I need a hero! Hum in my audio!

[556]

OK, I am running a Robyn T-240D, D104 lollypop mic, a Blackcat one tube modulator, and an Antron99. Ive been running this set-up for about three months. Nothing but complements on the thing. Three days ago i got a couple reports that there was a hum in my audio. Its only humming when the one tube modulator is turned on. Reports say that the barefoot radio is clear as a bell. I did have one report say they could hear a slight ringing but that could be coincidence. The Robyn is dking 4 watts swinging 13 or so. With the one tube turned on I have it dking 10 swinging 50-55 watts. I had 90 degree connectors on all my coax connections. I removed them and found one connector that was broken. Now im running everything straight without any extra connecors. I thought this fixed my hum problem but during the coffee club this morning, reports said the hum was still there. Evidently its only humming when the one tube is turned on. What can i do to try to figure this out. Its killing me, I dont have any experience with tube radios so i have no idea where to begin. I went from top shelf audio to having a hum over night. Any help on this will be greatly appreciated. I need a hero on this one because i dont have a backup base radio or a power supply to bring my mobile indoors.I dont think i can handle not having a radio for very long lol.

HELP MEEEE! lol

[Night Crawler]

Check the high voltage filter capacitors in the blackcats power supply.

[556]

Ok, Im not sure how to test them. Im guessing i just use a multimeter. Do you know what reading i would be looking for? I have no experience doing any of this, but if you can tell me what the reading should be when i put the meter on them, that would be very helpful.

I know i should probably be paying a technician to do this but times are hard and money is tight, and did i mention id rather not go without my radio? lol

[Sheriff Bart]

if the D-104 is the amplified type check the battery.


3's

[Night Crawler]

Im not sure how to test them.

Testing an Electrolytic Capacitor
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If there's a hum coming from that amplifier it's in the power supply and can almost 100% guarantee the filter caps are the cause of it when you replace them use a 40uf @ 450vdc.

[556]

Im not sure how to test them.

Testing an Electrolytic Capacitor
[Please login or register to view this link]
[Please login or register to view this link]
If there's a hum coming from that amplifier it's in the power supply and can almost 100% guarantee the filter caps are the cause of it when you replace them use a 40uf @ 450vdc.

Thanks so much for this post.

[556]

if the D-104 is the amplified type check the battery.


3's

Its Non-powered.

[Radio 75]

Since no one else has said it yet I feel compelled to.
Be careful when working on tube equipment!!! There are some lethal voltage potentials in there.
Those HV caps in the power supply might not have a bleeder resistor across them, so they will store energy for quite a while. You really don't want to discharge those things with your fingers.
It hurts.
(ya, I did it once)
(once!)

[556]

Ok, the locals are telling me, "Its a tube radio, glass has some hum in it. Its normal." I don't agree. Yes you can hear the tubes hum on a tube radio, but my problem is that it doesnt hum when running barefoot. The hum that i have just started within the past week. So i know that its not normal. I am in the process of checking the high voltage filters on the Blackcat's power supply. As soon as i can figure out where they are. After i get those checked ill update this post. Thanks for the help so far. I'm gonna figure this thing out if it is the last thing i do.

[Night Crawler]

Ok, the locals are telling me, "Its a tube radio, glass has some hum in it. Its normal."

Are they serious never heard that before maybe because it's not true.

[Radio 75]

Hey 556 I just thought of something silly. Back in the day when I used to play guitar and such, if our amps hummed we had a ground lift switch. Is your amp using a 2 prong non-polarized plug? If so, pull it out, rotate it 180 degrees and plug it back in. I know, sounds stupid, but it's a quick and free test....

[556]

Yep, needed new high voltage filter capacitors. Thanks Night Crawler. You are my hero.

[Ritual kill]

I have a galaxy dx 919 , a 2290 FATBOY, D-104 power mic , and wilson 1000. I am getting that same buzzing noise you are talking about. I can even hear it aswell as others on the recieving end. I hooked my stock mic up and buzzing went away. Did you figure out what your buzzing sound was from, just curious. Thanks James

[420Snowman]

Yep, needed new high voltage filter capacitors. Thanks Night Crawler. You are my hero.

Glad you're still around to tell us you.got it fixed! I was bit by my tube amp once, and let me tell ya, I'm surprised it didn't kill me, seriously. It knocked my **Censored** to the ground and it took me a while to come around, when these guys say be careful, they are just looking out for ya, that's a fact!

Snowman
Sent from my HTC mobile.

[420Snowman]

I have a galaxy dx 919 , a 2290 FATBOY, D-104 power mic , and wilson 1000. I am getting that same buzzing noise you are talking about. I can even hear it aswell as others on the recieving end. I hooked my stock mic up and buzzing went away. Did you figure out what your buzzing sound was from, just curious. Thanks James

I would say your Mic is obviously the issue, did you check the battery? Check the wires inside the Mic and the connector to make sure nothing has come loose.

Snowman
Sent from my HTC mobile.