Suggestions for output transistors

I am replacing the output stage of a Denon PMA355UK.

The original devices are Sanken;



2SB1383 2SB1383 pdf, 2SB1383 description, 2SB1383 datasheets, 2SB1383 view ::: ALLDATASHEET :::

My question is, does anybody have suggestions for similar devices which may 'sound better' in your experience and if so, in what way.

The amplifier is stock but I perhaps add a second transformer plus slightly increase the supply capacitance.


Ian Finch

Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
As BenY says, these are Darlingtons and Sanken types are unique in that you can't just drop in an industrial power transistor
type with the hope of getting similar or better quality audio.
SANKEN ELECTRIC : Power Transistors : For Power Amplifier

The types you wish to replace are obsolete and looking at Sanken's newer types, the Ft is now much higher at 70MHz than the
original at 20MHz and SOA is strangely lower at a nominal 30V. Maximum DC current is now 3A in lieu of 4. Perhaps someone else
has a view on this but they seem a bit lightweight on current for ~100W rated parts.

Adding a second transformer is a strategy for making independent or "dual mono" channels. It entails completely dividing the
amplifier circuits, grounds and power supplies. The channels should also be matched in all aspects, including the power supplies,
as far as practicable - otherwise it's a waste of time and money, whatever some others may have tried and make claims about.

If these parts don't make suitable replacements (and the thermal compensation is also uncertain), your only realistic option is to
replace the amplifiers completely with new discrete ones ones which may not be viable or even fit in the available space.