EA iAmp Doubler power module replacement

[pete.young]

My Euphonic Audio iAmp Doubler died silently at rehearsal a couple of days ago. Lights carried on working but there was no sound. The amp wasn't particularly stressed at the time, running at about 10 o'Clock on the Master.

 

I'm pretty sure that it's the power module that has failed. If I take a line from the effects send into the effects return of another amp, it works fine and I can hear a difference in sound with the mute switch engaged (total silence or a slight hissing when not muted).

 

The power module is an ICEpower 250ASX2. I'm assuming that there are no serviceable/replaceable parts in this module, and that replacement is the best option.  It appears that it's a straightforward case of disconnecting the old module, removing the screws and swapping the new one in. Does anyone know if any additional configuration is required? There don't appear to be any jumpers on the board.

 

There is a slight complication: there is what looks like a thermal sensor attached to the power amp heat sink, which connects to the fan control circuit. I'm assuming I can either re-use this sensor or replace it. Can anyone suggest a suitable adhesive for this application? It's also an option to just wire the fan so it runs all the time, but I don't think I've ever heard it running in normal operation.

[Chienmortbb]

Before you do anything make sure it is the power module. The fact that the MUTE button mutes the hiss suggests that the failure is not there but elsewhere. Those modules are not especially noisy on their own. 
 

Before the module there will be a preamp and a balancing circuit as the 250ASX2 is it is two amplifiers working in bridge or anti-phase. 

[pete.young]

I don't have a schematic for the amp, but the data sheet for the power module does identify the inputs. Is it reasonable to assume that, provided I have a voltage on the connector that carries the input to the board, that everything upstream of the power amp is working as it should?

 

[Chienmortbb]

You will not find any service information for the amp, as with all major class D makes, Powersoft, Pascal and ICEPower do not publish any service information. 

The upside is the we, the users get a well engineerded power amp that saves on development time and keeps purchase prices low. The downside is that you cannot easily service them.

 

Looking at the block diagram, the mute circuit is very early in the signal chan so it is likely that you power module is working. One small issue with this series is that the auxiliary supplies that power the preamp and signal balancing circuits are protected by fuses on the pcb. If there is a fault on the these lines you may get no output from the small signal circuits. These are hard to find and even harder to replace ( yes experience talking). 
 

In reality it really is a job for an amp tech, I am wary about advising on mains powered devices online.

[pete.young]

By "amp", I meant that I don't have any information for the EA Doubler. I did find the data sheet for the 250ASX2 module, but the block diagram on there doesn't appear to show a mute switch. Which block diagram are you looking at?

 

I think the SMPS part of the module is working, since there is DC power going to the pre-amp boards and I get a signal from the Effects Send output.

 

Thanks for the help you've given me. I think this will be going to an amp tech, assuming that I can find one with the skills, experience and inclination to work on it. Most of the guys I know round here are old-school valve amp types. I'd just like to gather as much information as possible to pass on.

 

 

[Chienmortbb]

 

Enable is the input used to mute the amp.