Hi,
Thank you in advance for any input.
I am a novice in this field and would appreciate any help.
I use minelab gold detectors and a booster ( headphone amplifier) in my hobby.
I recently had two boosters die and when i took them apart I noticed that one was based on the LM386 chip. The other had the chip details ground off.
These booster when purchased at the store cost more than $150.
The detector output is in the 75 -1200Hz range.
Standard headphones supplied with the detectors are 32 ohm.
There seems to be a trend towards 150 ohm or greater headphones.
I tried a set of studio monitoring headphones and found the signal crisper, easier to pick up faint signals from the detector coil.
I would like to make my own portable headphone amp.
Low noise or distortion is the goal along with amplification of faint signals.
I would like to be able to drive headphones up to 300 ohm.
Battery size would be a maximum of 9 volts DC.
What amplifier chip would best suit my project?
I have noticed that some cheap chinese boards also incorporate a "microphone amplifier" as well as a amplifier chip. Such as the MAX9812.
Would incorporating a microphone chip provide any benefit?
Eventually I would like to go to a lithium battery with a micro or mini usb port.
Once again thank you.
Thank you in advance for any input.
I am a novice in this field and would appreciate any help.
I use minelab gold detectors and a booster ( headphone amplifier) in my hobby.
I recently had two boosters die and when i took them apart I noticed that one was based on the LM386 chip. The other had the chip details ground off.
These booster when purchased at the store cost more than $150.
The detector output is in the 75 -1200Hz range.
Standard headphones supplied with the detectors are 32 ohm.
There seems to be a trend towards 150 ohm or greater headphones.
I tried a set of studio monitoring headphones and found the signal crisper, easier to pick up faint signals from the detector coil.
I would like to make my own portable headphone amp.
Low noise or distortion is the goal along with amplification of faint signals.
I would like to be able to drive headphones up to 300 ohm.
Battery size would be a maximum of 9 volts DC.
What amplifier chip would best suit my project?
I have noticed that some cheap chinese boards also incorporate a "microphone amplifier" as well as a amplifier chip. Such as the MAX9812.
Would incorporating a microphone chip provide any benefit?
Eventually I would like to go to a lithium battery with a micro or mini usb port.
Once again thank you.
The JRC386 (better copy of LM386) is still a fine headphone amplifier. On 9V battery it will be plenty loud even in 300 Ohm phones. You must use *all* the capacitors on the LM386 data-sheet: power, bias, and the R-C network on the output. Sometimes they "work" when some of these caps are left-off, but they are prone to supersonic squeal, which spoils the fine audio, and could mess-up a metal detector.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.