push pull transistor pairs

[Phil Allison]

pf...@aol.com wrote:

Phil Allison wrote:

Whether they re-label or not in actuality, they *say* not.


** Really - where ?

Being in the US, I may pick up the phone and give Mouser
(or the ON factory in Mexico, if I wish) a call at no cost.
I have spoken to Mouser on just this issue on the 3772,
and their statement is that the higher the suffix letter
(they are up to G, now), the more upgraded the unit.

** The "G" suffix indicates a Pb free package.

Some dude on the phone ain't gonna know or care which chip is inside what package.


> But they stated that the 2N3772 is not a re-label,

** I never mentioned the 2N3772.

The Motorola/On 2N3773 is a re-label.

Because it is a HUGELY popular transistor

** That is complete bollocks - Mouser list the 2N3772 ( both ON and ST versions) as *obsolete* and it has been so for decades.

FYI:

2N numbers are open to be manufactured by anyone who cares to and no two makers do it the same way. Plus they can change them as they please, cos they only have to meet the minimum spec published for the part number.

MJ and MJE numbers are owned by Motorola/ON - so they can change what is inside any time and they do.

Anyone who wants to use exact transistors to repair a vintage amplifier HAS to find vintage parts.



..... Phil

 

[alpibucky]

legg a couché sur son écran :

On Mon, 15 Feb 2016 09:01:57 +0100, alpibucky <alpibucky@mail.be
wrote:

Marantz superscope MS-30

I'd be surprised if the MS-30 had output transistors. These
multichannel all-in-one one units often just used a power IC for each
channel.

Sounds like you don't know if the output circuit is the actual
problem, here, or you'd be able to quote the part number from its
physical markings, on the assembly.

RL

Hello,

Thanks for the answers.
The MS-30 has a push pull stage with pair of transistors with their
bias mounted on the cooler. But I do not have the schematic. The
problem is distorsion in the left channel.

Kind regards

alpibucky

 

[legg]

On Tue, 16 Feb 2016 20:39:13 +0100, alpibucky <alpibucky@mail.be>
wrote:

legg a couché sur son écran :
On Mon, 15 Feb 2016 09:01:57 +0100, alpibucky <alpibucky@mail.be
wrote:

Marantz superscope MS-30

I'd be surprised if the MS-30 had output transistors. These
multichannel all-in-one one units often just used a power IC for each
channel.

Sounds like you don't know if the output circuit is the actual
problem, here, or you'd be able to quote the part number from its
physical markings, on the assembly.

RL

Hello,

Thanks for the answers.
The MS-30 has a push pull stage with pair of transistors with their
bias mounted on the cooler. But I do not have the schematic. The
problem is distorsion in the left channel.

.....and their numbers are.....

RL

 

[pfjw@aol.com]

On Tuesday, February 16, 2016 at 7:37:17 PM UTC-5, Phil Allison wrote:
FYI:

Anyone who wants to use exact transistors to repair a vintage amplifier HAS to find vintage parts.

I would no more use "exact" replacement parts on any vintage item as I would put 30W non-detergent oil in a vintage automobile. Improvements are generally a good thing, cost little, and greatly increase longevity.

http://www.mouser.com/ProductDetail/ON-Semiconductor/2N3772G/?qs=vLkC5FC1VN8Eu77x0AB6Xw%3d%3d Not obsolete.

You may not have mentioned the '72, but I never mentioned the '73.

Peter Wieck
Melrose Park, PA