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I realize this is an older post, but I'll say this for someone searching the forums. I would definitely recommend using an isolated ground for the recording equipment. It's used more to prevent noise in the recording industry. Especially if you are using vintage gear, and you should be:grin: Isolation transformers are also a must if this guy is a "real" recording engineer. Battery back up is also great, it stinks to be in the middle of an awesome take, and have it lost forever because of a problem. Just my 2cents...
 
guitarsarge said:
I realize this is an older post, but I'll say this for someone searching the forums. I would definitely recommend using an isolated ground for the recording equipment. It's used more to prevent noise in the recording industry. Especially if you are using vintage gear, and you should be:grin: Isolation transformers are also a must if this guy is a "real" recording engineer. Battery back up is also great, it stinks to be in the middle of an awesome take, and have it lost forever because of a problem. Just my 2cents...
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Or you can install a proper electrical system grounded per the NEC and have the EXACT SAME results.
 
I ran a 50a 120/240v feeder to an 8-circuit sub-panel for my home theater, using six circuits (saving the other two for future lighting.)

I used regular 6/3 NM for the feeder. No IG, shared feeder neutral, normal installation. The system is dead-quiet with no audio signal.
 
LarryFine said:
I ran a 50a 120/240v feeder to an 8-circuit sub-panel for my home theater, using six circuits (saving the other two for future lighting.)

I used regular 6/3 NM for the feeder. No IG, shared feeder neutral, normal installation. The system is dead-quiet with no audio signal.
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I'm glad it worked out. I wasn't suggesting to not ground it properly, I if you've ever worked with sound engineers you will understand they hear things most do not. That's why I suggested the isolated ground. You should still have a properly grounded system and adhere to the code. Or am I overlooking something?

I'm always willing to learn something new. Thanks.
 
I'm surprised that nobody mentioned to install ground rods ( or ges if other are there ) at

the detached sub panel, as this is a code requirement, and it's for lightning !!
 
guitarsarge said:
I realize this is an older post, but I'll say this for someone searching the forums. I would definitely recommend using an isolated ground for the recording equipment. It's used more to prevent noise in the recording industry. Especially if you are using vintage gear, and you should be:grin: Isolation transformers are also a must if this guy is a "real" recording engineer. Battery back up is also great, it stinks to be in the middle of an awesome take, and have it lost forever because of a problem. Just my 2cents...
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I'm curious as to how would you install an isolation transformer and an IG ground system for this guy's studio?
 
The isolation transformers I refer to are used to cancel DC and eliminate hum. This is a separate system from the IG receptacles. Vintage audio/transmission equipment from the mid to late 1950's often have ground loop issues which can be dangerous and noisy. These I would use an isolation transformer for. Other more modern equipment I would use on the IG circuits. There is always noise when it comes to recording gear, at least tubes and tape. (which is what I've always used) I guess digital and solid state gear may not pick up these noises, but that is why it doesn't sound authentic... Of course on the IG I would make sure my enclosures are grounded. At least that's what I think I know :smile:

I think the confusion is the isolation transformers I'm referring to are used to decouple the circuits, not to isolate the ground?
 
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If you use NM you already have isolated grounds, a transformer will not isolate the grounding if installed as per the NEC, this is because we are required to bond the primary neutral to the secondary neutral, as Brian has said, a NEC compliant install will not cause hums and ground loops. Noises are what line filters and surge suppressors are for.

I spent 4 months at Electro Voice in training to get my contractor certificate, to do EV PA sound installs, these are large concert type installs, and I have done a few recording studios, as long as you don't have 60hz current on your grounding you wont have ground loops which is the cause of that nasty 60hz hum in the first place:roll:

The NEC does not allow us to use the grounding conductor as a current carrying conductor, so Brian has it right.

Isolated grounds are a wast of money.


By benaround: I'm surprised that nobody mentioned to install ground rods ( or ges if other are there ) at

the detached sub panel, as this is a code requirement, and it's for lightning !!
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Where in the code does it require GE's at a sub panel?:-?
 
guitarsarge said:
I'm glad it worked out. I wasn't suggesting to not ground it properly, I if you've ever worked with sound engineers you will understand they hear things most do not. That's why I suggested the isolated ground. You should still have a properly grounded system and adhere to the code. Or am I overlooking something?

I'm always willing to learn something new. Thanks.
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Over the years I have trouble shot hum issues in recording studios, TV studios, radio stations, I-Max, war game rooms for the Feds, video rides, data centers out the ying yang and a slew of Mega-churches. In each case all issues with hum were associated with improper wiring methods.

Iso transformers were helpful when the end user wanted a quick fix and did not want to spend the bucks to locate the issues.

IG as I said before were of little use and in most cases complicated the issues.
 
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brian john said:
Over the years I have trouble shot hum issues in recording studios, TV studios, radio stations, I-Max, war game rooms for the Feds, video rides, data centers out the ying yang and a slew of Mega-churches. In each case all issues with hum were associated with improper wiring methods.

Iso transformers were helpful when the end user wanted a quick fix and did not want to spend the bucks to locate the issues.

IG as I said before were of little use and in most cases complicated the issues.
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That was always my find also, using a transformer to isolate DC and noises?
DC I can see but what can DC do to sound equipment? I have never seen sound equipment that didn't have power transformers somewhere in the line of supply. even tube type amplifiers still have a transformer, so how is DC getting passed that? as for line pops and noise on the AC system, well a transformer will not stop them, and can even amplify it.
Like I said this is where a good quality line filter comes in, and even one with voltage regulation would be a great plus, and as for stopping 60hz hums, it will not if wired as per the NEC, current on the grounding is what causes ground loop hums and as long as there is a primary to secondary neutral connection, you will not get rid of ground loops.

Active UPS systems (ones that are always on battery power and only use the POCO to recharge) would be another plus as then no interruption in the recording and the fact your always off the POCO grid.

I have heard these same statements made by many old time sound guys and they are in most part myths, you have to understand the circuit at hand before you can solve the causes.:D
 
I will say that many of the older tube type amps did ground one side of there chassis to the neutral, and many had a polarity reverse switch, I rebuilt an Amp-Peg bass head that had this also, which I removed and installed a 3-wire cord and plug assembly, the bass player was getting shocks from the strings of the bass guitar when on concrete or outside venues. So yes there are some of the older equipment that can cause problems in a NEC compliant electrical system.
But they have to be dealt with on individual bases. this also caused many problems with DI-ing out of these old amps to the sound system, but the cure was to install a 1-to-1 mactching transformer in the XLR/?" low level audio cable, not isolate the grounding.
Besides, many who had liked the sound of the voltage amplifying effect of tube amps have now gone to the FET solid state type amps that have the same voltage amplifying effect, such as the 1000w FET Carvin.
 
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