So today while Dan was doing some final testing on Proto Two*, which is now owned by Seattle area musician Chris Gallegos, I posed the insightful question: “So what’s up with the power supply?” This is what was up…
Dan: Well… the power supply is very precisely regulated to maintain a constant voltage at all times except for when our Precision Current Limiting Circuit (which Max did a bang-up job on, by the way!) senses that you are drawing too much power, in which case it slowly reduces the volume of your preamp until it’s in a safe operating range.
Kelly: So… it basically protects your amp from damage that could be caused by stuff shorting out?
Dan: Right, exactly. It provides a very robust protection system for your output tubes, your output transformer, and adds an extra level of protection for all the circutry in your amp.
Kelly: Wow, are shorting situations typically a real problem for tube amps?
Dan: Ya, well traditionally in tube amps there are a number of things that could go wrong that cause a cascading effect on your other components. The most common point of failure is the power tubes, which could take out your whole output transformer. So, you know, frying a $40 set of tubes could also mean you need to replace a $200 output transformer. But in our case if your tubes start failing the current limiter will roll back the output to protect your output transformer.
Kelly: Yikes, and other amps don’t do that?
Dan: Right, most tube amps don’t have any kind of solid state regulation or current limiting.
Kelly: So why are we doing it?
Dan: Well, the main reason to have current limiting in your power supply is to keep you from blowing fuses a lot or destroying your tubes in different shorting situations. It also reduces the risk of fire and protects your output transformer when your output tubes die.
Kelly: I noticed you said “when” your output tubes die, not “if” they die…
Dan: Ya, that’s the most common failure in tube amplifiers. Typically you need to replace your tubes every 6 months. So, this power supply design is meant to extend, even double, the life of those tubes. But also in the case that they completely fail, this will prevent the output transformer from dieing along with them.
Kelly: Sweet, Gnome Amps rule!
* Proto Two has been dubbed by Max as the Black Thunder, along the same vein as the late White Stallion which sustained some minor face plate damage and a few broken tubes in an unfortunate van wreck on the Gun Outfit tour. Van, gear and band careened into a semi-truck after an unlucky tire blowout on the freeway. Fortunately everyone in the van was able to walk away with only a few non-life-threatening injuries. Proto One, code named White Stallion, is in for repairs before rejoining Gun Outfit. Speaking of Gun Outfit, check out this nice review of Gun Outfit from PostPresentMedium.com.
