I am currently rebuilding one of those Chinese U94 ptts into a new case. What is always the problem with these things is the fact that they don't have an amplifier built in. The XPI has a dynamic microphone. In original Peltor PTTs the microphone signal is amplified before it goes into the Motorola GP380.
I have tried to recreate this amplifier. For this I tried the following circuits:



Without the amplifier, the speech is very quiet, as you might expect. Unfortunately this setup with amplifier did not work for me. A strong noise comes out and the speech is not amplified.
Has anyone had any experience with either of these?

Knowing nothing else about this beyond the circuit diagram posted, I read it as a conversion circuit to allow a Dynamic Microphone to replace an Electrec Mic; not the other way around.

The 'Ztac wire transform adapter' is actually an inline amplifier. There is a tiny circuit board inside the female end that accomplishes what you're trying to build. You could probably remove the circuit board and wire it inside a PTT if you wanted, may be easier than trying to make the circuit yourself? The easiest thing to do would be to just run the adapter in line between the headset and PTT as intended, that's what I'm doing and it works perfectly. The cable is only a few inches long so it's not changing much in terms of cable length.
I'm using Baofeng radios with non amplified PTTs along with military headsets (dynamic mics). The adapter cable works as the amplifier. I have one of the adapters connected to each of my military headset downleads. I wrapped some electrical tape around the connection and leave the adapter connected permanently. An inline amplifier has an advantage over using an amplified PTT if you ever want to use a commercial headset also. I have both commercial and military headsets, so having the PTTs unamplified is better for me.

This is one of the adapters I'm talking about
https://www.ebay.com/itm/Z-TAC-Z-tactical-Wiring-Transform-Adapter-Headset-Connect-Military-PTT/283511702744?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Edit= I just noticed this. Looks like Ztac started making amplified PTTs now. Doesn't seem like it's worth the effort trying to build an amplified PTT yourself when you can just buy one for $17?

Copy and paste link below.
t.ly/XOoY

I have also seen these adapters. And they have an amplifier built in? Can you send me a picture? That would make me very happy. :)
Where did you get the information that Ztac now make amplified PTTs?

Yes, they have the amplifier built in. I've glued mine together so I can't take a picture now, but it did have a small circuit board inside that amplifies the signal. The PTT that I linked works with headsets that only work with amplified Ptts, so it must be amplified also. I believe Earmor PTTs are amplified and also work with military headsets.

Here this is a better option, they work great.



https://www.sigtronics.com/_assets/air_assets/StudioSessionParts/900119B-Helmet-Adapter.jpg





   Changes the signal levels and impedances of military headsets or helmets to work with general aviation electronics.
   Maintains the military headset type U-174/U plug.

   Part Number: 900119B - 18 inches
   Price: $101.00

   Part Number: 900119D - 48 inches
   Price: $101.00

Note: To change the signal levels or impedances of military headsets / helmets, use one of the 900119 series adapters listed above.

The Headset Adapter Cables listed below will not change the signal levels or impedances of the headset. They are plug converters only. Military headset will not work with general aviation radios without an adapter such as the 900119 series above. General aviation headsets cannot be used in aircraft with military electronics.

I assumed you were looking for an inexpensive way to amplify the signal since you were attempting to make one yourself? Here is another option that may be more durable, if you want to spend a little more. I haven't tried one of these but I'd guess it's the same as the other adapter with an aluminum casing vs. polymer.

Copy and paste link.
t.ly/rvI0