QSI 5022 chips

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Quadchuck

Well-known Member
Joined
Jun 14, 2005
Messages
173
Location
Quadsylvania
This is directed to "tcdriver", 8 of 2002
I never really understood how to use this forum.
A tcdriver back in 2002 queried a source
for qsi 5022 chips.
Back in 2005 when I joined,I queried about
ECG813 chips and the possible retail hardware
they were used in.
It was acknowledged the chips were the same
but I never searched,so I missed the connection.
I have however finally found a source on the internet
for the chips.
I blew my original ECG813s hooking up power reverse
polarity(damn).

Coincidentally I recently discovered the commercial
product that used the chips and why the ECG813
schematic would never work that was included
in their catalogs of that era.
I won't go on if no one has interest.
 
This is directed to "tcdriver", 8 of 2002
I never really understood how to use this forum.
A tcdriver back in 2002 queried a source
for qsi 5022 chips.
Back in 2005 when I joined,I queried about
ECG813 chips and the possible retail hardware
they were used in.
It was acknowledged the chips were the same
but I never searched,so I missed the connection.
I have however finally found a source on the internet
for the chips.
I blew my original ECG813s hooking up power reverse
polarity(damn).

Coincidentally I recently discovered the commercial
product that used the chips and why the ECG813
schematic would never work that was included
in their catalogs of that era.
I won't go on if no one has interest.

Please, go on.
 
as far back as the 80's I saw the chip in ECG's catalog and decided to build the circuit.
It never worked and tough the 28 pin chip and associated parts seemed relatively
simple it still took care and time.
ECG was no help,they wrote back there was no supporting reference.
Seemed funny they sold a chip(made by QSI) and didn't know seemingly
what need it filled,other than quad cd-4.

I gave up several attempts to make it work until the 90's and I thought it was
strange the PLL pin went to ground and most other circuits using PLL balance
those pins between grnd and b+.
So I copied a FM stereo PLL circuit and it worked,although poorly.
I thought if there was that mistake,what other mistakes could exist in the
circuit diagram.
I also tried this site,but missed that 2002 post and no one else had info.
I tried many variations until one day I connected power wrong and blew both
chips that cost $28 each.
Now ECG was gone and NTE no longer listed it.
I've looked on and off the web and only found a few of those dealers that
don't list prices til you fill out a order list.
Then last year I saw a site "NeedleGuy.com" and he had them reasonable.
Got new chips but while he shows them as ECG813 they are really QSI chips.
That renewed my search to find what is wrong with the circuit.
I came across a heathkit ad1507 and realized it used that chip.
Now after comparing the schematics there are numerous differences in the
part selections,though many seem marginal i.e. 3.6k vs 3.9k resister.
The PLL was almost as I modified, but there are several other important
changes I'm going to make.
I'm thinking out changing 1 pin at a time to the Heathkit circuit til I find
other than the PLL what really improves the sound.
The Heathkit is good and maybe the best decoder I've had
though it has sonic deficiencies.
I've had Pioneers,Panasonic,Harmon Kardon,Akai, and the great thing about
this 2 chip design is that there is only 2 controls.
1 for PLL and 1 for separation all the other CD-4 decoders have numerous
adjustments internally that are daunting.
The heathkit uses 3 filters in this circuit and the other brands used 1 or 2
but never all 3.
I'm sure the new CD-4 decoder will make all this unnecessary,but after
20+ years I'd like to get "closure". (hate that cliche)
 
Very interesting! Thanks. I love this kind of story.
 
Chuck (I'm assuming that's your name \:^),

Have you looked at the Technics SH-400 schematic?

OldQuadGuy has it on his quadraphonic info site.

It uses those chips too (I'm sure you know this).

Doug
 
Hi Chuck,

My Technics SA-8500X uses the QSI 5022, I could get you a schematic of the CD-4 board if it would help.

Spence
 
Thanks for the additional reference!

Technics was the higher line of Panasonic right?

My SE-405 doesn't use those chips.

I will compare the schematics of Technics to the other
2.
QC
 
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