Zesto Audio EROS 500 Select
2022
13 |
P a g e
What if you break the “Key” on an output tube?
If you look at the bottom of the tube, there is a black plastic cylinder in the center of the pins
with a notch, this is your alignment key. This plastic is fragile and can easily break if you rock
the tube. You can fix it with a 5-minute 2-part epoxy glue.
If you break a key, you must be very careful to install the tube in the correct orientation
or you will damage the amplifier. (See warning below)
If you break the key in the socket, just push it thru and it will fall to the bottom of the
amp. Don’t worry! It won’t short out anything, but it will rattle when you move the amp.
Broken keys do not affect the performance of the amp
Broken keys are
not covered
under warranty.
Warning!
You can blow up a power amp with considerable drama by inserting an
output power tube incorrectly.
This happens when you break the plastic alignment key and do not insert the pins with
the proper orientation into the socket.
Notice there are 8 pins in the socket, but only 7 pins in the tube with pin 6 missing, so
it’s easy to get it wrong. Intuitively you think the open pin matches the key, but it doesn't.
The key orientates at 6 o’clock, but the missing pin 6 orientates at 10 o’clock.
Tip:
The
logo on the metal collar and the alignment key on the tube faces forward. There is
usually a notch in the metal tube collar that lines up with the key.
For your safety, all Zesto Audio power amps ship with a copper plug inserted in the pin
6 socket to avoid any accidents. The good news is your power amp can be repaired at
the factory or authorized service technician if inserted incorrectly. The bad news is any
repairs caused by tubes installed incorrectly are
not covered under warranty.
Changing Tubes
Turn the power OFF, then wait for both the Amber and Green LEDs to go OFF.
For the best performance, this amp needs to warm up for 30 minutes.
If your amp is already warmed up, you only need 15 minutes for the new output tubes to
warm up.
Tubes are fragile when hot, so handle carefully with a cotton towel and place them to
cool down on a cotton towel, not a hard surface and not your carpet.
Warning!
Hot tubes will melt Microfiber cloths, most synthetic fabrics, and your carpet.
See Trouble Shooting on page 17 for more tube info
