Gents,
I need some help with acquiring reliable replacements transistors for the common pair of transistors - C3200 GR and A1268 GR when used as differential pairs.
I read through numerous threads and datasheets. I purchase at Mouser, most of what is recommended is either not available (either or/complimentary), the gain is way lower than the c3200/1268 pair, or the voltages are not high enough to be substituted in place of the 3200/1268 pair.
In the lanzar opti thread I repaired, it came close to having to replacing the differential pair, but the problem was solved prior to this. I have a couple more Korean amps that came in all utilizing 3200/1268 transistors. I haven't assessed them as yet as see what's required but I'd like to be prepared.
In other parts of the circuit I can work around them but thus far not the differential pair.
all help will be appreciated.
I need some help with acquiring reliable replacements transistors for the common pair of transistors - C3200 GR and A1268 GR when used as differential pairs.
I read through numerous threads and datasheets. I purchase at Mouser, most of what is recommended is either not available (either or/complimentary), the gain is way lower than the c3200/1268 pair, or the voltages are not high enough to be substituted in place of the 3200/1268 pair.
In the lanzar opti thread I repaired, it came close to having to replacing the differential pair, but the problem was solved prior to this. I have a couple more Korean amps that came in all utilizing 3200/1268 transistors. I haven't assessed them as yet as see what's required but I'd like to be prepared.
In other parts of the circuit I can work around them but thus far not the differential pair.
all help will be appreciated.
Thread moved.
One of the few low noise, small-signal transistors with 120v Vce rating and still in production, is KSC1845, Fairchild/Onsemi's clone of the obsolete NEC 2SC1845. The PNP complement is KSA992 and they're used in many new designs and as replacement types for repair work. Their SPICE models are widely used in simulations posted here too. These should be just fine for the diff. pair at least.
Search results for: KSC1845FTA Bipolar Transistors - BJT Datasheets – Mouser Australia
https://au.mouser.com/datasheet/2/308/KSA992-1301291.pdf
Search results for: KSC1845FTA Bipolar Transistors - BJT Datasheets – Mouser Australia
https://au.mouser.com/datasheet/2/308/KSA992-1301291.pdf