John Sayers' Recording Studio Design Forum Archive

Hi all-

I've been getting my basement studio built for about 6 months now and we're nearing the finish line. I've finally been able to get some gear down and have been able to make some assessments of issues that I'd like the electricians to examine before I sign off on the project, which is still a little ways out from completion.

Here the link to my Studio Build Thread.

Let me lay out the important points about what was done with the electrical:

1) We installed a completely new panel and upgraded the service to 200 amps.

2) We used a Star grounding scheme, so every new outlet that was added has a direct link to the ground (as I understand Star-grounding, that's the point). My electricians worked from documentation provided to them about Star-grounding (sourced from this forum and Rod G.'s book), so presumably they get the idea and did it correctly.

3) I specified that all of the studio-based outlets should be off of any circuit (?) with mechanical items connected to them, including HVAC, Fridge, Water Heater, Dish Washer, etc... I'm presuming this was done correctly, but was going to have them double check.

4) All electrical work done was based on recommendations from an acoustic consulting firm we contracted who specializes in building studios.

5) There are no dimmers in the studio and no lights with transformers. All lighting was spec'd for studio usage.

6) The actual HVAC unit is about 15 feet, through a big wall, away from the tracking room, but you can't hear it, mechanically speaking.

7) Because of the small size of the space, there's no way to get any further away from the panel, which seems to have some affect on the noise issue.

Issues/Uncertainties I currently have:

So far I've got some different amps and guitars downstairs and have played maybe a total of 2-4 hours tops downstairs at different hours.

I've encountered the following, some of which may be normal to some degree...I'm not sure what's able to be totally elimated by the work we've done and what is merely "tame-able."

Tests with my Tele (Single-coils)

• I'm getting 60 cycle hum from my SF Deluxe Reverb, my (new) Champ 600, Silvertone 1485 head and, my Narrow panel tweed deluxe. All hum exists while the amps are set to 0 volume and the volume of the hum is different with different amps.

• The guitar noise is most prominent when in close proximity to electrical panel, which is in my small "live" room behind my amps, or in front of the amps.

• The noise level can be affected by the direction I'm facing.

• Re: the noise experienced @ the panel – It's louder and the hum has more low-end as I go towards top of panel.

• The noise experienced in closer proximity to my amps has more low-end than the panel hum.

• The 60 cycle hum in the amp (I tested the Tweed Deluxe) is something that also seems to occur upstairs as well, but I'd just never noticed it before. I'm unsure if this means there's a global problem or that this is all just "normal" to some degree.

• One particular night right after I got my amps setup the noise seemed really bad. This is what got me worried I had a problem. That I evening I was not able to pin down what might have been happening, such as Heater was running or something, but I knew that I had done plenty of guitar recording upstairs and the noise had never been that bad.


Note - these results are not significantly different with a Humbucker guitar. These are all excellent guitars that have done well in several other enviornments.


Questions:

• Is 60 cycle hum of some sort to be expected with any tube amp?

• What degree of noise is "normal"? How do I determine if my power is "too dirty" or connected correctly? Is any degree of 60 cycle hum acceptible or to be expected or does that mean the grounding isn't correct, period?

• Is there a diagnostic tool that can definitively say that there are or are not ground loops or dirty power issues?

• Is there a way to shield the panel to stop EMI that it might create?

• Can anyone suggest further testing ideas that I could use to gather more info?

I just got my mixing setup put together yesterday and I wasn't aware of getting hum through the Mac-->Aprogee Ensemble-->Speakers setup, so I don't know if that means the power is perhaps fine? I wasn't listening super critically, but certainly didn't notice anything horrible.

I am aware that amps make noise. I don't think tube amps are like solid state amps and I know that some degree of crackle and noise is going to happen. I'm just having a hard time deciding what's too much noise and I was want to make sure I address this is thoroughly as possible before I sign off on the end of the project and write the last check.

I'll stop with this for now and see if anyone has any direction to suggest. I did read some other threads with similar issues and they lead me to think that the Star ground system might not be config'd right somehow, but that's all a little over my head, so I need help.

Many thanks in advance.

The studio looks nice...

OK, as far as 60hz ground loops...

Start w/ the basics...Put a ground lift adapter on your power cord. If it goes away, then we know where to start.

Move your guitar and amp away from the electrical panels. With those pickups, it's almost a guaranty it's going to pick up the interference.

Those lights in your room, are they halogen or incadescent?

The new panel, is this for the whole house, or a sub panel for the studio, or a dedicated panel for the studio?

Let's start there, and see what happens, and answer some of the above questions.

Thanks for the feedback Aaron.

I'll go through you're questions

Q - Put a ground lift adapter on your power cord.

A - Done and no change. Hum's still there with no guitar attached to the amp. I just checked and it seems the hum is a B or B flat.

Q - Move your guitar and amp away from the electrical panels.

A - There's only so far away I can get since it's a small space. The hum I'm hearing in the amp is happening regardless of the amps proximity to the panel. There's additional hum when I get pretty close to panel or the amp...

Q - Those lights in your room, are they halogen or incadescent?

A - Incadescent with no faders.

Q - The new panel, is this for the whole house, or a sub panel for the studio, or a dedicated panel for the studio?

A - The entire panel is for the whole house although I did ask that the house's stuff stay off the phase of the studio as much as possible. I'm not sure how successful this was at the end of the day and this will be double checked as we get deeper into this process.

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I just spoke to a friend of mine who's my local electronics peep and he thought that the fact that the amp is humming without a guitar plugged in meant that it couldn't be a ground loop because the amp itself is single-ended and without the guitar plugged in, there's no loop. Thoughts?

Thanks again for the help Aaron. It's appreciated.

Lee

PS - I'll attach a pic of my Dr. Z and the proximity to the panel...

Is there any way you can shield your pickups some?

Do you have one or two different grounds? (eg: one for the house, and one for the studio or just one?)

Arron:

1) Pickup Shielding - Yes, I guess there is a way for me to shield the pickup cavity, I've just never done it before. I've got a lot of guitars though, so things could get real expensive...

-2nd site - http://www.stocklogic.com/nohum/

2) Do you have one or two different grounds? (eg: one for the house, and one for the studio or just one?)

Here's the response I got from my Contractor: "My understanding is just one, the seperate grounding box is tied into the house box with one connection, the house box is then grounded. I will verify this with Justin Mon. A.M."

Any other thoughs?

Thanks!

Look up "Faraday Cage" in google. If the EM interference is primarily coming from your electrical box, then you could try building a partial faraday cage (basically just a conductive mesh) an inch or two in front of the box and then grounding it . . . that should block any interference coming off of the electrical box.

I have a very very similar problem with gtars and amps in my studio. Heres an email I just sent to John - no response yet. Any one heard anything about line conditioners? Could this be a fix?
________________________________________________________

I have a small electrial problem in the studio that I was hoping you might have some advice on:

The power on our street is quite "dirty" and electric gtars are picking up alot of line noise. It is really constant and to the level of being really
noticeable on recordings especially if overdrive or distortion is being used. A builders electric drop saw was really clearly coming through the gtar amp this morning and he was working about eight houses away across the road and down the street!!.

I had a electrician around this today who checked the studio's earth and all wiring in the studio and the house and everything is is grounded and connected really well. We put in a new earth for the studio but that changed nothing.

He mentioned installing a "line conditioner" to filter and clean up the power supplycoming to the studio. He seemed to think this would elimiate the noise getting picked up by the gtars and feed to the amps. Do you have any experiance with these in any of the studios you have done? Do you know if they work? If so can you recomend a type or brand to use or where to get them from? if not any other ideas?

I know there are work arounds like putting bare feet on a steel plate attached to the gtar with wire but it's not really a great look for paying customers to be honest. Alot of guys using the studio are doing Gtar overdubs once the drums are tracked at bigger rooms so it's quite important for me to try and tidy this issue up.

There are line conditioners, but I would recommend using one that has the isolation transformers and balanced power. But they're expensive.

6.1.07 Electrical Update

- I checked with the electrician and it seems there's a single ground for the whole system.

Newest issue is, after working on mixing an LP I've been recording here, there are definitely some issues with the electrical... The lights seems to pulse when what I assume is the HVAC system is cycling on. I also seem to be getting occasional pops in guitar amps and headphones while monitoring mixes and recording.

I spoke to my contractor and electrician and despite the whole premise of this project being that the studio needs clean power with no major appliances connected, I now learn that 240 appliances are on both "legs"
of the power and are therefore connected to my outlets, lights, etc... The house was always just going to have a single, upgraded service panel which no one said was of concern, but evidently this means that by default the 240 appliances have to be on the same circuits as my gear.

Perhaps this is obvious to some of you, but this was news to me and seemed totally at odds with the entire premise of the project.

Are there any solutions to this? Am I understanding the issues properly? Are dimming lights/significant electrical draw normal with single service households with a big HVAC unit? My knowledge of electrical is lacking to say the least, so any help is appreciated.

Lee

Hi Lee,

Yes, unfortunately that is the way it works. Most residential here in the states is single phase (which the kicker here is...although you have 2 legs (@120VAC each, it's still considered single phase).

I'm not an electrical engineer as far as main power systems coming in from the grid, but that is how it works.

Thanks for the reply Aaron-

After doing some searches I just found this reply of Steve's to an earlier post:

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.

Do you have any suggestions for a device that would accomplish this goal? Is there a way to isolate or reduce the "pulsing" effect that the HVAC seems to be having on my equipment? The lights don't worry me so much, but clicks are the bane of my existance and make recording virtually impossible since you're always waiting for one to pop up somewhere...

Thanks again.

Lee

Ah yes. I remember that as well. I haven't been on the site much lately, and remembering where stuff is has kind of gone blank.

But, that's why I mentioned above to get some isolation.

Aaron-What kind of isolation do you mean? You mention a possible line conditioner/transformer/balanced power device, but I'm unsure if that's what your referring to. If you have any specific product family or brand recommendations that would be very helpful as I'm unsure ever what to Google to look into products that could accomplish what Steve mentions above, "adding some noise suppression to the heating circuit to avoid noise getting into the technical power."

Question - Is the issue that there's a sag in the AC current when the HVAC comes on? If so, would a line conditioner like the Furman AR-15 SERIES II or AR-1215 make a difference since it would ensure a steady 120V current?

Thanks-

Lee, sounds to me like you have more than one problem, one being noise spikes and the other being the sags in power - if your entire studio gear draws less than about 12-13 amps, then the AR-1215 should help clean that up. It's a pretty complete approach, lacking only UPS and balanced power ability.

I'm kind of wondering, though, about your amp noise - if it's happening with nothing plugged in, that's telling me the amp(s) itself is too close to power. From your pix, they seem to be sitting right in front of your panel??!?

Have you tried putting the amps on the opposite side of the room? There's an awful lot of "antennas" in the wall where the panel is, and if your HVAC is drawing off that panel then the high current will radiate even MORE hum in that immediate location.

If there's any way to do it, I'd consider trading places between amps and drums, using high pass filter on all drum inputs except low toms and kick.

I think what may be happening with the "no input" amps humming is this inductive coupling to the input circuit - I'm not sure all amps short out the input jack when nothing's plugged in - you might also try soldering a wire across the terminals of a spare phone plug and inserting THAT into the input of the amp - if the noise gets less, you're on the right track.

With the sags going on though, I'd not hesitate to use something like the AR-1215 - assuming your total load is less than 13 amps, that is... Steve

Edit - instead of the 1215, for a studio I'd go with the slightly more expensive AR-15 II - the 1215 is intended primarily for live use, and can generate audible noise from the toroidal autoformer used to switch voltage ranges. The AR-15 II and the AR-20 II have additional circuitry, etc, to keep them QUIET for studio use.

Steve-

Thanks so much for the suggestions. I've actually already implemented the flip-flop of amps and drums and that's helped a lot. I have to be mindful of my position when holding the guitars, but otherwise I think it's workable for now.

Re: the spikes and sags, I spoke to my contractor yesterday about developing some sort of solution. This project is not complete yet and the goal was to create a space that doesn't have these issues, so I clearly expressed my expectation that the project meet the goals we laid out and I've paid for thus far, which he feels is a reasonable expectation.

He's going to look into the possibility of perhaps creating a subpanel for the studio outlets with an islolation transformer inbetween those outlets and the main box or perhaps just looking into putting an isolation transformer onto the HVAC's circuit pre-panel to keep it isolated from the other circuits, if that's even possible.

Regardless, what we're shooting for is a more centralized fix as opposed to just patching the problem. It's good to know there's a solution in a box out there though if need be. The problem with the Furman would be the need for several throughout the space for amps in the live room and iso-booth and the control room. These little guys aren't light either, so moving one around the space wouldn't be a sensible solution.

Hopefully this can be sorted out on the panel level. If you have any thoughts in this regard I'd love to hear them.

Thanks so much for your feedback. It's appreciated!

Lee