Replacemet NEC power transistor

Archived from groups: rec.audio.tech (More info?)

On Mon, 29 Aug 2005 09:19:10 +0200, Zeljko <no_mail@nospam.com> wrote:

>Can I use 2SD188 without "A" and 2SB545 with "A" on the left channel and
>2SD188A and 2SB545A on the right channel?

Suffixed versions are usually high gain versions. I would suggest that you
measure the -A transistors, then try to find standard versions with similar
characteristics.

Archived from groups: rec.audio.tech (More info?)

On Tue, 30 Aug 2005 12:17:19 GMT, "Mark D. Zacharias"
<spammenot@nonsense.net> wrote:

>It's likely that the replacements you found aren't NEC product, but made by
>God-Knows-Who.

You can still find the original NEC transistors.

>And trust me on this - you want to be able to trust the parts
>you use. Inferior replacements may not just cause a re-do, they may cause
>much more damage than the amp originally had.

Agreed. There are many regadged inferior parts in circulation, not to forget
numerous Chinese fakes.

>Quality TO-3 package transistors are a bit hard to find these days - I
>recommend using replacements from Onsemi, the former Motorola semiconductor
>company.

If similar devices are available... Or if you're ready to modify the amp.

>Hard to beat MJ15024 and MJ15025's. Over-rated for your application, but
>that's not a problem.

Hmmm. The MJ15024 / -5 are quite different. For instance their Hfe is
spec'ed at 15 / 60 while the NEC are spec'ed at 30 /120.

Archived from groups: rec.audio.tech (More info?)

On Tue, 30 Aug 2005 19:30:19 +0200, Zeljko <no_mail@nospam.com> wrote:

>what is mean letter "A" of NEC
>transistors

As said in an earlier post, various suffixes designate (Hfe) gain classes.

>or can you send me datasheet of those NEC transistors

Sorry I don't have them handy, only short forms as already posted.

Archived from groups: rec.audio.tech (More info?)

"François Yves Le Gal" <flegal@aingeal.com> wrote in message
news:5lm8h1pboltjlj77g9fttaveb6hdjl4i5o@4ax.com...
> On Tue, 30 Aug 2005 12:17:19 GMT, "Mark D. Zacharias"
> <spammenot@nonsense.net> wrote:
>
>>It's likely that the replacements you found aren't NEC product, but made
>>by
>>God-Knows-Who.
>
> You can still find the original NEC transistors.
>
>>And trust me on this - you want to be able to trust the parts
>>you use. Inferior replacements may not just cause a re-do, they may cause
>>much more damage than the amp originally had.
>
> Agreed. There are many regadged inferior parts in circulation, not to
> forget
> numerous Chinese fakes.
>
>>Quality TO-3 package transistors are a bit hard to find these days - I
>>recommend using replacements from Onsemi, the former Motorola
>>semiconductor
>>company.
>
> If similar devices are available... Or if you're ready to modify the amp.
>
>>Hard to beat MJ15024 and MJ15025's. Over-rated for your application, but
>>that's not a problem.
>
> Hmmm. The MJ15024 / -5 are quite different. For instance their Hfe is
> spec'ed at 15 / 60 while the NEC are spec'ed at 30 /120.
>
>

Sounds as if you're more knowledgeable than I regarding technical specs of
transistors - but isn't the hFe group (such as O,P,Y) marked on the case of
the device?

In practice I've never had a problem with this, though I have heard horror
stories, like using NTE outputs on a McIntosh MC-2300 for example -
something I would never do anyway.

BTW - B & D Enterprises is an Onsemi distributor.

I'm pretty sure the old NEC product is no longer available from NEC.
Toshiba, for example, hasn't nade the 2SD 424 and B554 for many years now,
even though they were quite popular in their day. I think the 2SD188 etc go
back to the '70's.

Mark Z.