replace toshiba b688/d718 with b817/d1047

[b0red2tears]

hi
I need to replace 2SD718 and 2SB688 in my old Super A JVC a-x30. After bad experience with some Ebay fakes i'm fed up. I have several pairs of B817 and D1047's that I know are good, can I use these as a replacement? Sorry if this is a stupid question, don't know what to look for when making comparison.

 

[kevinkr]

Probably better in solid state so will move this thread there

 

[joshvi]

Hi

Yes, B688/D718 pair can replace with B817/D1047 pairs.But use the same HFE classification devices.

B688/D718 B817/D1047

R ................................. D
O ................................. E

Best Regards
Joshvi

 

[b0red2tears]

thanks josvi. I have much to learn. How do I find the HFE? The B817 all have Y 228 written on them and the D1047 all have Y 229.

My JVC manual specifies 2SB688LB (R,O) and 2SD718LB (R,O)
Parts have R 2F written on them.

I looked up manual for the Onkyo that i'm taking the B817/D1047 parts from, it says:
KTB817-Y, KTB817-O and KTD1047-Y ,KTD1047-O

So are you saying I need the same HFE classification in the replacement parts as the old ones i.e. : R

 

[Welcome]

hFE doesn't matter. If the other specs match up (too lazy to look, on mobile), you're fine.

 

[joshvi]

Hi,

Hfe classification no.is the letter coming after the part no.In your case R is the classification no.It is a lower gain part no.So you can use either R(lower) or O (higher)

KTB 817/KTD 1047 is the korean version of original sanyo 2sb817/2sd1047 made by a company called KEC and their classification letters are Y and O not D and E

You can use KTB817 Y/KTD1047 Y in place of B 688 R /D718 R

best Regards
Joshvi

 

[widi]

Substitute transistors

I also have a JVC A-X30, and I think it can be replaced by these transistors NJW1302G (PNP) and NJW3281G (NPN).
They are of greater dissipation power, voltage and current.
Do you think it would work well after resetting the bias?

 

[Mark Tillotson]

I also have a JVC A-X30, and I think it can be replaced by these transistors NJW1302G (PNP) and NJW3281G (NPN).
They are of greater dissipation power, voltage and current.
Do you think it would work well after resetting the bias?

The higher bandwidth might mean the compensation would need adjusting, at least check for stability if upgrading to 30MHz parts.