Phase Linear 400 Series 2, White Oak Drive Board, Fully Complimentary Outputs

Description: Phase Linear 400 Series 2, White Oak Drive Board, Fully Complimentary Outputs, Further Upgrades Price: $1,995.99 + 69.99 flat-rate ground shipping to US mainland states only Description: Vintage Restomod -- See NOTES Below for DetailsUpgraded beyond White Oak Kit -- See Details belowNice cosmetic condition with some signs of wear due to use & age-- some marks & scuffs about the unitExactly as seen in picturesAn electronic copy of the user's manual will be emailed to the buyer upon requestA copy of the power vs. distortion report will also be provided to buyer upon requestWork performed by the techs at MC Mobile, Thousand Oaks, CA NOTES: Later production PL 400 Series II, with the better extruded Al heat sinks (not the double folded U heat sinks), was modified by building and installing the White Oak Control Board, Rev. G, and the was amp converted to a fully complimentary output stage. We deviated from a typical White Oak build and install in a number of areas to improve performance as noted below. 1. Matched sets of MJ150024 and MJ150025 outputs were used in a fully complimentary output stage. Bank matching was less than or equal to 7% at the extremes for each bank of three as measured at 112W RMS per channel. It makes little difference whether MJ21195 and MJ21196 are used instead.2. Pre driver transistors were also MJ150024 and MJ1500253 We installed new 20,000 uF PS filter caps instead of the usual 15,000 uF suggested by White Oak4. We installed inrush protection along with the new PS caps. The inrush is our board.5. We also increased the filter capacitance on the low voltage secondary with 5X larger new capacitance.6. When the White Oak kit was built for fully complimentary outputs, there was no base resistor for one of the two driver transistors per channel, so we installed equal for the P and N sides for both channels.7. There was no provision for quiet ground and changing the single level PL grounding scheme, so we added quiet ground and reworked the grounding off board.8. The bias circuit did not correctly compensate for temperature increase and it did not have enough drive to elliminate visible crossover distortion for a fully complimentary output stage, so we changed/improved the bias circuit to correct for those deficiencies.9. We installed speaker and DC protection that was not part of the White Oak kit. Like the inrush, the protection board is our board.10. We ran power tests and found the power output at clip to be about 263 W RMS per channel, one channel driven in to 8 Ohms at 1 kHz, and about 250 W RMS per channel both channels driven.11. We performed a THD + N scan from 20 Hz to 20 kHz at 1.5 W to 252 W RMS both channels driven, and found the THD + N to be less than or equal to 0.063% for both channels.THD+N above 200 W RMS is less than 0.0075 % until onset of clip at 252 W RMS (above 1%). A copy of the distortion report will be provided.12. We added additional stabilization elements at the pre-driver stage for each channel to prevent oscillation.13. We installed new 5 Amp AGX fuses for each rail. If this amp is driven to full power on both channel for extended periods of time, 8 Amp AGX fuses and fan cooling for the heat sinks are recommended. Overall, this amp turned out quite well after all of the modifications. The performance improvement was significant over where it started with the as built White Oak kit. This is a one of a kind build as noted above. The visible, uncorrected, crossover distortion before the bias circuit was changed was around 0.25 to 0.50 % at low output levels, so we are puzzled by what some other sellers claim about as built performance with this kit. We have included a couple of scope traces with the visible and corrected crossover distortion. When done carefully, the White Oak Kit can be a decent upgrade for these amps. Basically, it is a PL Series 2 design with some upgrades and some deficiencies to overcome. For those who desire even higher performance, our PL option 4 restomod amp is the ticket. Some Original Specifications:Power output: 210 watts per channel into 8Ω (stereo)Frequency response: 12Hz to 40kHzTotal harmonic distortion: 0.09%Damping factor: 1000Input sensitivity: 1VSignal to noise ratio: 110dBSpeaker load impedance: 4Ω (minimum)Dimensions: 483 x 178 x 254mmWeight: 16kg

Price: 1995.99 USD

Location: Newbury Park, California

End Time: 2024-09-07T21:05:35.000Z

Shipping Cost: 69.99 USD