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Yamaha C-4 pre-amp help

avionic said:
Do you have another pre-amp or pre-amp out?
Click to expand...
I assume with this question you believe the amp is at fault, I agree since there is no voltage on speaker outs and the meter is not showing any signs of life.


Do you have a phone cable with RCA outs to connect your phone to the M-4 and see if the meter moves and if there is voltage on speaker outs?

Nashou
 
Nashou66 said:
I assume with this question you believe the amp is at fault, I agree since there is no voltage on speaker outs and the meter is not showing any signs of life.


Do you have a phone cable with RCA outs to connect your phone to the M-4 and see if the meter moves and if there is voltage on speaker outs?

Nashou
Click to expand...
I have a bluetooth receiver with RCA outs. I will try this and report back! I didn’t even think that would work!
Nashou66 said:
I assume with this question you believe the amp is at fault, I agree since there is no voltage on speaker outs and the meter is not showing any signs of life.


Do you have a phone cable with RCA outs to connect your phone to the M-4 and see if the meter moves and if there is voltage on speaker outs?

Nashou
Click to expand...

Nashou66 said:
I assume with this question you believe the amp is at fault, I agree since there is no voltage on speaker outs and the meter is not showing any signs of life.


Do you have a phone cable with RCA outs to connect your phone to the M-4 and see if the meter moves and if there is voltage on speaker outs?

Nashou
Click to expand...
I have a Bluetooth receiver with RCA out
: ELEVENKR

Bluetooth Adapter for Stereo Receiver - aptX HD RCA/3.5mm Output​

I’ll give that a try on the M-4 and report back.
 
Osito22es said:
I have a bluetooth receiver with RCA outs. I will try this and report back! I didn’t even think that would work!



I have a Bluetooth receiver with RCA out
: ELEVENKR

Bluetooth Adapter for Stereo Receiver - aptX HD RCA/3.5mm Output​

I’ll give that a try on the M-4 and report back.
Click to expand...
Ok I plugged in the Bluetooth receiver into the Yamaha m-4. Connected my phone by Bluetooth. No levels indicated on lights and no AC current detected on speaker outs when playing something.

I think that the Bluetooth receiver should go through a pre-amp because it outputs a line-level analog signal. I don’t have another pre-amp so I will have to brainstorm how else to test this just in case.

Sounds like I need to regroup and start evaluating the M-4 in parallel.
 
Osito22es said:
Ok I plugged in the Bluetooth receiver into the Yamaha m-4. Connected my phone by Bluetooth. No levels indicated on lights and no AC current detected on speaker outs when playing something.

I think that the Bluetooth receiver should go through a pre-amp because it outputs a line-level analog signal. I don’t have another pre-amp so I will have to brainstorm how else to test this just in case.

Sounds like I need to regroup and start evaluating the M-4 in parallel.
Click to expand...
If no meters and no AC then most likely the M-4 is faulty. when you turn that on do you hear the relay click?

PS: your BT device had volume so it basically is a pre amp

Athanasios
 
Nashou66 said:
If no meters and no AC then most likely the M-4 is faulty. when you turn that on do you hear the relay click?

PS: your BT device had volume so it basically is a pre amp

Athanasios
Click to expand...
I definitely hear the relay click on the M-4. Speaker button lights turn on and off. And I see a flicker of audio level lights when I turn the M-4 on.
 
Osito22es said:
I definitely hear the relay click on the M-4. Speaker button lights turn on and off. And I see a flicker of audio level lights when I turn the M-4 on.
Click to expand...
did you adjust the volume on the BT unit when it was connected to the M4?

And you are using the Left and right Audio outs on the BT unit right?

Do you have audio cables that can go from your phone to the amp?

Make sure your volume on the phone is all the way down and slowly raise the volume.
 
Nashou66 said:
did you adjust the volume on the BT unit when it was connected to the M4?

And you are using the Left and right Audio outs on the BT unit right?

Do you have audio cables that can go from your phone to the amp?

Make sure your volume on the phone is all the way down and slowly raise the volume.
Click to expand...
Yes I adjusted the volume.
I am using the left and right audio outs on the BT unit.

I don’t have any audio cables that can go directly from my phone to the amp right now. I’ll do my best to get the right stuff and try this.
 
I just reread your original post , and now realize you have T-1 tuner.

This has a variable out put !!! you can use that as a source to the M4.

On a Yamaha T-1 tuner, the variable output volume is controlled by a small thumbwheel located on the bottom of the unit near the front center. [1]

Adjusting the Output
    • Locate the thumbwheel: Look underneath the front edge of the chassis, right in the middle, to find the protruding edge of the volume attenuator

      • Connect correctly: Ensure your audio cables are plugged into the Variable RCA output jacks on the rear panel, rather than the Fixed outputs. [1, 2]
      • Turn to adjust: Rotate the thumbwheel up or down to raise or lower the output signal level, which is helpful for matching volume levels with other audio components during A/B testing. [1]
      • Athanasios
 
Nashou66 said:
I just reread your original post , and now realize you have T-1 tuner.

This has a variable out put !!! you can use that as a source to the M4.

On a Yamaha T-1 tuner, the variable output volume is controlled by a small thumbwheel located on the bottom of the unit near the front center. [1]

Adjusting the Output
    • Locate the thumbwheel: Look underneath the front edge of the chassis, right in the middle, to find the protruding edge of the volume attenuator

      • Connect correctly: Ensure your audio cables are plugged into the Variable RCA output jacks on the rear panel, rather than the Fixed outputs. [1, 2]
      • Turn to adjust: Rotate the thumbwheel up or down to raise or lower the output signal level, which is helpful for matching volume levels with other audio components during A/B testing. [1]
      • Athanasios
Click to expand...
I will try this!! I’m also wondering if I can connect my c-4 to my bass guitar amp. Using some rca to 1/4 cable if that exists just to confirm C-4 is working.
 
Osito22es said:
I will try this!! I’m also wondering if I can connect my c-4 to my bass guitar amp. Using some rca to 1/4 cable if that exists just to confirm C-4 is working.
Click to expand...
you could connect the C-4 output to an input on the kenwood , have to volume of the C-4 all the way up or past 12 O'Clock at least .

Or if you have a RCA to 1/4" phono to connect to the amp you can check one channel at a time with the guitar amp.

Athanasios
 
Look over the solder connections for the RCA input jacks on the little circuit board of the M-4. Make sure the two cables ar properly plugged into the amplifier assemblies.
 
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