miniDSP Flex

[antcollinet]

By going from balanced to unbalanced with Flex, one looses something like 15 dB of SINAD.

No, that is only on the analogue input going from unbalanced to balanced. Even than you are dropping from around a SINAD of 105 to a SINAD of 90. Not a problem for most analogue sources. Or any source come to that.

Flex Balanced connectivity: Which TRS to RCA cable should I use?

The Flex balanced is balanced in/out. If you'd like to use an unbalanced amplifier (e.g. Powered subwoofer) downstream of the Flex series, here is the recommended TRS to RCA cable to minimize detrimental effect on the audio quality. Note how...

support.minidsp.com

EDIT : Ahhhggg - what they ^ all said.

 

[antcollinet]

What's the point using low noise components if they're about to degrade so much?

But degrading from very very inaudible to just very inaudible. And this on a LFE channel. I don't think this is going to be an issue.

 

[Sokel]

But degrading from very very inaudible to just very inaudible. And this on a LFE channel. I don't think this is going to be an issue.

As long as the device is safe and no noise heard,agree 100%.
It's the company's warning that worries me.

 

[antcollinet]

As long as the device is safe and no noise heard,agree 100%.
It's the company's warning that worries me.

It is an odd way of putting it for sure.

I've always taken it as a sign of the importance of good measurements ASR is managing to drive into the industry. Companies bought into it like MiniDSP don't want their reputation for good measurements tarnished, so are making the warning of degraded performance very prominent.

I can't see any mechanism whatsoever that would result in any sort of "safety**" issue. Certainly what they are warning of (a 15dB loss of SINAD) has absolutely zero safety implications. I've been using unbalanced to balanced on the input to my flex since day 1 (for turntable) and have seen no problems, audible or otherwise.

(** I assume by safe, you are meaning safe for the equipment - obviously there are not going to be any personal safety issues here)

 

[Igordit]

Thanks all for answers. Antcollinet, as I understood you use recommended cable by developer for inputs and outputs of your flex balanced and its safe. What about quality of minidsp cables? I have master who can do hi quality cables for the same price.

 

[antcollinet]

Thanks all for answers. Antcollinet, as I understood you use recommended cable by developer for inputs and outputs of your flex balanced and its safe. What about quality of minidsp cables? I have master who can do hi quality cables for the same price.

For the input I use standard RCA to TS (no ring) cables. This is fine, since on the input connecting the cold terminal to sleeve (ground) is not only safe, it is needed. The cable suggested by MiniDSP should not be used on the input, since it leaves the cold terminal floating and able to pick up noise.

On the output I've made up my own cables, by cutting the RCA off the end of a standard interconnect and soldering on a TRS in place. This means I don't follow the exact wiring suggested by MiniDSP (in mine, the shield is connected at both ends and is used for the analogue return). It works fine. MiniDSPs reccomendation would give some better immunity to ground loops - but I seem not to suffer from that in my current installation.

Regarding source of cables - go with whatever is most convenient.

 

[Sokel]

(** I assume by safe, you are meaning safe for the equipment - obviously there are not going to be any personal safety issues here)

If it was about personal safety (apart that if something expose the full output and blow ears) it would be a different conversation

 

[antcollinet]

If it was about personal safety (apart that if something expose the full output and blow ears) it would be a different conversation

In my just posted reply to @Igordit I've just noticed something. In the warning they state:

We've noticed a performance drop (15dB SINAD drop) when using such adaptor for INPUTS of the FLEX

The adapter they are talking about is the one they've specified for outputs - but it leaves the cold terminal unconnected and uses a signal wire for the ground return. I wonder if that could be a source of the loss of SINAD when using it for an input.

Two problems - the low impedance shield is not used for the analogue return - which means the impact of a ground loop is worsened, and secondly the cold input terminal is left floating and able to pick up any interference.


I have a feeling they've just used a poor method of connection for the RCA to balanced conversion. Certainly using a thin signal wire for ground rather than shield on an unbalanced connection is really bad.

 

[Sokel]

In my just posted reply to @Igordit I've just noticed something. In the warning they state:



The adapter they are talking about is the one they've specified for outputs - but it leaves the cold terminal unconnected. I wonder if that could be a source of the loss of SINAD when using it for an input.

Two problems - the low impedance shield is not used for the analogue return - which means the impact of a ground loop is worsened, and secondly the cold input terminal is left floating and able to pick up any interference.

That would be nice to know when I measured it (and returned it) but I guess makes sense to think about it this way.

 

[Igordit]

Is my amplifier can be volume master when it connect from flex trs outputs to fixed balanced inputs? Because when I connect my receiver to amplifier using fixed rca inputs, I can control volume of receiver from amplifier - like back connection.

 

[radix]

Is my amplifier can be volume master when it connect from flex trs outputs to fixed balanced inputs? Because when I connect my receiver to amplifier using fixed rca inputs, I can control volume of receiver from amplifier - like back connection.

If the Helel volume control is applied AFTER the digital out loop, then this will not work with the subs coming off the Flex. They would see full volume. You would have to use the Flex volume control. If the Hegel volume is applied BEFROE the digital out loop, then this would work with the subs.

If the volume is AFTER the digital out loop, you would need to put the subs on the VARIABLE OUT from the Hegel. The Flex would still equalize them, but it would not be able to independently do time correction or cross over the mains and sub.

 

[Igordit]

But now I use hegel like front amplifier in my 5.1 HT. And when I control volume from hegel, my receiver marantz 1609 also change volume in center and back speakers including sub. I can see in it in receiver screen. It’s synchronise through rca, like back connection.

 

[radix]

But now I use hegel like front amplifier in my 5.1 HT. And when I control volume from hegel, my receiver marantz 1609 also change volume in center and back speakers including sub. I can see in it in receiver screen. It’s synchronise through rca, like back connection.

How are you changing the volume on the Hegel?

My understanding of your setup is you have the 1609 using internal maps for center and rear and use RCA out from 1609 to Hegel Analog (1 or 2). I do not know of any mechanism for the Hegel to affect the volume of the 1609, unless there's something going on with the remote.

 

[Igordit]

It works from remote and manual. In Hegel I change setup for rca input to fixed. I ask this question about volume because I use Apple Music on IPad-Hegel and it is very comfortable control all from tablet without any additional remote. It is easy check if you have Flex in Your system, but in any case I buy it . It is important for me - it depends the location of Flex and length of cables.

 

[Igordit]

I find super video about cables for Flex!

 

[gilency]

How do you connect the Flex digital to a DAC?
If connected to a DAC like ADI2 which DAC is active? Flex or ADI2?
Would it be better to use the Flex by itself without the ADI2 (which I already have)
And I guess the digital Flex has no sub output?

 

[holbob]

The Flex Digital has digital outputs. 2 for 2 channels each. What you then choose to connect to these channels from the downstream dac(s) is up to you. If you have subs, you would need the dacs to be at full volume and control volume from the flex digital.

 

[gilency]

So the digital out from the Flex goes out to the ADI2 digital input which then connects to the amplifier.
Which one is active? Am I double DACing?
Can something like this be connected from one of the Flex digital out to go to a sub?
Sorry for so many questions

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[antcollinet]

So the digital out from the Flex goes out to the ADI2 digital input which then connects to the amplifier.
Which one is active? Am I double DACing?
Can something like this be connected from one of the Flex digital out to go to a sub?
Sorry for so many questions

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The flex digital doesn't have a DAC in it. A DAC is Digital to ANALOGUE converter. If you are not getting an analogue signal out, then you are not using a DAC.

Because it only outputs digital it doesn't need a DAC.

And just like you have 4 outputs on the analogue flex, you have four outputs on the digital. 2 on each of the digital outputs. (Coax/Optical carry the same 4 channels)

So one Toslink 1 into your ADI2 gives you your left right channel, and Toslink 2 into another DAC gives you the other two outputs. For Sub or headphone amp or whatever.

And yes - one of those cheap Dacs can be used - but you've no idea what quality you are going to get from it.

 

[gilency]

Thank You. So the digital Flex sounds interesting after all. I had thought about the balanced one and selling the ADI2.