Thursday, November 27, 2014

Marantz 2230 Receiver

Marantz 2230 Receiver

Power Amplifier P750
All the electrolytic here were replaced with Silmic II's and  a matched pair of FG's at C754/55. C751 was replaced with a 1uf MKS2 WIMA (a .47 can be used).  The idle current regulator at H757 has a SB released, recommending to replace with a thermistor +18ohm resistor to the heatsink at H755. I discussed this with Catrafter and was found after some testing that a single 1N4148 diode will work in place here, following the PCB orientation.  The ceramic near the sister array was replaced with a Kemet NPO/C0G type. All the TO-3 had nice insulators and compound applied, along with the foil side regulator to diode.  Bias was monitored at J759 and 757 adjusted at J765 to 10.5mV stabile.  All the capacitors were matched board to board this time (that took awhile with the old 179 fluke)

The large filter cap was replaced with my favorite 10000uf Panasonic THA and the coupling caps with 6800uf Nichicon KG's. The power switch was replaced with a standard 1257A dpdt (EG108-ND) and safety cap replaced. LEDs and vellum were already done.

Power Supply P800
Once again I went with the robust Panasonic FC's here, pretty straight forward. Also H804/805 S1B-01-02 diodes were replaced with a single UF4005  diode in the pcb orientation. Measured and stabilized voltage at J808 to ground at 35.5VDC.

Tone P400
Silmic II's were used here in most places, I tried some Elna RBS BP type at C404/405 this time VS the MUSE BP, I think I like the elna's more. C414/415 were replaced with MKS4, and C404/405 with MKS2 WIMA's. C401/402 were replaced with .22uf Mundorf Evo Oil capacitors. I think these made a definable difference, lil costly but not too bad from partsconnexion.

Phono P750
The tantalums on this board were replaced with polar Silmic II's along without he large cap, their also a axial above the board to the tone, this was replaced with a TVX 220uf 50V axial, a great standard axial. The compensation varistor at H709 a VD1212 was replaced with two 1N4148 in series and heatshrinked, Id imagine a 4448 would work as well, their damn near identical.  H707/708 were replaced with single 1N4148 diodes and the failure prone 2sc458's were replaced with new KSC1845's with matched Hfe's. The original films were the "Fat Browns" and frankly im not convinced I could find something as original sounding, so they stayed, had they been say the greenies type, PP ECW or Sonicaps die try.

I think the only things Id really like to try are the Panasonic FR's in the PS and AM/FM/process boards, though I think mayhap low impedance type for the PS might be better than a low ESR type that would be best for a general robust grade AM/FM cap. Still up for debate here. Also I may try the Mundorf pole type Pat's used. He said he's had phenomenal results with em.

All AM/FM Tuner circuits were recapped with Panasonic FR/FC capacitors, with a full band AM/FM and separation alignment performed.

All in the 2230 is my favorite go to 22XX class receiver. The sound is typical of Marantz, with a nice lush presentation.

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