miniDSP kits, our answers to your technical questions - Page 33 - diyAudio
Go Back   Home > Forums > Commercial Sector > Manufacturers > miniDSP

miniDSP Low cost, modular Digital Signal Processor (DSP) kits for the DIYer from miniDSP.

Reply
 
Thread Tools Search this Thread
Old 5th June 2011, 01:49 PM   #321
diyAudio Member
 
Join Date: Apr 2010
Location: In an old house on a hill needing repair looking over an old cemertry.
Default shielding will get you closer to god.

Quote:
Originally Posted by DQ828 View Post
I'm working on a Power Board with filtering.

There are plenty of people who don't have my problem, I'm not sure if its the configuration I am using. I'll build the filter & then see how I go.
Try some ferrite's on you twisted pair power supply cables and line in cables and if it helps you have got a hint of your problem. The large ones that samwhich over ac leads. If you want trick filtered ac leads get thick ac home twin and earth. Strip it and weave it macramé style. Works great. Straight out of Allen wrights cable cook book . God rest his soul.

Want to try somthing trick on ac input sheilding. I cant stress how important sheilding and rf filtering is with digital.

http://www.dhtrob.com/schemas/afbeeldingen/Cinch.gif This is somthing I am about to try.
  Reply With Quote
Old 5th June 2011, 11:20 PM   #322
DQ828 is offline DQ828  Australia
diyAudio Member
 
DQ828's Avatar
 
Join Date: Mar 2010
Location: Lake Macquarie, East Coast Australia
Quote:
Originally Posted by fatbattery View Post
Try some ferrite's on you twisted pair power supply cables and line in cables and if it helps you have got a hint of your problem. The large ones that samwhich over ac leads. If you want trick filtered ac leads get thick ac home twin and earth. Strip it and weave it macramé style. Works great. Straight out of Allen wrights cable cook book . God rest his soul.

Want to try somthing trick on ac input sheilding. I cant stress how important sheilding and rf filtering is with digital.

http://www.dhtrob.com/schemas/afbeeldingen/Cinch.gif This is somthing I am about to try.
I'm making one of these http://lampizator.eu/AC%20FILTER/SILK/FILTER.HTML
  Reply With Quote
Old 6th June 2011, 08:53 AM   #323
diyAudio Member
 
Join Date: May 2009
It might be worth running minidsp off a 12 V battery just to see if mains born interference is a problem (before going to the trouble of building a filter - no doubt that design is very effective).

I thought i had nose issues with miniDSP balanced. Ran it off a 12V car battery yesterday (in the house). No change to noise. However connecting up a rather expensive pre-amp for comparison i'd have to say miniDSP sounded essentially the same in terms of noise, so not that bad. The noise needs about 15 dB of attenuation before it is acceptable via a power amp with 38x voltage gain into 101dB ribbon tweeter.

I have managed to get rid of a high pitched squeal (very very quiet), not sure how.
  Reply With Quote
Old 6th June 2011, 09:50 AM   #324
DQ828 is offline DQ828  Australia
diyAudio Member
 
DQ828's Avatar
 
Join Date: Mar 2010
Location: Lake Macquarie, East Coast Australia
Quote:
Originally Posted by mrwireless View Post
It might be worth running minidsp off a 12 V battery just to see if mains born interference is a problem (before going to the trouble of building a filter - no doubt that design is very effective).

I thought i had nose issues with miniDSP balanced. Ran it off a 12V car battery yesterday (in the house). No change to noise. However connecting up a rather expensive pre-amp for comparison i'd have to say miniDSP sounded essentially the same in terms of noise, so not that bad. The noise needs about 15 dB of attenuation before it is acceptable via a power amp with 38x voltage gain into 101dB ribbon tweeter.

I have managed to get rid of a high pitched squeal (very very quiet), not sure how.
I like the 12V battery idea, will give that a go. I already have all the parts for the filter so will build it anyway

That 15db attenuation is on the DSP outputs I assume
  Reply With Quote
Old 1st August 2011, 08:39 PM   #325
diyAudio Member
 
Join Date: Jun 2011
Can someone tell me if EXACTLY the miniDSP Balanced Kit US$125 is in the miniDSP Balanced 2x4 US$145 ? Because the docs are different (e.a. no volume pot, no I2S on the second one) . I think this is only because of the enclosure, but if the pins are in there i can drill a hole for the volume pot.

For the project i want to build (digital amplifier with miniDSP in the same enclosure) it is maybe better to use the second miniDSP with a closed aluminium enclosure to avoid EMC troubles ?
  Reply With Quote
Old 1st August 2011, 09:00 PM   #326
doug20 is offline doug20  United States
diyAudio Member
 
Join Date: Mar 2009
Quote:
Originally Posted by mrwireless View Post
It might be worth running minidsp off a 12 V battery just to see if mains born interference is a problem (before going to the trouble of building a filter - no doubt that design is very effective).

I thought i had nose issues with miniDSP balanced. Ran it off a 12V car battery yesterday (in the house). No change to noise. However connecting up a rather expensive pre-amp for comparison i'd have to say miniDSP sounded essentially the same in terms of noise, so not that bad. The noise needs about 15 dB of attenuation before it is acceptable via a power amp with 38x voltage gain into 101dB ribbon tweeter.

I have managed to get rid of a high pitched squeal (very very quiet), not sure how.
FWIW, I ran a little measurement test with my TAD TD-4001s. I use a ATI 602 amp, its the best comercial amp I have found wrt to SNR and it has gain control on the back.

Ignore the dB Scale, I never calibarted the exact voltage levels in ARTA (think of 120dB on it as really 90dB). The MiniDSP does not really effect the signal chain that much. The DCX definitely increases the output by around +6dB and also increases distortion levels.





TAD + ATI 602
TAD_NO_DSP.gif

TAD + MINIdsp (unbalanced) + AT 602
TAD_minidsp.gif

and for reference of with the popular DCX
TAD + DCX + AT 602
TAD_DCX.gif

Last edited by doug20; 1st August 2011 at 09:13 PM.
  Reply With Quote
Old 2nd August 2011, 09:02 AM   #327
minidsp is offline minidsp  Hong Kong
diyAudio Member
 
minidsp's Avatar
 
Join Date: Dec 2009
@ katarakt

The miniDSP balanced 2x4 in a box is indeed the exact same board as the miniDSP balanced kit. It's just in a box. :-)

So providing you drill the front panel, I guess that you could indeed upgrade it to a version with a volume pot with ease.

Hope this helps.

DevTeam
__________________
www.minidsp.com - Low cost & modular audio DSP kits for DIYers - Follow our tweets @ minidsp
  Reply With Quote
Old 2nd August 2011, 09:35 AM   #328
minidsp is offline minidsp  Hong Kong
diyAudio Member
 
minidsp's Avatar
 
Join Date: Dec 2009
@Doug20,

Thanks for sharing these measurements. Always good data to see things side by side...

DevTeam
__________________
www.minidsp.com - Low cost & modular audio DSP kits for DIYers - Follow our tweets @ minidsp
  Reply With Quote
Old 3rd August 2011, 02:29 PM   #329
doug20 is offline doug20  United States
diyAudio Member
 
Join Date: Mar 2009
np, I have always been curious about the differences between the DCX and MiniDSP. I have always had gain issues and an excessive amount of hiss when using the DCX and 110dB CDs. The miniDSP made definitely more manageable.

Now can you please "somehow" add linear phase filters !!! Im about to spend $2K on the DEQX but before I do that I want to give you a chance to have more of my $$$
  Reply With Quote
Old 3rd August 2011, 02:54 PM   #330
diyAudio Member
 
otto88's Avatar
 
Join Date: Dec 2007
linear phase filters would be a plus for me too
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Utter novice looking for answers to easy questions: shnaggletooth Tubes / Valves 24 23rd August 2009 10:10 AM
simple questions, can't find the answers pjaneiro Multi-Way 14 8th August 2007 11:28 AM
#halojoy - Answers DIY audio questions In Person halojoy Everything Else 1 10th August 2003 02:52 PM


New To Site? Need Help?

All times are GMT. The time now is 04:50 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2