Transformer tap and impedance

[riehmc]

I have four CVS 6 ceiling speakers that have a transformer tap control. These speakers will be the front elevation and rear surround. Can anyone please tell me what setting I should use for a home receiver that does 100 W x7 at 6 or 8 ohms?

 

[slipperybidness]

I have four CVS 6 ceiling speakers that have a transformer tap control. These speakers will be the front elevation and rear surround. Can anyone please tell me what setting I should use for a home receiver that does 100 W x7 at 6 or 8 ohms?
View attachment 43652

I think those are for commercial applications, and will not work with consumer level gear.

Granted, I have never seen anything quite like this!

@TLS Guy

 

[James S.]

I saw in the manual it says off for low impedence applications.

 

[TLS Guy]

I have four CVS 6 ceiling speakers that have a transformer tap control. These speakers will be the front elevation and rear surround. Can anyone please tell me what setting I should use for a home receiver that does 100 W x7 at 6 or 8 ohms?
View attachment 43652

It needs to be off. The transformer is for use with 70 volt high impedance PA systems. These are mainly used in commercial large building applications.

The way you set those transformers in 70 volt systems, is that the total number of watts after adding the total of the settings must equal the power of the amplifier, then the impedance is correct for the amp. This allows different power to be applied to each speaker. For instance if one speaker is set to 10W it will receive twice the power of one set to 5W.

 

[riehmc]

My initial thought was to turn it off too but then they don’t work at all. I had someone from support reach out and tell me to use the low frequency or the LOZ setting. I’m definitely not happy with the audio levels and I’m hoping that Denon’s audyssey will compensate

 

[TLS Guy]

My initial thought was to turn it off too but then they don’t work at all. I had someone from support reach out and tell me to use the low frequency or the LOZ setting. I’m definitely not happy with the audio levels and I’m hoping that Denon’s audyssey will compensate

I have just investigated further. You can not use those speakers. You have bought the wrong ones. They have three versions of that speaker, the 6 ohm version, which is what you need, and they have the 70 volt and 100 volt versions. You have the 70 volt version. The transformer is always in circuit. Sorry by you need different speakers.

This is the info you need.

 

[Speedskater]

Or buy a transformer to convert your 100 W @ 8Ohms to 70 Volts.
Parts express sells the transformers, but their web-page is asleep at the moment.
look in the commercial section
Transformer # 300-225
* * * * * * * * * * * * * * *
The web-page woke-up!

https://www.parts-express.com/70V-100W-High-Power-Line-Matching-Transformer-300-225?quantity=1

$24.00

 

[lovinthehd]

Or if you have pre-outs you could perhaps get an appropriate amp....

 

[Verdinut]

Or buy a transformer to convert your 100 W @ 8Ohms to 70 Volts.
Parts express sells the transformers, but their web-page is asleep at the moment.
look in the commercial section
Transformer # 300-225
* * * * * * * * * * * * * * *
The web-page woke-up!

https://www.parts-express.com/70V-100W-High-Power-Line-Matching-Transformer-300-225?quantity=1

$24.00

That won't work.

 

[TLS Guy]

That won't work.

You are correct. It will not work. That type of system is not Hi-Fi quality. You certainly could not go through two transformers. 70 volt amps are all mono and again, voice and background music quality and not intended for a situation like his. He has the wrong speakers and there is NO fix for it, except different speakers.

 

[highfigh]

It needs to be off. The transformer is for use with 70 volt high impedance PA systems. These are mainly used in commercial large building applications.

The way you set those transformers in 70 volt systems, is that the total number of watts after adding the total of the settings must equal the power of the amplifier, then the impedance is correct for the amp. This allows different power to be applied to each speaker. For instance if one speaker is set to 10W it will receive twice the power of one set to 5W.

Actually, the power taps should be set to 80% of the amplifier's power, for headroom. Less strain on the amplifier, too.

 

[highfigh]

You are correct. It will not work. That type of system is not Hi-Fi quality. You certainly could not go through two transformers. 70 volt amps are all mono and again, voice and background music quality and not intended for a situation like his. He has the wrong speakers and there is NO fix for it, except different speakers.

An output transformer could be used, but it would be better to not use the transformers in the speakers with a receiver.

I didn't know Tannoy made anything like this, but now that they're owned by Behringer, I guess anything is possible.

 

[TLS Guy]

Actually, the power taps should be set to 80% of the amplifier's power, for headroom. Less strain on the amplifier, too.

I agree, it is a good idea to derate it a bit, but it is not required.

 

[Speedskater]

That won't work.

Sure it will work.
We are talking about: four CVS 6 ceiling speakers that will be the front elevation and rear surround speakers.
The transformers are more than adequate for those speakers and the intended use.

 

[highfigh]

Sure it will work.
We are talking about: four CVS 6 ceiling speakers that will be the front elevation and rear surround speakers.
The transformers are more than adequate for those speakers and the intended use.

Since the speakers have a position for bypassing the internal transformers, they should be set that way- there's no reason to add another one to the mix when it's not a constant voltage system and the speaker wire runs aren't extremely long.

 

[TLS Guy]

Sure it will work.
We are talking about: four CVS 6 ceiling speakers that will be the front elevation and rear surround speakers.
The transformers are more than adequate for those speakers and the intended use.

So you will have four inductors ahead of each speaker, and then the induction of of the VC. So five inductors in each speaker circuit. To me that sounds like a real witched brew and a blown receiver. There will be a significant quality loss. If he does do it, then he had better get a woofer tester and measure the impedance of the circuit and phase angles before turning it on. The chance of disaster with your plan sounds high to me.

 

[TLS Guy]

Since the speakers have a position for bypassing the internal transformers, they should be set that way- there's no reason to add another one to the mix when it's not a constant voltage system and the speaker wire runs aren't extremely long.

If you read the instructions, they actually don't really. If you set it at off, then its off, no sound. The low impedance is as low as it gets, but his volume is low. They do not spec the impedance of the VC of these speakers, but you can be sure it is high by the OP's experience. He needs the 6 ohm version.

 

[highfigh]

If you read the instructions, they actually don't really. If you set it at off, then its off, no sound. The low impedance is as low as it gets, but his volume is low. They do not spec the impedance of the VC of these speakers, but you can be sure it is high by the OP's experience. He needs the 6 ohm version.

Since these are in-ceiling speakers, what possible reason could they use for shutting the speaker off, at the speaker? Not only would someone need to climb a ladder or use a lift, they would need to remove the grill in order to access the settings -it would make no sense to shut off the speaker(s) in that way when it can often be done at the amplifier if they were set up in groups for each area.

It's hard enough to find people who want to climb a ladder- try to find someone who wants to go up in a lift on a regular basis.

It's hard enough to find people who

Show me where, in the instructions, it shows anything about the OFF position stopping the sound. I have installed hundreds of speakers for constant voltage systems and when they have a dial like this, the OFF position always bypassed the transformer. They're made for 100V, 70V and low impedance applications and the stated nominal impedance in the latter is 6 Ohms.

The instructions show:

"Close the wiring cover and tighten both screws on the cable clamp. Use the rotary switch located on the front of the unit to select whether you wish to use the speaker in a low-impedance or distributed-line application. THE SPEAKER IS SUPPLIED IN LOW IMPEDANCE MODE. NEVER CONNECT THE SPEAKER TO A 70/100 VOLT AMPLIFIER WHILE IT IS SET FOR LOW IMPEDANCE.", but nothing about the sound stopping in the OFF position.

https://mediadl.musictribe.com/media/PLM/data/docs/P0BSJ/CVS-8_CVS-6_CVS-4_CVS-4-MICRO_QSG_EN.pdf

 

[TLS Guy]

Since these are in-ceiling speakers, what possible reason could they use for shutting the speaker off, at the speaker? Not only would someone need to climb a ladder or use a lift, they would need to remove the grill in order to access the settings -it would make no sense to shut off the speaker(s) in that way when it can often be done at the amplifier if they were set up in groups for each area.

It's hard enough to find people who want to climb a ladder- try to find someone who wants to go up in a lift on a regular basis.

It's hard enough to find people who

Show me where, in the instructions, it shows anything about the OFF position stopping the sound. I have installed hundreds of speakers for constant voltage systems and when they have a dial like this, the OFF position always bypassed the transformer. They're made for 100V, 70V and low impedance applications and the stated nominal impedance in the latter is 6 Ohms.

The instructions show:

"Close the wiring cover and tighten both screws on the cable clamp. Use the rotary switch located on the front of the unit to select whether you wish to use the speaker in a low-impedance or distributed-line application. THE SPEAKER IS SUPPLIED IN LOW IMPEDANCE MODE. NEVER CONNECT THE SPEAKER TO A 70/100 VOLT AMPLIFIER WHILE IT IS SET FOR LOW IMPEDANCE.", but nothing about the sound stopping in the OFF position.

https://mediadl.musictribe.com/media/PLM/data/docs/P0BSJ/CVS-8_CVS-6_CVS-4_CVS-4-MICRO_QSG_EN.pdf

What you say is true. However the OP has found that OFF in this case means OFF, and he gets no sound from the speaker at all!

 

[highfigh]

What you say is true. However the OP has found that OFF in this case means OFF, and he gets no sound from the speaker at all!

I have to wonder if he's using the correct terminals- the Phoenix connector has four terminals- two for input, two for passing the signal to the next speaker(s). If the wrong ones are used, I would bet that it disconnects the speaker from the input.