Fax (301) 498-0554 Dear Customer: We at Jolida want to take this opportunity to thank you for purchasing the JD 502B Integrated Stereo Tube Amplifier. The company that stands behind your amplifier draws on a decade of tube design and manufacturing experience. In addition to our engineering knowledge, Jolida is committed to provide its customers with the highest level of quality sound at an affordable price.
SAFETY PRECAUTIONS IMPORTANT SAFEGUARDS PLEASE READ CAREFULLY ALL THE FOLLOWING IMPORTANT SAFEGUARDS THAT ARE APPLICABLE TO YOUR EQUIPMENT. _________________________________________________________________________ _________________________________________________________________________ The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user CAUTION to the presence of uninsulated “dangerous voltage” within the product’s enclosure that may be of suffi- RISK OF ELECTRIC cient magnitude to constitute a risk of electric shock...
SAFETY PRECAUTIONS CONTINUED INSTALLATION ENVIRONMENT MAINTENANCE 1) Water and Moisture - Do not use this product Cleaning - Unplug this product from the wall outlet near water - i.e. near a bathtub, wash bowl, kitchen before cleaning. Do not use liquid cleaners or sink or laundry tub;...
The JD 502B is housed in a heli-arc welded chassis and uses 2 sets of matched pairs (4 pieces) of 6550 power output tubes, two pieces of 12AT7 power drive tubes and 2 pieces of 12AX7 tubes for the preamplifier.
When turning the unit on, make sure the volume control is at its lowest point. 5. Your JD 502B will now operate satisfactorily. However, a full stabilization or warm-up period of at least 5 minutes is recommended for best sonic performance.
Note: Jolida, Inc. does not recommend leaving your JD Volume control: 502B "on" 24 hours a day as is the custom of some This control is used to adjust the output volume level.
"GND" terminal on the JD 502B and the red, "+", or positive speaker terminal is wired to the "4"or "8" ohms terminal on the JD 502B. If these wires are reversed (reversed polarity), the sound will be unnatural and will lack bass (out of phase).
Page 9
IMPORTANT NOTE: Use the best available speaker wires and interconnects between your equipment. This material is available at your local audio store. Jolida cannot emphasize this enough. Our experience has been that a set of top quality cables hooked up to speakers...
This section is dedicated to those who do not have an abundant amount of experience with tube amplifiers. The above drawing is a schematic of the top panel of your JD 502B amplifier. Your amplifier uses a complement of 8 tubes spread over three vacuum tube types.
6550 electron tubes are installed. 3. In general, after the initial biasing, you do not have to bias the JD 502B for six months to three years. There will be fluctuations in the bias of the amplifier that are due to either the changes in voltage (in some regions of the...
Page 12
4. Jolida has found that if the bias is incorrectly adjusted so that the electron tubes' bias levels are grossly out of balance (more than 75% or in other terms more than 300 millivolts), a reduction in the life of the tube and other problems can result.
Page 13
A quick and easy method to bias the amplifier, to make certain the tube is at the right bias point or to re-bias. For this type of biasing only a small plastic handled flathead screwdriver is needed. 1. To start the process, turn the unit on with the volume knob turned to zero. No audio source should be playing at this time.
CAUTION: The JD 502B amplifier contains sufficient levels of voltage and current to be lethal. Do not tamper with a component or part inside the unit. Even with the power turned off, a charge remains in the energy storage capacitors for some time.
Service Return Authorization and complete shipping instructions. Either way, you'll need to present the original bill of sale to establish the date of purchase. Please do not ship your Jolida unit to the Maryland address without our prior written authorization.
Page 17
Weight: 39 pounds (18 Kg) net, approximately 46 pounds (21 Kg) packaged Warranty: Two year limited parts and labor. One year or 1000 hours whichever comes first on Jolida Tubes. Bias Settings: 50 millivolts + 5 mV Fuse: 110 - 120 VAC, 6.3 Amp Fast Blo; 200 - 240 VAC, 3 Amp Fast Blo...
Need help?
Do you have a question about the JD 502B and is the answer not in the manual?
Questions and answers