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2SA1102 and 2SC2577 Upgrade / Replacement
2SA1102 and 2SC2577 Upgrade / Replacement
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Old 8th December 2008, 07:36 PM   #1
chipinnc is offline chipinnc  United States
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Default 2SA1102 and 2SC2577 Upgrade / Replacement

Hi Everyone!

We have a Yamaha RX-300U Stereo that has 2SA1102 and 2SC2577 Output transistors.

We are going through and replaceing capicitors and fixing some cold solder joints and wanted to replace the output transistors as well.

There are notes on this forum showing that these output transistors can or should be replaced with 2SA1106 and 2SC2581 (NTE36 / NTE37) respectivly.


We were looking around and saw another reference for upgrading those transistors to 2SA1943 and 2SC5200.


I've also seen some projects here using the C5200 tranies too.

The question is, can we use the newer A1943 and C5200 transistors?

Do we need to do anything else to the system other than upgrade the caps? (Upgrading means keeping the same / or very similar values)


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Old 8th December 2008, 07:54 PM   #2
lineup is offline lineup  Sweden
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Location: the north
yiou can get some crossreference/replacements hint here

Search for: 2SA1102 in Equivalents / Cross References

2SA1943 and 2SC5200 transistors?
I do not know.
Maybe you can use them. You should have a look how fast these are in compare.
If there is a substancial difference in speed (fT), then you may have to alter the compensation capacitoras and other components (like base stopper resistors) that keep your amplifier stable (avoids oscillation).
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Old 9th December 2008, 11:27 AM   #3
chipinnc is offline chipinnc  United States
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Thanks Lineup!

The 2SA1943 and 2SC5200 have a speed (fT) of 30 Mhz, so it looks like I shouldn't use them unless I was re-tuning the circuit. Maybe the article I saw was talking about using these in a new amp design. (Like the DIY designes I've seen here)

I looked at the SanKen line card, and the 2SA1102 / 2SC2577 were discontinued many years ago. The standard cross for this is: 2SA1693 / 2SC4466...

However looking down the list, I saw that 2SA1492 and 2SC3856 may be better choices. Here's what we've got:

Transister Combo    PC(W) VCEO(V) IC(A) hFE(min) fT(MHz)
2SA1693 / 2SC4466     60     80     6      50       20
2SA1492 / 2SC3856    130    180    15      50       20
Info above from:

I had been thinking that the 2SA1943 / 2SC5200 would give us better quality / fidelity because of the higher frequency, but to do that I'd probably have to adjust for that in the circuit, and I'm not sure how hard / easy that would be. (Any ideas?)

Do you think that the 2SA1492 / 2SC3856 combo would be a better selection based on the info above?
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Old 24th August 2011, 01:26 PM   #4
Coconuts 500 is offline Coconuts 500
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Bumping this thread.

I'm looking for replacements of the exact same transistors. 2SA1102 and 2SC2577.

Does anyone have a suggestion? All of the transistors mentioned earlier do not seem to be available anymore, either. So I am totally lost.

Thank you very much.

Last edited by Coconuts 500; 24th August 2011 at 01:29 PM.
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Old 17th December 2011, 01:18 PM   #5
svkr2k is offline svkr2k
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Join Date: Dec 2011
Default 2SA1102 and 2SC2577 Upgrade / Replacement

Dear forum members,

I have a Kenwood amplifier that has 2SA1102/2SC2577 pair.
I could not find a replacement for 2SA1102. But, I havee got 2SA1104. The specifications looks similar.

I request the experts here to advice me if 2SA1104 can be used in circuit where 2SA1102 was used? (i.e., can it be replaced without doing any modifications to the amplifier circuit?

(Please note : One thing that worries me is that the Collecter-Emitter saturation voltage is different for the two transistors.)

Thanks in advance for your help.
Rajesh Seenivasan.
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