Altec Lansing 9444a

[rjdv1963]

The Onkyo output to my speakers runs through a speaker distribution panel I installed during construction. It provides impedence protection to my impedence matched volume controls at each speaker pair location. The output on the Onkyo receiver to the distribution panel uses Class 2 wiring and is Rt & Lft, positive and negative. I used 16 guage wire thoughout my home. Speaker runs are between 10' to 40.' I don't understand "step down transformers" and the wiring you mention is foreign to me. I just hoped I could hook up normal speaker wire or cables I'd pick up at a Best Buy or Circuit City retail store. Any other guidance? Thanks!

[Todd W. White]

Do you know what impedance the amplifier "sees" on each of the main feeds going to the distribution network? The actual impedane can be determined by an Impedance Bridge.

If it's 4 ohms or more, but not too high, you'll be ok - no need for line matching transformers.

[LICORNE]

Hi RJDV 1963,

I found an article on 70V distribution. I don't know how old and accurate this is. The transformers today claim a frequency response of 35HZ to 20 KHZ. THe quality amps today will make all the difference between what was called a PA
application only to a HI FI application.

http://www.colomar.com/Shavano/spkr_wiring_tr.html


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[Old Guy]

Originally posted by CONVERGENCE:
The transformers today claim a frequency response of 35HZ to 20 KHZ. .


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<font size="2" face="Verdana, Helvetica, sans-serif">Could you provide a link to those transformers?

I could use some but all the ones at parts express are 100-12000 and frankly I think that is down 6 DB.

I haven't seen any as good as you mention. My first reaction is they must be expensive.

If they are rated that by a Far East manufacturer I would have trouble believing it.

[LICORNE]

Hi,

The company is EDCOR electronics.

http://www.edcorusa.com/transformers/ea/ea.htm

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[Old Guy]

Not bad- 60 watters at $30 or so.

Thanks Convergence- I may have use for those.

Most of the stuff around is horrid.

Of course there is the problem of the Amp end- it has to be good too- and when you go high wattage the cost goes way up. For 6 pairs of speakers we are looking at over $500 in transformers.

It is possible to buy amps that will feed a 70 volt line directly (no transformer at the amp end)

I think wiring codes are different though if you take out the transformer.

[LICORNE]

Hi Old guy,

Your welcome.

Getting back to RJDV1963.

Your distribution pannel is fed via the power zone 2 of your ONKYO.

quote

The Onkyo output to my speakers runs through a speaker distribution panel I installed during construction. It provides impedence protection to my impedence matched volume controls at each speaker pair location

<font size="2" face="Verdana, Helvetica, sans-serif">It sounds like the whole thing is transformer driven.

Edcor makes volume controls for their step down transformers.

You might have to call in a electronic technician,
cause from here it sounds like a guessing game.No offence intended.

THE WHOLE THING COULD BE SERIES AND PARALELL ALSO ; it's easy to design but in stereo could be a headache.

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[LICORNE]

One company that has been building zone distributors for a long time is Mcintosh.

Their product is a 4 zone distributor and comes with an 8 discrete channel amplifier.

http://www.mcintoshlabs.com/data/brochures/CR16br.pdf

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[Old Guy]

The zone distributors I am familiar with have an autoformer to match impedances. They are not 70 volt however. Simply allows 4 ohm speakers on an 8 ohm amp and combos like that.

I think the best thing is just dump the 70 volt and live with the losses. Even a 20% loss on 600 watts shouldn't matter that much.

[LICORNE]

Hi,
Autoformmers are similar in that you still need a former tap on each speaker .

I want to set up four pairs of speakers in four different rooms -- what kind of amplifier I should use

The use of a 70V transformer system will work, but I am always hesitant to place a pair of transformers between the amplifier output and the speaker input. Unless the transformers are of particularly good quality, you will experience a loss in audio quality.

A speaker selector switch is a very good idea, as this eliminates the transformers. However, if you want to play music in more than one location simultaneously, it will not meet your needs. The use of individual volume controls also works, but a good quality control must be used to prevent loss of audio quality. You amplifier also has to drive all of the loads all of the time.

An alternate is to use independent power amplifiers in each location. This can be implemented in either of two ways:
- Use a stand-alone preamplifier and amplifiers in each room.
- Use an integrated amplifier or receiver with a preamp output, using its amplifiers to drive the speakers in one room, and separate power amplifiers in the others.
This method allows you full, independent control of each room. It is probably the most expensive option. With careful shopping, a reasonable pair of entry-level speakers and a two-channel power amplifier can be had for under US$1000 per room.

Powered speakers (a speaker with an integrated power amplifier) are also available. A good quality pro audio monitor can be quite suitable (e.g., Genelec, external link). Don't just hook up powered computer speakers, as these are rarely that great.

You will need to use a quality audio interconnect cable for wiring your rooms. For example, Belden makes several that are suitable for long runs under the trade name "Brilliance Broadcast"; two length of their four-wire microphone cable, each wired in a star-quad configuration, would be suitable. You may require a line driver at the preamp output to isolate the separate lines electronically and to provide output buffering. Every cable introduces some signal loss and your preamp may be unable to drive all of the lines. (This is also true of post-amplifier distribution systems.)

It is important that any cable used, post-preamp or post-amplifier, be selected with care. You want to minimize the impedance of the wire, as well as its capacitance and inductance. Long cables function like a low-pass filter and can introduce problems, especially at the post-amplifier stage

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