Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

Thanks bud m i will do that ...and thanks again rj

[petehall347]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

you could test the rest of the amp circuit without an stk fitted . a couple of 1k resistors in the right places will allow this .

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

thanks pete but thats beyond my ability and have no interest in doing that

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

apparently sanyo does not make these STK4191 II chips anymore and it appears all the ones sold as new on ebay are chinese knockoffs

i dont want my sound system sounding like shit...where can i get an original quality stk4191 II chip from? or am i stuck with buying cheap chinese knockoff?

[R_J]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

You might find new old stock on the internet, if not you don't have much choice, hopefully the Chinese ic is ok.

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

thanks
it seems i may have to buy cheap chinese knockoffs they are less than 10$..i guess ill buy the cheapest..they are all made in china knockoffs so it doesnt matter i guess

10$ or 30$ they are all the same...and there is no way to prove its new old stock other than weight

the knockoffs are much lighter in weight..but im sure every seller on ebay will say they are orignal sanyos and not knockoffs

[petehall347]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

if you use a fake one don't turn the vol up high .

[petehall347]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

here you go .. new ones here . https://nikkoe.com/catalogsearch/result/?q=STK4191+II

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

If i cant crank it up to my 1970s black sabbath tapes then there is no sense wasting my time with a cheap chinese knockoff...ill look for an original....how do u know that stk link is original?...its looks like knockoff....fyi i live in usa so not uk....and are all stk 4191 II same pins?...im seeing some with 22pins...mine has 18pins...im messaging many ebay sellers to find out if orig or knockoffs...one guy said he thinks his is from 70s 80s nos...but he has to verify...one other question...using my original board would i b able to use a diff upgraded stk or do i have to use stk4191 II...assuming no modifications....fyi my original sanyo stk4191 II weighs 42g if anyone has a chinese knockoff to confirm weight difference it would be appreciated

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

https://youtu.be/EZJjqpDaSZs

Shows counterfeit vs real

Weight can be the sign of fake...unless china starts adding dummy weight to trick people

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

im about to buy a genuine on ebay however there are 3 sekllers with stk4191 but some are

stk4191
stk4191 II
stk4191 V


mine is stk4191 II

what importance is the value after the 4191 mean? and the plain 4191?

[R_J]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

The stk4191 V I believe is a newer version, and is pin compatible with stk4191 II There are datasheets available for all

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

Thanks rj
I did see a post saying the unmarked and II and V are compatible but diff versions that have diff THD values? Totsl harmonic distortion ..whatever that is...im going to stick with II unless there is a good reason not to....newer is usually not better...newer is almost always cheaper made

[eccerr0r]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

Some of these knockoffs apparently can run full wattage fine but I don't have a distortion meter to tell how bad it is... Unfortunately I don't have the Fisher anymore so I can't test.

I still have a probably fake, extra STK4191V that someday I'd like to test...

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

Hi easter
Do u know what the unmarked 4191 and II and V mean?

[budm]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

II, V are just the version, see the V spec.
What are the numbers printed on the heatsink of your IC? Most of the faked one do not have number printed on the heatsink to tell what the module number and other codes printed on the heatsink.
Pictures are my NOS of STK's I kept from the late 70 ~ 80, my cost at that time was $15.99 so I do not see how they sell the NOS for <$10 on EBAY.

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

Hey budm can u weigh ur genuine stks..i bet they r about 45-47g

Thanks..i still think weight is the way to tell if fake or not..printed stamped numbers is easily faked ..as far as price goes...i have no idea..i see people selling fakes for $30...so price means nothing to me...one thing for sure every china seller on ebay selling stk ...i can just about guarantee those are knockoffs

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

Bud see this video..fakes have numbers on back too

https://youtu.be/EZJjqpDaSZs

[budm]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

Great video.
I do not have any weight scale to measure something that low.
I made crude balance beam using 12" ruler, it weights about 7 Quarters and 2 pennies.
So 5.67g x 7Q = 39.69g, 2.5 x 2p = 5 g, so total is 44.69g.
BTW, look at the line weight of the print on the heatsink of the faked, you will see that it has thick dark line weight compare to my STK's and probably yours too.

[shelby5041]

Re: Vintage Fisher Studio Standard CA-39 amplifier R channel bad?

hey budmn or anybody....i found a guy who has some stk4191 V and he guarantees they are genuine sanyo ..he said he bought them in yr 2000

my question is my stk4191 II is orig from 1980....would a snayo chip made in 2000 be comparable to the 1980 stk or did sanyo become cheaper in their product in the final years?

i guess im asking is would the internals be basically the same quality from 1980 as compared to 2000 genyuine sanyo stk?

he also told the the V stk is a newer version with less distortion than the II stk

my common sense says the older one would be made better but thats just me thinking logically.

and yes my original weighs about 45g so that seems about a good weight to go by when buying these stks..i like your weighing scale very nice lol...it appears the chinese versions are about 33g...

yes i see the diff in line weight thickness..i was trying to come up with an alternative way too by telloing fake and real...i looked at all the chinese ebay sellers and compared to known genuine and couldnt come up with anyhting repeatable..it even seems like sanyo changed their text and location of the text throught productions process..ill have to review the line thickness maybe thats a key factor as you mentioned.. the line thickness on my 1980 orig is like your orig stk..

my stk is 41912BCA5