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is this a tube issue?
- Thread starter causeBASS
- Start date
- Feb 12, 2006
- 60,960
- 5
- 220,630
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
If there's nothing wrong with the preamp tube, then the "why not" is because of higher early failure of new tubes. A typical preamp tube will last ~7.5k - 10k hours if it's not actually defective.
I've had 2 amps in the shop in the last 2 months where all of the problems were due to defective new tubes, and one of the owners tossed the old tubes... a perfectly fine set and had to buy another set because the set he bought was not under warranty. A costly lesson that others can learn from. If it's not broken, leave it alone.
I've had 2 amps in the shop in the last 2 months where all of the problems were due to defective new tubes, and one of the owners tossed the old tubes... a perfectly fine set and had to buy another set because the set he bought was not under warranty. A costly lesson that others can learn from. If it's not broken, leave it alone.
Al Kraft
Supporting Member
- May 2, 2016
- 10,768
- 40,436
- Disclosures
- Mesa Boogie beta product tester and player support
These days I think many people believe the goal of troubleshooting is to "do things until an item is working again" and that removing and replacing parts until things work again is actually a professional repair process. In my world the goal of troubleshooting is "verifiable fault isolation (usually involving instrumented tests) leading to a corrective action procedure which almost always includes deeper inspection/examination relative to potential secondary and tertiary issues, all followed by appropriate acceptance testing to return the item to a safe, ready for use condition".
I've seen technicians who will replace an obviously failed part multiple times in a row in the interest of expediency without asking let alone determining if there was a reason the part failed in the first place. I've also seen those same people neglect to examine and/or test related components that might have been damaged or overstressed by the part they replaced having failed. Fault isolation gets to root cause which then informs the various procedures that must be undertaken to ensure the end item is 100% back in operating condition and reliable to use.
I've seen technicians who will replace an obviously failed part multiple times in a row in the interest of expediency without asking let alone determining if there was a reason the part failed in the first place. I've also seen those same people neglect to examine and/or test related components that might have been damaged or overstressed by the part they replaced having failed. Fault isolation gets to root cause which then informs the various procedures that must be undertaken to ensure the end item is 100% back in operating condition and reliable to use.
Wanting a quick fix an amp is desirable. Can’t blame them for trying. Simple things can take weeks to resolve. Unfortunately, for most in this industry, fast turn around at a reasonable cost is rare. Taking an amp to a tech is right up there with going to an auto mechanic or the dentist. A good tech is worth their weight in gold. As Al implied, there are a lot of tech school graduates out there that can’t systematically diagnose an issue if their life depended on it. Service center business models want time constrained module swapping. Assuming that they have the parts.
