Virtual Audition of Very Simple Quasi MOSFET Amp

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#222
pinnocchio said:
I'm almost certain they will be fake on Aliexpress since they're "precious" obsolete parts. You can buy originals from forum members if you post in the swap meet.

Ciao!
Do
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Maybe not original, maybe fakes, but sometimes fakes are made to similar specs and work like intended. For the low low price I might take a gamble and get some. I have bought bags of cheap 2sk170's and 2sj74's from Ali - they seem to work just fine.
 
#226
#227
xrk971 said:
Maybe not original, maybe fakes, but sometimes fakes are made to similar specs and work like intended. For the low low price I might take a gamble and get some. I have bought bags of cheap 2sk170's and 2sj74's from Ali - they seem to work just fine.
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"Sometimes" ....🙄
Instead of possibly struggling in an amp with unknown transistors I would try to use genuine IrF610/9610 instead (however with different spec than the good Toshiba....but at least you will know what you get....) and be able to repeat the same amp performance with other builds....
Of course my preference would go for genuine Toshiba...😉

Fab
 
#229
My M2 has the same excessive 3rd harmonic signature when played on speakers as measured by others and as discussed by Mr Pass. It's the use of the auto-transformer that gives it its sound and HD. The same (fake) 2sk170's seem to build a fine sounding Circlophone and ACA so I would not blame the Ali 2sk170's.
 
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#230
xrk971 said:
My M2 has the same excessive 3rd harmonic signature when played on speakers as measured by others and as discussed by Mr Pass. It's the use of the auto-transformer that gives it its sound and HD. The same (fake) 2sk170's seem to build a fine sounding Circlophone and ACA so I would not blame the Ali 2sk170's.
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It does not mean that your 2sk170 are fake or even bad fake for the operating conditions used in your amp. It just mean that buying stuff from these improvised suppliers is risky so you may get lucky... or not...
even from the same vendor you can get a mix of genuine or fake parts...have in mind that they are simply distributors and they may not well control their sources....
The fake is not meant to be a direct replacement of the genuine part, there is no rule.

Frankly I habe already bought parts from EBay or Ali but I knew the risks involved and verified several data sheet parameters by myself to get more confidence before using the parts....but even so I can not test some parameters such as the absolute ones before damage for example....
Even if your amp works it may not be the exact amp you intended to build as per the schematics...🙄

Fab
 
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#232
2sk2013/2sj313

xrk971 said:
I guess none of my amps sound as per schematic then given 90% of my parts are from China. 🙂
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I said maybe...😉

But getting back to the original 2SK2013/2Sj313 part subject -as a hint , if you are interested...- you should at least pick the part from a vendor showing a picture meeting the datasheet indication about marking and shape of body... Only trying to help here....🙄 now I will shut my mouth...
Fab
 
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#233
Toshiba 2SJ/2SK

I hope it will be helpfull. Couple of years back I have bought a bunch of 2sk2013/2sj313 transistors on ebay, on the auction there was picture of the oryginal Toshiba packing box (hope it was ORI).
I allways dreamed to build sony 777es amp but I never did. I have checked Vgs voltage and it was approx 2,2V so seems to be OK. So on the pic bellow should be the ORI trannies.

I have bought also a lot of IRF540/9540 transistors on ebay because they were cheap, and they are 100% fake, Vgs is approx 2,5V and after breaking the plastic off the silicon structure is very, very small. So it is a bit of a gamble to get good parts from ebay/alliexpres/dhgate etc.

I have opened a lot of transistors, maybe I will take a better foto someday and post all of them just for reference.

bimo
I have a small mod for FX8 for checking for you, the lower part of the VAS is already well buffered, by adding a few components you can buffer better the top side of the VAS too.
What would you think ??
 

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#239
D:\apexaudio\fx8 sonal
bimo
I have a small mod for FX8 for checking for you, the lower part of the VAS is already well buffered, by adding a few components you can buffer better the top side of the VAS too.
What would you think ??[/QUOTE]

Hi borys, did you test your mode? How about SQ?

Regards,
Boyet
 
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