As most of you reading this guide will know, alot of people who own Audio Innovations EL34 valve based amplifiers wonder what all the fuss is about changing the EL34 valve to a 5881.

The Reason ?

Simple Border Patrol advise that you should change your EL34 for a 5881 valve, but I say think before you do.

Border Patrol advise the change as they assume you are going to use one of the exellent Power Supply Upgrades and they rightfully do so as the current output is far higher than your Audio Innovations built in power supply,  there is a small risk that "IF" the grid inside the EL34 should short, then you will have considerable damage to your amp.

Now here is why I say "THINK" before you change your EL34's for a 5881.

Not all models of Audio Innovations amplifiers are suitable for a direct replacement from EL34 to 5881

Series 1000 Mono Blocks for instance work on a plate voltage of 455volts and a 5881 valve is rated at 400volts MAX depending on the munufacture, that's a 55volt difference and to make matters worse, some manufactures of 5881 valves MAX rating is only 360volts that's 90volts difference

I hope you can see from this what I mean by not all Audio Innovations amplifiers are suitable for a direct replacement from EL34 to 5881

Now before you all worry Audio Innovations Series 500 - 700 and 800 are in my view a safe bet for direct replacement as these amplifiers work on a plate voltage of around 360 to 390 volts so you are in a safe operating area for the 5881 valve

But even so for these models, do bare in mind that the Cathode Bias will be different for the 5881 valve to the original EL34, even though most Audio Innovations are Auto-Bias, I advise you to replace  the Cathode Resistor for the correct operating condition for a 5881 - this would be prudent if you are to use a 5881 in your Audio Innovations amplifier on a perminent basis.

Any other reason ?

Yes, Audio Innovation designed their amplifiers around the specifications of the EL34 valve, this is how the amplifiers were intended to be