Minidsp Flex Review (Audio DSP)

[BenjaminB]

So as per SOLEN.CA, i CC'D them on all emails with MINIDSP support. So they are aware of whats happening.......but now that i remember they were supposed to call me back on Friday but that came and went.

Yes i arrived at the same thought. Please exchange my unit with another one. I will call them on Monday.

Thanks for your help

Hi Monty,

I have suggestions:
1) test with another USB cable. The one I got with my Flex was not working 100% which caused some confusion
2) connect the inputs to your miniDSP Flex and connect a PC/Mac via a USB cable to the miniDSP. select one input as eg the Wiim (coax) you have and start that one so it does have output to the coax connection. Power up your PC/Mac and start the miniDSP program.
a) does the pc/mac program recognize your MiniDSP Flex?
b) is the input levels visible on the miniDSP program display? these levels should go up and down with the input variation.
c) how is the output configured? Input channels 1 and 2 should each be connected to an output (1-4).

The miniDSP program is a bit confusing at first sight, it takes some time to adapt to how the miniDSP designers were thinking

 

[Th0805]

Choose Balanced inputs whenever you can, so in this case, the Flex Bal.

If you have ground loop noises with a store-bought RCA->TRS cable between Phono Pre and Flex, then this can be solved with a custom cable.

This makes your Phono Pre's single-ended RCA output impedance balanced, which comes with all the noise-cancelling and ground loop breaking attributes of a native TRS/XLR output:

Topping DX3 Pro+ Review (DAC & Headphone Amp)

Nice, have not seen that error thought but i dont play loud or have demanding headphones. Will wait until some ppl in this thread can confirm the update works without issue until i update. Well, I've updated and do not notice any difference. (Used windows 11, turned the DAC on and simply ran...

www.audiosciencereview.com

So interesting, I was getting ready to order the balanced model and saw this on MiniDSP website. So I guess I need the unbalanced version and get rca to xlr adaptor for the outputs

“WARNING: This adaptor(TRS to RCA) is ONLY to be used for the Flex OUTPUTS. We've noticed a performance drop (15dB SINAD drop) when using such adaptor for INPUTS of the FLEX. For that reason, we do not recommend customers to use an unbalanced to balanced cable on the "input" side of the Flex. If you want to have unbalanced in/out for both inputs and outputs, it's strongly recommended that you just use the miniDSP Flex unbalanced version. The miniDSP Flex was engineered with best performance in mind and it's therefore our intention to stay consistent on making sure best audio quality is kept for this platform!



Once again to clarify, there isn't any performance drop for OUTPUTS. i.e. TRS to RCA cable for an unbalanced amplifier or subwoofer if perfectly fine. This limitation is for INPUTS only. i.e. RCA source to TRS input of the Flex.”

 

[staticV3]

So interesting, I was getting ready to order the balanced model and saw this on MiniDSP website. So I guess I need the unbalanced version and get rca to xlr adaptor for the outputs

“WARNING: This adaptor(TRS to RCA) is ONLY to be used for the Flex OUTPUTS. We've noticed a performance drop (15dB SINAD drop) when using such adaptor for INPUTS of the FLEX. For that reason, we do not recommend customers to use an unbalanced to balanced cable on the "input" side of the Flex. If you want to have unbalanced in/out for both inputs and outputs, it's strongly recommended that you just use the miniDSP Flex unbalanced version. The miniDSP Flex was engineered with best performance in mind and it's therefore our intention to stay consistent on making sure best audio quality is kept for this platform!



Once again to clarify, there isn't any performance drop for OUTPUTS. i.e. TRS to RCA cable for an unbalanced amplifier or subwoofer if perfectly fine. This limitation is for INPUTS only. i.e. RCA source to TRS input of the Flex.”

It's possible that what miniDSP experienced was just the result of a poorly constructed, 2 conductor RCA->TRS cable where Cold was shorted to GND directly at the TRS plug. Like this basically:


For RCA->TRS/XLR, you specifically want a 3 conductor cable where Cold and GND only meet at the RCA GND:


miniDSP didn't provide details on the cable used afaik, so this remains speculation, but I'm fairly confident that with the right cable, no performance drop will occur.

I'd personally go with a Flex Bal, despite miniDSP's warning, but only because I can make my own cables and can measure the input's THD+N.

If you decide to go with the regular Flex, then the impedance-balanced RCA->XLR cable stuff applies to the Flex->Amp connection instead.

The disadvantage being that if you get a GND loop between Phone Pre and Flex using RCA->RCA, then you're kind of stuck with it.

 

[Joffy1780]

So interesting, I was getting ready to order the balanced model and saw this on MiniDSP website. So I guess I need the unbalanced version and get rca to xlr adaptor for the outputs

“WARNING: This adaptor(TRS to RCA) is ONLY to be used for the Flex OUTPUTS. We've noticed a performance drop (15dB SINAD drop) when using such adaptor for INPUTS of the FLEX. For that reason, we do not recommend customers to use an unbalanced to balanced cable on the "input" side of the Flex. If you want to have unbalanced in/out for both inputs and outputs, it's strongly recommended that you just use the miniDSP Flex unbalanced version. The miniDSP Flex was engineered with best performance in mind and it's therefore our intention to stay consistent on making sure best audio quality is kept for this platform!



Once again to clarify, there isn't any performance drop for OUTPUTS. i.e. TRS to RCA cable for an unbalanced amplifier or subwoofer if perfectly fine. This limitation is for INPUTS only. i.e. RCA source to TRS input of the Flex.”

This issue is for unbalanced RCA to TRS balanced inputs only, does not affect output.
Says so very clearly on Minidsp site.
Any balanced TRS to XLR cable will work fine for the outputs.

 

[Joffy1780]

So interesting, I was getting ready to order the balanced model and saw this on MiniDSP website. So I guess I need the unbalanced version and get rca to xlr adaptor for the outputs

“WARNING: This adaptor(TRS to RCA) is ONLY to be used for the Flex OUTPUTS. We've noticed a performance drop (15dB SINAD drop) when using such adaptor for INPUTS of the FLEX. For that reason, we do not recommend customers to use an unbalanced to balanced cable on the "input" side of the Flex. If you want to have unbalanced in/out for both inputs and outputs, it's strongly recommended that you just use the miniDSP Flex unbalanced version. The miniDSP Flex was engineered with best performance in mind and it's therefore our intention to stay consistent on making sure best audio quality is kept for this platform!



Once again to clarify, there isn't any performance drop for OUTPUTS. i.e. TRS to RCA cable for an unbalanced amplifier or subwoofer if perfectly fine. This limitation is for INPUTS only. i.e. RCA source to TRS input of the Flex.”

Pardon me, didn't read original post.

 

[Th0805]

It's possible that what miniDSP experienced was just the result of a poorly constructed, 2 conductor RCA->TRS cable where Cold was shorted to GND directly at the TRS plug. Like this basically:
View attachment 350951

For RCA->TRS/XLR, you specifically want a 3 conductor cable where Cold and GND only meet at the RCA GND:
View attachment 350950

miniDSP didn't provide details on the cable used afaik, so this remains speculation, but I'm fairly confident that with the right cable, no performance drop will occur.

I'd personally go with a Flex Bal, despite miniDSP's warning, but only because I can make my own cables and can measure the input's THD+N.

If you decide to go with the regular Flex, then the impedance-balanced RCA->XLR cable stuff applies to the Flex->Amp connection instead.

The disadvantage being that if you get a GND loop between Phone Pre and Flex using RCA->RCA, then you're kind of stuck with it.

They sell trs to xlr cables as part of their pail packages. I would assume that they would have tried all possible incarnations to make it work

 

[Th0805]

Pardon me, didn't read original post.

Right. So for someone like me to has a balanced in on my power amp coming from the flex outputs but an rca phono preamp our going into the flex inputs, I would assume this point that I need to buy the unbalanced version

 

[staticV3]

I would assume that they would have tried all possible incarnations to make it work

I would not.

 

[Th0805]

I would not.

So you think they they went to the trouble to note a measurable difference when using a certain configuration, and that their engineers knowing there’s more than one way to make said cable didn’t try it the other way?

 

[staticV3]

So you think they they went to the trouble to note a measurable difference when using a certain configuration, and that their engineers knowing there’s more than one way to make said cable didn’t try it the other way?

I think they bought an RCA->TRS cable/adapter online for validation, measured a performance drop, and reported on it accordingly.

If they went into greater detail, like testing different cable constructions, series resistors for impedance balancing, etc, then I would expect them to report on the matter accordingly, not just "we tried an RCA->TRS cable and found worse performance".

 

[Monty67]

So as per SOLEN.CA, i CC'D them on all emails with MINIDSP support. So they are aware of whats happening.......but now that i remember they were supposed to call me back on Friday but that came and went.

Yes i arrived at the same thought. Please exchange my unit with another one. I will call them on Monday.

Thanks for your help

So as un update i received an email last night (MONDAY) from SOLEN.CA. Asking that i send back the unit to SOLEN.CA. And they say "Upon receiving the unit, we will handle the return process with MINIDSP for warranty assessment".

So thats where things are at this moment.

 

[ekpln]

Hello everyone,

I have a Minidsp Flex unbalanced version. Can I use its analog input for measuring my other DACs' performances, can I make FFT or Jitter analysis?

Thanks,

 

[staticV3]

Hello everyone,

I have a Minidsp Flex unbalanced version. Can I use its analog input for measuring my other DACs' performances, can I make FFT or Jitter analysis?

Thanks,

Yes. Details are here: https://www.minidsp.com/applications/advanced-tools/analog-recording-with-minidsp-adc

 

[ekpln]

Yes. Details are here: https://www.minidsp.com/applications/advanced-tools/analog-recording-with-minidsp-adc

Thank you! Can you suggest a software for measurement, not recording?

 

[staticV3]

Thank you! Can you suggest a software for measurement, not recording?

Room EQ Wizard, or Multitone Analyzer.

 

[Cassadamius]

My current setup is laptop > USB to Topping DX3Pro+ > RCA split to Power Amp & Sub > Passive Speakers. I'm looking for sub integration, EQ, and Dirac. I was initially leaning toward the Flex, but I think I can get away with the DDRC-24 if I keep the DX3Pro (I need volume control). Would it be possible for me to just add the DDRC between the DAC and the power amp via RCA? Any issues with this setup?

 

[Joffy1780]

My current setup is laptop > USB to Topping DX3Pro+ > RCA split to Power Amp & Sub > Passive Speakers. I'm looking for sub integration, EQ, and Dirac. I was initially leaning toward the Flex, but I think I can get away with the DDRC-24 if I keep the DX3Pro (I need volume control). Would it be possible for me to just add the DDRC between the DAC and the power amp via RCA? Any issues with this setup?

You'd be introducing an analogue to digital conversion and another digital to analogue conversion that way.

 

[Cassadamius]

You'd be introducing an analogue to digital conversion and another digital to analogue conversion that way.

Where does the analogue to digital conversion happen?

 

[staticV3]

Where does the analogue to digital conversion happen?

Inside the DDRC-24, since it can only process digital audio.

If you want to keep the DX3Pro for volume control, then the DDRC-24 needs to first convert the DX3Pro's analog Line out back to digital, then apply EQ, then convert it to analog again.

 

[Cassadamius]

Inside the DDRC-24. It can process only digital audio.

If you want to keep the DX3Pro for volume control, then the DDRC-24 needs to first convert the DX3Pro's analog Line out back to digital, then apply EQ, then convert it to analog again.

I see, thank you. I was hoping to use the DX3 since a) I already own it, and b) it appears to be a better DAC than that in the MiniDSP. But either way, I'm going to have to use the DAC in the DDRC-24. So maybe my best bet is to just go for the Flex and ditch the DX3 in order to streamline the system.