Saturday, January 25, 2014
Marantz 1060 Console Stereo Amplifier
If you have never listened to a 1060, do it! Do it now! This is one of those magical amps, that will make you second guess yourself where you will be thinking 'Does it really sound that good?!' Yes, yes it does sound that good, and always impresses. Rated at a conservative 30 watts per channel it has plenty of power and its three-tone pre-amplifier is where all the magic happens. Derived from the Marantz 7T- the transistorised version of the Marantz 7C which is a pre amplifier that sits in legendary status land, this amplifier is sure to bring you hi-fidelity joy! So go out there and listen to one!
I've rebuilt quite a few 1060s'. They're really worth saving. When I did do restorations for people, I'd always ask if they had ever listened to one, if their answer was 'no' I would bring one out for them to have a listen to while I serviced their unit. By the time their unit was ready, they wouldn't want to let go of the 1060!
This amplifier was from a previously mentioned job lot of amplifiers I had acquired which included the Sansui AU-101 and Yamaha CA-610. It actually came with its matching tuner, the Marantz 105- an article I will have published soon. Although it was working, it was suffering from old age, very dirty switches and it had also been repaired previously.
On the workbench, ready for the operation.
Inside it was pretty clean, but the work that had been done was quite obvious. From what I could work out, something went wrong with one channel specifically on the power amplifier board, but the repairer has tried to replace everything on that channel both on power and pre-amplifier boards. More on this later..
First up is the power board, quite simple to rebuild but easily overlooked on the international model as the fuseboard is directly over it. Only 4 capacitors are needed to be replaced, as always Panasonic capacitors are being used for this rebuild.
Next up is the phono pre amplifier board. Specifically made for turntables its very low input means that ageing capacitors and faulty transistors can really make a difference in the quality of sound coming from your record player. Of significant point, every transistor was replaced in this circuit. Commonly used transistors of the time 2SC458 and 2SC1000 were notorious for drifting in their value and just going bad all together. These were all replaced with the surperior modern day KSC1845 which retains the original musical presence without the failings of the original components.
Next up is the Pre-Amplifier board. This is where the real work had to be put into this restoration. As you can see in the before photo below the left side was rebuilt in the previous repair, resistors, capacitors and transistors were replaced. Although the previous repair was successful, it was not up to the standard that I would consider acceptable. Resistors were soldered in by their ends, leaving them floating in the air, you can really see this on R414, R410 and R417. One of the resistors (R404) is actually made up of two resistors to create the right value, which is technically correct but looks like a mess.
For the same reasons that transistors were replaced in the phono board, all the transistors were replaced in this pre-amp board. KSA458 and 2SC1000 transistors were replaced with KSC1845, there were also two 2SA493 transistors which were replaced with KSA992. All electrolytic capacitors were replaced with Panasonic AM/FM series capacitors.
Next up the power amplifier board. This was also repaired as can be seen on the left side below. Capacitors, resistors and transistors were replaced. Although the transistors were correct and were left alone. Mostly, this was a cleanup and capacitor replacement job.
Last of all the main filter caps were replaced. In this amplifier there are 3 sets of caps, the largest is for AC-DC current filtering from the transformer. The two smaller ones are actually for each channel of the power amplifier board
As you may have noticed from all the other capacitor replacements, the size has significantly dropped in the past 40 years! Below you can see the size difference between the old (3000uF @ 55v) and the new (3300uF @ 63v).
With the above capacitors I was pretty lucky that they had the same diamater, which meant clamping back into the system was a breeze. However for the larger of the three, this was not the case. Instead, thick double sided tape was used to wrap and curl around the capacitor for it to fit into the existing clamp and hold it into place. You can see in the image below how much smaller the new filter capacitor is.
All of the parts that were removed and replaced. It might not look like much but below is a good few hours of work to be done the right way, not the rushed way.
As said over and over in the first few paragraphs, this is an amplifier that needs to be heard. It's the right combination and hits the sweet spot like a sublime malt :). Paired with a good set of speakers, this is the kind of combination that you'll always go back to. Every time I rebuild one and give it a good listening session I always love it and i'm sure you will too.
Enjoy the pictures below, as always you click on any image to get a larger photo.