@

Wisdom in mind,   enthusiasm at heart.

Home Products Warranty Shop Contact Us Shipment Chinese


@

LP-1
RIAA Preamp

Regenerative power supply
Pure class A PSUs power supply
Fully non negative feedback ACSS design
"Linear Fidelity"  RIAA design
@

   

   

   

Summarize Use Manual Specs Shipping Cost

Price:  (Exclude shipping cost .)
LP-1MM Version : USD1120 (Only for MM pickup)
LP-1MC Version : USD1160 (Only for MC pickup)


What's the "Linear Fidelity" RIAA design :

       These years the phono RIAA preamp design most prefer with the passive attenuation design. Because the negative feedback RIAA design exist the larger TIM native that serious effect the middle and high frequency listen sense ,cause that most apply by the low end design . Below diamond is the the passive attenuation design.



       But there is an issue on the design, look at the below RIAA character diagram.
       The pickup output signal at the frequency 20KHz has 20DB boost than 1KHz. So even the amp's output voltage low to 500mV at 1KHz, the amp must output 5V at 20KHz, which is a high voltage output .
       The issue is not the amp if can output 5V , that is the 5V output at 20KHz compare to  500mV output at 1KHz , the distortion must has larger different.



         
I don't want to design an ultra low distortion RIAA amp because the phono configures has high distortion natively ,  it may sound analog and smooth because the distortion.
         But I prefer the RIAA amp can has linear distortion because that that different distortion must effect on the sound .


          The upon diagram show the different instruments frequency band . For example, if playing piano music recorder, cause by the larger different distortion on the frequency band, you can hear the low frequency band like playing a brand A piano, the middle frequency band like playing a brand B piano, and the high frequency brand like a brand C, the music recorder like the different brand pianos playing together.
          Please see the block diagram and the detail diagram, that is our LP-1 design.





        In our design, there is a lowpass (75uS) filter at the input side of the amp , It can make the signal over 1KHz roll off and final the signal frequency band become flat between 1KHz to 20KHz, so the amp has same output voltage level between 1KHz to 20KHz.
        I don't know if others has this design , but I call it "Linear Fidelity RIAA design" .
        Below diagram show the distortion of the LP-1 which is quite flat .


        The RIAA character of LP-1 .

@

LP-1 summarize :
        Built in Regenerative Power Supply.
        Built in 4 groups pure class A PSUs for power supply to the regenerative power parts and the RIAA analog amps.

        Full non negative feedback ACSS design
        Apply the best sound FET 2SK170 pair as input and output buffers .
        The MM Version :
        The input impedance has 10K,22K,33K,47K , 100K  and 200K ohm can selection by user for match with the different phono picker request. (Default the MM version need 47K input impedance ,use can choice other impedance follow the picker manual or listen sense. )
        Input cap has 50P,100P,150P and 200P can selection by users for match with the different phono picker request. (Please note : Usually the cap value lower , the sound is more transparency, the cap value higher , the sound become warmer . )
         The MC Version :
        The input impedance has 50,100,150,300,600  and 1000 ohm can selection by user for match with the different phono picker request. (Use can choice other impedance follow the picker manual or listen sense. )
        Input cap has 1000P,2000P,3200P and 4200P can selection by users for match with the different phono picker request.
@

Pure analogous Regenerative power supply :
        The regenerative power supply like a proprietary electric generator built in the unit.
        It can block most disturb from the power line , supply the ultra clean power supply for the audio amps , reproduce the most neutral and analog sound like audio signal for the system and the users.
       In the regenerative power supply design, the AC power through the regenerative input transformer , conversion to DC power ,through the class A PSUs power supply for the regenerative wave generator and driver stages .
       A balance regenerative regular wave generator produce the ultra low distortion 50Hz wave ,through the balance  gain amps and the strong  output stages , drive the regenerative transformers produce the clean AC power supply feed to the separate class A PSUs power supply for the L and R channel preamps .
        The class A parallel connection PSU has very high input impedance to avoid disturb through the PSU from affecting the signal parts and low output impedance with very fast speed and high linear,  it is a very clean power supply.
         Audio-gd on the regenerative power supply design points  :
         1, Through analyzed the AP SYS-2722 ,do a lot practises ,test and listen , full analog design of the regular wave generator have much lower distortion than the digital generator.
         2, Digital drive stages have higher efficiency , but full analog drive stages have much better analog sound like .
         3, 400Hz regenerative wave have higher efficiency , 50Hz regenerative wave had much far away the human ears sensitivity area than the 400Hz, boost the sound have much better analog sound like.


@

@


@

               备ק号: 粤ICP备05020367号

@              权Ҧ: ͧӭ响

Copyright(C) 2004 www.audio-gd.com All Rights Reserved
@