Beautiful Yamaha CA-2010 Integrated Amplifier Repair & Restoration

Yamaha’s beautiful CA-2010 must be one of the best-looking integrated amplifiers of all time. Come with me in my last article of 2018, as I explore, repair and restore this classic beast.

The Yamaha CA-2010 integrated amplifier is just beautiful and Yamaha knows it. In fact, this aesthetic works so well that Yamaha recently introduced a whole range of high-end products that mimic these classic looks, almost to a tee! The new Yamaha A-S3000 for example looks very much like its older sibling, as do the A-S2100 and A-S1100.

Wow, don’t you want one of these too..?

Anyway, this is of little consequence because you’d be insane to drop the $9000 AUD needed to buy an A-S3000. Why would you do it, when you can have the original CA-2010 for much less than that – if you can find one of course. The older Yamaha CA-2010 has better specs than the $4000 AUD A-S2100 and maybe even the A-S3000 too. Better specs! I know which one I’d prefer.

But before we go further, for a detailed video overview of the work I did here, check out my CA-2010 Repair & Overhaul video.

Features & Layout

The Yamaha CA-2010 is a heavy, very well-made amplifier and comes in a lovely wooden case, with flush edges. It’s a clean, minimalist aesthetic, and, despite the room-friendly appearance, as soon as you lift the CA-2010, the classic 1970’s build-quality is obvious.

Hewn from 21kg of wood, aluminium and steel, this amplifier clearly means business. It has a range of features typical of Japanese amplifiers from this era, including tape loops, tone controls, filters, MM / MC phono preamp, switchable class-A operation, power and record level metering, and more.

This of course means a proliferation of controls on the front panel, but they are hard-wired, board mounted, high-quality Alps parts. Everything in this amplifier is serviceable and almost everything is repairable, 40 years later. Try doing parts-level repairs on something modern with embedded processors, micro-controllers containing custom (unknown) code and with their labels removed!

The amplifier has two modes of operation – class A and class-A/B. In class-A, the amplifier supposedly delivers 30 Watts per channel. With with 175 Watt power consumption at idle in class-A mode, that’s probably not far off. In class A/B, she apparently delivers around 120 Watts per channel and I’m sure that’s accurate.

My only real issue with the CA-2010 is the thermal design. With no fan, the unit relies on two closely-mounted internal heatsinks, and convection cooling. Class-A mode is great in Japan where it’s cold and you can use the room-heating. Here in Australia though, the heatsinks quickly become too hot to touch in class-A, breaking a classic rule of thermal design.

All the heat is dissipated by these two back to back modules and heatsinks. The heatsinks are decently sized, but the idle current spec I feel is too high.

In class-A/B mode, the unit draws a more relaxed 60 Watts or so and doesn’t get nearly as hot. This is how I would be using it if I owned one, or I would reduce the class-A idle current.

Specifications, courtesy of HiFi Engine

Power output: 120 watts per channel into 8Ω (more than Yamaha’s new amps)
Frequency response: 5Hz to 50kHz
Total harmonic distortion: 0.005% (better than Yamaha’s new amps)
Damping factor: 45
Input sensitivity: 0.5mV (MC), 2mV (MM), 120mV (line)
Signal to noise ratio: 71dB (MC), 82dB (MM), 100dB (line)
Output: 120mV (line), 1V (Pre out)
Dimensions: 461 x 360 x 170mm
Weight: 21kg (heavy!)

Problems

The owner of this stunning Yamaha CA-2010 brought her to me because one channel was cutting in and out and the controls were unreliable. He’d sat on the unit for years, not using it and not knowing who he could take it to for repairs. I’m really pleased he found me.

The reasons for the faults became apparent as I worked, we’ll examine them in logical steps, below. Given her age and the heat generated in class-A mode, I advised my customer that an overhaul or restoration would be sensible for this unit if he planned to keep it. We agreed that I would do a major overhaul, basically a restoration, so let’s proceed.

Repair & Restoration

Well start with a look at the overall layout of the amplifier and then get down to a per-module overhaul of the unit.

The Yamaha CA-2010, before I started work on her.

Gotta love illuminated power meters.
The belly of the beast. Here we see the power supply and protection board (left), amplifier modules (middle) and the very nice Alps potentiometers and switches (bottom). Note how little wiring there is for a Japanese amplifier.
Eight (8) gang Alps volume and balance potentiometer. Nice.
Close up of some of the other controls. I cleaned and lubricated all of these.

Can you see the signs that someone has been in here before..? They didn’t do much of value and I didn’t like how they re-soldered the amplifier signal connections and routed these power supply connectors.

The Function Selection / Phono Board

This is a good starting point. There were some real problems with this board too, I addressed them before doing anything else.

I’ve missed a couple of pics here, but you will see more in my video. Amplifier modules to the left, function/phono board to the right. Note the board-mounted switches, selector rods and uni-joints.
In this shot you might notice the layer of grime, maybe even the large crack. I replaced all the aluminium electrolytic capacitors on this board and extensively repaired and re-worked it.
I found a big crack around the screw hole, top left. A large force damaged this at some point.

 

This is the crack before any preparatory work.
Here it is after washing and cleaning away solder mask with a glass fibre pen. You’ll note the crack has propagated through I think 6 traces.
Another angle. I glued the board by this point, using cyanoacrylate adhesive, so it is mechanically secure.
This is as far as the crack progressed. Something bad obviously happened to this board to cause this amount of damage.
The head of the screw I referred to at the top left of the board has sheared clean off. I removed this of course, unlike whoever looked at her previously.
Here are the repaired traces. After baring fresh copper, I applied a high-grade Sn/Pb/Cu alloy solder. This repair, combined with the glued board is good as new.
After these repairs, I re-worked many dry joints and replaced all the Al electrolytic caps.
New parts on the clean, repaired function board. Some caps in this part of the circuit differed from those in the schematic. I evaluated the schematics and decided Yamaha had cheaped out with a couple of these parts during production. I replaced them with the originally specified parts.
New caps…
The repaired, refreshed board. The switches on this board were gummed up. I cleaned them with solvent and then DeoxIt.

The Power Supply / Protection Board

The heart of any amplifier is its power supply, so it’s always a good place to spend some time.

This board comes out easily, despite everything being hard-wired.
Here we see the board prior to restoration. Note, the largest electrolytic capacitors you can see here were perfect. I left them in place. Even new parts didn’t test as well, and I have some very good new parts… I replaced all others though and I serviced the protection relay, which was causing problems, bottom right.
Very fluxey board, lots of dry joints to repair.
Like these…
This relay was playing the biggest part in the intermittent signal issue, along with the cracked selector board and damaged breakout board on the back of the amplifier. I use a process for servicing relays like this and they are as good as new afterwards. There is absolutely no need to replace them in most cases.
The power supply and protection board after repair and restoration. Several of the smaller capacitors on this board were dying.

The Amplifier Modules

All the heavy lifting happens in the amplifier modules, so I always pay very close attention to them.

The two modules, removed from the chassis and after washing. Yamaha were clever here, they used only four electrolytic capacitors per module. Layout is neat and three trimpots per module cover class-A bias, class-A/B bias and DC zero point.
I split the modules, re-work dry joints, replace any parts needed, re-mount devices on new thermal interfaces, de-flux, reassemble and test.
Output and driver devices on original thermal interfaces. The paste is dry, the mountings are loose and the mica washers are too thick.
These Sanken bipolar output devices are quite fast at 10 & 15 MHz. This is much faster than many other modern parts.
I separated each module, removed devices and cleaned away all traces of the old thermal paste.
Looks like I’d defluxed the board at this point and probably replaced the four small electrolytic capacitors.
Cleaned and prepped heatsink.
New silicone thermal pads (silpads) for TO-3 and TO-220 devices. plus new insulating washers for the TO-220 devices.
I remade the thermal interfaces of these TO-220 transistors with fresh thermal paste. Note the film capacitors I used to replace the Al electrolytics. These are higher spec, longer life parts, with almost zero ESR, perfect for their role hanging off the power supply rails.
One module down, one to go.
The second overhauled amplifier module…
…and from the other side. Again, I prefer this neater, more reliable silicone thermal solution. Having said that, fresh paste and good, thin mica is also a very good, though messier solution.
Restored power supply and amplifier modules back in the CA-2010. Note the re-soldered amplifier module signal connections.

The Breakout Board

These silly breakout boards are a weakness in just about every amplifier that has them. They are trouble because they carry the signal through crappy little slide switches, though extra joints and wires, often near mains wiring and they are fragile. The RCA connectors always seem to break and I just don’t like them.

This one is no exception. It had been smashed in, repaired, only one switch worked, and the RCA connectors were broken. Here, I am in the middle of epoxying the screw holes on the RCA connectors…
What a shemozzle, it’s already bad, without the crappy repairs! I wired the preamp directly to the amplifier and bypassed all this crap.
I repaired the connectors with epoxy so I could attach the board securely after I’d bypassed it. The bypass is in the wiring, bottom right. The signal now runs right by all the silly switches and connectors for a cleaner, more reliable signal path. And yes, it’s now DC coupled all the time 🙂
Phew! That took a few parts, but it was worth it.

Reassembly, Testing & Adjustment

The hard work comes together at this point. Time to set bias current in both amplifier modes, DC operating points, phono preamplifier distortion nulling and meter symmetry.

Everything back in place. The selector shafts are trickier than they look to install, so that switches line up etc…
Setting the class-A bias current. This amp gets HOT, even with the covers off. For the heat-sinking, 175 Watts is a lot, maybe too much, but that’s what Yamaha specify…
We need 300mV per channel for the Class-A bias adjustment. This amp consumes 175 Watts in class-A, continuously!
This is my Tektronix AA501 distortion analyser, analysing a signal fed into the phono preamp and output through the tape loop. We are looking at ‘A’ weighted distortion of 0.0021% after adjustment. Prior to adjustment, it was twice this figure, around 0.0040%. This is very low distortion, superb for a phono preamplifier being fed a large, 20kHz input signal! I have an extraordinarily low distortion signal generator for use in these sorts of tests, otherwise you can’t null down to these levels.

Cleaning, Polishing, Waxing

I find the cleaning jobs very therapeutic, especially when it comes to knobs, controls, and WOOD!

As always, I remove all the knobs and controls.
Then thoroughly clean the fascia…
…and knobs, trust me, they’re in there!
Time for the wooden case. Here it is before cleaning…

Special wood soap applied…
It lifts junk off the surface of the wood and nourishes it at the same time.
Then I apply a premium Australian furniture-grade beeswax…
After all that, the wood really pops. Note the scratches you saw before are gone.
Wow, I didn’t want to give this back..!

Final Thoughts

It really was a pleasure working on this Yamaha CA-2010 integrated amplifier and I am pleased to have restored her performance and repaired her faults. This raises an awkward realisation though, as we near 2020, because it reminds us of just how good Japanese hi-fi gear used to be in the 1970’s and 80’s. Sadly, this era is long gone.

Remember, this CA-2010 dates back as far as 1977 and still contains every one of her original semiconductors, switches, potentiometers and, until recently, capacitors. She works as well now as the day she was made, probably better after this overhaul.

Do you think an amplifier you buy today, like Yamaha’s new A-S2100 will still be working in 2058? Do you think it will be collectible, or will the Yamaha CA-2010 still be the one that people want, in another 40 years time…? I think I know the answer to that.

If you’d like me to look at your Yamaha CA series amplifier, you need only get in touch. I’d be happy to help!

If you get a chance to buy one of these classic amplifiers, don’t think about it for too long.
Remember, to replace this with something new, you’ll need at least $4000 AUD, probably a lot more. Even then, this will probably still be better.
I hope Yamaha’s stylist received a raise for this series of designs!

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