I know, I was just pointing out the differences in the components for others to see. Lots of people just lurk.
The upstream circuitry was tested and found to be fully functional. This is a matter of a clone not being equivalent to the original. When I have it on my workbench I will tear it to shreds and write a full report. With PICS!
Related to the clones I received and didn't work. Its not like these shady places are trying to create a clone equivelant of a hybrid. They are just getting something in the same case, with the same amount of pins, removing the printing, and reprinting with the part you need. They don't care that they will never work.
Begs the question: why bother? If I were to contest a device like this with Aliexpress it is hassle and bad rep for them. It will take effort to document it all (that I will embark onto anyway) for a pittance. Apparently it is cheaper to churn out some default design and reprint the device as wanted. But I fail to understand the business model. To forego STK clones I would be tempted to build a true Cordell LM3886 Gain Clone and put it in place of the power amp in a unit like this Akai. Did I mention I hate STK modules?
I have a stack of Ford JBL car amps in my workshop with bad STK 2240's and I have run out of replacements. Whenever the working one in the car dies I'll gut the connectors out of the amp to make an adapter so a commonly available amp will just plug in to the factory harness. Probably will use the lid to make a mount plate so it even mounts to the factory holes. I'm over trying to find replacement modules at this point.
Is “wehavethatitem” their eBay ID?
Maybe the reason I don't hate STK modules (and others like them) is I think they sound pretty good, and as long as they aren't abused, they usually hold up. The other reason maybe is that I have such a stock of NOS replacements (1 and 2 channel) that I can usually find what I need, or a replacement that will work.
A view of 2 boxes of Sanyo STK's , and a sleeve of Sanken S-80W
I don't contest that. Truth be told I prolly can't identify an amp that uses one in an ABX test. I hate them because when they go phut you must replace them and you're at the mercy of suppliers. Like Jack Ma (big boss of Alibaba).
Yes. But Orrin (passed away), and Adele (his wife) recently sold out. The "new" people sent me obvious remarked fakes and argued about it. I no longer trust them. In fact, eBay had to refund my money after I sent them back because they kept stalling and stonewalling me. It's possible they still have genuine stock, but I won't be their guinea pig to find out. Neither Orrin or Adele would do such a thing.
Got the two borked STKs. This is the original Sanyo burned out module:
It is clear that the thick film resistors have suffered damage.
And this is the non-functional clone:
The clone has pin 8 and 9 wired and that must be the reason it doesn't work in place of the original STK2145:
Note there are no emitter degeneration resistors in the clone.
I will need some time to reverse engineer the clone (and the original).
It is clear that the thick film resistors have suffered damage.
And this is the non-functional clone:
The clone has pin 8 and 9 wired and that must be the reason it doesn't work in place of the original STK2145:
Note there are no emitter degeneration resistors in the clone.
I will need some time to reverse engineer the clone (and the original).
Well, sod my day job. I bit the bullet and reverse engineered the clone:
I don't know what those people were smoking but this is NOT a drop-in replacement. In brackets the original functions. What's going on on pins 9-11 f*ck if I know. No wonder that poor Akai it was put into started smoking. Even with a DBT. For comparison the original internals:
I have seen some weird **** but this ranks very high...
I don't know what those people were smoking but this is NOT a drop-in replacement. In brackets the original functions. What's going on on pins 9-11 f*ck if I know. No wonder that poor Akai it was put into started smoking. Even with a DBT. For comparison the original internals:
I have seen some weird **** but this ranks very high...
<grin>
But it is even worse. Because there are no emitter resistors the bias on pins 16-12 is set very low, at around 2.2 V. The original module is around 2.6 V. This means that there is a lot of crossover distortion. They needed to do this in order to prevent the output transistors blowing up in their application pinout.
But it is even worse. Because there are no emitter resistors the bias on pins 16-12 is set very low, at around 2.2 V. The original module is around 2.6 V. This means that there is a lot of crossover distortion. They needed to do this in order to prevent the output transistors blowing up in their application pinout.
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50 Green
Well-Known Member
Crazy... Part of the circuit begins to look correct, then they completely go off the map! Component count on the transistors appears to be right, but looks like there's one each extra diode and resistor (on the mysterious pin 9.) Forget about putting them in the circuit correctly, they couldn't even count what was there.
jeromach
With sufficient thrust, ducks fly just fine
In fact I was already waiting for you to do that, building a clone 
Having said that, of course all these units are different, but are they so different that it would be possible to make some sort of one size fits all replacement?
Of course there are larger differences between the units, but I think also a lot of differences is just the maximum power a unit can spit out. With present day parts it shouldn't be either difficult or exepensive to take the maximum power unit and to use it for lower power units as well.
Might save a lot of these in fact not bad amps from the trash, which also again saves the planet (a little).
Having said that, of course all these units are different, but are they so different that it would be possible to make some sort of one size fits all replacement?
Of course there are larger differences between the units, but I think also a lot of differences is just the maximum power a unit can spit out. With present day parts it shouldn't be either difficult or exepensive to take the maximum power unit and to use it for lower power units as well.
Might save a lot of these in fact not bad amps from the trash, which also again saves the planet (a little).
