Semiconductor Companies Reviews

[DiodeDipShit]

Hi All, Which Semiconductor Companies, in Your experience, do You think make the best Transistors and Diodes?  I.E. Longevity and remaining true to rated tolerance.
I ask because I am refreshing 1970's H.H. Scott R77 Receiver/Amp and I am being forced into using different companies for matched NPN/PNP pairings. Thank You

[DiodeDipShit]

Any thoughts on ASI or  'S' (Solid State Inc) T03 Transistors ? These are the only two American companies that I can find for one side of the Driver pairs.

[T3sl4co1l]

BJT complements don't really match, they're just close enough.  Different brands would probably be fine.  If multiple (same type per side) are being used in parallel, depending on circuit design, it might be worthwhile matching them (equal Vbe at given Ic, Tj).  But that's usually a pretty shite design that needs matched BJTs.

Conversely, replacements of any type that fits (package, pinout) and has equal or greater ratings and parameters (including fT, hFE, and SOA -- check the SOA plot, make sure DC/100ms curve includes the same voltage range), will most likely suffice.  The main gotcha is, modern epitaxials and especially ring/perforated emitter types, can have much higher fT than their predecessors, most especially anything that was designed for ye olde hometaxial 2N3055, 2N3773, etc., a process that was obsoleted in the... late 70s, early 80s, somewhere around there.

Note this hazard includes 2N3055 etc. themselves, modern ones greatly outperform the originals; but they still have the same old dumb datasheets because they have to, it's a JEDEC registered part, "meets or exceeds" shall be taken seriously.

Usually, a ferrite bead on the base, or adding a series resistor or increasing the existing value, suffices to tame the higher fT parts.  You might also consider reducing wiring length, if they are much distance from the PCB.

Substitution requires a little bit of design knowledge so a one-to-one suggestion isn't feasible, but often little more than a judicious choice, and maybe a few resistor values, is all that's needed.

There's also NTE/ECG, the equivalents are usually alright.  You are getting a common-denominator part though (many types cross to one), and again if the fT is higher, that's the main thing.

Tim

[PCB.Wiz]

Hi All, Which Semiconductor Companies, in Your experience, do You think make the best Transistors and Diodes?  I.E. Longevity and remaining true to rated tolerance.
I ask because I am refreshing 1970's H.H. Scott R77 Receiver/Amp and I am being forced into using different companies for matched NPN/PNP pairings. Thank You

I've always found Nexperia (ex Philips Semi) to be very consistent and low failures.

Of course if you repair something old, you are probably less interested in modern SMD package parts, which is what all the big players now focus on.

If it matters to you, measure it.

[Siwastaja]

Hi All, Which Semiconductor Companies, in Your experience, do You think make the best Transistors and Diodes?  I.E. Longevity and remaining true to rated tolerance.

Basically all semiconductors from any company you can buy from the usual distributors last forever when used correctly, within specs, and stay within rated tolerances. Just avoid Aliexpress/Ebay counterfeits etc.

[Haenk]

I'd also say that I did not experience a certain bad brand yet - actually I find semiconductor failure surprisingly low. Failure usually only occurs when driving them close to or even above their limits - but that is not a manufacturer fault but a cheaping-out design error. Not valid for pre 70s stuff, though

[DiodeDipShit]

BJT complements don't really match, they're just close enough.  Different brands would probably be fine.  If multiple (same type per side) are being used in parallel, depending on circuit design, it might be worthwhile matching them (equal Vbe at given Ic, Tj).  But that's usually a pretty shite design that needs matched BJTs.

Conversely, replacements of any type that fits (package, pinout) and has equal or greater ratings and parameters (including fT, hFE, and SOA -- check the SOA plot, make sure DC/100ms curve includes the same voltage range), will most likely suffice.  The main gotcha is, modern epitaxials and especially ring/perforated emitter types, can have much higher fT than their predecessors, most especially anything that was designed for ye olde hometaxial 2N3055, 2N3773, etc., a process that was obsoleted in the... late 70s, early 80s, somewhere around there.

Usually, a ferrite bead on the base, or adding a series resistor or increasing the existing value, suffices to tame the higher fT parts.  You might also consider reducing wiring length, if they are much distance from the PCB.

Substitution requires a little bit of design knowledge so a one-to-one suggestion isn't feasible, but often little more than a judicious choice, and maybe a few resistor values, is all that's needed.



Tim

Tim, Thank YOU for the concise information.  Being olde school, I had to look up SOA and epitaxials and especially ring/perforated emitter) . Any new knowledge a is plus and this forum reminds me that I have forgotten more than I learned ! ! !    Changing any of the original design of this is beyond my thoughts as this amp fine as is.
You have given me confidence in ordering outside the original manufacturer parts as I had concern that the outputs would alter.
Again, Thank You for Your time and information.



I've always found Nexperia (ex Philips Semi) to be very consistent and low failures.

Of course if you repair something old, you are probably less interested in modern SMD package parts, which is what all the big players now focus on.

If it matters to you, measure it.

[/quote]
BCB.WIZ,  Siwastaja  and Haenk, You all have further boosted mt confidence in ordering parts. Thank You ALL ! ! !

As the amp is, it sounds great but, the channels are imbalanced. Capacitors are next in my acquisition of parts.

Best regards,
Eric