Laney Iron Heart IRT 120H head problem

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For all tech discussions relating to Guitars, Basses, Amps, Pedals & Guitar Accessories.

Re: Laney Iron Heart IRT 120H head problem

Post by Allen Puckett »

Hey guys, please help! I have the Laney Ironheart 120. It recently started sounding distorted on the clean channel. It makes a clicking sounds even after I turn it off. Im worried I messed up the tubes or something. The tubes get orange dots on them, but I saw in a video of a guy demoing the amp, they were orange on his, too. So I figured it wasn't an issue. I had been using a boss metalzone pedal through the fx loop return jack. What did I mess up? How would I run a pedal through the pre amp without messing it up? Any input is greatly appreciated. I want to think I know what I'm doing, but I need some advice.
Allen Puckett
Posts: 1 Joined: Wed Mar 18, 2020 2:32 am

Re: Laney Iron Heart IRT 120H head problem

Post by ef37a »

Hello Allen and welcome to SoS.
The Orange 'dots' are the weld points on the valve anodes ('plates' to the US peeps)

They should not be there as it indicates that the valves are dissipating more power than the specification states. Unfortunately some manufacturers run their valves so close to max spec that tolerances and a high mains voltage can push them into 'redplating', this will drastically shorten their lives. There is a following for the idea that valves MUST be run close to their limits for a good tone. BS IMHO and that of many top techs I talk to.

The fix is unfortunately not that simple. You need an amp tech, if the valves are 'fixed biased'* then they can have their anode current backed off (if there is a bias adjusting pot that is!) I suspect the 20 is 'cathode' biased and that means a slightly higher value cathode resistor. You could also find a different set of valves stay cooler but that is random.

In the normal course of events a pedal will not cause any damage to a decently designed valve amp. Maybe one of lesser quality might object if you drive the ***s off it for 3 hours?

*Fixed bias is usually adjustable. Cathode bias is fixed!

Dave.
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Re: Laney Iron Heart IRT 120H head problem

Post by Wonks »

Unless you've swapped them over for EL34s, then the amp should come with 4 x 6L6 valves. However, the amp can be fitted with EL34s, and there is a bias switch on the back to select the valve type fitted. Just make sure that the switch hasn't got knocked and is still on the 6V6 setting.
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Wonks
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Reliably fallible.
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