Price: $2,167.99 + $129.99 flat-rate fully insured ground shipping to US 48 states only
Description:
- Vintage Restomod -- See NOTES Below for Details
- Repaired, restored and upgraded
- Nice cosmetic condition with some signs of wear due to use & age -- some marks & scuffs about the unit
- Exactly as seen in pictures
- An electronic copy of the user's manual will be emailed to the buyer upon request
- Work performed by MC Mobile, Thousand Oaks, CA, Est. 1997
- Six Month parts and labor warranty
NOTES:
1. Amp was repaired from a non-functional state which involved replacement of transistors, capacitors, and resistors
2. This is an early production PL 700 series two which used XPL909 output transistors and LF356 input stage op amps
3. We replaced the driver transistors (RCA 410 or 66546) in the left channel to have a better matched set
4. We replaced some of the XPL909 outputs in the left and right channels for better gain match and current balance
5 Absolute current matching at 112 W RMS per channel is 15% or less at the extremes for each bank of 5 outputs (better than stock spec)
6. Amp retains the quasi-complimentary output stage
7. Bias adjustment pots are new, and the amp is re-biased to remove excess notch distortion up to 20 kHz
8. A clean sine wave at 20 kHz is shown in our 3rd to last picture, and is the performance of both channels after service
9. Our 2nd to last picture showed the notch distortion before correction
9. Compensation elements were added to remove out of band oscillation in both channels (original oscillation shown in our last picture)
10. DC offset was measured at the speaker outputs for both channels, and was found to be acceptably small
11. Sockets were added for the input op amps, so the op amps can easily be replaced or changed as desired
12. We replaced the original LF356 metal can op amps with a better op amp that fits into an 8 pin DIP socket
13. Power output after service with mains at 120 VAC is 425 W RMS per channel, one channel driven, into an 8 Ohm load
14. Grounding modified to provide quiet ground for the input stages which changes the factory single level grounding
15. The second level of grounding improves THD+N performance especially for lower level input signals (low volumes)
16. All electrolytic capacitors on the drive board were replaced
17. Low frequency cut off was lowered to improve bass response in conjunction with the PS filter capacitor upgrade
18. New massive 33,000 uF filter capacitors replace the original 10,000 uF power supply capacitors which dramatically improves bass response, energy storage, and dynamic power
19. New bypass capacitors were added to the power supply which were not included from the factory
20. Inrush protection to limit the inrush to the 66,000 uF power supply capacitance is installed (our custom board)
21. Speaker protection & DC protection is also installed (also our custom board) to protect the speakers & to eliminate turn on & turn off thump
22. Low voltage power supply for the meters, relays, etc., is upgraded with 5X more filter capacitance to lower noise & ripple in the meter circuits
Additional Notes:
This is a unique option 2 restomod with noticeably improved performance vs stock. These amps take some time, so this is our first Phase Linear 700 listing for this restomod package.
Once energized, the inrush protection is switched out by relay after 3 seconds, and is ready again after 5 minutes with the amp in the on or off condition. Failure to allow the inrush protection to recover with rapid power cycling will put significant stress on the fuses, power transformer, and power switch due to the massive power supply filter capacitance.
The speaker protection will connect the speakers after a 6 second delay after turn on. If excessive DC is detected, the protection relays will disengage. If DC protection is activated, the amp will need to be turned off for 60 seconds for DC protect to reset. The DC protect will not reset if the amp power remains on.
We also have a White Oak modified PL 400 series two on eBay. Please keep in mind that a new White Oak drive board, even with the output stage converted to fully complimentary, will not perform as well as a properly serviced amp with the original PL drive board and output stage unless the White Oak drive board kit is upgraded. Improved performance can be achieved with a new White Oak drive board and/or drive board plus back plane board only if proper improvements are made.
Please feel free to ask questions before purchase as this amp has underwent a considerable amount of service as noted above.
Some Original Manufacturer's Specifications: