1. The minus 20V regulator is now completely symmetrical with the positive regulator and employs the complement to the TIP31C, the TIP30C. My ongoing quest for improvement in turn on and turn off thump reduction. This I have modeled into the current RevA board in true dead bug fashion.
2. Added BIAS L/R test point at the upper edge of the PBC to allow easier access for bias adjustment. The positive meter connection is made to this point. The negative meter connection is the speaker (positive, red or white) output binding post which is readily accessible.
3. Improvement in the infrastructure to allow easy use of the 5VDC generated by the Light Board Assembly to eliminate the Boost+ capacitor used in the current design. This is currently uncharted territory and will be testing it out on the next gen board now that both the light board and the control board have the proper hooks in them. At this point, I would paint this one as a crap shoot.
4. The Gepetto fix is an official part of the base board, not reworked in. Locations for 4 additional 1N4148 diodes has been provided. Added the Gepetto fix diodes as D15L/R and D16L/R.
5. Moved the main connection points downward (closer to the bottom board edge) by 0.015" (0.38mm). Kept the same hole to hole spacing that existed before so the Phoenix Contact Terminal Blocks will still fit with improved clearances.
6. Moved all wire pad connections along the lower board edge and the 6 bias connections to be on 0.100" X-Y grid. This allows the easier creation of a board test fixture to test assembled but uninstalled boards. These changes were made to enable a pogo pin functional test fixture creation. I will post photos of my pogo pin assembly tester after I complete it.
7. Move D13L and D13 R upward, closer to the center of the board and away from the board wired connections to allow use of Phoenix Contact Terminal Blocks P/N 1729209 and get these diodes out of the way.
8. C11L and C11R are moved upwards by 0.025" closer to the center of the board and away from the board wired connections to allow easier installation of the Phoenix Contact Terminal Block board connectors, if desired.
9. Request: Not Done on purpose. Drill a hole and make a solder bridge adjacent to the connection between R81 and R73R to provide +20V for auxiliary devices. Make a similar hole and solder bridge adjacent to the connection between R84 and R74R to provide -20V for auxiliary devices. Response: Auxiliary devices are not supported, the onboard power supplies are ONLY for powering the front end of each amp channel.
10. Request: Consider creating solder links between the pads on the top side of the board to connect the higher current components: R17L to R18L, R80 to R79, and R17R to R18R. Response: Increased trace widths across the board to accommodate this request.
11. Pad holes for the bias transistors and the 3 rear board jumpers have been increased to 1.3mm hole diameter to allow easier installation and re-use of the board if previously soldered. In addition, these 3 holes are now “on-grid†to allow the use of a 3 position Phoenix Contact Terminal Block on the backside of the board for attachment of the bias transistor wires.
12. Renamed C31R to C20R effectively eliminating "Where's Waldo". Sorry guys, no more brain teaser.
13. Increased the pad sizes and holes for all 1N4004 diode locations to improve solderability and board ruggedness.
14. Increased ALL signal and power trace widths where ever possible.
15. Provided a clear, pad-free horizontal channel between Pads 5L1 and 5R1, 11L1 and 11R1, 12L1 and 12R1 to neaten up the rear of board connection wires when used. The revision A board had minor conflicts with pad locations soldered in from the front side. This is a cosmetic update and a quality improvement.
16. Board width increased from 6.300" to 6.400", symmetrical around the center mounting posts. The board height remains the same as the prior revision at 4.875"
17. Overall, improved upon the already high quality of the RevA board in the creation of the RevC artwork by making small moves of components to improve assembly clearances, shorten and widen traces, increase trace clearances and improve signal integrity to maximize audio quality.
2. Added BIAS L/R test point at the upper edge of the PBC to allow easier access for bias adjustment. The positive meter connection is made to this point. The negative meter connection is the speaker (positive, red or white) output binding post which is readily accessible.
3. Improvement in the infrastructure to allow easy use of the 5VDC generated by the Light Board Assembly to eliminate the Boost+ capacitor used in the current design. This is currently uncharted territory and will be testing it out on the next gen board now that both the light board and the control board have the proper hooks in them. At this point, I would paint this one as a crap shoot.
4. The Gepetto fix is an official part of the base board, not reworked in. Locations for 4 additional 1N4148 diodes has been provided. Added the Gepetto fix diodes as D15L/R and D16L/R.
5. Moved the main connection points downward (closer to the bottom board edge) by 0.015" (0.38mm). Kept the same hole to hole spacing that existed before so the Phoenix Contact Terminal Blocks will still fit with improved clearances.
6. Moved all wire pad connections along the lower board edge and the 6 bias connections to be on 0.100" X-Y grid. This allows the easier creation of a board test fixture to test assembled but uninstalled boards. These changes were made to enable a pogo pin functional test fixture creation. I will post photos of my pogo pin assembly tester after I complete it.
7. Move D13L and D13 R upward, closer to the center of the board and away from the board wired connections to allow use of Phoenix Contact Terminal Blocks P/N 1729209 and get these diodes out of the way.
8. C11L and C11R are moved upwards by 0.025" closer to the center of the board and away from the board wired connections to allow easier installation of the Phoenix Contact Terminal Block board connectors, if desired.
9. Request: Not Done on purpose. Drill a hole and make a solder bridge adjacent to the connection between R81 and R73R to provide +20V for auxiliary devices. Make a similar hole and solder bridge adjacent to the connection between R84 and R74R to provide -20V for auxiliary devices. Response: Auxiliary devices are not supported, the onboard power supplies are ONLY for powering the front end of each amp channel.
10. Request: Consider creating solder links between the pads on the top side of the board to connect the higher current components: R17L to R18L, R80 to R79, and R17R to R18R. Response: Increased trace widths across the board to accommodate this request.
11. Pad holes for the bias transistors and the 3 rear board jumpers have been increased to 1.3mm hole diameter to allow easier installation and re-use of the board if previously soldered. In addition, these 3 holes are now “on-grid†to allow the use of a 3 position Phoenix Contact Terminal Block on the backside of the board for attachment of the bias transistor wires.
12. Renamed C31R to C20R effectively eliminating "Where's Waldo". Sorry guys, no more brain teaser.
13. Increased the pad sizes and holes for all 1N4004 diode locations to improve solderability and board ruggedness.
14. Increased ALL signal and power trace widths where ever possible.
15. Provided a clear, pad-free horizontal channel between Pads 5L1 and 5R1, 11L1 and 11R1, 12L1 and 12R1 to neaten up the rear of board connection wires when used. The revision A board had minor conflicts with pad locations soldered in from the front side. This is a cosmetic update and a quality improvement.
16. Board width increased from 6.300" to 6.400", symmetrical around the center mounting posts. The board height remains the same as the prior revision at 4.875"
17. Overall, improved upon the already high quality of the RevA board in the creation of the RevC artwork by making small moves of components to improve assembly clearances, shorten and widen traces, increase trace clearances and improve signal integrity to maximize audio quality.
