Yes. Give us the circuit and we will be able to spec a transistor for you.
AND a photo to go on with (and comment on thos below).
A copper side view of PCB as well would help muchly (for the terminally enthused to start in on).
If you have a working unit so much the better.
I you can tell us the supply voltage, power taken and frequency it would help greatly. That would be enough to hazard a good gusstimate. Even voltage would possibly be enough !!!
BUT the more you tell us the better.
For example, telling us that it was in a metal T03 case on a heatsink about xxx big and was made in 2008 or ... would help.
eg - like this? Yes? :-)
May be used elsewhere in system, too?
Board level parts supplier here says
Item # Description Price
SS8G-PCA080 Generator Board, Acousti-pulse 6580 $91.91
SS8G-PCA120 Generator Board, Acousti-pulse 6580 $91.91
and... . Transistor is about certain to be the same given the peep of part number seen.
Item # Description Price
SS8G-PCA120X2 Generator/Driver Acousti-Pulse/Dual $165.44
You didn't tell us you knew board part numbers !!!!
More photos
Here and
here and
even Sonix's own photos are useful
You could look for a straight replacement in one of the plastic cases like TO-3P or TO-247, such as STW3040 (which is "not recommended for new design") or BUF420AW (surprisingly expensive.)
A better choice might be a pair of TO-220 transistors, but you need to look at the surrounding circuit first. Bipolar transistors can't be simply paralleled, but need some emitter resistors to ensure they share current properly and don't run away thermally.
For linear operation, most of the important design considerations will be expressed by the safe operating area graph (assuming you use the same size of heat sink, so thermal considerations are OK):
You are considering DC operation, which is the lowest line on the curve. You need to make sure the operation stays within that lower line. To just do a part substitution without circuit analysis, you can compare the SOA curve of the replacement with the original part, and make sure the original curve fits under the replacement curve.
Best Answer
The 2N3055 is quite a common output transistor for audio gear (I actually have a bunch of boards sitting right here for a preamp I am designing that use 2N3055's)
I think it was RCA who orignally made them, but now they are made by ST, On Semi, etc. From what I have recall the specs can vary very slightly between manufacturers (although I just checked the ST and ON Semi datasheets quickly and couldn't see any difference at all between them) but it's extremely unlikely to be enough to affect the performance of your amp (unless it's really being pushed to the limit)
So the answer is yes, any 2N3055 should work fine as a replacement in your amp. Note that the collector is actually the case itself in the TO-3 package, so make sure you bolt it firmly to whatever it's mounted on to get a good electrical contact (if the legs are soldered to a PCB, bolt first, then solder the legs to avoid putting strain on the solder when you fit the bolts if you were to do it the other way around) Also take careful note if the TO3's and heatsink are ISOLATED or not with mica, and/or dielectric grease, and/or the screws are PROTECTED by a insulating sleeve. Failure to note these details can destroy the amp further during re-assembly by shorting the output power circuit to its negative partner, ground or worse! (Dynaco brand units in particular)