ได้มาแล้วเหรอ เห็นสุดยอดมาตลอดเรย
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แหมพี่...ตัวที่ผมเล่น JPS Labs เงี้ย Hovland เงี้ย Tunami เงี้ย ผมว่ามันก็ดีหมดล่ะครับ แต่บุคลิกเสียงก็ต่างกันไป Top of the line ทั้งนั้น
ได้มาแล้วเหรอ เห็นสุดยอดมาตลอดเรย
-------------
แหมพี่...ตัวที่ผมเล่น JPS Labs เงี้ย Hovland เงี้ย Tunami เงี้ย ผมว่ามันก็ดีหมดล่ะครับ แต่บุคลิกเสียงก็ต่างกันไป Top of the line ทั้งนั้น
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สงสัย MSN for Mac มันทำพิษอีกแล้วครับพี่หมอเพชร.... ครั้งก่อน On อยู่ แต่เพื่อนๆ หลายๆ คนบอกว่าไม่ได้ On เห็นเป็น Offline.... สงสัยกลับไทยคงได้เรื่องลงเครื่องใหม่อะครับ...
ขออภัยเป็นอย่างสูงครับ..
^
สงสัย MSN for Mac มันทำพิษอีกแล้วครับพี่หมอเพชร.... ครั้งก่อน On อยู่ แต่เพื่อนๆ หลายๆ คนบอกว่าไม่ได้ On เห็นเป็น Offline.... สงสัยกลับไทยคงได้เรื่องลงเครื่องใหม่อะครับ...
1. Pre-set the BIASL, BIASR and BIASG trimpots to their minimum positions (fully counter-clockwise). You should feel a slight click when the stop is reached. Pre-set the BIASOPL, BIASOPR and BIASOPG trimpots to approximately the center of their control range. For example, if you use a 20-turn trimpot then rotate counter-clockwise to its stop, then rotate 10 turns clockwise.
2. Measure the resistance between the V+ and V- rails. It should not be short-circuited. Similarly, measure the resistance between pins 7 and 4 of each of the opamp sockets, as well as between these pins and the virtual ground (the IG contact) at the input pads. There should be no shorts.
3. Make sure your power supply outputs the correct DC voltage. See the Power supply section.
4. Install the ground channel opamp OPAMPG into its socket. Be sure the orientation is correct.
5. Connect the power supply to the amplifier, set the volume and bass boost controls to their minimum position (fully counter-clockwise), and set the bass boost switch to "off", if equipped.
6. Turn on the power. The power LED should glow. Measure the DC voltage across pins 7 and 4 of the opamp. You should get approximately the power supply voltage minus 1.5V to 3V. Also, check the DC voltage between pin 7 of the opamp to IG, as well as between pin 4 and IG. These should be half of the first measurement.
7. Measure the DC voltage across the R5G resistor. Adjust the BIASOPG trimpot until you get around 0.4V to 0.5V. This corresponds to 4mA to 5mA through the JFET cascode current source. This is an optimal amount of current, high enough to provide good MOSFET drive and keeps the opamp output stage deep in class A operation, but not too high as to strain the opamp.
8. Set the multimeter to DC mV range. Measure the DC offset voltage between IG and OG. At this point the MOSFETs are running with very little bias so the DC offset may be higher than desired, but should still be lower than 100mV.
9. Measure the DC voltage across the R9G+ resistor, and adjust the BIASG trimpot clockwise until you read 80mV. This corresponds to 80mA quiescent current through the MOSFETs (See note below). Check the voltage across R9G-, it should be within 5% of that across R9G+.
10. Turn off the power and wait at least 30 seconds for voltages to drop.
11. Repeat steps 4 through 10 for the left channel, except referring to OPAMPL, R5L, OL, BIASOPL, R9L+/R9L-, and BIASL.
12. Repeat steps 4 through 9 for the right channel, except referring to OPAMPR, R5R, OR, BIASOPR, R9R+/R9R-, and BIASR.
13. Leaving the amplifier powered up, re-check the DC offset voltage between IG and OL, IG and OR, IG and OG respectively. Each should now be less than 2mV, but tolerable at 5mV. Also, measure at the same points with the multimeter in AC mV range. The readings should be less than 0.1mV.
14. Let the amplifier warm up for a half hour. Re-check the DC voltage across the R9 resistors of each channel, and adjust the BIAS trimpots for 80mV if necessary (See note below). The quiescent current will change a bit over time. When first powered up, the quiescent current will be higher, but as it warms up, the negative thermal coefficient of the MOSFETs will automatically cause the current to drop and stabilize at a lower current. For this reason, you may want to set the quiescent current 10mA to 15mA higher than the target, so that after you close the chassis cover, the elevated temperature will cause the current will drop to where you want it.
15. Optional: If you have an oscilloscope, you may wish to connect it to the amplfier outputs to check for oscillation.
16. The initial setup is done. Before you connect any input source to the amplifier, measure the source to make sure it has no DC offset at its output. Any such DC offset will be multiplied by the gain of the M³ amplifier.
17. If all is well, you can now connect the input source as well as headphones, and turn the volume up for a listen.
ปล.ได้รับหูฟังแล้วครับ
1. Pre-set the BIASL, BIASR and BIASG trimpots to their minimum positions (fully counter-clockwise). You should feel a slight click when the stop is reached. Pre-set the BIASOPL, BIASOPR and BIASOPG trimpots to approximately the center of their control range. For example, if you use a 20-turn trimpot then rotate counter-clockwise to its stop, then rotate 10 turns clockwise.
2. Measure the resistance between the V+ and V- rails. It should not be short-circuited. Similarly, measure the resistance between pins 7 and 4 of each of the opamp sockets, as well as between these pins and the virtual ground (the IG contact) at the input pads. There should be no shorts.
3. Make sure your power supply outputs the correct DC voltage. See the Power supply section.
4. Install the ground channel opamp OPAMPG into its socket. Be sure the orientation is correct.
5. Connect the power supply to the amplifier, set the volume and bass boost controls to their minimum position (fully counter-clockwise), and set the bass boost switch to "off", if equipped.
6. Turn on the power. The power LED should glow. Measure the DC voltage across pins 7 and 4 of the opamp. You should get approximately the power supply voltage minus 1.5V to 3V. Also, check the DC voltage between pin 7 of the opamp to IG, as well as between pin 4 and IG. These should be half of the first measurement.
7. Measure the DC voltage across the R5G resistor. Adjust the BIASOPG trimpot until you get around 0.4V to 0.5V. This corresponds to 4mA to 5mA through the JFET cascode current source. This is an optimal amount of current, high enough to provide good MOSFET drive and keeps the opamp output stage deep in class A operation, but not too high as to strain the opamp.
8. Set the multimeter to DC mV range. Measure the DC offset voltage between IG and OG. At this point the MOSFETs are running with very little bias so the DC offset may be higher than desired, but should still be lower than 100mV.
9. Measure the DC voltage across the R9G+ resistor, and adjust the BIASG trimpot clockwise until you read 80mV. This corresponds to 80mA quiescent current through the MOSFETs (See note below). Check the voltage across R9G-, it should be within 5% of that across R9G+.
10. Turn off the power and wait at least 30 seconds for voltages to drop.
11. Repeat steps 4 through 10 for the left channel, except referring to OPAMPL, R5L, OL, BIASOPL, R9L+/R9L-, and BIASL.
12. Repeat steps 4 through 9 for the right channel, except referring to OPAMPR, R5R, OR, BIASOPR, R9R+/R9R-, and BIASR.
13. Leaving the amplifier powered up, re-check the DC offset voltage between IG and OL, IG and OR, IG and OG respectively. Each should now be less than 2mV, but tolerable at 5mV. Also, measure at the same points with the multimeter in AC mV range. The readings should be less than 0.1mV.
14. Let the amplifier warm up for a half hour. Re-check the DC voltage across the R9 resistors of each channel, and adjust the BIAS trimpots for 80mV if necessary (See note below). The quiescent current will change a bit over time. When first powered up, the quiescent current will be higher, but as it warms up, the negative thermal coefficient of the MOSFETs will automatically cause the current to drop and stabilize at a lower current. For this reason, you may want to set the quiescent current 10mA to 15mA higher than the target, so that after you close the chassis cover, the elevated temperature will cause the current will drop to where you want it.
15. Optional: If you have an oscilloscope, you may wish to connect it to the amplfier outputs to check for oscillation.
16. The initial setup is done. Before you connect any input source to the amplifier, measure the source to make sure it has no DC offset at its output. Any such DC offset will be multiplied by the gain of the M³ amplifier.
17. If all is well, you can now connect the input source as well as headphones, and turn the volume up for a listen.
ปล.ได้รับหูฟังแล้วครับ
ให้กำลังใจ 0
หยิกหู 0
แจกหู 0
ความคิดเห็นที่ : 423
ManPlayEar
31/10/2010 09:36:49
21
ข้างบนไม่ใช่ SPAM นะ ดูให้ดี 5 5
ข้างบนไม่ใช่ SPAM นะ ดูให้ดี 5 5
ให้กำลังใจ 0
หยิกหู 0
แจกหู 0
ความคิดเห็นที่ : 424
AscoGenetic5
31/10/2010 09:38:40
175
^
เออ..เหมือนเลย 555
^
เออ..เหมือนเลย 555
ให้กำลังใจ 0
หยิกหู 0
แจกหู 0
ความคิดเห็นที่ : 425
leenawat_sri
31/10/2010 09:39:47
1
wow ขอบคุณคับป๋า
wow ขอบคุณคับป๋า
ให้กำลังใจ 0
หยิกหู 0
แจกหู 0
ความคิดเห็นที่ : 426
Uthen
31/10/2010 09:58:47
17
mini 3 lot ใหม่เอาแบบ solid body เลยมั๊ยครับป๋า อิอิ
mini 3 lot ใหม่เอาแบบ solid body เลยมั๊ยครับป๋า อิอิ
ชิวๆครับ เพิ่งจะยกตู้อาหารขึ้นมาได้เมื่อบ่ายสองนี้เอง ตอนนี้ไม่อดแล้วจ้า แต่ Gas Gen เดี้ยงไปตัวนึง ตอนนี้นายช่างทั้งหลายกะลังรุมกันอยู่ไม่งั้นเดี๋ยว ดีเซลสำรองหมดจะหง่าวกันถ้วนหน้า อิอิ
ชิวๆครับ เพิ่งจะยกตู้อาหารขึ้นมาได้เมื่อบ่ายสองนี้เอง ตอนนี้ไม่อดแล้วจ้า แต่ Gas Gen เดี้ยงไปตัวนึง ตอนนี้นายช่างทั้งหลายกะลังรุมกันอยู่ไม่งั้นเดี๋ยว ดีเซลสำรองหมดจะหง่าวกันถ้วนหน้า อิอิ