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3.5mm to 4.4mm. What am I missing?

Jimbob54

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So I just watched a review for the new hi senior mega5est bass iem. No I won't be buying at £500 but that's not my point.

The review I watched the contents very clearly showed a TRS 3.5mm plug on the cable and a separate 3.5 to 4.4mm adapter like in this pic.

How on earth is that meant to work? If the 3.5mm was trrs I could figure it, the cold leg from each earpiece would connect to a different part of the plug to match the 4.4 adapter.

Cant believe the company would release an amp /iem killing adapter with the unit.

Treat me like I'm an idiot.

Cheers
 

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The adapter as shipped would work on a number of budget "balanced output for convenience" amps that are internally single-ended (think Topping L50, SMSL DL200 and a bunch of others). Now portable gear tends to be voltage-limited and as such generally has "real" BTL outputs behind balanced jacks, which accordingly would be not amused. Given that portable use will be likely for an IEM, that's definitely a bit of a fail there. They should have gone with a Pentaconn on the IEM cable and an adapter the other way round.
 
So I just watched a review for the new hi senior mega5est bass iem. No I won't be buying at £500 but that's not my point.

The review I watched the contents very clearly showed a TRS 3.5mm plug on the cable and a separate 3.5 to 4.4mm adapter like in this pic.

How on earth is that meant to work? If the 3.5mm was trrs I could figure it, the cold leg from each earpiece would connect to a different part of the plug to match the 4.4 adapter.

Cant believe the company would release an amp /iem killing adapter with the unit.

Treat me like I'm an idiot.

Cheers
Unfortunately, I have seen something like this a lot in recent years.
Headphone connection cables keep appearing on eBay, Aliexpress, Amazon, etc. that are definitely 3-pin on the headphone side, but have a TRRS 2.5mm, 4.4mm Pentacon or 4-pin XLR connection on the amplifier side.
The same applies to adapters.
Note to everyone, such adapters and cables could destroy your headphone amplifiers (desktop/mobile, DAP, etc.).

There are probably two reasons for this.
- Ignorance on the part of the manufacturers of these cables and adapters.
- Strong increase in SE amplifiers with symmetrical headphone connections in recent years.

Adapters or cables that are 4-pin on the headphone side, but have a 3-pin connection on the amplifier side, are of course never a problem.
 
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The adapter as shipped would work on a number of budget "balanced output for convenience" amps that are internally single-ended (think Topping L50, SMSL DL200 and a bunch of others). Now portable gear tends to be voltage-limited and as such generally has "real" BTL outputs behind balanced jacks, which accordingly would be not amused. Given that portable use will be likely for an IEM, that's definitely a bit of a fail there. They should have gone with a Pentaconn on the IEM cable and an adapter the other way round.
and @Roland68

Thanks for confirming I wasnt going daft (found that youtube vid a few minutes after posting).

I actually have one headphone cable that is a truly balanced 3.5mm connection that I adapt to 4 pin xlr so knew it was possible - but thats a TRRS 3.5mm .

Per that video I linked looks like manufacturer is aware - interestingly in their distributor/ retailer of choice(Hifigo) its now available with a hard wired 3.5 OR 4.4 termination. Hopefully nobody gets a unit with an adapter and uses it with bad results.

If in doubt - dont ever go single ended (heaphone) to balanced (amp) unless you absolutely know how things are wired would be a wise move for anyone
 
and @Roland68

Thanks for confirming I wasnt going daft (found that youtube vid a few minutes after posting).

I actually have one headphone cable that is a truly balanced 3.5mm connection that I adapt to 4 pin xlr so knew it was possible - but thats a TRRS 3.5mm .

Per that video I linked looks like manufacturer is aware - interestingly in their distributor/ retailer of choice(Hifigo) its now available with a hard wired 3.5 OR 4.4 termination. Hopefully nobody gets a unit with an adapter and uses it with bad results.

If in doubt - dont ever go single ended (heaphone) to balanced (amp) unless you absolutely know how things are wired would be a wise move for anyone
I came across this cable a few years ago.
Not expensive at all, especially compared to the original cable and the amount of work involved with the Lemo connector.
But the Lemo connector for the AKG K812 and K872 is definitely 3-pin and there is no indication of this, although I pointed this out to the dealer at the time.
Of course ideal for an SE amplifier like the Topping L50.

I have noticed adapters and cables like this many times since then.

Bildschirmfoto 2024-12-10 um 14.55.46.png
 
Unfortunately, I have seen something like this a lot in recent years.
Headphone connection cables keep appearing on eBay, Aliexpress, Amazon, etc. that are definitely 3-pin on the headphone side, but have a TRRS 2.5mm, 4.4mm Pentacon or 4-pin XLR connection on the amplifier side.
The same applies to adapters.
Note to everyone, such adapters and cables could destroy your headphone amplifiers (desktop/mobile, DAP, etc.).

There are probably two reasons for this.
- Ignorance on the part of the manufacturers of these cables and adapters.
- Strong increase in SE amplifiers with symmetrical headphone connections in recent years.

Adapters or cables that are 4-pin on the headphone side, but have a 3-pin connection on the amplifier side, are of course never a problem.
Yup, I bought one myself from Aliexpress. I had previously asked the vendor on whether it had floating grounds or if it was a shorted circuit design, he assured me it wasn't. When it got home I measured it with my multimeter and found out it indeed was shorting the negatives into a common ground. Since then I have an useless chord to fidget with on my desk.
 
Yup, I bought one myself from Aliexpress. I had previously asked the vendor on whether it had floating grounds or if it was a shorted circuit design, he assured me it wasn't. When it got home I measured it with my multimeter and found out it indeed was shorting the negatives into a common ground. Since then I have an useless chord to fidget with on my desk.
Unfortunately, there are many sellers and manufacturers who have no idea what they are selling.
Basic knowledge and understanding of the respective technology is often lacking.
You can see this in many places, not just in China and not just in the audio sector.

You only have to look at the many unusable implementations of 2.1 subwoofer outputs in amplifiers. Full range output of frequencies for the speakers, but only the lower frequency range is output for the subwoofer.
Exactly the opposite of what is needed.
Manufacturers sit down, grade 6-
 
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