Hello, yes there is a trace around the board but there is an open area in the back by the bridge rectifiers. After doing the recommended grounding I still have a hum. I will say that when I moved the amplifier to the kitchen table and used a different wall socket the hum dropped considerably. could it be coming from my wall?
there is some lighting connected to the same outlet. 2 plugs on the outlet. the lights are on a switch but the audio stuff is on constant.
Have you rounded up the "Usual" suspects. Speaker RCA jacks not grounded to chassis "make sure they are not", cables tight to connectors, all polarity is correct both input and output. Have you changed source? Did you have a couple of "Cocktails" to get your Clarity of Vision up to a Higher level. Did you walk away for 24 hours?
I have not used XLR inputs before but I am sure they need to be isolated from the chassis as well.
All of the above info is from an Old Retired Guy, so be careful
Best of Luck
I have not used XLR inputs before but I am sure they need to be isolated from the chassis as well.
All of the above info is from an Old Retired Guy, so be careful
Best of Luck
The amplifier shows XLR, but I am using single-ended rca connections on the other side. the 2 grounds have been joined together via a wire soldered in place at the xlr connectors on the back plate,........the Hum is present with the source and the pre amp off
Check the ground on your power cable. Make sure it isn't open. Then to be sure, check the ground from inside of the amp to the ground prong that goes into the wall with the cable plugged into the amp. Also, check the outlet for proper ground.
Crooner, did you try rotating the toroid transformer?
Did you measure the resistance between amplifier signal ground and chassis ground? It should be the thermistor cold resistance.
The power supply PCB does not take the Ground from the board at a optimal location. That may cause some hum. The PS ground should be located between the last V+ and V- capacitors. So disconnect the V+ and V- grounds from the screw connectors and solder them to the location shown. The location is at the board side of the thermistor connection.
According to their specifications, your Klipsch speakers are 94.5 dB @ 2.83V/1m so they are fairly sensitive (if the sensitivity specs are accurate). Noise would be more audible than with lower sensitivity speakers.
Did you measure the resistance between amplifier signal ground and chassis ground? It should be the thermistor cold resistance.
The power supply PCB does not take the Ground from the board at a optimal location. That may cause some hum. The PS ground should be located between the last V+ and V- capacitors. So disconnect the V+ and V- grounds from the screw connectors and solder them to the location shown. The location is at the board side of the thermistor connection.
According to their specifications, your Klipsch speakers are 94.5 dB @ 2.83V/1m so they are fairly sensitive (if the sensitivity specs are accurate). Noise would be more audible than with lower sensitivity speakers.
Attachments
The XLR-wired Aleph J, if used with a single-ended (RCA) source, will require a ground lift resistor (negative is shorted to shield/ground). Later on, if an XLR source is used, the ground lift resistor will not cause any harm... Furthermore, it can be bridged out by soldering a wire link across that resistor... no need to remove the PCB...
The above can be tested first...
The above can be tested first...
Hi, yes I tried moving the transformer, didn't really make much of a difference. I also checked the signal to chassis ground= 13.2 ohms
You can test if it is going to work from the top side as per the second photo I attached above... but the mod needs to be done from the underside, i.e. you have to remove the AMP PCB... as per the first photo I attached above.
Is the lighting controlled by a dimmer(s)? These are known to create dc on the line and may explain why the hum was less while plugged into the kitchen outlet. Try turning off the lights, or if on dimmers have the lights on full intensity and see if it changes the amount of hum. May be that you have more than one issue causing or exaggerating the hum.
I have removed the lighting and only the audio cd player, preamp, and Aleph j on the wall socket......I Still have the hum😕
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I was also going to install the single-ended RCA jacks. will I have to do the 10-ohm resistor mod for that?.......I don't currently have an XlR set up at the moment.
Ok, here are the mods you recommended. I also decided to put a connector on the driver boards and add a single-ended connection ....there is a very slight hum but you have to put your ear to the speaker. I think I can live with that.....thanks to everybody and to Extreme_bolky for all the 👍 help on this site.
