9090 vs 9090db?

dsk

Well-Known Member
It has been delicately pointed out to me that there is a difference between a 9090 and a 9090db. I feel stupid asking what it is, but I know I will make all of you Sansui nuts happy to have an opportunity to expound. So, what is the difference?:dunno:
 
DB designation

125 wpc rating and Dolby, thus the DB.
I'm sure there are other differences but these are the two most obvious to me.

Tal
 
9090 vs. 9090DB

The FM Dolby feature is, for what it's worth, inherently meaningless as transmission in such a medium (FM Dolby) has gone the way of the dinosaur. On my Sansui unit (G9000DB), it's merely another "pretty button".

Zeke
 
I'm hip, I have the same feature on my Marantz. So is there a power difference? And what is market value of the G9000db?
 
Sorry man, I don't know the value. Although it sounds reflexive, market value is based entirely upon what one person will pay, so it is pretty subjective (G-series stuff).

I, also, am not up on the 9090DB specs and the like, although some sort of search on this site should serve you well.

Zeke
 
EW, you are like a walking (typing) encyclopedia. Now I want to know what the value of the storage cap thingys are in the 4300!:D
 
Re: 9090 vs. 9090DB

Originally posted by Zeke
The FM Dolby feature is, for what it's worth, inherently meaningless as transmission in such a medium (FM Dolby) has gone the way of the dinosaur. On my Sansui unit (G9000DB), it's merely another "pretty button".

Zeke

That's true for FM Dolby, but if I'm not mistaken, the Sansui DB units can also add Dolby NR throgh the tape input/output. This allows you to record in Dolby NR even if your tape deck doesn't have Dolby. Pretty cool for vintage guys.

- Pete
 
I'm certain that's correct. The Marantz receiver has that capability as well, dolby encoding and decoding.
 
I've mentioned this in previous posts: I've seen quite a few comments on line from 9090db owners that the Dolby ciricuit has failed over time, and there is no good way to repair it, other than swapping a working circuit out from a parts unit.

For some reason I can't quite understand, the 9090db has a greater market value than the 9090. The db has a higher output rating, but some have noted tha the 9090 actually has a little bit better build quality.
 
I do believe that there is a way to remove the db circuit from the path by hardwiring around it.
EchoWars am I right??

Tal
 
I dare say that with the right tech or schematics and know-how that is within the realm of possibilities.
I'm sure the wizard EW will chime in and tell us if he could do the mod or not...

I can't see how it would cost you more than about a buck in parts but the labor I wouldn't know.....

Tal
 
The biggest difference is the now useless dolby circuit which added much to the cost. In fact you get a metal cage over the heatsink on the 9090. The circuit is higher powered in the 9090db but I think the dolby circuit was the big difference.
 
Assuming the dolby chips on the board themselves don't go all the other resistors and caps that make it up should be possible to find. If it ever goes in my 990DB I will see what the real deal is. No sense messing with working units. The Fisher RS-1080 has the same deal, but the board can apparently be cut out of the path with a flip of the Dolby switch if I remember the schematics correctly. You could use the dolby to do dolby tapes on non dolby reel-to-reel decks (or 8-Track!) if you so desired. I can't say I ever used it that way. I think the 9090DB commands a premium because people believe it was better. Since it was considered TOTL, for some reason TOTL stuff always seems to have a market value higher then the next one down. Same goes for power level. More power more $. Even if the model down was better built. I could care less, if its stereo equipment, it comes to me at a reasonable price, I will take it regardless of what it is :D Like that stuff I bought Tuesday, did I really need that Marantz Model 30? Am I ever going to use the 5030 cassette deck? Will that Radio Shack receiver ever exit the basement? I dunno but at $6.98 each I was not going to not buy them. Same thing when the 990DB crossed my path. I did not need it but for $24 I would have bought it if it hadnt worked. Besides I need 125wpc in the computer room! ;)
 
Well the higher powered circuit brought bigger caps. 12000uf I think vs 6800uf? I have 50wpc receivers with 6800uf caps. Kinda puny for the 9090's power level. For comparison's sake the MCS 3125 has 4 6800uf caps, the Fisher RS-1060 has 15000uf (even the lowly 1058 has 15000uf). Other than that I guess I am just complaining about trivial matters. But geez, the price of those 9090DBs is climbing. Some are up around 1/3 of original retail. As nice as it is I could not spent $300+ on it, even my black faced version. Would want something more for that price.
 
Originally posted by qboneus
I dare say that with the right tech or schematics and know-how that is within the realm of possibilities.
I'm sure the wizard EW will chime in and tell us if he could do the mod or not...

I can't see how it would cost you more than about a buck in parts but the labor I wouldn't know.....

Tal


The big problem with trying to bypass the dolby circuit is the tape outputs are built into the dolby circuit. You could bypass the dolby by jumpering the connections in the OFF position of the switch but why mess with something that isn't broke. All of the parts for the dolby circuit are available including the Dolby IC. The switch cleans up very well with deoxit. The only other problem is on the early units the dolby circuit was connected to the switch CB via a flexible printed circuit board which was prone to failure the later units used a ribbon cable which is much more reliable.
 
One of the major differences in the two receivers (besides the dolby) is the power output.

The 9090DB is 125 watts 20-20,000hz with no more than .1% THD
The 9090 is 110 watts 20-20,000hz with no more than .2% THD

Note that the 9090 distortion figures are twice that of the 9090DB this in no doubt because of the power supply in the 9090 being much weaker than the 9090DB.

9090DB power consumption Max 650 watts, rated 435 watts
9090 Power consumption (no max listed) Rated 270 Watts just over half the power consumption, no doubt this is caused by the power transformer and the much smaller filter capacitors.

The smaller power supply is probably the cause of the greater distortion figures.

The only plus the 9090 has is the FM multipath circuit.
 
I'd suggest that likely the higher distortion is due to the quasi-complimentary output stage (all NPN devices) design of the 9090, versus the full complimentary design (NPN and PNP outputs) of the 9090db. The positive NPN's on the 9090 provide a nice low impedence signal path to the load, but the negative side of course has to drive the load from the collector, which is a high impedence source. I've never been crazy about this scheme, but sometimes the result is pretty damn good.

FWIW, I measured the distortion on the last 9090 that I rebuilt at about 0.09%...quite a bit lower than spec. I would say that the last 9090db I worked on, the distortion was a bit lower (0.05%).
 
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