Volume attenuator question - Monitor Controller DIY

[jho-audio]

Any reason why you couldnt just use a switched attenuator to set the dim levels? -30dB in 6dB steps or something like that.

 

[Viitalahde]

I wouldn't use the two 1k resistors for the mono. Too high an output Z. Mine's just tied together after the attenuator. Yes, if you listen at the loudest , you'll have a short. Don't do that! :razz: At normal levels, you have enough resistance before the mono switch..

 

[Black Dog]

[quote author="Viitalahde"]I wouldn't use the two 1k resistors for the mono. Too high an output Z. [/quote]

I tried it both ways, but couldn't hear a difference when feeding the Hypex UCD modules thats driving my Dynaudio BM-15's.

:guinness:

Lars

 

[Purusha]

The 1k connection would require more contacts on a switch or relay ...

Are you saying that double relay is needed for each unbalanced channel to
completely put out the 10K and 1K from the circuit. Am I correct?

I wouldn't use the two 1k resistors for the mono.

Personally I am going to go with active version of the mono sum as
suggested by NYD. Has anyone tried this yet?

 

[Purusha]

Another puzzle, I was thinking to use a RelVol1C audio attenuator.

Now if i got things right, the RelVol1C can be implemented into my unbalanced MC design as stereo volume attenuator.

The only thing I don't understand yet is the part about the impedance values. Standard values are
1k, 5k, 10k, 20k, 50k and 100k but I don't know which one suits my purpose. I need some help with this.

Basically I need the MC to choose the input signal coming from my mixing desk, additional stereo
audio converters and optional third source like CD player. The signal will then be controlled through the MC
toward 3 different pairs of monitors. In the middle there will be mono, dim and attenuation options and that is it.

 

[valvehead]

[quote author="Purusha"]

The 1k connection would require more contacts on a switch or relay ...

Are you saying that double relay is needed for each unbalanced channel to
completely put out the 10K and 1K from the circuit. Am I correct?

[/quote]

Without the 1k you only need one spst per channel to short out the 10k's. With the 1k you need one spdt per channel. There is only a small difference in cost for extra contacts and resistors. Due to lower impedance with the 1k resistors, the benefits are lower noise and less interaction with the load (HF rolloff).

 

[Purusha]

OK, thanks for the info. I already changed my DIM layout to a dual relay per
channel so both rersistors are out when not using it. :thumb:

 

[tim-burns]

sowter do a few attenuating transformers. a friend of mine did a monitor controller with a couple of those. not cheap but much better than lots of resistors according to him. better top end at lower levels was one thing he mentioned.
t

 

[Purusha]

Thanks for the tip :thumb:

But I already bought the RelVol1C boards for my balanced version.

 

[tim-burns]

cool!
let us know how it goes! love your boxes by the way... will score some soon....
t

 

[Purusha]

I need to get confirmation for the idea...

I will use this active mono summer from NYD for my balanced monitor
controller (I changed my mind so I will make it balanced)

I guess I need to double this circuit for the balanced version?
One for the positive L & R signal and second for the negative L & R, right?

 

[laitue5]

Right.