jeromach
With sufficient thrust, ducks fly just fine
I have a weak spot for the Technics SU-8600.
I already did a "refresh" on one once (repair + recap "light") and I know it's not an amp for the fainthearted, nevertheless I got myself one yesterday as a project successor to the Technics
SU-8088 I recently finished.
The 8600 has been produced from 1975 to 1976, so it's one of the earlier Technics integrated amps. Its specs are ok, not outrageous, but delivering 73 Watts at 8 ohm isn't bad.
The one I bought yesterday was a bit of a gamble, the seller couldn't tell me anything about it, not even if it was working, but the price was ok, so I just bought it from a couple of pics.
When I got home and did some quick inspection it appeared to be above expectation. It's missing two of the small black plastic knobs which is not really exceptional, since they all crumble away
getting older. Also the power switches tend to break, although in this one it's still ok. The front plate is quite nice, no scratches, that IS exceptional.
Technically it appeared to be completely original, something I can really appreciate. I fired it up on a dbt initially, but the lamp dimmed immediately and the relay engaged, so no problems here.
A lot of distortion though when engaging the switches and turning the potmeters. It's rather normal for the 8600 unfortunately, all switches need to be taken apart and cleaned, no deoxit here
and the volume pot is particularly nasty to get right. But I knew what I was up to.
Still, this particular amp is even more nasty than what I was used to. Dropping channels and distortion could be evoked with the stereo/mono/reverse switch, the selector switch, the
tone on/defeat switch, the balance pot and - but not even that much - the volume pot.
The tone on/defeat switch was the nastiest source of distortion, so much that it also affected the volume, in fact in a way I was happy to have speakers with overload protection. On top of that
there was another strange phenomena; when selecting phono 1 or 2 there was a very loud noise (nothing connected to the inputs), like the wind through a forest, but then on a storm level.
Apart from this the amp sounded fine . I did manage to find an equilibrium in all the states the switches can be in, all ok, except the tone switch only operating normally at defeat.
The inner environment had collected a lot of dust, also nothing strange here. Although, maybe just one thing though; the voltage selector was at 240 volt, but no finger prints in the dust.
That's a little awkward, changing the voltage from 220 volt to 240 in these amps is something of a relatively recent fashion, so either the dust was collected recently too, or it somehow was on
240 for a longer time already, that would be strange.
Today I removed most of the dust. Not the final cleaning, that will be more thorough, but it's nice to work in an environment as clean as possible. The phono pre-amp / input selector board had
the most dust on it, apparently even so much that once removed also the phone 1 and 2 inputs stopped making the stormy noise. Problem 1 solved .
So, the next step will be dismantling to a further stage. One of the other nastities of this amp is the difficulty getting to all parts of the main board at the solder side. There is a latch, but removing
that doesn't give access to all parts of the board. I will try to remove the complete bottom plate, but that is uncharted territory yet, so I need to see how to do that. At the "refresh" I did earlier I
removed the complete board, but that's a "never again", since reconnecting all the wires to the board is a small disaster.
All right, enough of all the blahblah, here's some pics;
The dusty phono pre amp / input selector board
And seen from another angle
Original power outputs, nice!
And the bottom with the serial number (built 27th of July, 1976, thank you MacPhantom ) and the small latch
To be continued....
I already did a "refresh" on one once (repair + recap "light") and I know it's not an amp for the fainthearted, nevertheless I got myself one yesterday as a project successor to the Technics
SU-8088 I recently finished.
The 8600 has been produced from 1975 to 1976, so it's one of the earlier Technics integrated amps. Its specs are ok, not outrageous, but delivering 73 Watts at 8 ohm isn't bad.
The one I bought yesterday was a bit of a gamble, the seller couldn't tell me anything about it, not even if it was working, but the price was ok, so I just bought it from a couple of pics.
When I got home and did some quick inspection it appeared to be above expectation. It's missing two of the small black plastic knobs which is not really exceptional, since they all crumble away
getting older. Also the power switches tend to break, although in this one it's still ok. The front plate is quite nice, no scratches, that IS exceptional.
Technically it appeared to be completely original, something I can really appreciate. I fired it up on a dbt initially, but the lamp dimmed immediately and the relay engaged, so no problems here.
A lot of distortion though when engaging the switches and turning the potmeters. It's rather normal for the 8600 unfortunately, all switches need to be taken apart and cleaned, no deoxit here
and the volume pot is particularly nasty to get right. But I knew what I was up to.
Still, this particular amp is even more nasty than what I was used to. Dropping channels and distortion could be evoked with the stereo/mono/reverse switch, the selector switch, the
tone on/defeat switch, the balance pot and - but not even that much - the volume pot.
The tone on/defeat switch was the nastiest source of distortion, so much that it also affected the volume, in fact in a way I was happy to have speakers with overload protection. On top of that
there was another strange phenomena; when selecting phono 1 or 2 there was a very loud noise (nothing connected to the inputs), like the wind through a forest, but then on a storm level.
Apart from this the amp sounded fine . I did manage to find an equilibrium in all the states the switches can be in, all ok, except the tone switch only operating normally at defeat.
The inner environment had collected a lot of dust, also nothing strange here. Although, maybe just one thing though; the voltage selector was at 240 volt, but no finger prints in the dust.
That's a little awkward, changing the voltage from 220 volt to 240 in these amps is something of a relatively recent fashion, so either the dust was collected recently too, or it somehow was on
240 for a longer time already, that would be strange.
Today I removed most of the dust. Not the final cleaning, that will be more thorough, but it's nice to work in an environment as clean as possible. The phono pre-amp / input selector board had
the most dust on it, apparently even so much that once removed also the phone 1 and 2 inputs stopped making the stormy noise. Problem 1 solved .
So, the next step will be dismantling to a further stage. One of the other nastities of this amp is the difficulty getting to all parts of the main board at the solder side. There is a latch, but removing
that doesn't give access to all parts of the board. I will try to remove the complete bottom plate, but that is uncharted territory yet, so I need to see how to do that. At the "refresh" I did earlier I
removed the complete board, but that's a "never again", since reconnecting all the wires to the board is a small disaster.
All right, enough of all the blahblah, here's some pics;
The dusty phono pre amp / input selector board
And seen from another angle
Original power outputs, nice!
And the bottom with the serial number (built 27th of July, 1976, thank you MacPhantom ) and the small latch
To be continued....
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