Lead Curtain
New Member
Hello, I am new here & also new to the idea of audio engineering.
I have built a simple system which worked almost perfectly before I recently added some new components.
It incorporates the following...
(A drawing is attached in pdf format)
----------------------------------------------------
Inputs:
1. 1 x 3.5mm jack socket straight to the power amps. This is for playing pre recorded music from a phone or ipod where the device has its own volume control.
*2. 1 x 3.5mm jack socket via a potentiometer. This is for an electric guitar but could be used to control the volume with the mobile phone out of reach.
Outputs:
1. Left & right speaker "Front"
2. Left & right speaker "Rear"
User interface:
On Off switch.
1 x 2 channel 25Kohm 270 degree potentiometer
Preamps: 2 x KEMO #M040N (solid state) - just added.
Power amps: 2 x Pioneer GM-D1004
-----------------------------------------------------
I don't expect anybody is on fire about any of that!
Input 1 is no issue at all. It works as expected.
Input 2 is working but the signal was too weak.
I have just put a pair of solid state preamps in the guitar side. They have some issues which I can explain.
When wired in stereo, as per drawing attached, they make a low frequency repetitive thumping noise regardless of the input level or if there is any input at all. This has happened with 2 other power amps which have been used for testing.
When the power to one preamp is cut, the thumping noise goes but with a guitar plugged in the sound level at the speaker is way too high even with everything turned down.
I have either wired it wrong or bought the wrong bits or both.
I would appreciate some guidance but please bear in mind, it is only for a little guitar rig built into a noisy V8 hotrod, not a recording studio. There's no space, only a small alternator & battery. And I don't play the guitar either.
*That is why there are two preamps. The inputs would be shorted in the event of a mono jack plug being inserted. Maybe this is my problem. maybe I need one preamp & a switch, maybe they should be further apart, maybe the pot should be bigger or something but what I really need is some audio experts to look it over. Thanks in advance.
Alec
I have built a simple system which worked almost perfectly before I recently added some new components.
It incorporates the following...
(A drawing is attached in pdf format)
----------------------------------------------------
Inputs:
1. 1 x 3.5mm jack socket straight to the power amps. This is for playing pre recorded music from a phone or ipod where the device has its own volume control.
*2. 1 x 3.5mm jack socket via a potentiometer. This is for an electric guitar but could be used to control the volume with the mobile phone out of reach.
Outputs:
1. Left & right speaker "Front"
2. Left & right speaker "Rear"
User interface:
On Off switch.
1 x 2 channel 25Kohm 270 degree potentiometer
Preamps: 2 x KEMO #M040N (solid state) - just added.
Power amps: 2 x Pioneer GM-D1004
-----------------------------------------------------
I don't expect anybody is on fire about any of that!
Input 1 is no issue at all. It works as expected.
Input 2 is working but the signal was too weak.
I have just put a pair of solid state preamps in the guitar side. They have some issues which I can explain.
When wired in stereo, as per drawing attached, they make a low frequency repetitive thumping noise regardless of the input level or if there is any input at all. This has happened with 2 other power amps which have been used for testing.
When the power to one preamp is cut, the thumping noise goes but with a guitar plugged in the sound level at the speaker is way too high even with everything turned down.
I have either wired it wrong or bought the wrong bits or both.
I would appreciate some guidance but please bear in mind, it is only for a little guitar rig built into a noisy V8 hotrod, not a recording studio. There's no space, only a small alternator & battery. And I don't play the guitar either.
*That is why there are two preamps. The inputs would be shorted in the event of a mono jack plug being inserted. Maybe this is my problem. maybe I need one preamp & a switch, maybe they should be further apart, maybe the pot should be bigger or something but what I really need is some audio experts to look it over. Thanks in advance.
Alec
