Phase Linear 200 Series Two Power Amplifier PL-200 II Amp, Extensively Serviced

Description: Phase Linear 200 Series Two Power Amplifier Model: PL-200 IIPrice:$507.99 +$54.99 flat-rate ground shipping to US mainland states onlyDescription:PreownedSeller refurbished, extensively serviced -- see NOTES belowIn very good working conditionNice and clean cosmetic condition with some minor marks and scuffs around the unit due to age and useExactly as seen in our picturesAn electronic copy of the user's manual will be emailed to the buyer after completion of sale, if requestedAll work performed by the techs at MC Mobile, Thousand Oaks, CANOTES: 1. Replaced blown fuses caused by an internal short2. Replaced components as required to elliminate the internal short3. Replaced whimpy 3000 uF PS caps with 15,000 uF PS filter caps, so now 5X energy storage in the power supply4. Lowered the corner frequency for both channels to improve bass response which works in conjunction with the larger PS caps5. Modified biasing circuit for both channels and rebiased amp so that all the visible crossover distortion up to 20 kHz is removed6. Replaced the bias adjusting pot on the right channel as the original was having issues7. Replaced all eletrolytic caps on both drive boards with new low ESR caps8. Serviced the protection relay to elliminate noise and dropouts9. Installed balanced sets of original FT 324 and FT 424 outputs in each channel (transistors are authentic originals from our stock)10. Power output of the amp into 8 ohms at 1 kHz, one channel driven, is now 235 W RMS for the left channel and 239 W RMS for the right channel at the onset of clipping,which is our best to date for a PL 20011. Repaired power indicator LED circuit (remained factory red) Items 3 and 4 noticably improve amplifier performance, especially at low frequencies, and greatly increases dynamic power. Item 5 is the difference between our last two pictures which are captures of our scope display at 20 khz. Please notice the visible crossover distortion in the second to the last picture, which is what results from the PL biasing circuit and the procedure in the service manual. Our last picture is the modfied circuit rebiased to elliminate the visible crossover distortion. This is a significant improvement as the distortion noted in our second to last picture plagues many PL amps if not corrected, and the level of this distortion greatly exceeds the distortion specifications claimed by Phase Linear (PL). Hence, there is significant benefit and improvement. Item 10 notes that this amp, after service, is producing as much or more power than the larger PL 400 amps. Caution must be exercised because there are only 2 pairs of outputs per channel, and the amount of current at the +/- 70 V internal rail voltages are close to the maximum SOA of the output transistors into 8 Ohms. Hence, if this amp is driven to its maximums, it is recommended that the rear heat sinks be cooled with at least a low velocity muffin fan. In addition, if driving 4 Ohm speakers, the user must be careful not to drive this amp to its maximums. Overall, a great modified PL 200 seriies amp to give the passionate user a noticalble edge over stock PL 200 amplifiers. Some Original Specifications:Power output: 120 watts per channel into 8Ω (stereo)Frequency response: 12Hz to 40kHzTotal harmonic distortion: 0.009%Damping factor: 1000Input sensitivity: 1.5VSpeaker load impedance: 4Ω to 16ΩDimensions: 483 x 140 x 222mmWeight: 7kgYear: 1978

Price: 507.99 USD

Location: Newbury Park, California

End Time: 2024-09-11T01:49:37.000Z

Shipping Cost: 54.99 USD