I've had a Hartke 5000 for a few years....Alas, I wish I had purchased the 7000 for more power!! These two amps are the same, the only difference is the 7000 has an additional pair of output transistors on each channel (the power amp PC board shows the empty space with a note, "delete part for 5000) and I assume the 7000 has higher power supply rail voltages (so the toroidal power transformer is different, unfortunately it's a custom wound job with taps for various preamp voltages). The preamp board and all other components are the same. Has anybody ever converted the 5000 to 7000 or even considered it? If anybody has a schematic for either one, that'd be nice too... I've emailed Hartke but the pessimist in me says they wouldn't be interested in doing it, though perhaps they'd sell me a new toroidal. Still, even if it's $200, it's cheaper than a new amp.