. He was complaining about pops and static. We tried to resolve his issue on the phone, but could not. So we send out our techs and guess what???

They stick a scope into his outlet and his electric is spitting out fire...It turns out, his electric grid is full of stuff. Now, it did not show up on his Mackie, but the Toft is a "pro" piece of kit. Now the guy tells us the ATB conosle is dead quiet when his grid is normal.

So, to all of you out there. Understand what Star Ground is...get your console professionally installed. Everything that is plugged into the wall and wired to the ATB is bringing ground to the console...WRONG!!!!!!! All grounds must be tied to the console, not floating.

Spend the money, get a big Iso tranny... We charge to come to your home(only LA Area) well...if you pay the bill we will fly there. If nothing is wrong with our stuff...you pay.

[rachel]

I've just found this on ebay:

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=200055346306

Which might help me in my current situation. Can I get an opinion?

Would I be able to <ahem> plug this into a wall socket in my (rented) house
here and then hook the rest of my gear up to it?

I assume the outlet would handle it (16 amps) but I just need to know if
it might be a suitable temporary solution. I definitely have some hum here,
coming from at least 2 of my keyboards. Since I am all spent up on my ATB
at the moment, I'm investigating local solutions suitable for Australian power,
which as Rick pointed out is pretty good, but I still get the hum.

If this iso transformer is suitable, I will probably buy it. Of course I will
check with the sellers as well.....


rachel

[Ausrock]

Rachel,

I suspect that unit was probably made by http://www.harbuch.com.au/default.htm ...........contacting them (it's a local call) should be able to tell you whether it is worth buying.

:cool:

[pianodano]

Rachel,

You may want to read the info on this isolation tranformer. It is one of the only ones I have found in the lower price range that has a rated amperage. http://www.posthorn.com/Furman_10.html

I know nothing about Australian power but here in the US it is marginal at best. I have used regulated and UPS power for years in my little studio and have been amazed that I have been lucky enough to avoid many of the failures other users of much of the same gear have suffered. The particular regulators I use keeps a log of incoming power and what it is able to buck it up to. In peek demand times voltage is reduced considerably.

Regards,

Danny