For sale is a USA-made Marantz model 250 stereo 125WPC power amplifier that has received an over-the-top restoration throughout! These are highly sought after classic Marantz amps for a reason...they're built like tanks, they sound incredible and they have that classic Marantz style to boot! This amplifier boasts a true 125WPC into 8 Ohms output stage and sports a total bandwidth of 2Hz to 100kHz - meaning every last bit of detail is able to make it through! These are some of the best sounding solid state amps made - they have a great output stage topology that allows for high bandwidth without sacrificing stability or low end performance and they use only top notch quality components throughout on these early USA-made Marantz! We have extensive experience restoring these classic USA-made Marantz power amplifiers and know exactly what parts to use and where to bring back dead amplifiers or even upgrade working amplifiers to be ultimately reliable for many years to come! Not everyone can work on these amplifiers - they can give even the most experienced repair people fits if they don't know how to properly choose substitute parts for these amps. Details of the amplifier and restoration can be found below.
Cosmetically this is the nicer of two 250's that we recently restored. The original meters still function perfectly and the original bezels/housings are still nice and solid without any major dings or breaks. The top grille had some rust and thus was cleaned up and repainted with high quality, ultra tough lacquer paint and of course everything else is detailed inside and out. The bottom does exhibit some paint issues but we did not think it was necessary to go nuts painting the part of the amp you see the least!
Electronically we really went all out on this one! First the power supply is rebuilt with all new high temperature, low impedance, long life electrolytic capacitors throughout as well as replacing any transistors in the power supply. Any failure prone diodes were replaced as well. The main filter capacitors were upgraded to a slightly higher voltage with the same capacitance rating for ultimate reliability. After going over all solder joints throughout the power supply boards, the relay was disassembled and thoroughly cleaned/contacts burnished until completely dropout free, distortion free operation was achieved.
Next the power amp boards are both pulled out and first had every single electrolytic and tantalum capacitor replaced. Any other heat stressed resistors etc were replaced and any failed or failure prone transistors were replaced as well. We have a lot of experience with these USA made Marantz amps and know exactly what substitutes to use where and how to gain match everything so that performance is restored to exactly as it should be! Next the front ends of the power amplifier boards are rebuilt with gain matched transistors where necessary as well as upgrading the wattage a bit as well. The failure prone bias transistors as well as clipping protection transistors are also replaced as are any other failed components. All solder joints are carefully checked over and touched up as needed - there's a few spots where these can have trouble that we've found over the years. All four output transistors on both sides are replaced with modern parts that have better ratings than the original parts in all aspects.
Lastly before powering up, the meter board is rebuilt with all new electrolytic caps, transistors, diodes and also replacing any burned up resistors with higher wattage parts (another common failure on these). Both meter circuits were matched carefully and then all lights were changed to modern LED's for a great crisp look and lower heat dissipation in the plastic meter housings.
The amp is then powered up and the bias/DC offset are set and checked multiple times over the course of a few hours until we are certain they are absolutely rock solid on both channels. All other internal controls are set according to the service manual and both meters are carefully matched so that they perform exactly the same throughout their range and match the output the amp is putting out into an 8 Ohm load (as specified in the service manual). All performance aspects are verified both on the bench and in our system...and this is one seriously kick ass power amplifier that is well deserving of its reputation!
We put a lot of work in these restorations and can't stand it when they get messed up in shipping. We will package and ship this amp so it arrives as it left here, plug and play ready to rock!
