Help needed for Sanken transistors LAPT-3

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eradoncic

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Joined 2004
Help needed for Sanken transistors, LAPT-3


Does anybody know what kind of replacements (or source) are suited for Sanken audio output transistors marked as LAPT-3?

On the Sanken web site I found only as info that these are custom made for Sansui, now discontinued, and nothing more! No suggested replacement, no equivalents... nothing at all! Even no e-mail contact addresse for asking them...
I sent an e-mail to AlegroMicrosystems (distributers of Sanken), but there's no any answer from them.

Here are the collected infromaton I found:

Sanken catalogue lists several transistors to belong to LAPT group, and I can recognize 2SC3519/2SA1386, 2SC3284/2SA1303, 2SC3264/2SA1295 which are incorporated in various Sansui amplifiers like: AU-X901, AU-X701, and AU-X911DG, respectively.

From the 1990's to the end of the company, they were used transistorsmarked as LAPT-2, LAPT-3 and LAPT 23 (these can be recognized as 200W devices, probably 2SC3264/2SA1295, but I dont know to what equivalents belong LAPT-3)

LAPT-3 looks lake standard TO-3P trannies, but collector base looks copper-alike (I guess it is a non-magnetic/antivibrating issue)

Thank you in advance


__________________
eddie
 
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eradoncic

Member
Joined 2004
Unfortunatelly, I have no any pics, the trannies are usual TO-3P type, and I did not find neither service manual, but I have for AU-X901, 701 and 911.

The driver transistors are 2SC3298/2SA1306.
On the emiter there two parallel 0,47 Ohm resistors

On the previous generations of cited amplifier, namely AU-X901 and AU-X701 the drivers are identical.

However, the outputs are different: AU-X901 (3x13oW/8Ohms) uses 2SC3519/2SA1386 and on the smaller AU-X701 (2x100W/8Ohms) are incorporated 2SC3284/2SA1303

Au-alpha707 is 2x130W, and to some extent is more similar to AU-X901, but the construction and PCB's are of the AU 911DG.
 
E

eradoncic

Member
Joined 2004
Sorry for confusing...
To clarify:

There's exist three type of these transistors: LAPT-2, LAPT-3, and LAPT-23, all made by Sanken, custom produced for Sansui.

In my amplifier are LAPT-3

I need the equivalent or replacment for LAPT-3, but I don't know the specs, because they are discontinued...
And no information on Sanken web other than they are dicontinued.
 
Loudthud

Loudthud

Member
Joined 2007
This page: Allegro MicroSystems - 2SC6145 and 2SC6145A Audio Amplification Transistor suggests that LAPT is some kind of trademark, process or technique that Sanken applies to transistors that have many small transistors in parallel with emitter balasting on one die. The parts have a high F(t).

This page, a selection guide for "Audio" transistors, has a separate column for LAPT devices between standard and Darlington with no clear explanation. Link: Allegro MicroSystems - Sanken Audio Transistors
 
Ian Finch

Ian Finch

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Joined 2010
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Here, this is what you are dealing with. As these are obviously Sansui house codes, you won't find them out there in the marketplace unless they have been a collection of spares from repair agencies long ago or just fakes, which means they could be anything in a TO3P-L package.

Any of the modern LAPTs from Sanken's site which fill the bill for power rating on your model will probably be better so don't obsess about this. You don't really have many options. SANKEN ELECTRIC : Power Transistors : For Power Amplifier
 
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Warseb

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Joined 2012

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