• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Sansui 9090(DB) and 8080(DB)

B

Bannon

New Member
I am on a quest for an 9090DB but I also may consider the non-Dolby 9090 or the two variants of the 8080. I'm about to do research to understand the differences between the four units but at the same time I wanted to get the expert (you) opinions, suggestions, etc. on these units? Also, I'm searching eBay, Facebook Marketplace, and HiFiShark but do you have other recommended sources?

Thanks for your input
 
Register to hide this ad
Biggest difference really is the lack of the dreaded double sided board on the 8080 and 9090. Any I/O weirdness on a "DB" series can usually be traced to failed pass through connections on that board, and it's a REAL PITA to fix.
 
Thanks for the information sKiZo. So, I may want to forgo the additional WPC of the DB model for greater sanity and problem avoidance of the non-DB models, correct?
 
IMHO anyway. Both types are plenty powerful and have the famous Sui glow in de audio ...

PS - if you want a DIY project that includes the double sided board, don't half step ... I rebuilt my QRX quad, but wouldn't try that again on a bet ... ;-}

(my preciouosssss )

front-panel-lit.jpg
 
Here's the best of CDFixer's summary of the differences between the DB and non-DB models. It's much more than just with or without Dolby.


CDFixer said:
Here are all the differences that I know of in the two receivers

Tone and filter circuits, Identical on 8080/8080DB and 9090/9090DB, the 9090/9090DB versions have crossover selection switches on the tone board that the 8080/8080DB series do not have.

Dolby circuit only on the 8080/9090DB

Speaker selection 8080/9090 places the speakers in Parallel in A+B and A+C, the 8080/9090DB places them in series.

Tuner the 9090 has a noise canceller/multipath circuit incorporated in the tuner. the 8080 and 8080/9090DB receivers do not.

The 8080/9090 tuner lights are on only when the tuner is selected the 8080/9090DB they are on all the time. (Note the 8080/9090 can be modified to do this)

The 8080/9090 has one phono input, the 8080/9090DB has two.

The Amp section on the 8080/9090DBs is more robust, using a standard NPN/PNP complementary Push/pull amplifier. The 8080/9090 use a quasi complementary NPN only amplifier

The power supply on the 8080/9090DB is larger and has a much higher current capability. The filter caps on the 8080/9090 are 6700UF on the 8080/9090DB they are 12000UF.

The 8080/9090DB have two pre-out jacks, the 8080/9090 only one.
Click to expand...

- Pete
 
LBPete said:
Here's the best of CDFixer's summary of the differences between the DB and non-DB models. It's much more than just with or without Dolby.




- Pete
Click to expand...

Pete and by reference, CDFixer, thanks for the detailed explanation. Functionally, any of the four of these receivers will meet my needs.
  • Unlike so many here I have only one pair of speakers so parallel vs serial connections are not a concern.
  • It's interesting that only the 9090 has FM noise cancelation b ut we do not currently listen to FM radio but I am looking for a pair of rabbit ears so that may change.
  • I like lights so that's a plus for the Dobly models
  • I only have one turntable so the fact that the non-Dolby models only have one phono input isn't an issue.
  • The more robust amplifier and power supply on the Dolby models is something of value to me.
  • The one vs two pre-outs isn't of much value since I do not have a separate amplifier.
Thanks again for this information because I definitely find it valuable.
 
sKiZo said:
IMHO anyway. Both types are plenty powerful and have the famous Sui glow in de audio ...

PS - if you want a DIY project that includes the double sided board, don't half step ... I rebuilt my QRX quad, but wouldn't try that again on a bet ... ;-}

(my preciouosssss )

front-panel-lit.jpg
Click to expand...

I haven't held a soldering iron in decades so I'm not likely to try DIY on something of this caliber. However, I am looking forward to the "Sui glow in de audio"
 
I have the 9090 and it sounds very good, though currently in bits getting recapped, noisy transistors swapped out and generally serviced.

My plan is to increase the filter capacitor size of the non-DB version to something like the DB, in fact a little more, as I think they use the same transformer anyway.
 
CDFixer mentioned the power supply was more robust in the DB models but he didn't go into detail in this particular post. It would need a different transformer to have a higher power output as well.

- Pete
 
Oh I see chaps, thank you for the correction.

I had assumed that as the service manuals give the same rail voltages for the 9090 and the 9090 DB that the power difference between the two models was due in the main to the almost double the filter capacitance of the latter as compared to the former.

They are also listed as having the same part number in the service manuals, 4002350
 
Bob Chieldon said:
I had assumed that as the service manuals give the same rail voltages for the 9090 and the 9090 DB that the power difference between the two models was due in the main to the almost double the filter capacitance of the latter as compared to the former.
Click to expand...
For a given design it is impractical to get any increase in power output just by changing component values, and certainly not by increasing filter capacitor values. The quickest and dirtiest method for a small power increase would be an increase in rail voltage, but this would place additional demands on the output stage which may cause premature failure.
 
Last edited:
After additional thought I altered the wording of my post, really 'rail voltage increase' is the only way. But if a given amplifier is not powerful enough or loud enough for you, then you need a different amplifier or speakers or both. :)

Remember, doubling an amplifiers power will only give a 3dB increase (just audible), you need 10 times the power for it to be twice as loud. (I think I got that right)
 
Last edited:
No, no. Nothing like that. It’s a fine amplifier and I am unlikely to push its limits at home.

It’s just that just that i can’t see how else the 9090db can have more power than the 9090, given they both have the same voltage.

I thought it would be something to do with the ripple being less with the larger caps, leading to a slightly higher DC voltage under load, giving the extra 20 or so watts we are talking about here.
 
Bob Chieldon said:
It’s just that just that i can’t see how else the 9090db can have more power than the 9090, given they both have the same voltage
Click to expand...
The circuit configuration is completely different which may explain the power difference. 'Quasi Complementary' for the 8080 & 9090 and 'Fully Complementary' for the 8080DB & 9090DB, the difference for the top model is 15 Wpc - in other words not audible.
 
Last edited:
The are only two ways to increase current draw, and thus, power, in the load. Increase applied voltage delivered to a given load impedance, or decrease load impedance for a given applied voltage. Power=Voltage squared, divided by impedance, or current squared, times load impedance.
 
Thanks for explaining chaps.

I’ll measure power before and after I increase the main filter caps out of curiosity and report back too.
 
You must log in or register to reply here.
Back
Top Bottom