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I recently bought this amp but when i turn it on there is a popping noise that is heard on the headphones. I tried different headphones and I get the same issue so I have narrowed it down to the amp. Anyone has any similar experiences with this issue?
EDIT: After some reading, I think I have the thumping noise some people describe and apparently it has to do with the AC Adapter. Is there a one that one would recommend for the amp?
It’s not the adapter. I have the original item purchased directly from JDS. It includes a a battery. The click appears here too. You can hear the click in a lot of amps. I hear it on the Dark Voice and other tube amps. You can hear it on loudspeakers from some power or integrated amps. It has to do with the power circuit design. Every time an amp is turned on or off you get a current surge (opening and closing currents). With cheaper or older designs this is transmitted to the headphone or speakers. When loud, it sounds alarming and may be harmful to the driver. When soft, it is probably just annoying.
The Objective amp is an example of how a simple but fundamentally sound design can result in a really clean and detailed sounding, but inexpensive amp.
Enjoy your amp. Don’t worry about the pop if it isn’t loud.
The most annoying thing about the JDS Objective (with battery) is that the power light shows no indication when the battery is charged. You can never tell if the charge has drained. When on low power, the music stops playing and the amp makes clicking sounds.
I love the amp, often carrying it around with me. I also get the fact that it’s supposed to be an example of really great sound from a simple circuit design. But a great car without brake lights or turning indicators? Come on!
But the popping/thumping sound does not stop until the amp is turned off. Sometimes I have to turn on and off the amp up to 20 times before I get the unit to work as intended. Are you telling me that is normal?
That’s definitely abnormal. I was referring to on-off pops. It’s hard to say for sure, but it could be something in the power supply system inside the amp. You need to have it looked at. Don’t plug any headphones into it till then.
I’m not sure about the AC adapter. You can replace it with anything on the market, provided it matches both the “volts” and “amps” rating on the amp spec sheet. Let me check too.
Massdrop has been a great idea and has largely worked well. But they have have had issues with paring down original products to achieve a certain cost level. Sometimes getting a really low price excludes a standard warranty. Look at my post on HE350 headphones. Still struggling with them.
Found this from JDS (https://www.jdslabs.com/pdf/Instructions_O2.pdf). This is the original avatar of your amp and hopefully identical except for the battery, which the Massdrop version doesn’t have.
Note the minimum amperage mentioned. Check the adapter to see if this value is at or below the recommended minimum.
Also, note the suggestion regarding a “stronger” adapter. I guess they mean with higher amperage.
There is also a caution regarding overdriving the amp with certain sources or headphones. Two headphones with the same “nominal” impedance may draw different currents. Also, a headphone’s impedance alters depending on the music being driven through it.
Let me know what music source you’re feeding into the O2 and if it has a “fixed” line-out. If the source has a manual that tells out the output from the line out, you may contact JDS asking if it is too much for the amp.