As a novice, finding replacement transistors for the amp section that
are pin compatible, cheap and readily available has proved to be time
consuming.

Currently a 2SD314 NPN (T220) is in the output stage.  TIP31C(T220)
appears similar , as is 2N3055 (T03) and the circuit board has been
designed to take either T220 or T03.

min/max hfe for  2SD314 and 2N3055 are 40/320  and 20/70 respectively.

As amp designers must consider a range of hfe's anyway and as I have a
handful of these (both TIP31C and 2N3055) it seem like the right
decision.  (I intend to change the other side PNP to it its complement
MJ2955 and similarly in the other channel)

All other specs appear to be an improvement.

Again, as a novice I am thinking, the 2N3055 can handle more power and
the only reason they are not in there  in the first place or something
similar was manufacturing cost.

But again as a previous thread pointed out there can be risks not
immediately obvious to the novice.

No real harm in experimenting as the amp is non-serviceable and would
not be a great loss.

However, I would welcome any recommendations either way.

For those still reading, the specs for the components are pasted  below.

Justin


Type Designator: 2SD314

Material of transistor: Si

Polarity: npn

Maximum collector power dissipation (Pc): 30W

Maximum collector-base voltage (Ucb): 60V

Maximum collector-emitter voltage (Uce): 60V

Maximum emitter-base voltage (Ueb): 5V

Maximum collector current (Ic max): 3A

Maximum junction temperature (Tj): 150=B0C

Transition frequency (ft): 4MHz

Collector capacitance (Cc), Pf: 130

Forward current transfer ratio (hFE), min/max: 40/320

Manufacturer of 2SD314 transistor: SANYO

Package of 2SD314 transistor: TO220

Application: Power, General Purpose




Type Designator: 2N3055

Material of transistor: Si

Polarity: npn

Maximum collector power dissipation (Pc): 117W

Maximum collector-base voltage (Ucb): 100V

Maximum collector-emitter voltage (Uce): 70V

Maximum emitter-base voltage (Ueb): 7V

Maximum collector current (Ic max): 15A

Maximum junction temperature (Tj): 200=B0C

Transition frequency (ft): 200KHz

Collector capacitance (Cc), Pf: -

Forward current transfer ratio (hFE), min/max: 20/70

Manufacturer of 2N3055 transistor: MOTOROLA

Package of 2N3055 transistor: TO3

Application: High Power, High Voltage, General Purpose

Type Designator: TIP31C

Material of transistor: Si

Polarity: npn

Maximum collector power dissipation (Pc): 40W

Maximum collector-base voltage (Ucb): 140V

Maximum collector-emitter voltage (Uce): 100V

Maximum emitter-base voltage (Ueb): 5V

Maximum collector current (Ic max): 3A

Maximum junction temperature (Tj): 150=B0C

Transition frequency (ft): 3MHz

Collector capacitance (Cc), Pf:

Forward current transfer ratio (hFE), min/max: 20/100

Manufacturer of TIP31C transistor: TI

Package of TIP31C transistor: TO220

Application: High Power, High Voltage, General Purpose

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