How to build DIY ground loop isolator with 1:1 transformer: seeking for correct connection scheme

Welcome to the forum!

Is the isolator to be placed between the guitar output jack and the amplifier input jack?

If so...

A passive guitar pickup has an output impedance typically between 5 kΩ – 20 kΩ.

I would therefore suggest the use of a 10 kΩ:10 kΩ audio isolation transformer. Simply connect the guitar output to one winding of the transformer and the amplifier input to the other winding.

https://www.ebay.co.uk/itm/18562675...aYXoefjAyzKnWfZoI/IzjJCBRk8=|tkp:BFBMiN2G1adi

Is that the information you need? If not, please give fuller details of your requirements.
 
are we talking single coil or humbuckers?

is it just me....it seems there's a bad trend of thinking that noise problems in audio are all "ground loops"!

and even after 25+ years in the audio service biz eliminating noise and hum pickup in a Strat style guitar is one of the prime reasons i have a love of scotch...

even the pioneers experimented with shielding schemes like covers that went over the strings.

i could be wrong be me thinks the OP should look here https://guitar.com/guides/diy-workshop/tech-talk-how-to-shield-your-guitar/
 
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Welcome to the forum!

Is the isolator to be placed between the guitar output jack and the amplifier input jack?

If so...

A passive guitar pickup has an output impedance typically between 5 kΩ – 20 kΩ.

I would therefore suggest the use of a 10 kΩ:10 kΩ audio isolation transformer. Simply connect the guitar output to one winding of the transformer and the amplifier input to the other winding.

https://www.ebay.co.uk/itm/185626755258?epid=1704490418&hash=item2b383780ba:g:Xc0AAOSwD4FjUmm9&amdata=enc:AQAIAAABAJcSlMl1jY0aLO/uKv+JgeDM3TUqlHokRL4z45pIM10U2oymJ3FzJeIc942iJxCF47gQCnQDZFpStJnQLeLqfuICyXJFpy8NOTw9hGTZSUI9dAIAyG1tedgCMU4eqXBtrGDieGPi/NnmPyy1rcuYpy4OSE0yUr0xMO1hgAbwXYFXAmRkwGCl7YNvYV3fN2KN1TFnpsePeHp7hjs7H2Kj50GZSrQPtf6OIb3K7CXWYesm5ZFlwaSlwfeAn3tPgV08mh5EK/UfLY4W5G/C+DN3uxMcXseej6nlFNH7/TXfFQgPwcb8Lac2wpOXtDDjaYXoefjAyzKnWfZoI/IzjJCBRk8=|tkp:BFBMiN2G1adi

Is that the information you need? If not, please give fuller details of your requirements.
Very thank you Galu, I needed exactly this information! I Hope I'll resolve definitely this problem! I'll keep you up to date!
 
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are we talking single coil or humbuckers?

is it just me....it seems there's a bad trend of thinking that noise problems in audio are all "ground loops"!

and even after 25+ years in the audio service biz eliminating noise and hum pickup in a Strat style guitar is one of the prime reasons i have a love of scotch...

even the pioneers experimented with shielding schemes like covers that went over the strings...
@turk 182 do you mind sharing some of the basics that you learned over your tenure as you grew your scotch appreciation? I am new to electric guitars, have two basic standard single coil strats now (I only bought one, I swear - they multiply!), and I already appreciate the buzz they create. It did not help that my very first hard tail Squier strat had, upon investigation, the grounding wire under the bridge that slipped out, so the bridge was not really grounded.

I would love to learn simple DIY steps that I could take to reduce the buzz. Like I saw that some people line the electronics cutouts with foil - does that help at all?
@MicheleImperatore - apologies for thread hijacking but it looks like you got your question answered, maybe?
 
Like I saw that some people line the electronics cutouts with foil - does that help at all?

That would be done by the manufacturer or diy luthier as a matter of course.

The process creates a Faraday Cage that blocks external EM fields from being picked up by the volume and tone pots.

The metal cases of the pots should be connected to the coaxial cable screen braid, as should the foil.
 
after pouring a glass and thinking to myself "what would constitute the basics?"
i think bad bridge grounds and lack of cavity shielding covers the majority of noise troubles with single coil guitars.

does cavity shielding help?? you bet your a** it does! even backside of the pick guard foil helps so long as it see's ground properly.

with bridge grounds it becomes a crap shoot of conditions that stem from the fact most rely on pressure between the bridge and the wood body of the guitar which can shrink or the finish softens or becomes corroded due to moisture.
and most bridges are nickle plated and you can't solder to them so insuring a good mechanical connection becomes a bit of a trick.

short of foil i have experimented with conductive paint (and used the paint as a binder for foil ) with varying results but foils are better, as to which ( tin or copper) is better that's for others to debate. ( and to be clear i am talking tin not aluminum, aluminum is poor for shielding)

even without cavity shielding you can reduce hum with pickup selection, a few manufacturers make "stacked" single coils that behave as humbuckers but sound like single coils!

time for another!
 
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...does cavity shielding help?? you bet your a** it does! even backside of the pick guard foil helps so long as it see's ground properly...
@turk 182 , thank you for your recollection (hope scotch helps to offset the memories :) It is getting to the Friday night in my time zone, so I'll join you there in a few hours!)

Is it much better to do the tape on the back of the pickguard, or I can buy a foil cutout like this one? Seems like much less mess with the holes and cutouts. But it seems to be aluminium.

What about the tape, is this tape ok?

Thanks!
 
I am new to electric guitars, have two basic standard single coil strats now (I only bought one, I swear - they multiply!), and I already appreciate the buzz they create.
You may already know this - the "in-between" positions of your five-way 'Strat pickup selector switch usually result in far less buzz / EMI. Most guitar players refer to these as positions 2 & 4.

This is done very simply. Most manufacturers reverse-wind the middle pickup coil, and also reverse the polarity of the magnetic pole-pieces. When you parallel the signal from the middle pickup with either of the end pickups, the noise from EMI cancels - but signals from the vibrating string add.

In other words, the combination of the middle pickup with one end pickup in parallel produces a humbucker pickup, albeit with the two coils a few centimetres apart.

-Gnobuddy
 
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A passive guitar pickup has an output impedance typically between 5 kΩ – 20 kΩ.

I would therefore suggest the use of a 10 kΩ:10 kΩ audio isolation transformer. Simply connect the guitar output to one winding of the transformer and the amplifier input to the other winding.
1. This is not a power transfer. So 10k:10k transformer will not be the correct choice.
We need to transfer maximum voltage. Which will require 100k impedance of transformer on the guitar side.
That is why the impedance of guitar preamps vary from 220 k to a few meg.
2. The transformer just carry whatever signal that the guitar output provides.
If the signal has interference added, it will be carried out by the transformer
The best way is to avoid EM interference by shielding. Every guitarist live with it.
3. You need to think of isolation only if you experience ground loop interference (hum) between many devices connected to each other.
For smaller setups, just locate the problem to solve.
Regards.