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MiniDSP 4x10HD Modification Assistance


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Hi team,

 

I have built a pair of LXMini's and added a B&G neo 3 planar tweeter + I'm running a Rel T7i sub.

The speakers are being driven by an Elektra Theatre 6 channel amp.

I have a MiniDSP 4x10HD unit that's doing the crossover work and processing. I would like to modify this unit for better sound. 

 

I have been given some instructions from an experienced user in France - only problem is, I do not possess the required electronic knowledge and soldering skills etc.

As a start, I would like to bypass the input and output caps.

 

You can see his recommendations here: https://mapoulin.wixsite.com/audiobymartin/minidsp-4x10hd-impression

and here is his actual work with images: https://mapoulin.wixsite.com/audiobymartin/audio-upgrade

 

I would be highly appreciative (and happy to compensate) if someone would be kind enough to assist me with some of these modifications.

I am based in Sydney and happy to travel.

 

Please reach out to me if you, or someone you know would be able to assist.


Many thanks,
Aaron

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6 minutes ago, Peter the Greek said:

I can't help you, but gee, he's pretty scathing of the unit. I thought it had a better reputation than that....

You have to remember that it was built to a budget. I am ok with using it for the subs but would 1avoid putting the mains through it.

 

Had a similar experience with the Behringer DCX2496. Thought it was ok until I had the input and output stages upgraded..

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1 minute ago, Snoopy8 said:

You have to remember that it was built to a budget. I am ok with using it for the subs but would 1avoid putting the mains through it.

 

Had a similar experience with the Behringer DCX2496. Thought it was ok until I had the input and output stages upgraded..

Can I ask how you had your Behringer upgraded? Did you do it yourself or did someone assist you?

Any ideas where I might be able to find someone to help me?

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Guest Peter the Greek
1 minute ago, Snoopy8 said:

You have to remember that it was built to a budget. I am ok with using it for the subs but would 1avoid putting the mains through it.

 

I was thinking this some time ago, but didn't really have any evidence as to why.....what other options are there for active dsp/crossover? DEQX obviously....is there anything in between? price wise?

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2 hours ago, Allyouhaveisyoursoul said:

Can I ask how you had your Behringer upgraded? Did you do it yourself or did someone assist you?

Any ideas where I might be able to find someone to help me?

I am useless with a soldering iron.  A fellow SNA member in Melbourne did it for me, using a commercial kit which had detailed instructions.  You probably need to find someone in Sydney to help?

 

2 hours ago, Peter the Greek said:

I was thinking this some time ago, but didn't really have any evidence as to why.....what other options are there for active dsp/crossover? DEQX obviously....is there anything in between? price wise?

I used these Behringer Mods for my upgrade; previously they sold fully modified boxes but no longer.  There are other Behringer kits as well, but all are DIY.  There were 2 other European suppliers, based on upgraded Behringers a few years ago, but they may have gone out of business.

 

Other than the Deqx unit, the only other unit I would consider is the DSpeaker X4, available from DeepHz Audio. Maybe this based on Stereophile review?

https://www.oktoresearch.com/dac8pro.htm

I am sure that there are Pro audio DSP units, but I am not familiar with them.

 

Please note that I have no issues with miniDSP doing things in the digital domain; my concerns are about the cheap analog stages.

 

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1 hour ago, Snoopy8 said:

I am useless with a soldering iron.  A fellow SNA member in Melbourne did it for me, using a commercial kit which had detailed instructions.  You probably need to find someone in Sydney to help?

Yes I agree, that is the purpose of the post I put up here.

How did you find the person through SNA?

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9 minutes ago, Allyouhaveisyoursoul said:

Yes I agree, that is the purpose of the post I put up here.

How did you find the person through SNA?

It was someone I knew already and we agreed to trade his soldering time for my computer skills.

 

Maybe put a WTB with an agreed hourly rate and minimum payment? Yes, it may not be economic to modify the unit... 

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Guest Peter the Greek
2 hours ago, Snoopy8 said:

 

Please note that I have no issues with miniDSP doing things in the digital domain; my concerns are about the cheap analog stages.

 

 

Pardon my ignorance, if you could please clarify for me. My need is as active crossover and dsp. So I believe the only way to do this is to take an analogue output from a pre amp, into the minidsp, it does its thing (presumably a to d, then d to a) and sends analogue output to an amp.

 

Is that correct?

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29 minutes ago, Peter the Greek said:

 

Pardon my ignorance, if you could please clarify for me. My need is as active crossover and dsp. So I believe the only way to do this is to take an analogue output from a pre amp, into the minidsp, it does its thing (presumably a to d, then d to a) and sends analogue output to an amp.

 

Is that correct?

That is how many people are using the miniDSP HD. But not many people realise that the analog input and output stages are not that good (as per that modder's post). Ignorance is bliss!

 

I was just as ignorant, using my unmodded DCX2496 to feed my SGR active speakers and dual subs.  But the mod kit opened my eyes and ears; there was a significant improvement after the upgrade.

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54 minutes ago, Peter the Greek said:

 

Pardon my ignorance, if you could please clarify for me. My need is as active crossover and dsp. So I believe the only way to do this is to take an analogue output from a pre amp, into the minidsp, it does its thing (presumably a to d, then d to a) and sends analogue output to an amp.

 

Is that correct?

It depends on your source. If you have digital only you can avoid the first AD conversion and send digital direct. 
 

something like the miniDSP SHD will do active crossover and DSP

and volume control and be much cheaper than a DEQX

Edited by sir sanders zingmore
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1 hour ago, Peter the Greek said:

 

Pardon my ignorance, if you could please clarify for me. My need is as active crossover and dsp. So I believe the only way to do this is to take an analogue output from a pre amp, into the minidsp, it does its thing (presumably a to d, then d to a) and sends analogue output to an amp.

 

Is that correct?

 

 

Basically, yes - that's the first setup I had:

  • preamp (analogue) output into my miniDSP 10x10HD
  • XOs and room EQ in the miniDSP, and
  • 8x analogue output channels into my amplifiers (subs/bass panels/mid panels/ribbons).

 

But now, my setup is:

  • A2D converter on my phono stage
  • digital source selector (other inputs are digital - CDP, DAB+ tuner and Foxtel box)
  • digital input into miniDSP nanoDIGI 2x8
  • XOs and room EQ in the miniDSP
  • 4x Topping E30 DACs, and
  • 8x analogue output channels into my amplifiers.

So now I have:

  • a higher-spec A2D conversion on my vinyl than I had with the 10x10HD
  • no conversion on the 3 digital inputs, and
  • a higher-spec D2A conversion for my 8 amplifier channels.

 

Andy

 

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Guest Peter the Greek
29 minutes ago, andyr said:

 

Basically, yes - that's the first setup I had:

  • preamp (analogue) output into my miniDSP 10x10HD
  • XOs and room EQ in the miniDSP, and
  • 8x analogue output channels into my amplifiers (subs/bass panels/mid panels/ribbons).

 

But now, my setup is:

  • A2D converter on my phono stage
  • digital source selector (other inputs are digital - CDP, DAB+ tuner and Foxtel box)
  • digital input into miniDSP nanoDIGI 2x8
  • XOs and room EQ in the miniDSP
  • 4x Topping E30 DACs, and
  • 8x analogue output channels into my amplifiers.

So now I have:

  • a higher-spec A2D conversion on my vinyl than I had with the 10x10HD
  • no conversion on the 3 digital inputs, and
  • a higher-spec D2A conversion for my 8 amplifier channels.

 

Andy

 

 

Andy, this seems a good solution. A heap of boxes and cables mind you. Something to think about, thanks!

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11 hours ago, Peter the Greek said:

 

Andy, this seems a good solution. A heap of boxes and cables mind you. Something to think about, thanks!

 

I would not recommend a variable analogue input into the miniDSP (or anything with a similar SNR/distortion performance), unless you are extremely careful about the gain structure of the system 

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45 minutes ago, davewantsmoore said:

 

I would not recommend a variable analogue input into the miniDSP (or anything with a similar SNR/distortion performance), unless you are extremely careful about the gain structure of the system 

 

 

Can you explain what you are getting at with that comment, Dave - coz it's certainly eluded me?

 

If you use the analogue inputs on a miniDSP - then by definition, you have "variable analogue input " ... as the music contains loud and soft passages.

 

Alternatively, if you use the digital input - the signal coming in (ie. the output from an A2D converter) ... will also vary in level, as the music going into the ADC contains loud and soft passages?

 

Andy

 

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2 hours ago, andyr said:

 

Can you explain what you are getting at with that comment, Dave - coz it's certainly eluded me?

 

If you use the analogue inputs on a miniDSP - then by definition, you have "variable analogue input " ... as the music contains loud and soft passages.

 

Alternatively, if you use the digital input - the signal coming in (ie. the output from an A2D converter) ... will also vary in level, as the music going into the ADC contains loud and soft passages?

 

Andy

 

 

I think he means you should avoid controlling the volume on the analog in side of the miniDSP

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4 minutes ago, sir sanders zingmore said:

 

I think he means you should avoid controlling the volume on the analog in side of the miniDSP

 

 

You might well be right, Trev - but even if you don't touch the volume control ... the signal still various in level.

 

Andy

 

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6 minutes ago, andyr said:

 

You might well be right, Trev - but even if you don't touch the volume control ... the signal still various in level.

 

Andy

 

 

I think you are missing the point.

But it wasn't my point so I'll stay out of it

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Watching on with much interest, please keep posting as to how the miniDSP is modded to make it sound better.

 

Personally operate a similar "rig" as in a highly sensitive high output horn/bass reflex 5 way and the single best improvement to overall SNR, SQ and dynamic range was to eliminate analogue input completely (get rid of the TT :) ) and operate it with an isolated digital input . Beyond that running gains on all channels at below 0dB in the minuses eliminates the tiny amount of hiss the DSP can generate if the channels are driven in positive dB., this includes the main attenuation.

I looked at onboard mods to the 2 x 8 by way of replacing the garden variety operational amplifiers and upgrading the power supply on board. Decided in the end though that it wasn't really worth it for the probable 1% improvement if any over the standard device.  That option remains open although there are many ways to skin the proverbial cat to make incremental gains , room acoustics is one example.

The miniDSP is a superb device for what it is price wise amazing actually, but,  there is a need to operate it  within it's own limitations for best application to task, in your case an  "Audiophile Grade"  component.

A suggestion, before any modification to the miniDSP takes place "impulse time correction" could be employed into the digital line and explored. That was a bit of a light globe on  my rig moment although it is a fairly full on procedure and the device (DIRAC Room Correction) employed quite expensive.. Good though, better center image, clean and tighter bass was the best of the addition.

 

Good luck enjoy the media.

 

12.jpg

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On 23/01/2021 at 9:39 AM, Dirkgerman said:

Watching on with much interest, please keep posting as to how the miniDSP is modded to make it sound better.

 

Personally operate a similar "rig" as in a highly sensitive high output horn/bass reflex 5 way and the single best improvement to overall SNR, SQ and dynamic range was to eliminate analogue input completely (get rid of the TT :) ) and operate it with an isolated digital input . Beyond that running gains on all channels at below 0dB in the minuses eliminates the tiny amount of hiss the DSP can generate if the channels are driven in positive dB., this includes the main attenuation.

I looked at onboard mods to the 2 x 8 by way of replacing the garden variety operational amplifiers and upgrading the power supply on board. Decided in the end though that it wasn't really worth it for the probable 1% improvement if any over the standard device.  That option remains open although there are many ways to skin the proverbial cat to make incremental gains , room acoustics is one example.

The miniDSP is a superb device for what it is price wise amazing actually, but,  there is a need to operate it  within it's own limitations for best application to task, in your case an  "Audiophile Grade"  component.

A suggestion, before any modification to the miniDSP takes place "impulse time correction" could be employed into the digital line and explored. That was a bit of a light globe on  my rig moment although it is a fairly full on procedure and the device (DIRAC Room Correction) employed quite expensive.. Good though, better center image, clean and tighter bass was the best of the addition.

 

Good luck enjoy the media.

 

12.jpg

Hi @Dirkgerman,

Thanks for your feedback and notes regarding your experience.

I would love to eliminate the analogue input stage and bypass.

Also as per instructions "Out of four capacitive coupling capacitors stages per channel, two can safely be removed by shorting the pin and allow a direct signal to pass. This restores much of the dynamics, reduces coloration and renders a more accurate sound."

Do you know anyone who might be able to assist with these mods?

Thanks in advance!

Aaron

 

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Hi Aaron, someone who is good with surface mounting, mmmm, why not try a phone repair shop with micro soldering station. I would imagine if you had the parts and directions as per those (rather yucky looking as shown) modifications via the link posted earlier and the dude with the iron has some knowledge, you might just go ok. 

Keep us posted :)  cheers.

 

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  • 1 year later...

I just finished building the LXmini+2 running on a MiniDSP 4X10HD and these sound fantastic.

 

I am interested in these mods and will open the MiniDSP and and look into removing the caps on the analog outputs. I'll check DC offset and if it's not too high remove the caps.

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Update - No measurable turn on thump. The electro coupling caps have no DC bias, BAD, so removed them and installed wire jumpers.  I left the electro's between the analog input buffer and internal DAC. I may swap these electro's out for MKP's at a later date.

 

Next update is to look into bypassing the internal output DAC's. The plan is to take the I2S output into 4x I2S to SPDIF converters to enable the use of external DAC's.

 

For anyone wondering about the performance of the 4x10HD it is tested here

 

https://neurochrome.com/pages/minidsp-4x10hd

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I have been modifying a 10X10 HD and removed all the coupling caps and have been experimenting with the board mounted SMD caps, I have also swapped out the Nichicon KW caps on the board around the Opamps for Panasonic FM's. As there is a lot of digital stuff in close proximity I have used EMI/FRI absorber an added heat sinks with thermal tape too

 

Im letting it fully run in then I might experiment with alternative caps in a few places as I am only interested in bass as its used to control 4 subs

 

 

12F1A00A-70CC-4E07-B637-5C1E53FE9C10.jpeg

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