Transistor Substitutions in Pioneer M-22 and Harman Kardon A402

iPhoneSasuke said:
there are also a lot of low-current (preamp circut) 2SC1345E which are not such to easy to replace. Thanks to AK I've found and interesting suggestion in BC54*C. Let's compare 'em. I guess the BC546C is better than the BC547C. Or not? Anyway I think that both of them are should be added in a list in the beginning of these topic. Hard to compare hfe graphs due to BC are showed it only for lowest grade. Meanwhile the 2SC1345E is absolutely non-linear. But nevertheless the 402 amp sounds great. I wish to buy the transistors in reserve while they're still easy to buy. Maybe the 2SA844E should be positioned as the killer of the KSA992? Why I'm asking due to possibility to look at the datasheets: maybe there's a practice that sowed that some perfect on paper transistors are not good in sound or not in each circuit in the amp. If there's a proven experience that some good-in-paper transistors is good for some circuit and very bad for some another - it sould also be noticed in enchiridion so everyone could read it and do correct choice and personal consultations would have place to be in non-standard situations which would demand deep knowledge or experience.
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So is there any ideas about sub for discounted 2SC1345E? Required hfe 400+
For now i guess the BC556 is overkill. Is there any practice moments which revealed hidden flaws?
Or else there's a reason to choose 1845F? Sometimes people says about noize in BC transistors.
Sadly that there's no datasheet with graphs for the C grade BC5**.

Also found mention about 2SC2240. BL grade gives hfe 350~700
The 2240's having more wide range of hfe in relatively high current (0.7-40mA) but doesn't opens lower than at 0.3mA.
Than the 1845 having shorter range of high hfe (up to 0.8mA) but in more wide range of relatively low current (0.01mA).
In conclusion about 2240 vs 1845 I think that 1845 is usually faster on extra-low currents and better if limit of 10mA is enough.
 

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iPhoneSasuke said:
That means that the speaker drivers coil are being burned and after that the coil has to be rewound.
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If you have a piece of equipment with a failed amplifier channel, my best recommendation would be to start a thread dedicated to it, rather than trying to get help in several different threads that have nothing to do with it.
 
tarior said:
If you have a piece of equipment with a failed amplifier channel, my best recommendation would be to start a thread dedicated to it, rather than trying to get help in several different threads that have nothing to do with it.
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My target for non not to restore it but to select parts wizely. As you could see, I didn't ask: "I have the Pio, smw is wrong, what to do?". If to do - to do the best as it possible. That's all I am. Maybe I'll later create a thread, but only when I will have smth to say about so it would be useful thread which will be helpful for each other who want to restore these good and problematic amp.

I'm also thinking about improving my fully-original well-working Harman Kardon A402.
The information is only valuable when it gives an answers on all questions.
 

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iPhoneSasuke said:
My target for non not to restore it but to select parts wizely. As you could see, I didn't ask: "I have the Pio, smw is wrong, what to do?". If to do - to do the best as it possible. That's all I am. Maybe I'll later create a thread, but only when I will have smth to say about so it would be useful thread which will be helpful for each other who want to restore these good and problematic amp.

I'm also thinking about improving my fully-original well-working Harman Kardon A402.
The information is only valuable when it gives an answers on all questions.
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You'll still get better answers and suggestions by starting your own thread. Same for your H/K 402.
 
These thread is about the transistors and I'm asking only about the transistors. The thread is good and very helpful but there is to where to grow. Me correction about 2SA733 was proven and than accepted. There is a vacuum about the Hitachi's transistors that should be filled. For now I can't decide which sub for 2SC1345E is better: 1845 or BC55* 'cause both of them having advantages and disadvantages and need to decide which parameters are more important for the preamp and the pwr src. The 1845 looks easier to open and close rather than the BC, but the BC looks more thought. But as one of my friends said, in the preamp sec the transistors are working in linear mode, not in on/off, so the speed of on/off is not necessary (Vbe san/on).
 
iPhoneSasuke said:
These thread is about the transistors and I'm asking only about the transistors. The thread is good and very helpful but there is to where to grow. Me correction about 2SA733 was proven and than accepted. There is a vacuum about the Hitachi's transistors that should be filled. For now I can't decide which sub for 2SC1345E is better: 1845 or BC55* 'cause both of them having advantages and disadvantages and need to decide which parameters are more important for the preamp and the pwr src. The 1845 looks easier to open and close rather than the BC, but the BC looks more thought. But as one of my friends said, in the preamp sec the transistors are working in linear mode, not in on/off, so the speed of on/off is not necessary (Vbe san/on).
Click to expand...
 
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