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  • Reliability
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      27.11.2009 02:31
      Very helpful
      1 Comment


      • Reliability


      Simple circuit amp easy to upgrade if you wish.

      Welcome to my review of the BT928.

      I own 4 of these small amplifiers, the reason? They are such good value for money, all mine cost about £28 through Ebay and Amazon.

      The BT(BTech)928 is a headphone amplifier designed for the desktop. It does not run off batteries so is not portable and needs an 15-18v power supply.

      The ad above states that it can run off a SCART socket, but you would need a SCART to RCA adapter to do this.

      You can get this in black or silver.


      The BT928 has one RCA input and one RCA out(loop through) at the back, (left and right), as well as the power input. On the front there are two outputs, 3.5mm stereo jack socket and 1/4" stereo jack socket, a volume control and a tone control.

      The OP-AMP used in this circuit is a NE5532.

      This little headamp sounds OK standard, but the reason I have 4 is because it is VERY easy to upgrade!! If you can solder, you can make this little cheap headamp sound as good as one costing £300-ish

      HOW?? you ask... well, get onto an electronics site, or even maplins and order some metal film resistors, some decent capacitors and a TI OPA2132/4. Even just removing the tone control pot gives a totally surprising improvement in sound quality.

      This little amp started me on my journey towards DIY audio nirvana, I learnt alot from this!!

      If you are atall interested in audio then this little amp used in a diy project is a great way to start, before you know it you will be skint and building tube amps and thinking about electrostatic headphones and DIY speakers costing more than a decent second hand car!!!

      BE WARNED!! LOL.

      My '3' rating for sound quality is for stock item, this rises to 5* after just removing the tone control pot!


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