RTR BTSB Panel Mount Buffer GB

[xrk971]

This buffer was really designed for the OPA1656 which has FET input gates and circa 10pA input bias current and 100mA current output. The OPA1612, while lower distortion, has a BJT input gate and about 1000x higher input bias current and 30mA output current drive.

All of this is to reduce the THD by about 2x less down from 0.000029% to 0.000015% and overall lower noise from about 3mV/sqrt(Hz) to 1nV/sqrt(Hz).

I don’t think it’s worth it for the reduced output current drive.

It will probably work fine though.

 

[turion64]

Thanks X

 

[wirewiggler]

Do you have a BOM for the bare BTSB boards you are selling, or one on mouser you can share. It would be a nice touch if you include a copy of the BOM or link when you sell your bare boards.
Thanks
Bill

 

[xrk971]

This is the ready to run BTSB Panel Mount thread. There is a BOM on the main GB DIY thread here:

https://www.diyaudio.com/community/...e-bal-to-se-bal-buffer-gb.358142/post-6522803

Correction to above schematic: J1 and J2 (RCA shield) should connect signal ground and not chassis ground.

You can get to it from post 1. Several people have built this and probably can send you a link to their Mouser BOM. I think the problem is, we rarely ever place an order for a single project so there is always miscellaneous stuff mixed in the order. So the BOM is never clean.

Let me know if you need anything else.

Schematic:

BOM:
https://www.diyaudio.com/community/attachments/btsb_panel_bom_v1_2p-zip.919976/

 

[wirewiggler]

This one is going to be a challenge for me,
thanks
Bill

 

[xrk971]

You could just buy it ready to run.

It’s actually not that hard to assemble if you have some experience with SMT assembly technique.

 

[wirewiggler]

Nice, are you using chip quick solder? I need the smaller tip, I think you mention henna needles for the dispenser, and what temp are you setting your hot air gun at. Vunce is setting me up on a Mouser project. You know I didn’t know you had completed ones still available, stupid me.

 

[xrk971]

I set hot air pencil at 320C I think. Hot plate gets PCB to 150C. 22 ga blue henna tip.

Yes, ChipQuick paste:

https://a.co/d/hRz4y3k

Although the above video was done without a dispenser tool, I highly recommend a JBC manual dispenser ($50 but worth preventing cramped hands and makes precise paste dots):

https://www.jbctools.com/dpm-a-hand-solder-paste-dispenser-product-1709.html

I just saw this one recently but not sure how well it works - the JBC is really precise and ergonomic:

https://a.co/d/dh55zqp

You will need good tweezers and a good set of binocular magnifiers.

Or if you want instant gratification, order the RTR unit.

 

[xrk971]

I just noticed these RTR BTSB Panel Mount boards were not showing up in my shop lately. The listing had expired unbeknownst to me. They are back on line now.

 

[wirewiggler]

That explains it, I was looking for the RTR and purchased the bare board in its place. Can I return the board for credit to the RTR board?

 

[xrk971]

Sure, we can work it out on the Etsy store. I’ll probably just give you a discounted price and you can keep the board for your trouble. Thanks.