John Sayers' Recording Studio Design Forum Archive

Hello,

I'm in the process of building a private/home demo studio and i've already constructed the studio wall making one room into three!!! an ISO booth, live room, and the control room. I've kept the stock 15amp circuit along the perimeter of the studio for usage of non-audio power, and had the builder install two 20amp circuits on the new studio dividing wall. NOW my problem,
unfortunately i found this wonderful site too late and have the circuits in-place without my new knowledge of Star Grounding (BTW, this site has awesome information), both new studio circuits consist of 3 receptacles per circuit with the three receptacles in standard serial connection going back to the breaker!!

I know it's hard to predict the future but do you think I'm going to have ground loop problems once the studio is completed and i plug in my gear??? ALSO, does anyone have advice on if i can do something about this if there is a problem without opening the wall backup and doing it over??? Is there something i could do at the breaker box???

Sorry, for asking for help on a problem that might or might not be, but i just want to ovoid these later when it's time to make MUSIC!!!
BTW, my budget is already stretched and can't really spend anymore then $200 for a solution if there is one!!!!

THANKS,

~PTNEVE~

I know it's hard to predict the future but do you think I'm going to have ground loop problems once the studio is completed and i plug in my gear???

An impossible question to answer unequivably. Think of star ground as being an electrical version of a vaccine. The only way you can know for certain that a vaccine was needed by you is by getting the disease that the vacicne would have protected you against.

Clearly:
Andre

Greetings and welcome to the site.

First off, how far along is the construction? Is it something that you can take the layers off the walls and redo, or possibly in conduit? About the only way to have it completely isolated would be home runs for the grounds to the star point.

As far as if you'll have hum or other problems, you won't know until you plug it all in. What you may be able to do, is run those circuits into a subpanel, and isolate the power from the main panel through transformers (basically balanced power w/ the correct transformers).

Another solution, which I haven't discussed here yet, would be using a grounding scheme of what they call a Delta Ground. (Which I've only just recently learned about from a tech.)

There are 2 ways in which I was told how this can be accomplished. And really is more for RF problems than anything.

Option 1: Drive 3 grounding rods into the ground in a triangular pattern, tying all 3 rods together.

Option 2: Construct 3 grounding rods into a triangular pattern, tying them together, attaching the ground wire, digging as deep as you can go, bury the rods horizontally, and when filling the dirt back in, mix copper sulfate w/ the soil. Over time, the copper sulfate will bond to the copper rods creating a huge ground plane.

(Once again, that's more for RF, but I'm sure it could be used for more than that.)

How much gear will you be running? A fairly complete list if you can... Steve

Aaronw wrote:how far along is the construction? Is it something that you can take the layers off the walls and redo, or possibly in conduit?

Well the walls have already been sealed with acoustic sealer, and the walls have been painted, so as of now I'm not wanting to open the walls to fix a problem that might not be!!! BUT I'm interested in the "balanced power w/ the correct transformers" whatever the heck that is, how is that done, how much is it??? I think that sounds like the best option then more grounding rods and opening the wall?!?! Is it like adding another breaker box???

THANKS,

Steve,

as of right now Control room gear is:
002 Rack, central station, digimax 8 channel mic pre to ADAT, Powermac G5 w/ dual monitors, Adam Audio P11-a monitors, 3 or 4 more channels of assorted mic pres, AND i will have either a TRS or TT patchbay wired to the live-room and Iso booth panels and tie lines!! obviously i'll be buying more gear in months to come!!!


THANKS

You can run 'way more gear than that on just ONE 20 amp circuit; and you SHOULD run everything off the same outlet for now. This means that you would have the exact same ground for ALL the gear, so no ground loops should even be possible under those conditions.

Down the road, however, there may be a couple of problems; one, nothing's been said about whether those extra circuits are on the same PHASE of your power or not; before you go any further, that's the LEAST you should have your builder verify - you should be running all your audio gear off the same phase of your power, and any lighting/heating off the OTHER phase, unless the heating is 240 VAC - under those conditions, you would of course be using BOTH phases of your 240 volt supply for heating, and would need to look at possibly adding some noise suppression to the heating circuit to avoid noise getting into the technical power.

The other possible future problem could involve non-star grounding should you reach the point where you need more power than a single 20 amp circuit can provide - realistically, however, it will take quite a bit of "project studio" type gear to reach that point. I've run two 4 foot racks of gear, a computer, DAT deck, 1/2" reel-to-reel, 3 cassette decks, 1000 watt power amp (not putting out full power of course), 5 or 6 keyboards including a Hammond with Leslie, 2 small mixers, and a handful of lights all on ONE 20 amp circuit - actual draw was around 12-15 amps.

Not only did it work fine, but the noise floor was so low that with one mic up and approximately 10 feet away, I could actually SEE the noise floor raise if I breathed, even very slowly... (OK, the Hammond was off for that test )

HTH... Steve

knightfly wrote: before you go any further, that's the LEAST you should have your builder verify - you should be running all your audio gear off the same phase of your power, and any lighting/heating off the OTHER phase, unless the heating is 240 VAC - under those conditions, you would of course be using BOTH phases of your 240 volt supply for heating, and would need to look at possibly adding some noise suppression to the heating circuit to avoid noise getting into the technical power.

Steve, Thanks I'm gonna talk to the builder ASAP, about the phase. And as far as running everything off one outlet on one of the 20amp circuits, i'll take your advice and start doing that once i setup in my new control room!! But this brings up another issue, in the live room and iso booth are on the second circuit and running fender amps or tube mic power supplies will have to be plugged into the other studio circuits, i wonder if thats going to introduce the grounding/hum issues, i guess there is nothing i can fix if i'm plugin in el Neumann, well unless i don't want to use tube mics !!!!!!

THANKS,

It appears that we spend an commensurable amount of time being as specific and particular as we can on this forum, therefore I would like once again to jump in and clarify that household power is Single Phase. In saying so you cannot connect to "the other Phase" in a single phase system. You can connect to the opposite side of the phase, but not to the other PHASE. There is a phase relationship in single phase in so much as one leg is 180 degrees out of phase with the other, but that is merely related within the same phase. In 3 phase power you have true phases that are 120 degrees out of phase with each other. And in the same vain as single phase you have 180 degree inversion within the same phase of one phase relative to each leg within that phase, but you wouldn't call these all phases else you would have 6 phase power.

. . Two-phase electrical power was used in some early 20th century factories and the distribution systems that served them. It utilized two phases, 90° apart, and was usually supplied using four wires, two for each phase. Less frequently, three wires were used, with a common wire with a larger-diameter conductor.
. . Three-wire, 120/240 volt single phase power used in the USA is sometimes incorrectly called "two-phase". The proper term is 3-wire single phase.
. . Note that true two phase power, meaning the simultaneous provision of sine wave and cosine wave electricity (that is, 90 degrees out of phase) is no longer widely used. But some people incorrectly describe split single phase services as "two phase", when in fact such services are really still single phase power.

-Answers.com

Good point Mark; this, to me, has always been "mis-spoken", to the point that I'd given up "getting it right" and just gone along; much like the so-called "phase" switches on consoles - even the multi-thousand dollar boards can't seem to bring themselves to call that switch "polarity"...

How 'bout we all agree from now on to call this "other side" of single phase power the "other leg", or "opposite leg", and when someone unfamiliar with how it works asks, we just explain the actual relationship of the two possible sources of 120 VAC available at normal household power panels?

If you have a well-written blurb on this with illustrations that help explain it, I'll make it a "sticky" so we can just point to it in future... Steve