No Sound from Amp after Installing Speakers in Series

[Telemirror]

I decided to play around with/upgrade an unused mini amp (Joyo JA-02 https://a.co/d/5lYJb8Q) that I had. After removing the 8ohm/1w speaker from the original amp, I wanted to try two speakers to fit into a project I’m working on.

I picked up two 4ohm/3w speakers, and after wiring them in series, there is no sound coming from the speakers. The amp powers on and lights up (the OD channel clipping diodes even light up with signal, but zero sound.

The amp itself is 3w, so I figured that I would get a 50% output reduction from both speakers.

Recap:
Amp - 8ohm/3w
Original Speaker - 8ohm/1w
New Speakers in Series - 4ohm/3w

Any guidance is greatly appreciated! (Pics attached)

 

[PJS]

The wiring looks as if it should be correct. Did you try the 2 speakers individually to make sure they are both OK?

 

[jwin615]

Is the old speaker clearly labeled?
Check it with you DMM?
Check the new speakers with your DMM?
Only because we've all been there...
Sure you plugged into the correct jack?

 

[Telemirror]

Is the old speaker clearly labeled?
Check it with you DMM?
Check the new speakers with your DMM?
Only because we've all been there...
Sure you plugged into the correct jack?

The old speaker is clearly labeled (added pic)

I’m no sure what DMM is, can you clarify?

And definitely made sure I was using the correct jack, and a couple different cables. It has led clipping diodes in the OD channel that light up with guitar signal.

 

[Telemirror]

The wiring looks as if it should be correct. Did you try the 2 speakers individually to make sure they are both OK?

Not sure how to test them out individually, the amp is 8ohms and each speaker is 4ohms. Is there another way to test them? Sorry if that is a dumb question.

 

[TheHammer1982]

DMM = Digital Multimeter

 

[jwin615]

Yep. Multimeter.
The reason I ask is those consumer speaker a very loose with their ratings.
I.e. 4 ohm could mean 3.2-6.2
Often they're designed to be used with other speakers in parallel.
So 6.2 ohm driver and a 3.2 ohm tweeter work out to a happy 2 ohmsish.
Unsolder one outside wire from a speaker(not the series wire) and measure across the two speakers and check the resistance.

 

[PJS]

If you have a mulitmeter and you use it to test the DC resistance of the speakers, you should also see the speaker cone physically move one way or the other while under test. The meter tests DC resistance, while the specification is for AC impedance, so a 4 ohm speaker won't measure exactly 4 ohms. It should be close though.

Also, a solid state amp that can drive 8 ohms will probably also drive 4 ohms with no problem. Maybe just don't it to full volume so it's not trying to deliver the full current load. You could hook a single speaker up to the amp and test it on lower volumes just to make sure it works, and then test the other.

 

[Telemirror]

If you have a mulitmeter and you use it to test the DC resistance of the speakers, you should also see the speaker cone physically move one way or the other while under test. The meter tests DC resistance, while the specification is for AC impedance, so a 4 ohm speaker won't measure exactly 4 ohms. It should be close though.

Also, a solid state amp that can drive 8 ohms will probably also drive 4 ohms with no problem. Maybe just don't it to full volume so it's not trying to deliver the full current load. You could hook a single speaker up to the amp and test it on lower volumes just to make sure it works, and then test the other.

I attached just one speaker (tested both) but no sound. I tested the resistance of each speaker and got between 3.6 and 4 ohms each.

I don’t know if I ran the correct test, but there was no movement on the speakers.

 

[Telemirror]

If you have a mulitmeter and you use it to test the DC resistance of the speakers, you should also see the speaker cone physically move one way or the other while under test. The meter tests DC resistance, while the specification is for AC impedance, so a 4 ohm speaker won't measure exactly 4 ohms. It should be close though.

Also, a solid state amp that can drive 8 ohms will probably also drive 4 ohms with no problem. Maybe just don't it to full volume so it's not trying to deliver the full current load. You could hook a single speaker up to the amp and test it on lower volumes just to make sure it works, and then test the other.

I tested each speaker individually and got 3.6 - 4 ohms each. With each speaker connected individually, no sound at all.

 

[Telemirror]

Yep. Multimeter.
The reason I ask is those consumer speaker a very loose with their ratings.
I.e. 4 ohm could mean 3.2-6.2
Often they're designed to be used with other speakers in parallel.
So 6.2 ohm driver and a 3.2 ohm tweeter work out to a happy 2 ohmsish.
Unsolder one outside wire from a speaker(not the series wire) and measure across the two speakers and check the resistance.

Unsoldered one outside wire and read 7.6 - 8.1 ohms.

 

[PJS]

Your meter is saying that the new speakers should be OK. I think I would be trying the original speaker back in it, just to make sure that the amp is still working.

 

[jwin615]

No chance that the amp uses the chassis as ground is there?