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Old 25th July 2014, 02:42 PM   #1
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Default Transistor Replacement Question

I have an older teac ag-v8060 receiver I got at goodwill yesterday. Can I replace the output transistors with other ones when all the specs have higher ratings except the continuos current? (1.5 vs. 4) Only reason I ask is because the max voltage is 150V higher, so at a lower voltage it can maybe take more current.

2SC4468 to MJL4281A

If not, please suggest better transistors because the ones in there are Sanken.....can't be too great.
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Old 25th July 2014, 06:41 PM   #2
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Quote:
Originally Posted by ivandezande View Post
2SC4468 to MJL4281A
MJL has somewhat higher fT (good) but more than twice the Cob (not so good). I'd say it should usually work in an EF output stage, not sure about CFP. Also note TO-3P vs. TO-264.
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Originally Posted by ivandezande View Post
If not, please suggest better transistors because the ones in there are Sanken.....can't be too great.
???

Manufacturers wouldn't get away with underspec'd output stages nearly as well if (genuine) Sanken transistors weren't any good. They're not exactly too cheap.
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Old 25th July 2014, 06:53 PM   #3
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ok thank you. The cases are about the same I compared the measurements. I will probably stick with the originals, I had no idea they were decent!
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Old 25th July 2014, 07:07 PM   #4
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Is the original unit faulty ?
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Old 25th July 2014, 08:16 PM   #5
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no it is not. just thinking about upgrades.
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Old 25th July 2014, 09:46 PM   #6
llwhtt is offline llwhtt  United States
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Old 28th July 2014, 01:04 AM   #7
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actually, there is a fair amount of hiss on them. like bad.

had to replace the psu caps they were bulging.
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Old 28th July 2014, 02:33 AM   #8
sreten is offline sreten  United Kingdom
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Hi,

Replacing all the electrolytic capacitors in it is your best bet.

rgds, sreten.
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Old 28th July 2014, 02:47 AM   #9
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thanks, do you think the 4558 op amps could be adding to it too?
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Old 28th July 2014, 11:33 AM   #10
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by ivandezande View Post
.................all the specs have higher ratings except the continuos current? (1.5 vs. 4) Only reason I ask is because the max voltage is 150V higher, so at a lower voltage it can maybe take more current.

2SC4468 to MJL4281A...............
"so at a lower voltage it can maybe take more current."
This does not follow.

The published SOA curve will tell you.
Compare the currents at your rail voltage to see what difference the SOA makes to your choices.
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