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Transistor Substitutions

The 2SC
Dutch9600 said:
Which would be a better replacement for 2SC3329-GR, a KSC1845 or a KSC1815. Thanks in advance for any help.
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The 2SC3329 is not a common part. It is a low base spread resistance (rbb) transistor. The base spread resistance is not specified for most transistors. If you could find genuine new old stock parts the hitachi 2SC2545, 2SC2546, 2SC2547 may works there. Take a look at the dataseets for the 2SC3329 and compare the figures on page 4 with those of page 6 of the datasheet for 2SC2545, 2SC2546, 2SC2547. You will see that the noise figure is measured for varius input resistances. As the input resistance gets smaller the noise gets bigger. Making a transistor for low noise with low source impedance is hard, and not many were made.
The transistors that have this characteristic are hard to find now (another infamous one is the 2SD786), and some accidentally, may have los rbb. Horowitz and Hill's book mentions a few parts which -apparently- unintentionally ended up having this characteristic. If it is in a phono preamplifier, this is likely important. ZTX851 is one of them. Pin is EBC for the ZTX851 while it is ECB for the 2SC3329. Not yet out of production, but unfortunately unavailable untill next year. The SMD part 2SC2713GR might work there but it has a much lower dissipation capacity.
What equipment is is that you are trying to repair?.
 
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JoseHH said:
The 2SC

The 2SC3329 is no longer made. It is a low base spread resistance (rbb) transistor. The base spread resistance is not specified for most transistors. The transistors that have this characteristic are hard to find now (another one is the 2SD, and some accidentally, may have los rbb. Horowitz and Hill's book mentions a few parts which perhaps unintentionally have this characteristic. If it is in a phono preamplifier, this is likely important. ZTX851 is one of them. Pin is EBC for the ZTX851 while it is ECB for the 2SC3329. Not yet out of production, but unfortunately unavailable untill next year. The SMD part 2SC2713GR might work there but it has a much lower dissipation capacity.
What equipment is is that you are trying to repair?.
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The Carver MRX-180/Receiver 2000 phono section.
 
i thought it was for a phono preamplifier. See if you can find the parts i mentioned in my previoius post. If not, new old stock for the 2SC3329 some times show up but be aware of fake parts. The original is toshiba, and the ones I have seen have white-silver letters.
 
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Quick question. Has anyone come across a replacement for the 2SA666 PNP transistor? They are being used in a long tail differential pair at the input of the Driver board in a Sherwood S-7200 receiver. Any input would be much appreciated.
 
In my opinion, if the 2sa666 is used in a current source for a differential pair a pair of matched KSA1015Y should be fine. If they are used in the differential pair itself, a matched pair of the 2SA970BL would be good, if that is unavailable, KSA1015GR or KSA733G might work. Other alternatives, -if you can find them- are the Toshiba 2SA1048GR, and the KEC KTA1267 (rank BL (best) or GR )
 
JoseHH said:
In my opinion, if the 2sa666 is used in a current source for a differential pair a pair of matched KSA1015Y should be fine. If they are used in the differential pair itself, a matched pair of the 2SA970BL would be good, if that is unavailable, KSA1015GR or KSA733G might work. Other alternatives, -if you can find them- are the Toshiba 2SA1048GR, and the KEC KTA1267 (rank BL (best) or GR )
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They are used as a differential pair. I looked and have decided on using the available KSA1015YTA. Thank you for your help.
 
Looking for replacement of 2SC318A which is Q108/Q208 in the flat amp section of Sony TA 2000 preamp. When I took them apart, Q108 is expected as 2SC318A but Q208 seems been replaced certain point of time as a “C1213”. So what would be a good replacement for the original 2SC318A, I read KSC1845 or KSC1815 could but not really sure. Can you guys help? Thanks.
BTW, Q206, Q207 was replaced with “C1213” together with Q208, I assume and Q106/Q107 are “C632” both (original?) instead of C631, C632 on the SM. So confusing now,
 

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@eizner23 . Thx for looking this for me.
please clarify this for me.
someone replaced the original 2SC318a with C1213, and can I use KSC1845 now to replace C1213 or I better use KSC1815?
there are bad noises when I switch on “Tone” control and makes me think these transistors are the problem.
 
you probably can get away using either as a sub in low level amp circuit. C1845 has ic of .05 C1815 is .1 amp.
But in a low level amp circuit i doubt that amount of current would be an issue.
C1845 is higher gain so id go there first.
 
Repairing a Nikko Alpha II which has the 2sc1627 which is of course obsolete. Would the Onsemi BC63916-D74Z be a viable replacement??
 
I don't know if this is already discussed before, for 2SD668A, the substitute is 2SD669A which is still available with some vendors. I also discovered KSC3503D is a fit.
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Working on a SAE 3100 and was wondering which would be a better sub for S1375, a 2N2102 or 2N2405 ? Thanks for any and all help.
 
Working on a SAE 3100 and was wondering which would be a better sub for S1375, a 2N2102 or 2N2405 ?
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Those are both the wrong case. Try the CEN-U07.

CEN-U07 PBFREE | DigiKey Electronics

Order today, ships today. CEN-U07 PBFREE – Bipolar (BJT) Transistor NPN 100 V 2 A 50MHz 1.75 W Through Hole TO-202 from Central Semiconductor Corp. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.com www.digikey.com
 
Ylli said:
Those are both the wrong case. Try the CEN-U07.

CEN-U07 PBFREE | DigiKey Electronics

Order today, ships today. CEN-U07 PBFREE – Bipolar (BJT) Transistor NPN 100 V 2 A 50MHz 1.75 W Through Hole TO-202 from Central Semiconductor Corp. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.com www.digikey.com
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Thanks, someone had put in the wrong transistor in it and I was going by what was in there and again Thanks.
 
This is going to be a double post as I've already asked the question in my original Pioneer SA-7500 thread but it seems better suited to ask here.

Getting ready to replace the transistors in the phono board (Equalizer Amp). It consists of 2SA725s and 2SC1313s. I know I'm going to put KSA992s in place of the 725s but the 1313s have KSC1845 or KSC1815 as recommended subs. I'd kind of like to hear a more informed opinion other than my own "guess" on this. Here's the schematic with some voltages.

Thanks

Screenshot 2024-03-29 at 8.25.55 PM.png
 
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