Tang Band Computer Speaker setup

Discussion in 'Home Theater Projects' started by Stephen Hopkins, Feb 15, 2004.

  1. Stephen Hopkins

    Stephen Hopkins HW Reviewer
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    I'm giving some thought to replacing my current Logitech Z-340 2.1 computer speaker setup w/ one consisting of a pair of Tang Band W3-871 Elfs and a ported W8-740C subwoofer (possibly going 5.1 w/ some more Elfs or Elf 1.5s later on).

    My question is this... do you think it would be possible to use the internal (amplification) from my current Logitech 2.1 system for this project since purchasing a 2ch amp of any kind and a sub-amp would drive the cost up considerably? I've had the Logitech speakers apart and it's physicly possible, but my big concern would be whether or not there's some kind of built-in EQ to boost the sub-responce or even the speakers.

    If you don't think it's a reasonable idea to use the amp(s) from the logitech system, what would be a cost-effective source of amplification for the speakers and sub? I was thinking the Velman 2x10 watt amp kit from Parts express ($30) would work well for the speakers, but what about the sub? If the velman amp kit were some-how bridgeable another one of those would work perfectly, but i seriously doubt there's any way to do that. I also wouldn't have any kind of crossover, so it's looking like some type of sub-amp w/ high-level inputs and a crossover is going to pretty much be mandatory to get this project working, right?

    I'd like to keep the project under $100 (excluding wood and finish) because otherwise i'm not sure it's worth it other than for the fun of building it all. Maybe a PE 100W 10" and building the ELFs would be a better choice? Would cost about the same as a 100w plate amp, velman amp kit, and all three TB drivers.

    Thanks [​IMG]
     
  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I took apart the amplifier from Altec Lansing ACS56 cpu speakers to power some DIY speakers and I definitely believe there is some type of equalization or "matching" going on with the satellites mating with the bass module.

    I also read about a guy replacing his Creative PC speakers with tag band full rangers and said the sound quality was much improved, but the frequency response wasn't as good since the bass and the satellite didn't match anymore.

    The problem is you can't really tell how well the new tag bands will match the bass unit until you hear it.

    Oh, I also took apart Klipsch 2.1 PC speakers to power a pair of Jordan JX92s full rangers and the amplifier quality was suprisingly bad. It wasn't until I used a separate 2 channel "full range" amplifier to power the jordans till I started to really enjoy the music.

    I'd look at the cheapest options for 2 channel amps, and the tag bands for now, then bass later. If you're willing to research, you can look for a schematic for a DIY amplifier called a GainKlone. (there's a forum dedicated to DIYaudio related to chip amps) It's very simple with about 7 or so parts, but the amp is copying one that sells for several thousand dollars (the gaincard by 47labs). It can output 25 or 50 watts per channel and prices range from $100-150 for everything. My friend and I built one together, and now I'm designing another.
     
  3. Nat Ward

    Nat Ward Agent

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    Check out Apex Jr. www dot apexjr dot com forward slash JBL12.htm . Sorry for the cryptic webpage, not sure if I'm over my requirement for linking. It's a 12W stereo amp that looks to have come from a pair of computer speakers, with transformer for $10. I've got a pair of Tang Bands that I want to build for computer speakers too, and I'm thinking about going this way. The amp in my current computer speakers is glued in really well. Keep us updated on the project, I always like to check out others ideas! Oh yeah, they have some small amps that you might be able to use for a sub too!
    Nat Ward
     
  4. Stephen Hopkins

    Stephen Hopkins HW Reviewer
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    The JBL 12W amps would be a good start, but they only put out like 6.5w into 4 ohms, so probably less than 4watts into an 8ohm load.

    How about the Dual 25W sub amp for the sub (either doing the bridge mod, using 2 of the subs, or maybe just using one channel of the amp), and the Dual 25W Full Range amp for the speakers? This would be $55 for amplification/transformers and $70 for drivers/ports/screws/terminals. A total of $130 is much more reasonable and when spread out over a few weeks would be very easy to digest.

    Anyone see any problems w/ using these amps, other than needing either 2 power inputs from the wall or needing to split one power line into 2? It would be pretty easy to mount both amps in the box for the sub and have a set of terminal cup outputs for each speaker. Would also keep me from destroying my Logitech setup, which migh get $20 - $30 on ebay and help keep the out-of-pocket right at the $100 goal i originaly set. And even if i found an old stereo receiver for less than $50 to power the mains, i'd still have to add a sub-amp once i added a sub, which is going to be pretty much mandatory w/ speakers who don't go much lower than 100hz.

    Any other suggestions?

    Thanks [​IMG]
     
  5. ThomasW

    ThomasW Cinematographer

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    Call Steve at ApexJr, I'm sure he can answer your questions regarding the amp/amps.
     
  6. JakubH

    JakubH Stunt Coordinator

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    my only suggestion is go for it! (replacing the speakers that is). I would forget the amps, as others said they likely have custom EQ. But, I've used the ELF 1.0 for computer speakers, and comparted to the Logitech. The ELF really blow them away. The imaging from the ELFs in the nearfield is eerie! Good luck, let us know how you make out.
     
  7. TimForman

    TimForman Supporting Actor

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