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Author Topic: home stereo in-wall volume controls  (Read 6365 times)

Charlie Zureki

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Re: home stereo in-wall volume controls
« Reply #10 on: April 18, 2008, 10:24:50 am »

Craig,

 By installing Transformers into the cabinet gives you NOTHING.
It defeats the idea of using Transformers.  
Please revisit my earlier posting on this subject

 Now, regarding adding Speakers:
 Using the equipment you already have and under the budget constraints, I would suggest that it would be a good oppurtunity to start using the 70volt method. You will still need to acquire another amp specifically to handle the addition to the system.
Make sure that it already has a 70volt transformered output. Then run your wiring, I'd Use 18ga atleast. Then install your new speakers with the transformered 70volt input.
Run the source output into both amplifiers in parallel.
 You'll have two different "systems" 1 70volt and 1 8ohm, but alteast they will keep the cost down and you can change the original system to 70volt in the future.

This would be the easiest method.  
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Hal Bissinger/COMSYSTEC

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Re: home stereo in-wall volume controls
« Reply #11 on: April 18, 2008, 05:34:23 pm »

That is IF he can get the old system to work. Lots of good advice on that subject but I think if that were possible either Craig or someone before him would have done that by now. If it were me I would recommend to the customer that the speakers HAVE to be changed (whatever the cost and difficulty), new volume controls (one for each zone, not the way it is now) and a new amp installed then let THEM make the decision- all or nothing.

I don't want to get into your business but it seems like you have your pet project and you don't want this to get in the way of them going forward with it. You have to understand that these places are notorious for being cheap. They went cheap when the place was being built, that's how they got that system instead of hiring a sound contractor, and they are going to cry poverty now when it doesn't work.

-Hal

Charlie Zureki

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Re: home stereo in-wall volume controls
« Reply #12 on: April 18, 2008, 11:31:41 pm »

Hal
 I agree that most "places are notorious for being cheap".
It's possible that Craig should have approached this project a bit differently from the beginning (no offense Craig) but, we're all human and sometimes we fall for the "poor us" story. It's happened to me too many times.
He's explained some reasons why they cannot/will not allow for major changes to what they already have. Craig needs to complete this job... if nothing more for than to maintain his dignity.

I am familiar with the volume controls and believe that they have been installed with the wrong pin settings.(he claimed he didn't get much info from the sales literature) If this were true, two things may or have occurred. 1.) is the amp would see a extremely low impedance and "burn" up,(explaining the amp failures) and 2.) possibly ruin the speakers. (which is why I suggested he meter the individual speaker runs, checking the impedance).
  Craig also claimed that the speakers did not have transformers installed. (standard 8 ohm spkrs), If he could get to the speakers he could install transformers directly to the speakers they have already,and proceed to go the 70volt method, but he claims that it's impractical.
 As we know, installing transformers at the "head end" of the speaker wire run would do nothing more than he has now, 8 ohms .
 The Technical guys at Russound are very good and will be willing to help him.
But, in any case they will need to spend SOME money, no matter how it all shakes out. If they are not willing to listen to reason it maybe time to run... but I put it all in writing to cover his rear.
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Charlie Zureki

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Re: home stereo in-wall volume controls
« Reply #13 on: April 18, 2008, 11:31:36 pm »

Hal
 I agree that most "places are notorious for being cheap".
It's possible that Craig should have approached this project a bit differently from the beginning (no offense Craig) but, we're all human and sometimes we fall for the "poor us" story. It's happened to me too many times.
He's explained some reasons why they cannot/will not allow for major changes to what they already have. Craig needs to complete this job... if nothing more for than to maintain his dignity.

I am familiar with the volume controls and believe that they have been installed with the wrong pin settings.(he claimed he didn't get much info from the sales literature) If this were true, two things may or have occurred. 1.) is the amp would see a extremely low impedance and "burn" up,(explaining the amp failures) and 2.) possibly ruin the speakers. (which is why I suggested he meter the individual speaker runs, checking the impedance).
  Craig also claimed that the speakers did not have transformers installed. (standard 8 ohm spkrs), If he could get to the speakers he could install transformers directly to the speakers they have already,and proceed to go the 70volt method, but he claims that it's impractical.
 As we know, installing transformers at the "head end" of the speaker wire run would do nothing more than he has now, 8 ohms .
 The Technical guys at Russound are very good and will be willing to help him.
But, in any case they will need to spend SOME money, no matter how it all shakes out. If they are not willing to listen to reason it maybe time to run... but I put it all in writing to cover his rear.
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Jason Lavoie

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Re: home stereo in-wall volume controls
« Reply #14 on: April 20, 2008, 12:02:43 pm »

Charlie Hammer wrote on Fri, 18 April 2008 23:31


 As we know, installing transformers at the "head end" of the speaker wire run would do nothing more than he has now, 8 ohms .  



the only upside to adding transformers at the head end is that then you can parallel them all and put in one volume control per zone as it should be.
Transformers are cheap, 70V volume controls are cheap, and they need a 70V amplifier if they're to have any hope of getting the system to work the way they want it and be expandable and reliable. so that expense literally is the minimalistic approach.

I'm all for being cheap, and I've done some workarounds to save customers money, but when their cheap system is burning amplifiers, and even if that gets solved they still have the multiple control per zone issue, and then the inexpandability then they should see (or be shown) the writing on the wall that they don't have the equipment they need.

If they had bought too small of a grill and couldn't get their food out to the tables fast enough, would they call the grill guy and ask him to bend the laws of physics so that the small grill could magically cook faster without burning anything? no. they would find a way to get a bigger grill.

Jason
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Hal Bissinger/COMSYSTEC

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Re: home stereo in-wall volume controls
« Reply #15 on: April 20, 2008, 04:59:49 pm »

...they would find a way to get a bigger grill.

I think that's the problem here. The customer needs to be "motivated". As far as those speakers go, I've dragged even 12 foot high step ladders into restaurants, moved tables and chairs and straddled booths to get at those speakers. Many times the ceilings were painted with a faux finish too. (Matter of fact most of those times that was a reason for replacing the speakers- the grills were painted shut.) So it can be done without that much trouble, even to just add transformers.

-Hal

Craig Hauber

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Re: home stereo in-wall volume controls - update
« Reply #16 on: May 13, 2008, 11:04:48 pm »

I put a 70V transformer on the end of each 12ga home run and the system woke up.  Each speaker is tapped at 15W and actually sounds really good -much more clarity and definition -the owners actually thought I changed out all the speakers (In hindsite should have said I did and billed them for it Smile

I was able to install new attenuators so there's now 1 100W for the dining room instead of 3.  Bathrooms, Entry, private dining 1 and 2 are on 35W ones.  
I was then able to add 4 new EVID bar speakers on their own attenuators as well as a bathroom hallway and office ceiling monitor speaker also on new attenuators.  Still plenty of room for the patio upgrade and cabanas they want to add.  

Meanwhile the amp is barely having to work to accomplish all this. (E-V PA-2250t)

Each of the old 8-ohm volume controls sounds and works okay by itself at the shop,  Just something about them seems to bog down amps when you run that many at once because the amp that I thought they had killed is now running fine at the shop when used with normal PA speakers.
What led me to do what I did was that each home-run and speaker combination worked excellent under test by itself.  So if it isn't the amp, speaker or wiring it had to be those volume controls.

I was happy that I could solve the client's problem without scaffolding, painting and service interruption -and for a much lower cost than replacing everything would have been.

I was never able to get real data from anyone for use when designing systems using those type of volume controls.  What I can gather from impedance sweeps is that the 2X 4X 8X switch increases the impedance on the input lines of the volume control from somewhere around 4-ohms to 32-ohm (depending on frequency)the sweeps have many spikes but I do not know how much of that is from an attached speaker.  They do not give a reading without a speaker attached so I guess they aren't a true transformer like 70V equipment tends to have.
I do have some Phoenix Gold branded versions of these type of volume controls in the junk box at the shop that have dozens of resistors instead of a coil and they tend to have better impedance responses -much more linear.

thanks for the advice and ideas to get me some testing methods to see if this would work.

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Craig Hauber
CSA Productions Inc.
Ventura-Santa Barbara CA
www.csaproductionsinc.com

Hal Bissinger/COMSYSTEC

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Re: home stereo in-wall volume controls - update
« Reply #17 on: May 14, 2008, 01:03:59 pm »

What I can gather from impedance sweeps is that the 2X 4X 8X switch increases the impedance on the input lines of the volume control from somewhere around 4-ohms to 32-ohm (depending on frequency)the sweeps have many spikes but I do not know how much of that is from an attached speaker.

If you want to eliminate the speaker artifacts just use an 8 ohm resistor instead of a speaker for your tests. Keep in mind however that the speaker may present less than an 8 ohm load at some frequencies and will bring the combined impedance way down. So your tests with a speaker are actually real world and explains why the amp had a problem driving the combined impedance. It's always been my opinion that those impedance matching volume controls and speaker selectors are bad news.

I'm happy that you got the problem resolved. Smile

-Hal
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