When we upgraded to a 8.33 trig radio the intercom volume was very low. The avionics guy replaced some capacitor (or something – its in the manual) which resulted in the intercom being much louder.
I’m with A and C (didnt listen found out the hard way) that ps engineering units are excellent.
I just wish they did a plug in compatable spa-400 replacement with their intelivox auto squelch feature.
Having owned three Sigtronics intercoms I have never found it to be a very good unit, that having been said it should work in satisfactory way with dissimilar headsets.
What I would be looking at would be the headset jacks and cables for poor / dirty connections. However if you are going deep into the system it might well be time to ditch the Sigtronics unit and use the intercom that is integral with your Trig radio IMO it is a much better intercom than the sigtronics unit.
When it comes to aircraft audio systems I have constantly found PS engineering to be the leaders in the field with Garmin following very close behind.
Helo headsets have coiled cables and (mostly) different jacks. Otherwise, AFAIK, identical.
I’ve had that incompatibility issue quite a few times over the years in various aircraft. Usually, but not always, managed to sort it out by extended fiddling with the intercom and headset controls. No idea why, @Peter may have an explanation.
@William why don’t you borrow a Bose and/or swap with the instructor and see what happens?
Do helicopter headsets differ from fixef wing headsets? I seem to remember we always had different Peltor headsets for use when filming from helicopters than rhe ones we used in fixed wing.
I think the solution here is to get into the hover solo without a second headset plugged in and see how a radio check goes. I’ll be able to tell if the volume of the reception transmissions has increased because right now all three volume controls are maxed out (headset/intercom/radio).
I sympathise – had a similar problem where the audio was distorted to the point of being completely unintelligible when having 2 headsets connected. My ’253 did not have an intercom, we were only using the built-in 2-seat intercom of the Funke radio. I solved the problem by reverting to an external intercom (PA-400 ASC). Not very convenient in flight to say the least! Now the aircraft is in Straubing to install, among others, a real audio panel!
You surely already thought of this: did you try whether the volume knob of your headset, as well as your instructor’s, has an effect?
@Canuck oops thinking of another audio panel
Different intercom, but I recognise this “different headset / different volume” story. My PPL instructor would always require the COM volume to be far too loud for me; well, he’s older than me but I have sufficient hearing loss that I barely qualified for IR at my initial medical, and it is a “subject of discussion” at each medical. So if anything, it should have been the opposite (me requiring higher volume). I’m using a Bose A20.
Are you sure you have to push the volume button? The ‘on’ switch looks inviting! 
Not an answer, but I sympathize. I had a similar problem with this intercom; the aircraft had 4 panel powered Bose headsets, but I preferred to plug my own Lightspeed Zulu 2 in for the pilot position. I had to fight with it to get the volumes correct – I am not sure that I ever did.
It was a few years ago, so my memory is not perfectly clear, but I recall I had issues where I thought the voice activation was holding the intercom channel open (from the mic on my headset). I would get fairly loud aircraft ambient noise, but very low volume from the radio and/or other headsets. I tried a mic muff, which did not seem to help. I recall there are also DIP switches inside the Lightspeed handheld control for various adjustments, perhaps check the manual.
I sold my share in this aircraft before figuring the problem out… haha from RobertL18C – I didn’t know that you had to push the volume knob!! Oh my. I think it was always ‘on’… but who knows!
