Universal buffer/headamp based on OPA1622

[TNT]

I would be interested in a bord without power section.

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[OlegSh]

Thanks for your interest! Both designs, with and without the PSU part will go to production during the coming week. So there should be boards available within a couple of weeks from now.

 

[OlegSh]

Actual schematics for the boards with and without the PSU.

 

[TNT]

This chip package type, does it have galvanic contact with its pads and the board copper or is connection created with a layer of solder?

I.e. do the "legs" protrude from the plastic "box"?

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[OlegSh]

The thermal pad has to be connected to the most negative supply externally. It should also be soldered to the copper pour for heat sinking. The other pins do not protrude outside of the package but as is typical in electronics all the pins should be soldered to the respective pads on the PCB

 

[TNT]

I was thinking about if listening "through" solder is very "high end"

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[OlegSh]

 

[OlegSh]

PCBs arrived!

All is fine except there are some traces left from the snubber circuit on the bottom layer of the PCB with PSU (next to the PSU input connector) and there are two exposed GND pads next to the power pads of the regs. Electrically everything is fully OK. Just aesthetics The CRC transformer snubber is now on the transformer board.

The other PCBs are all OK.

Regards,
Oleg

 

[ammel68]

Nice boards!
What brand of terminal blocks did you use on the transformer board(3rd photo)?

Thanks...

 

[OlegSh]

These are German made 5mm pitch terminal blocks from reputable German ebay seller. The one on the mains side has better creepage distances. Below are the closeups...

 

[ammel68]

Those are noticeably better made than the typical Chinese blue blocks.

 

[OlegSh]

They are really well made. I've used them on several projects already and they never broke on me despite quite some overtorque sometimes...

 

[Idiosyncrasy]

I have also made reduced version of the pre/head amp without the PSU part. This PCB is only 3x4 cm in size. I am going to order both designs with and without the PSU. Most probably I'll get a dozen of each design but I need only fraction of it. So I'm curious if there is interest in such PCBs from forum members?

Regards,
Oleg

Hey Oleg, I'd definitely be interested in a couple of the reduced boards and 1 of the larger boards.

 

[OlegSh]

Hi Jacques,

Thanks for your interest! I haven't tested the boards yet due to the lack of time. Just assembling the BOM to submit to mouser. If you aren't afraid to try before I test them, PM me for details, I have some extra boards.

Regards,
Oleg

 

[Idiosyncrasy]

Given my status as confirmed newbe, I'm perfectly fine with waiting until you've given it a go first. The PCB looks really nice though!

 

[OlegSh]

Another PCB design

Have been playing with Eagle CAD... Always wanted to design a small PCB for buffer/preamp based on dual op-amp in SOIC8 package. The preliminary PCB version is attached. Similar to OPA1622 PCBs this one also allows inverting/non-inverting/differential configurations. The PCB is not suitable for automated assembly due to tight spaces between parts but manual assembly using conventional soldering iron should be relatively easy.

Please have a look and let me know if I overlooked something.

Regards,
Oleg

 

[OlegSh]

I am currently looking for a suitable headphone jack socket which would fit on the 8~10 mm thick front panel. I'm planing to use 6.3 mm guitar sockets like these since they have very long thread. Does anybody have an experience with them, how reliable/robust these sockets are? I'd like to be confident that they are OK before drilling large hole in the front panel.

Thanks,
Oleg

 

[TNT]

CA and CB?

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[OlegSh]

What is CA and CB? I am not so familiar with terminology

 

[TNT]

It's in your schematic

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