With a few updates:
Star Point Ground Scheme for PL700B Amplifiers
Star Point Ground Scheme for PL700B Amplifiers
Star ground details for PL700B, the following wires attach to the copper bus bar "star point" ground (these connections are effectively CHASSIS GROUND in the PL700B):
1. Main transformer center taps (generally 2 wires)
2. B+ 9800uF cap, negative post
3. B- 9800uF cap, positive post
4. Left channel speaker negative binding post (black binding post, note connect both negative binding posts together with short copper bus wire)
5. Right channel speaker negative binding post (black binding post, note connect both negative binding posts together with short copper bus wire)
6. Ground wire to Light Board
7. Ground wire to the center terminal of the two 3 terminal barrier strips mounted on amp back wall. DO NOT connect the far right barrier strip center terminal to anything further to the right of this point. The original wiring had it connected this way and is a mistake.
8. Ground wire to pad 5L on White Oak Audio PL14_20 control board
No other connections should exist to the star point ground.
Other SIGNAL GROUND connections are made as follows:
1. Right channel RCA input shell to pad 2R on White Oak Audio PL14_20 control board, this is usually the shield ground in the shielded cable (note that this RCA jack shell and the copper metal plate MUST be isolated from CHASSIS GROUND).
2. Left channel RCA input shell to pad 2L on White Oak Audio PL14_20 control board, this is usually the shield ground in the shielded cable (note that this RCA jack shell and the copper metal plate MUST be isolated from CHASSIS GROUND).
3. There are generally 2-220K resistors from the input tip connection of both RCA input jacks to ground right as the signals come into the amp. The ground for these resistors must be SIGNAL GROUND, not CHASSIS GROUND. A picture of the recommended wiring for the input switch is shown below.
Notes:
1. The original PL700B amp wiring had the speaker negative binding posts attached to the copper input plate and by virtue of that to the input RCA jack shells as well as the DIRECT-NORMAL switch frame. These connections MUST be removed, they are a big problem for a single point ground.
2. The SIGNAL GROUND is connected to the CHASSIS GROUND on the White Oak Audio PL14_20 board through a 2.7 ohm resistor in locations R2L and R2R.
1. Main transformer center taps (generally 2 wires)
2. B+ 9800uF cap, negative post
3. B- 9800uF cap, positive post
4. Left channel speaker negative binding post (black binding post, note connect both negative binding posts together with short copper bus wire)
5. Right channel speaker negative binding post (black binding post, note connect both negative binding posts together with short copper bus wire)
6. Ground wire to Light Board
7. Ground wire to the center terminal of the two 3 terminal barrier strips mounted on amp back wall. DO NOT connect the far right barrier strip center terminal to anything further to the right of this point. The original wiring had it connected this way and is a mistake.
8. Ground wire to pad 5L on White Oak Audio PL14_20 control board
No other connections should exist to the star point ground.
Other SIGNAL GROUND connections are made as follows:
1. Right channel RCA input shell to pad 2R on White Oak Audio PL14_20 control board, this is usually the shield ground in the shielded cable (note that this RCA jack shell and the copper metal plate MUST be isolated from CHASSIS GROUND).
2. Left channel RCA input shell to pad 2L on White Oak Audio PL14_20 control board, this is usually the shield ground in the shielded cable (note that this RCA jack shell and the copper metal plate MUST be isolated from CHASSIS GROUND).
3. There are generally 2-220K resistors from the input tip connection of both RCA input jacks to ground right as the signals come into the amp. The ground for these resistors must be SIGNAL GROUND, not CHASSIS GROUND. A picture of the recommended wiring for the input switch is shown below.
Notes:
1. The original PL700B amp wiring had the speaker negative binding posts attached to the copper input plate and by virtue of that to the input RCA jack shells as well as the DIRECT-NORMAL switch frame. These connections MUST be removed, they are a big problem for a single point ground.
2. The SIGNAL GROUND is connected to the CHASSIS GROUND on the White Oak Audio PL14_20 board through a 2.7 ohm resistor in locations R2L and R2R.
