Budget Active nearfeild monitor: Edifier R1200 - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 18th February 2009, 05:38 PM   #1
DcibeL is offline DcibeL  Canada
diyAudio Member
 
DcibeL's Avatar
 
Join Date: May 2003
Location: Saskatchewan
Default Budget Active nearfeild monitor: Edifier R1200

Hello,
I have purchased a cheap cheap active speaker system for only CAD$56, the Edifier R1200. It's intended use is as a nearfeild monitor for my computer. Let me tell you about the R1200:

-5/8" real MDF enclosure (not fibre board like most cheap speakers)
-very good build quality
-4" coated paper/fabric (not exactly sure) woofer with foam surround
-3/4" fabric dome tweeter with large surround roll
-crossover consists of an electrolytic cap across the tweeter
-two inputs, input A has some high freq EQ applied
-input stage is a single op-amp NE5532
-only controls are volume and bass
-amp is a TDA7269 and is powered by a +/- 12V transformer rated at 1.15A

Surprisingly, this cheap speaker system doesn't sound terrible, but doesn't exactly sound fantastic either. So what DIY modifications can be done to make this better? I would like this system to still act and behave as stock when modifications are complete, so...

First things first:
-add stuffing to the enclosure, and maybe cut a couple of dowels for braces
-modify the input circuit to remove the EQ on input A

I was thinking to replace the amp with a Tripath TA2024 amp. The transformer is really not suitable for this, so I was thinking of an external SMPS. This would also remove the mass displaced by the internal transformer. However, I still need a negative supply to power the op-amp for the input circuit. So I thought to use something simple like this.

These modifications should be fairly simple for me as I already have the TA2024 amp, and a 12V LCD monitor SMPS that has worked well with the Tripath amp for the past few years. I'll just build the -12V supply on perfboard and glue it to the inside of the cabinet.

The tricky part becomes what to do with the speakers? I could just replace them with something else, and design a proper crossover. I would like to go the cheapest route initially and improve the crossover, but unfortunately don't have the ability to measure frequency response. I can measure impedance however, so should be able to get a starting point by measuring impedance of the tweeter with no cap, and with cap to see just what is being done electrically...

Comments? Suggestions?

Thanks!
__________________
The power of Science compels you!
  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
The Box MA1220A Active Monitor Schematics needed alexclaire Solid State 1 6th February 2009 08:32 PM
Active studio monitor modifications argonrepublic Chip Amps 0 30th May 2005 10:59 PM
Pix of new diy 10" Active Booth Monitor... lunchmoney Multi-Way 12 21st April 2005 04:08 PM
Help me build an active monitor for dj'ing lunchmoney Multi-Way 14 6th April 2005 01:50 AM
Loud budget monitor (UK) richie00boy Multi-Way 45 16th June 2004 11:52 AM


New To Site? Need Help?

All times are GMT. The time now is 07:28 AM.


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