HX/DA owners - Questions

[sws1]

I have a new HX/DA 30 watt combo. Couple questions.

When you first turn the power on (standby remains off), do you hear the hum from the amp? ie. you clearly know that the amp is on from a foot or two away. (I don't think any of my other amps, which are arguably modern style, make this noise. About all you hear is a fan if there is one.)

When the amp is up at a decent volume, and your guitar volume is up with ALL strings muted, do you hear a bit of 60 cycle hum and/or hiss? If I switch to a single-coil, it's quite hummy, and if I switch back to HBs, the hum dramatically drops, but it's not zero. Interestingly enough, when I turn the guitar volume all the way to zero, the minor hum goes away. I would think that if the amp was the source of the hum, turning the guitar volume off wouldn't cure it, unless of course the guitar volume is grounding all the stuff in the amp.

I'm still trying different outlets and / or cables. I like in an old house, but the wiring had been completely re-done 10 years ago. Could be that different outlets were done at different times. I have a Furman power strip for my rack, but I'm not sure if that would "correct" a bad outlet.

Thoughts?

 

[László]

I have a new HX/DA 30 watt combo. Couple questions.

When you first turn the power on (standby remains off), do you hear the hum from the amp? ie. you clearly know that the amp is on from a foot or two away. (I don't think any of my other amps, which are arguably modern style, make this noise. About all you hear is a fan if there is one.)

Yes, I think it's the old fashioned transformer, one of the things about the amp that gives it that vintage tone. It's a very low level sound, not a 60 cycle hum.

Interestingly enough, when I turn the guitar volume all the way to zero, the minor hum goes away. I would think that if the amp was the source of the hum, turning the guitar volume off wouldn't cure it, unless of course the guitar volume is grounding all the stuff in the amp.

You answered your own question. You're getting noise from the guitar, and/or your pedals, etc. If the amp is quiet when the guitar volume is off, it's not the amp.

I'm still trying different outlets and / or cables. I like in an old house, but the wiring had been completely re-done 10 years ago. Could be that different outlets were done at different times. I have a Furman power strip for my rack, but I'm not sure if that would "correct" a bad outlet.

The only thing that will "correct" a bad outlet is a true isolation transformer, not a power strip. Have you checked the outlet to see if it's grounded properly?

Also, describe your rig. Do you have any pedals hooked up or are you getting the guitar noise with the guitar plugged straight in?

 

[sws1]

This is with just guitar plugged into the amp. Played with both LP and Suhr modern. When pickup volume is up, you hear a single-coil type hum. But it's not single coil hum, because on the Suhr, when I switch to single coils, the buzz goes up dramatically.

 

[MOBirds]

Do you have the amp in the same strip as the rack you mention? I get a bit of hum if I have amp plugged into same strip as an ungrounded Boss PSA adapter for a DD-7 not on my actual pedal board (rest of pedals have voodoo labs grounded/shielded PS). I would say the HX/DA is just really sensitive to external interference. God forbid I plug one of my other amps into same strip or split the DD-7 out stereo to another amp - that doubles the volume of hum. I typically keep mine plugged into it's own power strip, with everything else in chain into another. When it's just the HX/DA plugged in and on, it's probably the quietest amp I've ever owned. I just have to make sure it's isolated and grounded properly.

 

[aristotle]

How do you have the HX/DA set? It can be set to be quite gainy if you want it that way...which is great if that's the tone you're going for... But any amp that can be set to achieve high gain will hum/hiss/make noise with any guitar...humbucker or not (though it's worse with a single coil.) Plug just about any guitar into...say... a JVM410 set to OD2 Red, and you'd better be set to roll off the guitar volume in a hurry whenever you're not actively strumming / picking. ....which is why they invented noise gates for high gain amps. If I dime the HX/DA volume control, I certainly will get noise off of a humbucker unless I turn down the guitar volume. Watch people performing live in a club type of environment and you'll see guitarists unconsciously roll off the guitar volume between songs for just this reason.

 

[László]

The problem is your flux capacitor.

 

[MOBirds]

Nah! it's the nearest airport's radar dish!

* I actually had this problem in early 90's when I lived near an Air Force base. Strange hum that would occur every 12.5 seconds. So after talking to music store folks, electricians, etc. someone mentioned the radar dish as a joke. I called the base and after getting transferred through several people I finally was able to ask an engineer what the rotation speed on their dish was. Being military, he double checked and confirmed - exactly 12.5 seconds! After running a deeper ground for my house, I was able to get rid of problem enough, then base closed about 2 years later and problem was completely solved.

 

[László]

Did you remember the plutonium?

I never forget the plutonium!

 

[sws1]

OK - So tried a better cable. Same thing.

Couple things I noticed. When I turn the amp on, standby is off. The slight hum I hear is coming through the speaker. When I disconnect the speaker jack, the hum goes away. What that means is that the PT is causing the OT to emit a hum, due to their proximity / orientation to one another. I've read/ heard about this on other amps.

Next, I turn the amp on. Volume around 10 o'clock, master up pretty high. With bridge hum bucker on 10, you can hear 60 cycle hum. If I take my hands off the strings, it gets worse, as you would expect. As I turn the volume down, the hum goes down as well.

Mine sounds like what you heard in the beginning of this video clip demo of an HX/DA 30.