hartke 3500 mod

[grmorrison]

is it advisable to swap out the factory AXL7 for a JJ Tesla ECC803s "hi gain" tube in the preamp? I wonder if the increased power and gain posses a risk of overheating the power amp or other circuitry. If this is a relatively safe mod
is there a way of opening the chasis without voiding the warranty?

[Enzo]

Hi, welcome.

Ever notice some guitars are just louder than others? SOme tubes are just "louder" than others. The higher gain in a high gain version of a tube is not that large a jump.

Is it advisable? If it sounds better to you, then it is OK. If it sounds about the same, then it is about the same.

There is no power in the preamp. Increased gain in the tube stage might deliver increased overdrive distortion, but all the preamp does is provide a signal to the power amp, so increasing the gain is the same thing as just turning up the guitar a bit. The power amp is what it is and can only provide so much output. Once it is driven up to clipping level, it goes no further.

Your warranty doesn;t cover the tube, at least not after a small period like maybe 90 days. It is perfectly normal to open an amp to change out a tube or replace fuses or whatever. You don;t void warranties by opening the unit. Unless you see a warning seal covering a screw, you can feel free to open it. Unplug the amp from the wall first though.

[grmorrison]

Hartke 3500

Enzo, thanks for the great answer. As you indicate the risk factor is negligable and the preamp tubes in question are inexpensive, (around $15.) it stands to reason one can afford to experiment with tone. A great online source is; tube depot.com.