Transistor Equivalents – old equipment restoration

Where to find transistor equivalents?

Restoring old gear can be a nightmare when it comes to some of the more obscure transistor types, and a pretty expensive exercise as well. Transistor equivalents for substitution is often a necessity when repairing vintage gear. This applies equally well to silicon devices and not just Germanium.

Years back we were confined to telephonic conversations or writing letters to the supplier, the snail mail variety.  In South Africa we are fortunate enough to have proactive suppliers in the electronics industry, unlike in the motor or metal industries where staff are still learning how to send emails, except if they see a big sale pending. Continue reading “Transistor Equivalents – old equipment restoration”

Speaker Impedance: 4 Ohm or 8 Ohm

Speaker Impedance and amplifier design

 

There’s been a lot of techno speak on the various forums to readers about the advantages of using loudspeaker impedances of specific values, some even discussing the merits of 4 Ohms as only being used in very high end systems. The question here is based on another question:  If a great sounding system works well driving an 8 Ohm why would you then think a 4 Ohm would make it sound better?

2 Way loudspeaker crossover
2 Way Loudspeaker crossover – Wiki Commons German Wiki Frank Klemm

Certainly car audio is often found with 4 Ohm speakers, sometimes in parallel to get 2 Ohms.  Does it sound better than 4 Ohms?

Is a system designed to drive an 8 Ohm speaker then  inferior to that which can drive a 4 Ohm speaker? Continue reading “Speaker Impedance: 4 Ohm or 8 Ohm”