Sansui 8080 to the tech and back.

[Dan887217]

Hey guys,
So I found a local tech brought the Sansui 8080 over yesterday with a pioneer sx580. I got them back today. He said he doesn’t like things to stack up and he had time.

In his words of broken English the source of my audio issues were the source selection control which in turn lead to the lighting issues as well.

It’s all fixed up an works rather well.

Now are all Sansui’s designed that at low volume the left side makes sound first then the right side joins in.
I noticed it on my back up unit a Sansui Au555a that at low volume the left makes noise first.

Now the Au555a is full stock un restored as far as I can tell as before I set it up I cleaned and lubed all the pots/ switches as that was last done 3 years ago. I am still surprised when I open it up that it’s sounds so good but looks so basic inside.

On the side note that Pioneer Sx 580 that tagged along was just needing a adjustment and R401 resistor changed and it sang. ( I got this for free and credit others on their insight for information to trace the problem quickly)

130.00 later and both units are ready to play.
Pic of the Sansui soon.

Also am I okay with running a set of Infinity Qe (4 ohm? Doesn’t say on them) with 8 ohm set of three way in the photo (Soma 735b 8ohm 75watt)?

Dan

 

[Sansuiman]

The left channel leading the right channel in output level is just an idiosyncracy of the volume pot not tracking pefectly on both channels. The pot has two sections stacked and controlled by a common shaft, and it isnt unusual for one section to track slightly off the other. So, not an intentional design quirk, but rather a limitation of sorts on the precision of the control.

4 ohm speaker loads can be risky to run on these old Sansui receivers, most will handle them at low to moderate levels, but don't push them too hard or damage to the amp can result. Also, if not aleady done, the fusible resistors on the driver amp board need to be replaced to ensure stability of the output stage. Those have accounted for a LOT of failures in the 8080 and related models of the same period. As well, make sure the bias current and DC 0V adjustments are right on the money.

 

[JJCalvillo]

The left channel leading the right channel in output level is just an idiosyncracy of the volume pot not tracking pefectly on both channels. The pot has two sections stacked and controlled by a common shaft, and it isnt unusual for one section to track slightly off the other. So, not an intentional design quirk, but rather a limitation of sorts on the precision of the control.

4 ohm speaker loads can be risky to run on these old Sansui receivers, most will handle them at low to moderate levels, but don't push them too hard or damage to the amp can result. Also, if not aleady done, the fusible resistors on the driver amp board need to be replaced to ensure stability of the output stage. Those have accounted for a LOT of failures in the 8080 and related models of the same period. As well, make sure the bias current and DC 0V adjustments are right on the money.

Sansuiman, the impedance matching/speaker selector box is working great with my 8080. Running two sets of 8 ohm speakers through the box like you suggest it the other thread. Might work for Dan as well.

 

[Dan887217]

In 3 years I have had two techs look at it.

First tech did bias and offset and replaced a a resistor or transistor that was causing a sound issue and did and general clean and check for 130.00.

Second tech fixed the source selection and caused lighting and audio issues which is now fixed and did a cleaning.
I didn’t get a write up of what was done which is a shame. On the other side compared to the first tech he had a really sweet looking o scope and sound frequency machine thingy.
To top it all off he’s the only guy left in Nova Scotia to work on reel to reel tape decks.

With running the Infinity Qe, and Soma 735b together I don’t even get to 8 o clock on the dial.

the only time it every got close to 10 o clock was when I was running a pair of Mach ones and Epi 100.
Sadly I have sold my mach ones a) I am in a apartment now b) I got cats and c) I had bills to pay.
Amazing speaker that I am glad I had time to enjoy.
Sold them to a realistic gear head so was a win win.

Dan