Hum hunter. Audio Isolator.

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Hubaxe
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Hum hunter. Audio Isolator.

Post by Hubaxe » Thu Feb 07, 2019 9:09 am

Hi!
With my band we are recording regularly, and I can spot hum from my amp.
An efficient noise gate takes care of the front signal (Guitar ==> some pedals ==> amp input).
I checked the wall power, all is fine, anyway, I’ll later probably put a EMI/RFI filter for other places I play. But in my place it is not the hum source.
The amp is totally silent as I unplug the “Return” from the effect loop (with a TC unit in). Does anyone already tried to ground isolate the signal with a 1:1 audio transformer? I’m waiting for the parts to arrive, and I hope this will fix the issue.
Any thought on hum hunting welcome!
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Les Paul Lover
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Re: Hum hunter. Audio Isolator.

Post by Les Paul Lover » Thu Feb 07, 2019 11:29 am

I use an EBTech unit that does that, but not for those reasons:

https://www.thomann.de/gb/morley_ebtech ... ifter2.htm

I use this as the fx loop of my Genz Benz Black Pearl 30 is line level and too hot. It sends my pedals into clipping, and the level returned by my fx is too low... so without it, all I get is a very weak, digitally clipped signal.....

Those transformers aren't 1:1 though, and whilst it works really well, as the unit is passive it loses quite a lot of volume along the way. Which is fine as 30w is usually way too much, and I still can't crank it with the line level shifter.


They've got a similar unit with 1:1 transformers. That should work equally well, but I'm not sure if you would experience any volume loss with it.

https://www.thomann.de/gb/ebtech_by_mor ... ator_2.htm

One of my next gear step is to get a properly regulated power supply too.
Some of my OD exhibits some hum, I'm wondering if a proper power supply will solve that..... and there's only one way to find out!!!!!
Ant

Orange Gear: RV50 MKI, R30, AD15, AD5, PPC212
Past Orange: Orange AD30TC Combo, Tiny Terror

Guitars: Gibson Les Paul Standard Faded, Vigier Expert Retro 54, Gibson SG 70s Tribute, Aria Pro II RS X80, G&L ASAT Special Tribute

Hubaxe
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Re: Hum hunter. Audio Isolator.

Post by Hubaxe » Thu Feb 07, 2019 2:23 pm

Thanks for your feedback.
That's the idea, put a 1:1 transformer. Sure there will be volume loss, but that's not an issue, I still can turn the TC output on.
I've seen the EBTECH and Behringer does one too. Basically it's just a 2 dollar audio transformer wired on a jack socket. So I decided to order some parts and build mine.

A 1:1 isolator transformer coupled with some op amp is basically... A DI :D

For the EMI RFI filter, it's also only a couple of cheap components. Gonna built it too.
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Les Paul Lover
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Re: Hum hunter. Audio Isolator.

Post by Les Paul Lover » Thu Feb 07, 2019 2:52 pm

Hubaxe wrote:
Thu Feb 07, 2019 2:23 pm
Thanks for your feedback.
That's the idea, put a 1:1 transformer. Sure there will be volume loss, but that's not an issue, I still can turn the TC output on.
I've seen the EBTECH and Behringer does one too. Basically it's just a 2 dollar audio transformer wired on a jack socket. So I decided to order some parts and build mine.

A 1:1 isolator transformer coupled with some op amp is basically... A DI :D

For the EMI RFI filter, it's also only a couple of cheap components. Gonna built it too.
Sounds like a neat project.
I'd be interested to see How you build the hum eliminator. I didn't look into this for myself, as I needed to adjust output levels.
Ant

Orange Gear: RV50 MKI, R30, AD15, AD5, PPC212
Past Orange: Orange AD30TC Combo, Tiny Terror

Guitars: Gibson Les Paul Standard Faded, Vigier Expert Retro 54, Gibson SG 70s Tribute, Aria Pro II RS X80, G&L ASAT Special Tribute

beninma
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Re: Hum hunter. Audio Isolator.

Post by beninma » Thu Feb 07, 2019 4:03 pm

I'm not sure you've given enough information to be able to tell.

If your rig is setup well you shouldn't get hum from the pedals in the FX loop if you've eliminated it from the input chain.

I messed with this a long time... here is how I have my setup to get it dead quiet.

Everything (amp + pedalboard) plugged into a Furman power strip with basic filtering. (This is not expensive)
All pedals on an isolated power supply (Truetone CS12 in my case) except for an EHX Hum Debugger which is plugged directly into the Furman with it's dedicated AC power brick.

Input is: Fuzz -> Drive -> Boost -> Hum Debugger -> Compressor -> Tuner

- If the Hum Debugger or tuner are before the Fuzz/Drive units it will create it's own weird Hum/Noise. If the Compressor is before the Hum Debugger the Compressor will amplify/raise the noise floor to the point the Hum Debugger doesn’t work. Keep in mind the Hum Debugger is not a noise gate so this stuff might behave differently than yours. I really really like the Hum Debugger cause it has none of the weird behaviors a noise gate can have, but it did take a lot of experimentation to get that placement right.

FX Chain (I have a Rocker 15) is:

Delay -> Reverb -> Tremolo

My Rocker 15 has a slight background hiss of it's own if it's running at full power, this isn't coming from the pedal board as it's there plugged direct into the amp. Otherwise this gets me dead silence, even if I was to stack Fuzz + Drive + Boost + Compressor, which I never do.

All the pedals I have are themselves quiet.. I don't think any of this will work if you've got an actual pedal that is noisy.

That said, I have a protoboard/breadboard setup of my own, I've got a booster I built on there right now, that is dead simple and has no noise filtering/power filtering of it's own and is not in an enclosure so it would/should pick up more noise than usual and I can even use that on my rig without undue noise. General rule is something on a breadboard is going to be much noisier than a finished pedal so if the rig can handle that it's pretty darn quiet.

If you've got something going on like the AMP + Input pedals + FX Loop pedals are not all on the same ground (this is why all my stuff goes into that same Furman unit) you're going to introduce possible new sources of noise.

Hubaxe
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Re: Hum hunter. Audio Isolator.

Post by Hubaxe » Thu Feb 07, 2019 5:49 pm

Looks like the hum debugge is an isolation transformer.

The furman cleam up the AC power by aligning the phases (EMI RFI filter). This is to prevent noise from DC power supply.
Now the other source of noise is the audio ground loop. The hum debugger as a simple ground loop isolator just cut the lead ground from the loop.
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beninma
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Re: Hum hunter. Audio Isolator.

Post by beninma » Thu Feb 07, 2019 7:27 pm

The Hum debugger isn't a transformer.. it's a pedal that you put in the chain, it has an AC input to the pedal instead of a DC input.

Internally AFAIK it has it's own transformer and uses that DC power to power a digital unit that analyzes the AC power signal + guitar signal and uses that to filter your guitar signal to remove the hum. It's possible it's actually analog too I guess but IIRC the circuit board pictures are out there and show some digital chips.

You actually probably don't need it if you're using humbuckers.. I have single coil pickups.

I think the Furman makes a small difference if any. The biggest things are cutting 60hz/120hz hum if you've got single coil pickups, isolating the power sources for the pedals, and ordering the pedals in a way that they play nicely together.

Les Paul Lover
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Location: Derby, England

Re: Hum hunter. Audio Isolator.

Post by Les Paul Lover » Thu Feb 07, 2019 10:07 pm

beninma wrote:
Thu Feb 07, 2019 4:03 pm
I'm not sure you've given enough information to be able to tell.

If your rig is setup well you shouldn't get hum from the pedals in the FX loop if you've eliminated it from the input chain.

I messed with this a long time... here is how I have my setup to get it dead quiet.

Everything (amp + pedalboard) plugged into a Furman power strip with basic filtering. (This is not expensive)
All pedals on an isolated power supply (Truetone CS12 in my case) except for an EHX Hum Debugger which is plugged directly into the Furman with it's dedicated AC power brick.

Input is: Fuzz -> Drive -> Boost -> Hum Debugger -> Compressor -> Tuner

- If the Hum Debugger or tuner are before the Fuzz/Drive units it will create it's own weird Hum/Noise. If the Compressor is before the Hum Debugger the Compressor will amplify/raise the noise floor to the point the Hum Debugger doesn’t work. Keep in mind the Hum Debugger is not a noise gate so this stuff might behave differently than yours. I really really like the Hum Debugger cause it has none of the weird behaviors a noise gate can have, but it did take a lot of experimentation to get that placement right.

FX Chain (I have a Rocker 15) is:

Delay -> Reverb -> Tremolo

My Rocker 15 has a slight background hiss of it's own if it's running at full power, this isn't coming from the pedal board as it's there plugged direct into the amp. Otherwise this gets me dead silence, even if I was to stack Fuzz + Drive + Boost + Compressor, which I never do.

All the pedals I have are themselves quiet.. I don't think any of this will work if you've got an actual pedal that is noisy.

That said, I have a protoboard/breadboard setup of my own, I've got a booster I built on there right now, that is dead simple and has no noise filtering/power filtering of it's own and is not in an enclosure so it would/should pick up more noise than usual and I can even use that on my rig without undue noise. General rule is something on a breadboard is going to be much noisier than a finished pedal so if the rig can handle that it's pretty darn quiet.

If you've got something going on like the AMP + Input pedals + FX Loop pedals are not all on the same ground (this is why all my stuff goes into that same Furman unit) you're going to introduce possible new sources of noise.
What do you think of the True Tone CS12?

I've got my eyes on that very unit. I'm waiting for a good deal on it.

Also, re: single coils noise, I've got a G&L ASAT Special Tribute that picks up light saving energy bulbs (need to switch to LEDs in that room) and i often have some band practice in my kitchen (Quite a large room) and there it pick ups the dishwasher....... little bugger...... got to insulate the pick up cavity as much as I can there. I like those jumbo MFD pickups.

My strat type guitar is loaded with DiMarzio noiseless single coils, they are amazing. Sounds better than any strat I've tried, and zero noise.
Ant

Orange Gear: RV50 MKI, R30, AD15, AD5, PPC212
Past Orange: Orange AD30TC Combo, Tiny Terror

Guitars: Gibson Les Paul Standard Faded, Vigier Expert Retro 54, Gibson SG 70s Tribute, Aria Pro II RS X80, G&L ASAT Special Tribute

Hubaxe
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Re: Hum hunter. Audio Isolator.

Post by Hubaxe » Fri Feb 08, 2019 7:54 am

I also play mainly with a strat. I use a EHX silencer noise gate. It works very well. This pedal takes the signal from the guitar, and also include a loop for all effects. As the guitar input gates the signal, the whole effect chain is gated too (and bufferized in a whole). Perfectly happy with this unit.

Now I work on the amp affect loop de-hum. I'll keep this topic updated as soon as I apply an audio transformer isolator.
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beninma
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Re: Hum hunter. Audio Isolator.

Post by beninma » Mon Feb 11, 2019 3:58 pm

Les Paul Lover wrote:
Thu Feb 07, 2019 10:07 pm
What do you think of the True Tone CS12?

I've got my eyes on that very unit. I'm waiting for a good deal on it.

Also, re: single coils noise, I've got a G&L ASAT Special Tribute that picks up light saving energy bulbs (need to switch to LEDs in that room) and i often have some band practice in my kitchen (Quite a large room) and there it pick ups the dishwasher....... little bugger...... got to insulate the pick up cavity as much as I can there. I like those jumbo MFD pickups.

My strat type guitar is loaded with DiMarzio noiseless single coils, they are amazing. Sounds better than any strat I've tried, and zero noise.
I don't have any real complaints with the CS12.

I am using most of the outputs on it, I haven't had any pedals not work well with it or seen any noise from it.

It'd be pretty cool if they came up with a modular option though where you could order one with a specific set of outputs.

Here is the thing with the CS12.. it has 2x18v outputs and a 9V AC output. If there was an option I might choose to order one 2 extra 9V outlets instead of the 18V ones, and maybe ditch the 9V AC output. The 9V AC output would be cool if it had selectable voltage levels though.

There aren't that many 18V pedals.. I should probably order the 18V->9V converter they sell. The only 18V pedal I've had was the OCD, but I really didn't like the OCD that much with my Orange amp.

I do really appreciate the 12V outlets though.. I have a bunch of the Orange pedals, they DO all work really well with Orange amps, and they all can take 12V. I've got the Kongpressor, Getaway Driver, Fur Coat, and 2-Stroke, so for any of those I appreciate the 12V outlets.

I switched my practice area to LED lights but there is ALWAYS a 60hz field.. I also reworked my Tele that has single coils and that helped reduce noise. But that EHX Hum Debugger I have really really helps if I need it.

Hubaxe
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Re: Hum hunter. Audio Isolator.

Post by Hubaxe » Tue Mar 05, 2019 1:12 pm

I undig my own post :D . So, I received isolated jacks and 1:1 converters (3 bucks for 10 pieces), and quicky solder an audio isolator.
And guess what, THAT WORKS!! Plugged in the effect return, the hum is drastically reduced. As Ant said, it tames a bit, so I compensated on the multieffect.
Ready for my next recording session in 2 weeks.
These are the best 10 bucks spent for a long time.
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Les Paul Lover
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Re: Hum hunter. Audio Isolator.

Post by Les Paul Lover » Tue Mar 05, 2019 2:34 pm

Hubaxe wrote:
Tue Mar 05, 2019 1:12 pm
I undig my own post :D . So, I received isolated jacks and 1:1 converters (3 bucks for 10 pieces), and quicky solder an audio isolator.
And guess what, THAT WORKS!! Plugged in the effect return, the hum is drastically reduced. As Ant said, it tames a bit, so I compensated on the multieffect.
Ready for my next recording session in 2 weeks.
These are the best 10 bucks spent for a long time.
Ace!

Do you have pics of it by any chance?

To be honest, I've found the volume reduction a blessing. I was pretty annoyed to start with, but since I use it with a very loud 30w amp, the volume drop enables to open up the amp a lot more.
Ant

Orange Gear: RV50 MKI, R30, AD15, AD5, PPC212
Past Orange: Orange AD30TC Combo, Tiny Terror

Guitars: Gibson Les Paul Standard Faded, Vigier Expert Retro 54, Gibson SG 70s Tribute, Aria Pro II RS X80, G&L ASAT Special Tribute

Hubaxe
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Re: Hum hunter. Audio Isolator.

Post by Hubaxe » Wed Mar 06, 2019 7:00 am

The one used is already boxed in metal. But I have enough parts to do more, then I will take some pics.

As the noise reduction can be an issue, I'm thinking about a passive/active version with a low noise opamp.
I need to talk to a friend who is a professional electronic engineer. It can be an interesting feature I think.
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Les Paul Lover
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Re: Hum hunter. Audio Isolator.

Post by Les Paul Lover » Wed Mar 06, 2019 7:14 am

Would a clean boost compensate for the volume loss?

For me, the volume loss is.probably more noticeable as my signal passes through isolating transformers twice. Once from +4db to -10db on the fx send, and once again from -10db to +4db on the fx return.
Ant

Orange Gear: RV50 MKI, R30, AD15, AD5, PPC212
Past Orange: Orange AD30TC Combo, Tiny Terror

Guitars: Gibson Les Paul Standard Faded, Vigier Expert Retro 54, Gibson SG 70s Tribute, Aria Pro II RS X80, G&L ASAT Special Tribute

Hubaxe
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Re: Hum hunter. Audio Isolator.

Post by Hubaxe » Wed Mar 06, 2019 9:08 am

Yes maybe, I need my friend to check the boost values needed to compensate. I think the boost need to be very little.
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