Spider iv 75

[robertinnes5]

My Spider iv 75 has just lost all power , I built a whole new casing to hold the brain and speaker was working ok but seemed to lose all power nothing lights up 

[fflbrgst]

Nice woodwork!

 

I see you've got 2 speakers there did you match the impedance to the original single speaker so you are not pushing the amp past its limits?

 

A lack of power (overall) could be something simple like a fuse or component in the power supply circuit, or the power supply itself.

[robertinnes5]

On 5/20/2019 at 1:39 PM, fflbrgst said:

Nice woodwork!

 

I see you've got 2 speakers there did you match the impedance to the original single speaker so you are not pushing the amp past its limits?

 

A lack of power (overall) could be something simple like a fuse or component in the power supply circuit, or the power supply itself.

Thank you , the top speaker is from my Line 6 amp  (75 watt) the other speaker is from another amp ( 30 watt ) but an 80 watt speaker ... Don't know nothing about impedance just thought the 2 speakers would work together , stupid eh ?

[fflbrgst]

Unfortunately, if you hooked them up in parallel (i.e. both + hooked up to same amp lead, both - hooked up to same amp lead), the impedance = R1xR2/(R1 + R2), so assuming two 8 ohm speakers  8x8/(8+8) = 4 ohms.  When you hook a solid state amp up like this, it ends up overpowering the output circuit (voltage, I assume), eventually frying a component.  If you are lucky, you may have just blown a fuse.  Back in the days of valve (tube) amps, we used to blow fuses all the time because of this, it was no big deal, we'd just pop another one in (they were easy access on the back panel of the amp, same fuses you see in cars.

When you are looking at the amp chassis to find anything 'blown', be careful of any power capacitors - these can hold a high voltage long after the amp has been unplugged.