The Muther of All Buzzes:

Eleanor Fudd

Eleanor Fudd

Member
I have my Blues Jr. connected (Rapco Horizon speaker cable) to the 8-ohm input of my Jettenuator, and then with a Fender instrument cable from the line output 1/4" of the Jettenuator to the guitar input of my Babyface. It buzzes like 90, whether I'm playing or not. I tried the mic sim output of the Jettenuator with an xlr cable but it made no difference, neither did either of the controls on the attenuator. The only thing that stopped the big buzz was turning off the amp. The problem is probably something obvious, isn't it? What am I missing?
Thanks

:confused:
 
Eleanor Fudd said:
I have my Blues Jr. connected (Rapco Horizon speaker cable) to the 8-ohm input of my Jettenuator, and then with a Fender instrument cable from the line output 1/4" of the Jettenuator to the guitar input of my Babyface. It buzzes like 90, whether I'm playing or not. I tried the mic sim output of the Jettenuator with an xlr cable but it made no difference, neither did either of the controls on the attenuator. The only thing that stopped the big buzz was turning off the amp. The problem is probably something obvious, isn't it? What am I missing?
Thanks

:confused:
Click to expand...

Does the Babyface USB cable go to a desktop PC or perhaps a laptop with charger attached?
If the latter, try the setup just on laptop battery and if that fixes the hum you have an earth AKA ground/hum loop.

If a desktop, make sure the amp and PC share the same power outlet or strip. The closer together you can get the mains plugs the better. The next step is a transformer isolator* box between the line out of the attenuator and the jack input of the AI. Failing that you need to try disconnecting the SIGNAL earth at one end of the att' to AI jack cable.

DO NOT EVER DISCONNET ANY MAINS WIRE SAFETY EARTHS !!!!!!!!

*It is IMO bloody disgraceful for there NOT to be a transformer in the line feed from that attenuator. Ground loops are WELL KNOWN to bedevil guitar/recording setups and clearly that box was designed to fit into that scenario. Ha'poth of tar thinking.

Orchid Electronics make a superb 1:1 single channel traff box, be about $30 USD I would think.

Err? "Buzzes like 90" ? Is that a euphemism for something Anglo-Saxon and very rude?
Dave.
 
What kind of buzz? 60Hz means an open ground somewhere.

But regardless, find where it starts: 1) unplug everything and turn on the amp, if it's buzzing, fix it, if not, plug in the guitar and play something - buzz? fix the guitar/cable, or 3) plug in the next piece, like mic the cab with your interface, etc... Where does the buzz originate, i.e., which piece of the chain introduces it.
 
and then with a Fender instrument cable from the line output 1/4" of the Jettenuator to the guitar input of my Babyface
Click to expand...
It may not make a difference, but the Line output of the Jettenuator is 'Line level'. The guitar input is high impedance and intended for the low level signal of a guitar. Try the Line inputs on the Babyface and see if that might make a difference. Very well could be a faulty or inadequate ground somewhere. Be sure the Blues Jr. has the ground prong on its plug and it might be worthwhile getting an outlet tester to be sure the outlets your plugging you gear into are wired correctly and are grounded >>> Outlet Tester

Not sure if this is the 'official' Jettenuator schematic, but likely close if not....
jettenuator-schaltplan.webp
 
keith.rogers said:
What kind of buzz? 60Hz means an open ground somewhere.

But regardless, find where it starts: 1) unplug everything and turn on the amp, if it's buzzing, fix it, if not, plug in the guitar and play something - buzz? fix the guitar/cable, or 3) plug in the next piece, like mic the cab with your interface, etc... Where does the buzz originate, i.e., which piece of the chain introduces it.
Click to expand...

That is the circuit I found Mark and caused my rant about no transformer. Between the level pot on the Jettie and the likely good headroom of the AI I doubt there is a problem? We ARE afterall talking RME here, not some wimpy F'rite!

Could try a basic passive DI box and go into the mic XLR assuming that is that the DI has an earth lift?

Ooops! Cocked that up! I sure you clever chaps can work it out. Got go out and busting for a wazz (Old Man's Disease)
 
Like 90: used to indicate a condition of great speed, eg. "dude was bombing down the avenue like 90". Can also be used to indicate conditions of abundance, great fortitude and/or positive affirmation. "They rocked like 90", "I require an opportunity to urinate like 90", "Steam came screaming out of her navel like 90".
 
:facepalm: Navel. Hah. so to the issue; depending on the frequency its either RF, interference on the mains, or as mentioned , line noise (60 hz hum , etc). I have gotten bug zapper type noise from things as disparate as televisions(turned off mind you,still cause noise), lights and power supplies such as wall warts and pedal board power supplies and even computers and moniters. Just some stuff to check. Unplug every thing not in use if you have to...
 
snow lizard said:
Like 90: used to indicate a condition of great speed, eg. "dude was bombing down the avenue like 90". Can also be used to indicate conditions of abundance, great fortitude and/or positive affirmation. "They rocked like 90", "I require an opportunity to urinate like 90", "Steam came screaming out of her navel like 90".
Click to expand...

Literacy Award.webp
 
ecc83 said:
Does the Babyface USB cable go to a desktop PC or perhaps a laptop with charger attached?
If the latter, try the setup just on laptop battery and if that fixes the hum you have an earth AKA ground/hum loop.

If a desktop, make sure the amp and PC share the same power outlet or strip. The closer together you can get the mains plugs the better. The next step is a transformer isolator* box between the line out of the attenuator and the jack input of the AI. Failing that you need to try disconnecting the SIGNAL earth at one end of the att' to AI jack cable.

DO NOT EVER DISCONNET ANY MAINS WIRE SAFETY EARTHS !!!!!!!!

*It is IMO bloody disgraceful for there NOT to be a transformer in the line feed from that attenuator. Ground loops are WELL KNOWN to bedevil guitar/recording setups and clearly that box was designed to fit into that scenario. Ha'poth of tar thinking.

Orchid Electronics make a superb 1:1 single channel traff box, be about $30 USD I would think.

Err? "Buzzes like 90" ? Is that a euphemism for something Anglo-Saxon and very rude?
Dave.
Click to expand...

You're one to talk. What the hay is "Ha'poth of tar thinking?"

It's a Gigabyte desktop.

Thanks for all the good suggestions. I'll go back to it now. If you don't hear from me again, there was a short.
 
Eleanor Fudd said:
Great!!!

What is it? What does it do? Can you find it on the Orchid Site for me? Their products may be the best, but their site is rather sad.
Click to expand...

This is a version of what Dave suggested >>> Audio Isolator

It has more connectors than what you would need. The idea is that the transformer couples the signals, but keeps the guitar side of the circuit isolated from the interface side, thus breaking any ground or hum path that's causing a problem.

When you turn the Blues Jr on is the hum there instantly or does it take a short bit for it to come through?
 
Eleanor Fudd said:
You're one to talk. What the hay is "Ha'poth of tar thinking?"

It's a Gigabyte desktop.

Thanks for all the good suggestions. I'll go back to it now. If you don't hear from me again, there was a short.
Click to expand...

Ha! "Two great nations divided...." T the tar ideom refers to ancient shipwrights who skimped on the tarring, ie. waterproofing of boats.

Ok Sis' so, a desktop. That means a solid IEC mains connector and earth so I suggest you cut the shield connection on the jack lead coming OUT of the attenuator. This might be tricky as often the shield is held by the strain relief clamp. Might be easier to just chop off one plug and just connect the 'hot' core.

Do you have soldering kit?

Dave.
 
Eleanor Fudd said:
Great!!!

What is it? What does it do? Can you find it on the Orchid Site for me? Their products may be the best, but their site is rather sad.
Click to expand...


Transformer Isolator

How do you know it is "sad" if you couldn't find......Ok, OE is a very small, maybe one man band electronics firm that makes DI boxes (of unique design) and other handy devices for audio solutions.

The gear delivers sound quality easily as good as some kit costing 3X the price but might be hard to find in US and cost about the same as the Art which does get good reviews anyway.

Dave.
 
jimmys69 said:
I use the Behringer between my PC's and PA system on opposite side of studio. Horrible hum without. Works great!
Click to expand...

FYI I would not want to use such an, a'Hem! 'Good value' device in a critical quality chain such as top line monitors but yes, to fix a PA feed great! Mind you, there is a two channel traff isolator available on Zon for about $5.00 and it seems excellent. Certainly good enough for distorted guitar!

Dave.
 
ecc83 said:
Transformer Isolator

How do you know it is "sad" if you couldn't find......Ok, OE is a very small, maybe one man band electronics firm that makes DI boxes (of unique design) and other handy devices for audio solutions.

The gear delivers sound quality easily as good as some kit costing 3X the price but might be hard to find in US and cost about the same as the Art which does get good reviews anyway.
Dave.
Click to expand...

In my opinion there are LOTS of companies which make excellent products but are hindered by their websites. (My favourite is grey fonts on a black background, requiring 7 Billion candlepower to be legible.) Yes, that looks like good gear on that site, really.
 
ecc83 said:
Ha! "Two great nations divided...." T the tar ideom refers to ancient shipwrights who skimped on the tarring, ie. waterproofing of boats.

Ok Sis' so, a desktop. That means a solid IEC mains connector and earth so I suggest you cut the shield connection on the jack lead coming OUT of the attenuator. This might be tricky as often the shield is held by the strain relief clamp. Might be easier to just chop off one plug and just connect the 'hot' core.

Do you have soldering kit?
Dave.
Click to expand...


My electronics chops are slightly better than my operatic vocals chops. Forget it. I ain't cutting and soldering nuthin'!
 
OK, here we go. The good news is that the hum is gone. The bad news is that I still don't know what caused it. Moved cables as suggested, and moved some plugs. One odd thing is that the TotalMix software panel was definitely causing significant buzz if it was open. When closed, it was silent. Odd. Also, Guitar Rig and S-Gear were I think contributors as well as I was experimenting with them, but the cables were probably the biggest factor. Trouble is, I don't know.

Here is the important bit of the Jettenuator manual:
=== Controls and Connectors:
1. MicSim - this is a low-impedance, mic-level output. Connect directly to the mixing console at a live venue or recording environement.
2. OUT SPEAKER - connect to your speaker cabinet to hear your amplifier as normal. Jettenuator is a full-load device, so it is not necessary to use this connector in all applications. Note a reduction in output level of approximately -3dB even with the level set at 9 is inherent to the design of Jettenuator. If a speaker is not connected, set the Jettenuator control at 2 to provide the proper ohm load on your amplier's output.
3. OUT LINE - this output runs at LINE or Effects level. Unlike the Mic-Sim, the LINE LEVEL out is not speaker-compensated. You can send this output to your effects processors and/or power amp for monitoring.
4. INPUT FROM AMPLIFIER - connect the output of your amp to the input of Jettenuator here. Choose 4 ohm, 8 ohm, or 16 ohm amplifier outputs, but do NOT use more than one of these input simultaneously.
5. Jettenuator Control - this continuously variable control is labled 0~9 for your convenience. Please note as mentioned above, when this control is set to the maximum of 9 your output will still be attenuated by approximately -3dB. ALSO note, when set to 0 you probably won't hear anything from the SPEAKER (if connected) but it is possible with an extremely powerful amp - 100 watts or so - running very loud, there might be a small amount of leakage to the speaker. Set at 2~3 for nominal ohm load.
6. LINE LEVEL - Set the level of #3 OUT LINE. Approximately 0dB ~ -10dB, however as with the output to speaker, it is possible and ex-
tremely loud input maye result in some LINE output level even when this control is set to 0. ===



arcaxis said:
It may not make a difference, but the Line output of the Jettenuator is 'Line level'. The guitar input is high impedance and intended for the low level signal of a guitar. Try the Line inputs on the Babyface and see if that might make a difference.
Click to expand...

According to the manual, the Mic-Sim out is at mic level. """MicSim - this is a low-impedance, mic-level output. Connect directly to the mixing console at a live venue or recording environement.""" It works going into either, with a change of cables of course, and the MicSim out sounds slightly different - better, to my year - than the instrument level.

Thanks for all the educational replies, everyone.
 
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