Ampeg SVT3Pro getting hum when I stand too close

[Throttlejunky]

I'm guessing your MarkBass amps are class D? It hasn't been an issue with my PF500, just the 3Pro.
Are you still using standard mono jacks with the TRS cables?

I'm not using any mon jacks. The trail is as follows; From the bass to my pedal board I use the 1/4" SRT cable (same connection effect as xlr), use SRT 1/4" patch cables between pedals and from pedal board to amp I use a 1/4" male srt cable with a male XLR cable at the other end (which you can buy on Amazon) which plugs into my amp at the xlr input (My Markbass has an alternate xlr bass input). Note, actually, based on what I have learned, the SRT 1/4" cable has the same wiring as an XLR cable, so you don't necessarily need xlr connection. You'll see the difference which is a second ring on the shaft. The cable itself is fatter than a mono to accommodate the second power wire. I'm not an expert. All I know is that it worked for me.

 

[byacey]

I'm not using any mon jacks. The trail is as follows; From the bass to my pedal board I use the 1/4" SRT cable (same connection effect as xlr), use SRT 1/4" patch cables between pedals and from pedal board to amp I use a 1/4" male srt cable with a male XLR cable at the other end (which you can buy on Amazon) which plugs into my amp at the xlr input (My Markbass has an alternate xlr bass input). Note, actually, based on what I have learned, the SRT 1/4" cable has the same wiring as an XLR cable, so you don't necessarily need xlr connection. You'll see the difference which is a second ring on the shaft. The cable itself is fatter than a mono to accommodate the second power wire.

Pretty much all pedals I have seen use a Tip Sleeve (TS) jack excepting when they are using a TRS for switching DC battery power; in any case, it still constitutes an unbalanced signal, regardless of whatever type of cable and connector is inserted into these connectors.

Very few bass guitars are balanced output (maybe 1 in 10,000 as a guess), and they would have been specially modified to be so. I don't recall seeing any bass or guitar amps that have a balanced input, excepting for a few cheap amps that have an XLR input for a sing-along vocal microphone.

Edit: As I previously mentioned, if everything was to be properly balanced and interconnected, this still wouldn't make one bit of difference in rejecting hum created by the pickups being too close to an AC electromagnetic field created by a power transformer.

 

[Throttlejunky]

I've never seen any basses, amps or pedals with provisions for balanced connections, unless they have been highly modified with transformers, connectors, balanced line drivers / receivers, etc.

Even if they were indeed balanced, the pickups would still produce the same hum when standing close to an AC magnetic field.

Interesting. You must not have basses with onboard electronics as the ring connection has to be grounded in order to complete the power supply circuit. This is done automatically by inserting a TS plug into the output jack on the bass.

I'm guessing your MarkBass amps are class D? It hasn't been an issue with my PF500, just the 3Pro.
Are you still using standard mono jacks with the TRS cables?

Yes, class D amps.

 

[BassmanPaul]

Never having heard of SRT cables I did a search. Sorting through the car hits all I saw were standard TRS plugs. I'm confused!

Did someone get the reference backwards?

 

[byacey]

Never having heard of SRT cables I did a search. Sorting through the car hits all I saw were standard TRS plugs. I'm confused!

Did someone get the reference backwards?

SRT is a TRS wired reverse phase.

 

[Passinwind]

SRT is a TRS wired reverse phase.

A buckhummer? Cool!

 

[BassmanPaul]

SRT is a TRS wired reverse phase.

How? The tip is wired to the ring at the other end and vice versa? That makes no sense.

 

[byacey]

How? The tip is wired to the ring at the other end and vice versa? That makes no sense.

It was a cheap attempt at non-literal technical humor, but a reverse phase cable would have the tip and ring reversed at one end.

 

[Throttlejunky]

Never having heard of SRT cables I did a search. Sorting through the car hits all I saw were standard TRS plugs. I'm confused!

Did someone get the reference backwards?

Sorry, that's TRS not SRT. I learned about them on Youtube. Setting aside all the technology jargon, all I know is that they worked for me in getting rid of my noise.

 

[BassmanPaul]

It was a cheap attempt at non-literal technical humor.

I missed that! LOL

 

[BassmanPaul]

A buckhummer? Cool!

A Bumhucker would be closer! LOL

 

[quickfix]

All of my single coil (read that as my two PJs) will hum when standing alongside my heavy iron/toroidal equipped amps. None of my Precisions will as they only have split coil humbuckers.

 

[chadds]

If it didn't hum I'd think it was dead.

 

[agedhorse]

Yes, class D amps.

Then you won't have the same problem as the OP, because the SMPS has an inherently low hum field.

Sorry, that's TRS not SRT. I learned about them on Youtube. Setting aside all the technology jargon, all I know is that they worked for me in getting rid of my noise.

That they worked at all is sheer luck. Often with pedals, the ring mist be shorted to the sleeve to allow the pedal to power up. If the output jack uses a TRS jack with the ring tied to sleeve, this will work, but most do not.

Your MarkBass with the XLR input is the exception to the rule regarding inputs, the OP's amp does not have a balanced input.

 

[Downunderwonder]

Sorry, that's TRS not SRT. I learned about them on Youtube. Setting aside all the technology jargon, all I know is that they worked for me in getting rid of my noise.

You probably replaced a dud standard cable with a good TRS cable. A good TS cable would have done same.

 

[LowActionHero]

Except that Trace never made any "small power supply" or SMPS based amps until Peavey acquired the company.

 

[agedhorse]

IIRC, the only SMPS based class D amp ever made by Trace was the ELF, a product of Peavey who has no relationship to any of the past owners of Trace (including one of the companies I worked for).

 

[Nevada Pete]

As am I; from time to time I have to do functional QC on electrical control panels, and we are usually running either 230V or 460V - not something you want to get zapped with! I don't like to energize any device I'm working on unless I absolutely have to.
It's the troubleshooting that drives me up the wall, though.

Okay, good. Thanks. Your obviously a qualified electrician. I won't go near 460V. Not qualified to work on it. I just get worried whenever I think of people working on equipment without proper training.

 

[DJ Bebop]

I recently eliminated my annoying hum by using nothing but TRS cables and or XLR connections to the input of the amp from my bass and between pedals. It seems to have worked like a charm. I use three different Fender basses through Markbass amps.

How?

 

[byacey]

Okay, good. Thanks. Your obviously a qualified electrician. I won't go near 460V. Not qualified to work on it. I just get worried whenever I think of people working on equipment without proper training.

450 volts is a swift and efficient teacher of respect, and where not to stick your fingers.