Sharp SA-606H Vintage Amplifier

SA-606H view from side.

The SA-606H is a Stereo Tuner Amplifier made by the Sharp Corporation of Japan. It is a vintage 1970s amplifier made in Japan.

The tuner section consists of FM, SW, LW, and MW bands. There are three station presets for the FM band. The presets have a rotary tuning control with a colourful bright linear dial.

The amplifier output is around 60 watts per channel. The power stage is based on the Hitachi 2SC1060 (C1060) power transistors. There are four of these for the power output stage.

At the front, there are four slide controls for volume, bass, tone, and balance. A switched headphone socket cuts out the main speakers when listening through headphones.

At the back, DIN sockets provide inputs for one tape deck, and one record player, and a slide switch selects between ceramic and magnetic cartridge types for the record player input. There are also sockets for the AM and FM aerial connections.

The outside case is made of solid wood with the dimensions 47.5 cm × 12 cm × 32 cm.

Quality Vintage Amplifier

Amplifier view from front.

This is a wonderful quality amplifier made in Japan by Sharp. This is a great example that shows how Sharp have always been the leaders of consumer electronic products. I managed to find this old timer on eBay and paid a fiver for it. Of course, now days everyone is moving on to the multi-channel surround sound receivers, however this amplifier has character, and a unique sound quality that will be hard to find.

The fact that this amplifier lasted all these years is a testament to the good engineering design of that era. All of these old timers deserve some respect for staying in a working condition for so long; hence, I always go out of my way to provide them a good service.

The power amplifier stage uses the 2SA1060 transistors. These are vintage Japanese transistors that would be hard to find these days. There might be some sellers on eBay with old stock though but as Scotty often says, 'I cannot guarantee it!'

This transistor has a maximum collector current rating of 3 A, with Vce of 50 V, which is impressive for transistors of that era. The great thing about this transistor is that it is a triple diffused NPN silicon construction in a TO-220AA case. This very hardy transistor would be difficult to damage, and probably one of the reasons why these amplifiers have lasted so long.

The sound quality of this amplifier is wonderful, and it is as its namesake, which is very sharp. The tone and bass are very powerful and noticeable.

'Allo 'Allo! France Calling London

Illuminated radio needle and dial.

The AM and LW bands sounded clear. Many stations on this band still have good content worth listening. It is ideal if you want to keep up with your French or Italian.

The SW band was the most fun though. You can detect some Eastern radio stations with strange sounding music. It is always good to see a belly dancer with it though...

When I was a young whippersnapper I used to have a valve radio that looked very similar to this and I used to have hours of fun tuning in to distant radio stations. I was always trying to improve the antenna so that it would detect more stations. It is possible to pickup stations as far as India and Russia.

Full radio dial showing all the stations.

On the radio dial there is a list of all the old radio stations such as Budapest, BBC Brussels, BBC Rias, SW Funk, Paris Bremen, Luxemburg, MT Carlo Wien, and many more...

The electronic engineering for the radio section is also high quality. The tuning capacitor is the traditional multi-plate construction of good quality. There is a large ferrite rod antenna with coils for all the radio bands that I mentioned above.

The FM stereo reception is good, as it uses the Toshiba TA7054P FM radio IC. I was able to detect many distant radio stations, which was impressive. BBC radio 4 was clear, as this is the radio station I sometimes listen to. The stereo channel separation was very noticeable in this tuner and far better than what my modern surround sound receiver produced. It made me wonder why I had DAB. Ah, yes, it is supposed to be progress...

Reviving the Old Timer

Amplifier back sockets and connections.

I bought him on eBay for a fiver and the description was that he was completely dead. However, I am an Engineer. We have the technology and expertise to revive anything. Was there a line like that on that 70s sci-fi show, The Six Million Dollar Man? Of course these days it would be, “How much? I think we will just bin that thank you very much!” Steve Austin will have to take his chances on the NHS like everyone else...

The first thing I checked was the fuse in the mains plug, which was OK. The power was certainly getting to the main power switch, and coming out from it, so that was fine. Checking the fuse array inside the amplifier revealed two fuses had blown thereby indicating a short on those power rails. Checking the power rails indicated that it was not loaded down; hence, whatever caused the short was no longer present. I therefore replaced the fuses.

Front Lights Illumination

With the fuses replaced, the old timer came to life, all the lights at the front came on and it was impressive because this amplifier has these wonderful bright colourful lights similar to a VFD display, kind of like the cockpit instrument panel on a 747.

I decided to check for sound and plugged in some headphones, however there was no sound. It was as quiet as a door mouse. Further investigations with a digital meter revealed that the transformer's secondary coil was producing AC current. This was rectified, and there was definitely DC present. There was plenty of juice in his veins but his circuits were shocked to Hell; he needed a little TLC.

The amplifier board was definitely receiving this DC current so I checked the transistors for shorts and opens. A quick check in-situ revealed that the transistors were fine, but there was nothing showing on their emitters, which is unusual. Hence, I checked the power resistor connected to their emitters, as this is the only other thing that completes the circuit across the rails in a Class A. Sure enough, they were open.

That was a good instinctual call I thought, considering I am working without a circuit diagram! Luckily, I had some recycled resistors of the same period and decided to replace all four to keep the channels identical.

I switched the old timer on again, and he began producing a wonderful sound through my headphones; I had the amplifier set to FM radio and it was playing, “It’s Not Unusual” by that Welsh god of music I then connected some test speakers and it sounded great. The amplifier board also has some presets for DC offset and bias calibration, so I hooked up the oscilloscope and signal generator and adjusted those as well. The presets also needed a good clean with a contact cleaner first and then I adjusted them precisely with pinpoint accuracy.

The sliders were crackling -- which is not unusual -- and some good quality contact cleaner sorts that out wonderfully. I liked this old timer so much that I used up a whole can of expensive contact cleaner for all the switches and contacts. Even the PCB received a good clean!

The next day I connected my turntable, and my Sony TC-152SD tape recorder, because it has a DIN audio connection socket, and I already had a DIN-to-DIN wire for connecting them. The sound quality was very impressive. I had no idea that these vintage amplifiers sounded so great. I will have to keep an eye out for more

Aerial and DIN sockets.

All the sockets at the back received a nice clean with contact cleaner. They are like new again!

An act of God

Wooden case, heat ventilation grills.

Old-timer to old-timer, dust to dust...

Just as I was sitting down to a nice hot cup of Earl Grey, there was a knock on the door. It was My Friend Father Clarke... As soon as he saw the amplifier, he had to have it. He would not take no for an answer. I of course received all the blessings of the Church, including a short sermon about how god will look my way this year... Yes, apparently this year is definitely my year. I will be sailing in my own yacht in the Bahamas...

Moreover, almost by magic, an act of god you could say, the amplifier was gone! Moreover, so was Father Clarke! I decided to let him have it. I figured the old timer going to another old timer was good cosmic symmetry.

This Article Continues...

Sharp SA-606H Vintage Amplifier
Sharp SA-606H inside View
Sharp SA-606H Radio Tuner Stage
Sharp SA-606H Transformer and PSU
Sharp SA-606H PCB and Back Chassis
Sharp SA-606H Back Sockets
Sharp SA-606H Amplifier Stage
Sharp SA-606H Front Lights