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About SvenMZ8

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  1. Designed another amplifier after taking apart my Pimeta amplifier. This time its a Pimeta without the use of virtual ground, thus its a two channel amplifier. A real dual supply, + and - voltages and a true ground is used. The merits of using such a design is covered here by NwAvGuy http://nwavguy.blogspot.sg/2011/05/virtual...annel-amps.html The negative voltage supply is generated by a charge pump TPS60403, which is a voltage inverter. The power supply is a 3.7V PSP Lithium ion battery, thus with the charge pump, the voltages supplied is +3.7V and -3.6V. To ensure that the performance of the charge pump is not affected by PCB layout, the recommended layout in the datasheet is followed closely. As you can see, the charge pump sits very closely with the ceramic capacitors to reduce parasitic inductance. The audio amplifier section is also similarly made compact to reduce the footprint and size of the amplifier. As the charge pump switching frequency is 250KHz, which is within the bandwidth of most opamps. Thus the chosen audio opamp requires a high PSRR to reject power supply noise generated by the charge pump. The chosen LTC6241HV has a minimum PSRR of 83dB when supplied with +-5V. The input and outputs of the amp is placed above the circuitry to reduce the footprint. The entire amp, including the PSP battery fits inside a hammond 1455C801 aluminium casing. Components Power Supply Section Battery: 3.7V Lithium ion battery Charge pump: TPS60403 Ceramic Capacitors: 1uF X5R 0603 Voltage Rail Capacitors: 220uF/4V Blackgates PK Series Bypass Capacitors: WIMA 0.1uF/63V Audio Amplifier Section Audio Opamp: LTC6241HV, Gain set at 2. Buffers: BUF634U Volume control: Alps Potentiometer 50K LOG
  2. changes to tube amp. simple yaha on 15v
  3. the opamp goes into oscillation caused by capacitive load from the shure earphones. same thing happens as u described with the fxc-70s (dynamic) no prob, but q-jays have problem. problem can be solved with voltage buffer after gain stage in opamp, or simply increasing the gain.
  4. did u happen to pass by the headphone shop at central, clarke quay? i saw the fxc-50 there last time. maybe they stocked with the new 51,71s.
  5. SvenMZ8

    toMMo amp

    same sentiment firefox. the current draw from such voltage splitting configuration is much higher, if used as a portable amp, the battery life is significantly reduced.
  6. Balanced Amp completed -Converts unbalanced signal to balanced -9V rechargable battery with charging circuit -Black and white Faceplate Balanced Audio Technica FC-700 to go with the new amp With imod + sonicaps
  7. SvenMZ8

    my diys

    braiding is a little loose
  8. im assuming HO means "headphone out"? u need to be more clear. it still works. i have the blackgates, pm if u want them.
  9. made 2 sonicap sets for forumer
  10. Mogami Japan Copper Balanced Headphone Amp Balanced headphone to single ended using headphone splitter
  11. SvenMZ8

    The MIG-15

    may 25th : studio shots the 3rd amp is half done and hopefully be completed at the end of the month.
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