Hi-Fi Stereo sound is a long term, potentially high dollar, investment. Speakers easily last decades with proper care, and potentially much longer than that. Amplifiers have remained highly unchanged since their solid state modernization in the late 60’s; sure the efficiency has gone up, but the basic in / out functionality are identical. Pre-amps and Receivers haven’t really changed much either in how they function; allowing you to connect multiple sources into one box, adding integrated volume control, and feeding that output to your amplifier and ultimately, your speakers.
What has changed dramatically in the last few years is the digital processing and wireless control now so common in all but the cheapest receivers available at your local big box store. How fair is it that a $200 receiver has better connection options then your classic high power silver age separates. The ability to wirelessly stream music to your sound system is a great advantage compared to conventional methods; now you can stay seated in your listening position while changing tracks and adjusting volume, or even move around the house and always be no further then a swipe away from controlling your music.
Many modern receivers / pre-amps also incorporate digital signal processing (DSP) that let you customize the sound of your audio, and can provide room correction and bass management. To fit many of these fancy features in modern electronics, the audio path itself tends to suffer; you can only fit so much stuff in one chassis before something starts to suffer. Power supplies become smaller, receivers have smaller and smaller power outputs, and we start losing phono inputs and other connection methods.
So if you already have a great sounding system, why not modernize it and breathe new life into your equipment?
The goal of this project was to take a classic Marantz 4300 Quadraphonic receiver, very conservatively rated at 100 watts x 2 into 8 ohms, and add all the modern conveniences. The customer wanted us to provide wireless streaming and volume control, Multiple USB ports for power, full DSP room correction, and provide outputs for S T E R E O subwoofers with full bass management (crossovers).
We started by adding a brand new product, Google Chromecast Audio; a wonderfully simple and cost effective streaming media unit. Google Chromecast operates over Wi-Fi and not Bluetooth like many other wireless receivers. Bluetooth has horrible compression, even with APTx, that can add harsh noise to many recordings. Google Chromecast has a 24bit 192kHz D/A converter, or alternatively has optical Toslink output if you have an external DAC. The Chromecast is powered by USB and is always on. You can control it from your Android or Apple IPhone and offers Volume control as well.
To add DSP and Subwoofer output to the receiver, we went with a simple MiniDSP 2×4 unit from MiniDSP. Again, a very cost effective but high quality DSP unit that offers all the features we required for this project. One of the distinct advantages older receivers have is they tended to have pre-out/pre-in loops for the amplifier stage. That means all the signal heading to the amplifier goes through this one loop before being sent to the amplifier itself. The miniDSP was simply hooked up in this loop and 2 of the output channels were looped back to the pre-in input. The other 2 outputs (2 inputs, 4 outputs on the 2×4 miniDSP) were used for S T E R E O subwoofer outputs and bass management.
The mini DSP is also powered by a standard USB connection, so we added an ANKER 5 port powered USB power supply to the mix. This allowed the customer to power the Chromecast Audio, MiniDSP and provided 3 additional USB ports for Charging their Phones and Tablets.
After making all the appropriate connections we did some initial set up in MiniDSP to get the outputs correct and set some basic crossovers. Since the customer had one primary listening position, we applied our Hi-Fi room equalization method with the appropriate acoustic measurements and calculated the required filters. Reviewing the in room measurements we were also able to level match and set time delay between the two speakers to perfectly time align them to the listening position. The customer did not have subwoofers already purchased at the time of installation, so this was left as a task for the future; however the system now allows the installation of two subwoofers, either in mono or true R/H stereo with full control over the crossovers, slope, and phase to the main speakers.
Through the use of some simple, but very high quality and well-made hardware, we were able to fully modernize this classic piece of audio history.