Hello everyone,

I used this schematic to make my audio amplifier, works great. I would like to add some base to the sound.

Can anyone suggest a mod to the circuit to give the output some base?

Thank you,

Mitch

If you jack up the output coupling cap to, say, 1000 uF it should improve the low-frequency response. As it is depicted (with 220 uF), the output will roll off at lower audio frequencies.

Also, if you increase the 0.047 uF capacitor's value, that will shift the high-cut filter rolloff point to a lower frequency. This won't increase bass response but by reducing the high-frequency content of the signal it will give the impression that bass is enhanced. This is the principle that most inexpensive radios used for tone control. You might try replacing the 10 ohm fixed resistor with a 500 ohm pot and the 0.047 uF cap with a 0.1 uF unit. That would give you a range of control over the filter's response.

Mitch,

Might take a look at an LM386 amp with tone circuit here:

http://www.qrp.pops.net/misc_2005.asp

Clifton

:Hello everyone,
:
:I used this schematic to make my audio amplifier, works great. I would like to add some base to the sound.
:
:Can anyone suggest a mod to the circuit to give the output some base?
:
:Thank you,
:
:Mitch
:
:
:

:Mitch,
:
:Might take a look at an LM386 amp with tone circuit here:
:
:http://www.qrp.pops.net/misc_2005.asp
:
:Clifton
:
::Hello everyone,
::
::I used this schematic to make my audio amplifier, works great. I would like to add some base to the sound.
::
::Can anyone suggest a mod to the circuit to give the output some base?
::
::Thank you,
::
::Mitch
::
::
::
:
:
Thanks to all,

I took the lazy man's way out. I finally settled on a .047uF capacitor and a 10K resistor in series installed between pin 1 and pin 5 of the LM386 amp. This is producing the sound I am satisfied with.

Mitch

::Mitch,
::
::Might take a look at an LM386 amp with tone circuit here:
::
::http://www.qrp.pops.net/misc_2005.asp
::
::Clifton
::
:::Hello everyone,
:::
:::I used this schematic to make my audio amplifier, works great. I would like to add some base to the sound.
:::
:::Can anyone suggest a mod to the circuit to give the output some base?
:::
:::Thank you,
:::
:::Mitch
:::
:::
:::
::
::
:Thanks to all,
:
:I took the lazy man's way out. I finally settled on a .047uF capacitor and a 10K resistor in series installed between pin 1 and pin 5 of the LM386 amp. This is producing the sound I am satisfied with.
:
:Mitch
:
Hello again everyone,

I took my own advice and built a two channel audio amplifier, works great with my turntable.

Listening to a 1955 Platters 16 Greatest Hits album ("Smoke Gets In Your Eyes") with my home brew amplifier.

Works with a 9 volt battery, on high volume it will blow you out of the room, any ideas on the wattage from this audio amp?

Mitch

Thank you,

Mitch

Works with a 9 volt battery, on high volume it will blow you out of the room, any ideas on the wattage from this audio amp?

It's probably in the low hundreds of milliwatt range per channel. A higher audio output level would make the amp eat 9V batteries like popcorn.

You could figure it out by measuring the current out of the battery when playing a record at high (undistorted) volume, dividing by 2, and applying the P=IV relationship. This is an "outside" approximation since the amp isn't 100% efficient and the record you choose (probably) has variable sound levels; but it will get you in the ballpark- or at least the parking lot.

Does you turntable have a built in RIAA frequency compensation circuit for records? Without that, you will lose bass and have too much high end because of the way they cut the record groove.

:Does you turntable have a built in RIAA frequency compensation circuit for records? Without that, you will lose bass and have too much high end because of the way they cut the record groove.
:
Hello Brian, (ALL),

The turntable does not have a built in RIAA circuit. I can make one for the two channels.

What do you think of this design?

http://www.reprise.com/host/circuits/riaa_preamp.asp

Responses welcome,

Mitch