ppl
Building amps and assuring water resistance.
- Joined
- Jun 21, 2001
- Posts
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Lots of folks request copies of my Portable headphone Amp Schematic. hanson Hostes them but I think the link may be forgotten so since I get the Most Requests for This Amp i have attached the schematic I hope it is readable i used a Program Called Vue Print Pro-32 ti Convert the MC-6 File and sometimes that Program is less than Perfect. It is hard for me to Judge Image quality since my vision is not so great.
This is my Origenal Design i made back in 1998 and ran off Two 9 volt batteries The Chip-set are AD-744 Usin Pin 5 as the Output rather than Pin 6 Pin 5 is the OPA's Compensation Pin. By using this Pin rather than the Normal Output Pin 6 of the Opamp the Opamp's output stage is by passed and as sutch no Current source is needed to obtain a Class A output stage since This method Connects the Opamp's Voltage gain Stage Directly to the Buffers Input. This is as Close to discreet Component Performance Obtainable in IC Form. The Output Buffers used are the BUF-634P in the 8 Pin Dip. Not Showen is a Resistor that the User can switch in or out on The bandwidth Pin of the Output BUF-634's This is to allow a Battery saving Low Bias mode or a High Bias Quality Mode. the value of this resistor is 470 Ohms but can be as low as 100 ohms. resistors less than 100 ohms cause the Buffers to Run hotter than i would like with no Heatsink and as sutch the sound suffers. My listening test resulted in the 470 ohm offer an inprovement over no resistor with 100 ohms being Ideal and lower values degrading the sound.
The J-fets are type MPF-4392, J174 or Equiv. the Bipolar transistors are Gen Purpose. Pnp/npn types like the 2N3904 & 2N3906 or 2N2222A and 2N2907 Or equiv. The Zener Diode is 6.3 Volts and the LED is a Blue radio Shack Type.
Oh Well I gess the bmp image was to large to post I give up i sent this to cmoy several times with out a reply and this did not work so i gess just go to hansons site. Please No more emails requesting schematics.
This is my Origenal Design i made back in 1998 and ran off Two 9 volt batteries The Chip-set are AD-744 Usin Pin 5 as the Output rather than Pin 6 Pin 5 is the OPA's Compensation Pin. By using this Pin rather than the Normal Output Pin 6 of the Opamp the Opamp's output stage is by passed and as sutch no Current source is needed to obtain a Class A output stage since This method Connects the Opamp's Voltage gain Stage Directly to the Buffers Input. This is as Close to discreet Component Performance Obtainable in IC Form. The Output Buffers used are the BUF-634P in the 8 Pin Dip. Not Showen is a Resistor that the User can switch in or out on The bandwidth Pin of the Output BUF-634's This is to allow a Battery saving Low Bias mode or a High Bias Quality Mode. the value of this resistor is 470 Ohms but can be as low as 100 ohms. resistors less than 100 ohms cause the Buffers to Run hotter than i would like with no Heatsink and as sutch the sound suffers. My listening test resulted in the 470 ohm offer an inprovement over no resistor with 100 ohms being Ideal and lower values degrading the sound.
The J-fets are type MPF-4392, J174 or Equiv. the Bipolar transistors are Gen Purpose. Pnp/npn types like the 2N3904 & 2N3906 or 2N2222A and 2N2907 Or equiv. The Zener Diode is 6.3 Volts and the LED is a Blue radio Shack Type.
Oh Well I gess the bmp image was to large to post I give up i sent this to cmoy several times with out a reply and this did not work so i gess just go to hansons site. Please No more emails requesting schematics.