Lack of Lows from Headphone Jack - Anan 7000dlemk2

[ron4094]

When using the Sony MDR-7506 headphones with the Anan radio, I notice a distinct lack of low frequencies with stations that have very low frequency bass. If I connect the headphone jack to my stereo receiver and then listen through its headphone jack the low frequencies are normal. The headphone jack has a 10uf cap in series with it which has a reactance of about 160 ohms at 100 Hz with higher impedance as the frequency goes lower. The headphones have a nominal impedance of around 50 ohms. Wouldn't this explain the lack of low frequencies with the headphones and why the sound is normal through the receiver which has a much higher input impedance? If so, why didn't Apache Labs use something like a 100uf cap in series with the headphone jack so that headphones would work properly when connected.

Thanks,
Ron
WB2RON

[KA5KKT]

Hello Ron,

I don't know if this will help or not. My setup includes a Win 11 laptop as my desktop computer. Under the laptop is a multi-port dock. The dock is fed via USB C from the computer. I too have a Hi-Fi receiver fed by a headphone-type jack 3.5mm on the dock. The setup in Thetis looks like this...

Thetis - Setup Audio VAC, etc..jpg (24.83 KiB) Viewed 5381 times

and the setup in Windows > Settings > System > Sound looks like this below.

Windows Settings System Sound.jpg (96.28 KiB) Viewed 5381 times

I don't know if you'll have that USB Sound in your setup, but the sound through the Dock greatly surpasses that of the Headphone Output on the laptop computer itself. It did take me some effort and trial and error and drivers, etc.

...best I can offer,
Dick - KA5KKT

[w-u-2-o]

The design of the audio interfaces in the various ANAN models can be traced to the original, open source, Hermes design. It would seem that the original design team had bigger fish to fry than worry about low frequency audio performance. This part of the design remains effectively unchanged since the Hermes days.

Those of us who love to optimize and play with the audio side of things have generally gone over to using semi-pro or pro USB audio interfaces, first relying on VAC, more recently on the cmASIO feature added by W4WMT.

[JJ4SDR]

Ron,

I do have the SONY head-phones that you are referencing and did make the same observation after - for kicks - plugging the head-phones into the front of my ANAN 7000 DLE MKII. My main configuration has a professional grade digital mixer (it can also be used as a USB/Audio Interface) via VAC talking to Thetis and, my primary pair of headphones (not SONY) are connected to a linear headphones amplifier using balanced cables. That works really well.

73!
Juha
NI2M