2SD845, 2SB755 subs

OMGCat!

Super Member
I'm working on a Technics SU-V8 that's in need of a few outputs among other things.

The originals are Toshiba 845/755 MT200s as mentioned in the title.

I've got a dozen or so of Sanken 2SA1494 and 2SC3858 in stock that look like they'd make a good sub the but I read someone mentioning the use of 2SA1215 /2SC2921 instead. The latter pair are LAPT transistors but I'm honestly not exactly sure what that should mean to me. The original transistors make no mention of that in the datasheet so I don't believe they are.
Any reason to use one over the other?

I need to make another order soon so I'll probably buy a stock of both since they only have a handful left at Digikey.
 
sure i have used mje something for those. clamped them under the old ones as lazy plus at a glance it looks original . used bd139 bd140 as drivers .
 
1494/3858 would be a good sub for the 755/845
Marginally higher CoB but equal or better for everything else

LAPT essentially means paralleled devices / multiple emitters on a single die (different brands use different names MET, RET, EBT).
20MHz is on the faster side for a single-device output transistor, so when you see fT figures of 50-70 instead, it's usually a sign that it's an LAPT output device (i.e. not "really" a single transistor). 755/845 are regular single devices. Toshiba did make multi-emitters too, eg. 2SA1095 / 2SC2565.

I'd definitely stick to the type that came in the amp (in general) when it comes to those multi-emitter outputs.
 
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