SX-Amp and NX-Amp

Thanks,
I need to order on Mouser. I have other things to order, so that I can avoid the shipping costs.
My problem is that I don't understand what is the appropriate package.
SOT323 seems appropriate, while SOT23 looks too large.
The original 771-BC847CT115 is declared to have SOT-416-3.
However in the specs (https://www.mouser.it/datasheet/2/916/BC847_SER-1598765.pdf) I don't see the BC847CT.
On Digikey the BC847CT https://www.diodes.com/assets/Datasheets/ds30274.pdf is declared to have SOT523 (that measures well on the PCB).
I'm quite lost!
 
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Hello,

The part should be a standard BC847 in SOT23 (not the other packages). Mouser are showing about 8000 in stock.

https://www.mouser.co.uk/datasheet/2/916/BC847_SER-1598765.pdf

Your document The-Ovation-nx-Amplifier-V2.0_9.pdf shows the transistor as 771-BC847CT115. This is package type SOT416, smaller than the SOT23. In post 2386 sx-Amp and nx-Amp the excel bom also lists BC847CT115. I built my unit with this part number but don't recall how the fit was to the board.

Scaling an image of the board, the layout appears to actually be for the SOT23.

Maybe the BOM just needs updated.
 
Bill, I think you are right - looks like an error on my part. Thanks for catching this.

It is supposed to be a SOT23 device.

(I probably need to redo the BOM anyway as it’s 9 yrs old now 2012 was when the nx and sx first came out. They’re still selling through Jim’s Audio. I think in total with the V1 and V2 boards he sold about 350)
 
Mouser has SOT23 BC847C transistors in stock from several vendors.
621-BC847C-7-F Diodes Incorporated 3,806 In Stock, $0.20 each
863-BC847CLT3G onsemi 97 In Stock, $0.16 each
621-BC847C-13-F Diodes Incorporated 1,098 In Stock, $0.20 each
726-BC847CE6327 Infineon Technologies 13,546 In Stock, $0.22 each

It appears that the 2N7002 (Q3) on the power supply is called out as a SOT323 instead of a SOT23.
771-2N7002PW-115 SOT323 Q3 on power supply bom
Mouser has SOT23 packages:
771-2N7002NXAKR Nexperia 618,494 In Stock, $0.19 each
512-2N7002L onsemi / Fairchild 5,051 In Stock, $0.28 each
757-T2N7002BKLM Toshiba 9,091In Stock, $0.17 each
 
I checked if the 2N7002, which is a SOT-23, fits in the amplifier PCB.
Yes! So, I'm ordering a 771-BC847C-T/R.
Doing the final checks (and ordering the few components with the wrong measures) for the amplifiers I realised that the fuse holders I have do not fit the PCB.
I'm unable to find any suitable fuse holder (the 504-HTC-201M is out of stock in Mouser -and not only).
Any suggestion?
Thanks

Amplifier Image
 
I'll do some work on the BOM this week end. Tyhese amps still have a lot of life in them despite going on for nearly 10 yrs old.

🙂
What can be better? Those amplifiers have a still modern architecture, and, to my knowledge and in my simulations, they conjugate simplicity with performances.
The only thing I hated are the SMD diodes in the PSU. I could find the cathodes only using a microscope.
And hoping for the best:
BAS21H.png

More: one of them is so small that I'm no more able to find it in my workbench. Lost! and to reorder 🙄.
Let me ask the N-th question: the BAS21H are impossible to find. Next builder will have difficulties.
 
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BAS21J is a bit smaller than BAS21H but should still be usable on the board. Might have to do a slight solder bridge to get it connected. Mouser part number 771-BAS21J115. Always order more tiny SMD parts than you need since it is easy to lose them and they are usually cheap.
 
BAS21J is a bit smaller than BAS21H but should still be usable on the board. Might have to do a slight solder bridge to get it connected. Mouser part number 771-BAS21J115. Always order more tiny SMD parts than you need since it is easy to lose them and they are usually cheap.
This would help all the people wanting to build that PSU (mine is quite complete, apart that diode that is somewhere!).
I checked the size of the BAS21J and it will be solderable on the PCB without any bridge.
BAS21J.png