Welcome to our TECH INFO pages!
As we have worked on tube amps for over 20 years now, we thought we would like to share some handy hints to keep your amp purring along in top shape. Follow these tips for many years of smooth,
To keep your amp in top condition Sherlock Amplifiers recommends the following tips:
1. ALWAYS MATCH THE SPEAKER IMPEDANCE with the amps output impedance. Unmatched impedance's will result in power loss, premature tube wear and at worse, tube failure. (see below for more info)
2. NEVER TURN ON OR OPERATE YOU AMP WITHOUT A SPEAKER PLUGGED IN. This can result in a tube failure and at worse, a blown output transformer. If you turn on, plug in your guitar, start playing and there's no sound, turn off immediately and check your lead,etc.
3. ALWAYS OPERATE YOUR AMP WITH THE CORRECT FUSES. Do not use higher rated fuse, nails or tinfoil as fuses! If your amp keeps blowing fuses, its for a good reason, get it checked out.
4. ALLOW YOUR AMP TO COOL DOWN after playing before moving it. The internals of the tubes heat up to very high temperatures and are quite fragile. Knocks and vibration can damage and shorten the life of tubes when hot.
5. REPLACE POWER TUBES ON A REGULAR BASIS before trouble starts. For average use, about every 1-2 years, but if you play every day and loud, you should be looking at every 6 months.
6. ALWAYS HAVE THE BIAS CHECKED AFTER REPLACING OUTPUT TUBES. A qualified technician should do this. Incorrectly biased output tubes will either run too hot, which will greatly reduce the life of your tubes or too cold resulting in distortion at any level. Don't use the amp, get the bias adjusted before you cook your tubes. (Pre-amp tubes don't require bias adjustments.)
7. PROTECT THE AMP FROM DUST AND MOISTURE. Don't store the amp in moist areas an keep it covered to protect it from dust etc.If you spill liquids into the amp turn it off immediately, unplug it, and get it checked out by a technician.
8. PROPER MAINTENANCE AND CLEANING COMBINED WITH REGULAR SERVICING by a qualified tube amp technician will ensure the best performance and longest life of your amp.
SPEAKER IMPEDANCES CHART
The following is a handy chart which gives the total impedance for any two
speaker cabinets connect to an amps output.
Speaker Cabinet 1 Speaker Cabinet 2 Total Impedance Ohms Ohms Ohms 4
If your using one 16 ohm cabinet the amps Impedance switch should be set to the 16 ohm position.
If the cabinet is 8 ohms, then use the 8 ohms position.
If using 2 cabinets each 8 ohms, then the Impedance switch should be set to the 4 ohm position.