Is the Sansui 8080db a great receiver?
- Thread starter Gdizard
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Sounds good (though a bit different from 5000X you previously inside on) and I find aesthetics quite appealing. Be aware that the Dolby switch board is prone to continuity problems owing to poorly design vias (pass throughs) and the driver board is prone to instability from fusible resistors that go way off value with age. Both will need to be addressed straight away for reliability, if not already done.
Gdizard
Member
T
The 8080db is $300 so I thought it would work even if I spend more to have someone fix it .
Not really sure though I am told that it is working now
thank you sir
The 8080db is $300 so I thought it would work even if I spend more to have someone fix it .
Not really sure though I am told that it is working now
dr*audio
Fish fingers and custard!
The 8080dB and 9090dB have major problems that are very expensive to fix. They have 80 feedthrus on the Dolby board that connect the traces on the 2 sides of the board. The technology was primitive at the time and the feedthrus become intermittent, causing channels to drop out. The audio signals go in and out of the Dolby board multiple times so this happens even if you have the Dolby switched off. The board must be removed, the selector switch must be removed, and a wire inserted through each feedthru, bent over on both sides of the board and soldered on both sides of the board. Some models have a green flat flexible cable on the Dolby board which goes intermittent and must be replaced with a ribbon cable. Get the 8080 or 9090 if you like the way they look.
on the 8080DB units, what does the Dolby 2 switch control? Thanks Al
Bright_Star
Active Member
The operating manual explains all the functions, can be found online via google search.
But where is there a Dolby 2 (or a 1 for that matter?) You can select a Rec 1 or Rec 2 for dolby depending on which tape unit
is connected to the Tape jacks, 1 or 2.
But where is there a Dolby 2 (or a 1 for that matter?) You can select a Rec 1 or Rec 2 for dolby depending on which tape unit
is connected to the Tape jacks, 1 or 2.
Bright_Star
Active Member
Some G series models had dolby as well, do they have the same issues as the 9090 & 8080db's?
I am also curious as to why the db's have their A & B speaker terminals wired in series, when parallel is much more common.
I was not aware of this when I used to own a 9090DB, to verify its wired that way.
I'm not aware of the G series having such issues, but by the time they were in production, Sansui probably had the process of making dual sided boards better refined. The 8080DB/9090DB and contemporary QRX-8001/9001 both had issues with failing vias on double sided boards, that the factory tried to address (by adding rivets) but never fully solved. Thus, anytime one is restoring any of the herein mentioned models, these boards need their vias pinned for long term reliability.
As to the series versus parallel speaker arrangement, series wiring lessened problems from low impedance on the output stage when running multiple sets of speakers.
As to the series versus parallel speaker arrangement, series wiring lessened problems from low impedance on the output stage when running multiple sets of speakers.
Bright_Star
Active Member
The 9090db came after the 9090 non db, and overlapped with the G series, so its still unclear as to why the dolby issues would be less problematic on the G series- unless they are, but just not as much discussed for whatever reasons.
And of course, series wiring adds to the impedance rather than reduces it, but if it was a matter of protecting the output stage, I am pondering why it was only on those two models, compared to all the other models Sansui made, be it larger or smaller.
And of course, series wiring adds to the impedance rather than reduces it, but if it was a matter of protecting the output stage, I am pondering why it was only on those two models, compared to all the other models Sansui made, be it larger or smaller.
A guy who lived in the barracks next to me back in the day had the 7070, And I remember it being very nice, Especially vinyl playback
@Bright_Star, I'd have to look at the G-9000DB service data, it may be it didn't have a double sided board to be an issue to begin with. I only have a G-9000, not A DB, so can't check the unit itself to see.
Another difference between the 8080/9090 and their respective DB variants, is that the former have quasi-complementary output stages, the latter are fully complementary. The change to fully complementary also yielded a modest power increase, 110WPC to 125WPC on the 9090DB
Another difference between the 8080/9090 and their respective DB variants, is that the former have quasi-complementary output stages, the latter are fully complementary. The change to fully complementary also yielded a modest power increase, 110WPC to 125WPC on the 9090DB
sKiZo
Hates received: 92644 43.20°N 85.50°W
All said, I figure an 8080 might be a better choice if you're not into the PITA that is a pass through repair ... (shudder)
Here's an example of what we're talking. This one's from a QRX 9001.
You can see several "pinned" connections here that connect a trace on one side of the board to a matching trace on the other side to complete a circuit. Maybe 50 of those silly things depending on the model. The OEM connections are riveted and soldered, but the solder dries out and cracks. letting the traces go open. Just touching up the connections won't work because the rivets corrode and lift from the traces as well. You have to strip the traces back a bit from the rivets, make a pin from old cap clippings, and solder that in place for a good reliable connection. Solder one side, let that set, then bend the other end of the pin to match the trace to the other side of the board. Once both sides are set, do a final touch up to build and cover each copper pad (both sides of the board) for a solid connection.
PS - first clue you've got a problem - the mode and source buttons will go wonky, dropping channels and such.
Here's an example of what we're talking. This one's from a QRX 9001.
You can see several "pinned" connections here that connect a trace on one side of the board to a matching trace on the other side to complete a circuit. Maybe 50 of those silly things depending on the model. The OEM connections are riveted and soldered, but the solder dries out and cracks. letting the traces go open. Just touching up the connections won't work because the rivets corrode and lift from the traces as well. You have to strip the traces back a bit from the rivets, make a pin from old cap clippings, and solder that in place for a good reliable connection. Solder one side, let that set, then bend the other end of the pin to match the trace to the other side of the board. Once both sides are set, do a final touch up to build and cover each copper pad (both sides of the board) for a solid connection.
PS - first clue you've got a problem - the mode and source buttons will go wonky, dropping channels and such.
dr*audio
Fish fingers and custard!
I don't know what you are referring to, but there is one selector switch for the Dolby and tape. It selects which deck you are listening to, whether the Dolby is on or off, and allows you to copy from deck 1 to deck 2 or vice versa. Because of the tape switching, all the signals go through the Dolby board, regardless whether the Dolby is on or not.
Thanks, my Dolby board seems fine as this thing is bone stock, never knew what the Dolby 2 switch was for. Dolby 1 works and passes audio just fine
STOP
If this is the Dave Culver "will ship" 8080DB that's infesting my local CL and OfferUp please don't.
Bright_Star
Active Member
Sansui was also weird about the ohm usage instructions, just look at the back and compare the 9090 and 8080 db and non db's,
what is said, or not said about using the A and B terminals.
what is said, or not said about using the A and B terminals.
Gdizard
Member
I
Can they arrest this person?
I guess it's possible but he's been operating for a long time. I would have to see the unit in person before I would even consider buying it. Having to pay an unknown person and hoping that they will ship it would not happen for me.
I have had a 9090db and an 8080db (neither one was restored) but it was at two different times so my opinion may not be valid. I thought that the 8080db was the best sounding of the two. I thought both sounded very nice.
