Manley SNAPPER - Manual (Page 9)

Here are some suggestions to try out in the event you encounter some of the symptoms below.
If you encounter some other symptoms, then maybe you have some other problems that we don’t know about.
HUM: Forgot the words. Try a mains ground adapter if they are legal in your country. They are
also called 3 pin to 2 pin adapters or cheaters and are available in hardware stores. There should
be one ground in your system and only one. If two or more pieces of gear have 3 pin AC mains
cables, and they are grounded into the wall, a ground loop can occur which will usually cause hum.
Either the preamplifier OR the power amps, when sharing an earth connection, are probably the
best ground reference for your system, but not both or all of them.
HISS: Stray snakes in the room. Switch to the unused input using the RCA / XLR selector. Did the
hiss stop? If so, then the source of the hiss is something upstream from the SNAPPER. If the noise
level is the same, then the problem is in the SNAPPER - probably a noisey 12AT7 or 7044. Try
swapping (with the power off please) one tube at a time across to the other channel to see if the hiss
moves over there. If it did, then you found the troublemaker and you can contact us and we will
report him to the proper authorities and send you a tube. And maybe sell you some spares for next time.
OUT O’ BALANCE: Mom told you not to put anything smaller than your elbow in your ear. The
two speakers sound different. It may be the CD or source and the way it was recorded. First try a
different source, or switch the source to the mono mode if possible, and listen for any level shifts.
Notice that each SNAPPER s overall gain is carefully set at the factory, and should be within 0.25
dB (or better) of each other. Next try swapping the inputs. Power down and swap left and right
inputs. If it is the source, then the problem will follow the swap. Return them to normal (L=L).
Power down again and next try swapping the speaker connections by putting the left speaker wire
in the right terminals and right wires into the left terminals. If the problem switched sides then one
SNAPPER is suspect; if the problem stayed on the same side it is probably a damaged or fatigued
speaker or some crossover switch that got changed by the cleaning lady.
NO SOUND, NO PILOT LIGHT, TUBES DARK: Did you pay your Edison bill? Check the
Snapper’s AC Mains fuse. Check AC power cord. Is the amp plugged into a working electrical
outlet? (This has happened to everyone at least once!).
NO SOUND, PILOT LIGHT ON, TUBES LIT: Forgot to lower needle onto record. Check
speaker connection, input selector switch and input connection (exchange with the other channel).
Take a bias measurement. Do all bias test points read zero volts? If so, the B+ fuse is blown.
CAREFULLY INSPECT ALL OUTPUT TUBES BEFORE REPLACING THE B+ FUSE because
you probably blew one. That B+ FUSE info is on the next page, page 10. (See also Replacing
Tubes on page 7 if you forgot already what a blown tube might look like).
ONE OUTPUT TUBE WILL NOT BIAS: It doesn’t want to. Try to will it to comply. If the bias
voltage one of the tubes will not adjust at all or reads zero volts, and the tube filament is lit, try
replacing replace that particular tube. If the reading still is way off or reads zero, turn the amplifier
off. Set your multi-meter to ohms (the Omega sign) instead of DC volts (NOT the wavey line,
that’s AC volts!). Now measure the bias test point resistance (that’s what Ohms do) between the test
point and the ground test point. It should read approximately 10 ohms. If it reads very high or not at
all, then the 10-ohm cathode resistor connected to the tube has become hurt by that tube not being
nice to it. One function of this resistor is to act as the final safety valve in case of a shorted (not
nice) output tube, preventing damage to the rest of the amplifier should a short occur. Replacing
this resistor can be done by anyone with adequate soldering skills. We recommend contacting our
service department here at the factory for specific instructions on how to do that because we are
only giving you enough information in this owner’s manual to almost be dangerous.
9
TROUBLESHOOTING