[Onik]

now I no longer hear any noise(BLACK), thanks a lot for your help. I really thought that I wasted my £20 LOL. Now I am gonna try different op amps to find the best setup for this little amp.

 

[Onik]

Is that a 4-pole 2.5mm TRRS plug, to 4-pole 3.5mm TRRS jack adapter?
If it is shorting any of the 4 signals on the 2.5mm TRRS plug together, it's not an appropriate adapter for the F1 Balanced output.

What are you planning to connect to the output of the F1?
The 2.5mm TRRS Balanced output is being driven by the pair of DRV134 Balanced Line Driver chips.
There's also a 3.5mm TRS Single-ended output, which is driven by the LM4562NA op-amp.

If you have balanced earphones, with a 3.5mm TRRS plug, then you can verify that the adapter you've found is correct - by plugging in you earphones, and then testing the 2.5mm plug with an Ohmmeter.
With the earphones on, measure between the Tip and Ring-1 - and you should hear a click in your right ear, and see the resistance reading of right earpiece.
When you measure between Ring-2 and the Sleeve - you should hear a click in your left ear, and see the resistance reading of the left earpiece.
If that works, then you can use the 2.5mm TRRS plug -to- 3.5mm TRRS jack adapter for your 3.5mm TRRS earphones.
If it doesn't work, then you can order a 2.5mm TRRS plug -to- 3.5mm TRRS jack adapter from VE Clan (for $5 - $20+, depending on parts used) - https://www.veclan.com/engappliance_sel_one?eng_ApplianceVo.eac_id=17

Is the 2.5 balance out only for Blanced iems? cus with the adapter I have don’t seems its working,maybe you are right it’s shorting something.

I’ll need spend another £10 for the right adapter now.

 

[DBaldock9]

Is the 2.5 balance out only for Blanced iems? cus with the adapter I have don’t seems its working,maybe you are right it’s shorting something.

I’ll need spend another £10 for the right adapter now.

Yes, the 2.5mm TRRS Balanced output is designed to drive balanced devices, where all four signals (L+, L-, R+, R-) are kept separate.
You only need to get a different 2.5mm to some other jack adapter, if you're actually driving a balanced load.
Use the 3.5mm TRS Single-Ended output for standard 3-wire (L+, R+, GND) headphones / earphones / earbuds.

 

[Themilkman46290]

Would it be possible to add a toggle switch between resistors? To have high/ low gain?

 

[DBaldock9]

Would it be possible to add a toggle switch between resistors? To have high/ low gain?

Your best bet, would be to select a resistor for your maximum required gain, and then add a switch that puts another resistor in parallel, to reduce the gain to the desired lower level.
That way, you always have a gain controlling resistor in the circuit, which wouldn't be the case, if you're switching between two separate resistors.

 

[Onik]

How can I replace my broken 3.5mm port?? Can Someone send a link for replacement port?

 

[DBaldock9]

How can I replace my broken 3.5mm port?? Can Someone send a link for replacement port?

This appears to be the correct part - https://www.aliexpress.com/item/10p...ted-6-feet-Double-track-gold/32879818101.html
But, it looks like you'll have to repair at least one of the solder pads - top-right pad in the photo.

 

[Onik]

This appears to be the correct part - https://www.aliexpress.com/item/10p...ted-6-feet-Double-track-gold/32879818101.html
But, it looks like you'll have to repair at least one of the solder pads - top-right pad in the photo.

Do I really need that pad?

And btw if I use only balanced iems do I still need that port?

 

[DBaldock9]

Do I really need that pad?

And btw if I use only balanced iems do I still need that port?

Just checked, and that pad, along with the one across from it, provides the GND signal for the 3.5mm jack.
If you're not using the unbalanced output, then there's no need to have the 3.5mm earphone jack.

 

[IcedFrosty]

Hello,
I've been wondering how does the F1 and V3 converts a single-ended input into a balance out? I need a simple block diagram for both F1 and V3 from the input to the 2.5mm output. Can anyone who understand electricity and audio signal path kindly explain this to me?

Thank you very much,
God bless.

 

[DBaldock9]

Hello,
I've been wondering how does the F1 and V3 converts a single-ended input into a balance out? I need a simple block diagram for both F1 and V3 from the input to the 2.5mm output. Can anyone who understand electricity and audio signal path kindly explain this to me?

Thank you very much,
God bless.

Here's a simple diagram of the F1 circuit -
.

 

[Merlin-PT]

They use DRV134 ?

EDIT:
I see a photo of DRV134 in 1rst post, but no reference to it in the specs.
@IcedFrosty
Take a look at DRV134 datasheet, it does it all.

 

[DBaldock9]

I found that they used the DRV134, either from what was written on the original sale page, or from the photo on that page.

 

[DBaldock9]

One thing to consider about the Differential Line Drivers, is that they are really designed to drive 600-Ohm balanced line level signals.

 

[ricesteam]

Anyone know if this device can operate without the battery?