Ethan Winer Builds a Wire Null Tester

[Blumlein 88]

I wonder how problematic the triboelectric noise is for audio as most sources are very low Ohmic, usually less than 100 Ohm.
All generated noise, this way, would effectively be 'shorted', even if it has a 1M input R 'loading' the cable as the source and 'load' resistance are in parallel for audio frequencies (and way beyond).

My 50 y.o. old ceramic element record player connected to a 1M input could be another story but I won't be hammering away on that old cable though.

Here is some triboelectric sounds. Zip file you can download. see this post. I believe from memory this was into a microphone preamp with a 3 kohm input impedance.

https://www.audiosciencereview.com/forum/index.php?threads/lets-talk-cables.3439/post-83565

Possible issue with microphone level signals though with nearly all cable not. Not an issue with line level signals that aren't seeing 40-60 db of gain added to the signal. Teflon and silver are the worst combination for triboelectric problems. So of course audiophiles love them.

 

[SIY]

I've experienced bad triboelectric effects on a few occasions, all of which involve audiophile-preferred silver and PTFE.

That really is the absolute worst practical combination for audio, yet so highly regarded...

 

[restorer-john]

Teflon and silver are the worst combination for triboelectric problems. So of course audiophiles love them.

Ah, that explains it. Their cables 'play' to the music and influence it at the same time.

 

[restorer-john]

I've experienced bad triboelectric effects on a few occasions

Flick your oscillsocope probe test leads on 1mV per div- that does it too.

 

[SIY]

There may be truth to that. That's my hypothesis on why direct-heated triodes have a niche popularity.

 

[restorer-john]

There may be truth to that. That's my hypothesis on why direct-heated triodes have a niche popularity.

You need tube dampeners and special isolating feet for your triode amps to get closer to solid state sound!

Don't think that'll fly with the tube boys...

 

[restorer-john]

...Attached is a zip file with some short triboelectric cable sounds...

You know, I've never downloaded a musical track from the internet, streamed audio or bought anything on iTunes, but I excitedly listened to your f#$king triboelectric sounds.

I'm such a geek.

(got posted in the other thread by accident due to link above)

 

[folzag]

Seems a lot of work just to prove expensive cables are snake-oil.

I don't know how one could synchronize input signals, but what I would find interesting is if this could be used to A-B different makes of DAC or amp or DIY mods such as power-supplies, capacitors, roll-off filters, etc. to the same make of DAC or amp.

 

[restorer-john]

Seems a lot of work just to prove expensive cables are snake-oil.

And the problem with that is? Amir spent as much as a brand new car on an analzyer to tell him Schiit is, well S#$t... Engineers do that sort of stuff, they can't help themselves- it's hardwired.

I don't know how one could synchronize input signals, but what I would find interesting is if this could be used to A-B different makes of DAC or amp or DIY mods such as power-supplies, capacitors, roll-off filters, etc. to the same make of DAC or amp.

You'd never be able to null much at all. Way too many variables to obtain a decent depth of null.

Even two identical analog Class AB amplifiers can't be nulled very well. Try it yourself, on a common ground (non BTL) stereo amplifier, lift the two speaker negatives and tie them together (or just hook your sacrificial speaker to the two hots) Play a mono source. Silence is your goal. Tweak volume and balance positions. I do it all the time to look for balance and volume tracking issues, along with preamp front end and tone control issues when repairing/restoring gear.

 

[folzag]

... on a common ground (non BTL) stereo amplifier, lift the two speaker negatives and tie them together (or just hook your sacrificial speaker to the two hots) Play a mono source. Silence is your goal. Tweak volume and balance positions. I do it all the time to look for balance and volume tracking issues, along with preamp front end and tone control issues when repairing/restoring gear.

Non BTL?

Why would the speaker be sacrificed? Except if something were pathologically wrong, which would result in... what, 2 * design voltage & max current. Or was that your point?

 

[Blumlein 88]

Non BTL?

Why would the speaker be sacrificed? Except if something were pathologically wrong, which would result in... what, 2 * design voltage & max current. Or was that your point?

Bridged Tied Load.
https://en.wikipedia.org/wiki/Bridged_and_paralleled_amplifiers
It is when ground isn't ground, it is a negative value of the positive side. Some amps have hot and ground, some are really hot and negative hot (or differential outputs). Connecting two black leads of those together will probably let the smoke out.

To elaborate, in a conventional amp, you might have 4 volts on the positive lead and ground on the negative lad. In a BTL amp, you would have 2 volts positive and a negative 2 volts on the negative lead for the same 4 volt difference across the speaker. Speaker doesn't care. But connecting the negative of two channels on the BTL configuration might cause trouble.

 

[Blumlein 88]

You know, I've never downloaded a musical track from the internet, streamed audio or bought anything on iTunes, but I excitedly listened to your f#$king triboelectric sounds.

I'm such a geek.

(got posted in the other thread by accident due to link above)

I awarded you double geek points in the other thread.

 

[folzag]

Bridged Tied Load.
https://en.wikipedia.org/wiki/Bridged_and_paralleled_amplifiers
It is when ground isn't ground, it is a negative value of the positive side. Some amps have hot and ground, some are really hot and negative hot (or differential outputs). Connecting two black leads of those together will probably let the smoke out.

OK, yeah, I've heard of that. And yeah, that always made me nervous around amps... how do I know if this thing is BTL or not?? Best just to never cross the streams.

 

[restorer-john]

...Why would the speaker be sacrificed?...

A good technician always has a supply of 'sacrificial speakers'. They are either one offs (where he destroyed the other one already) or single speakers he has scrounged for the purposes of audible soak 'testing' amplifiers after extensive repairs.

Sacrificial speakers get a thrashing before a 'nice' pair of speakers are attached for more critical listening.

No-one is perfect and occasionally, they are sacrificed at the altar of unstable amplifiers.

(haven't lost one in decades...)

 

[tomelex]

There may be truth to that. That's my hypothesis on why direct-heated triodes have a niche popularity.

yep, micro-vibrations are one part of their success story

 

[Blumlein 88]

OK, yeah, I've heard of that. And yeah, that always made me nervous around amps... how do I know if this thing is BTL or not?? Best just to never cross the streams.

Let me see, what is a simple way?

Okay everyone double check my thinking here.

Play a bit of music in one channel and none in the other. Maybe a 400 hz tone. Check voltage between the red and black lead in the active channel.
Let us assume it was 4 volts. Now check voltage between the black lead of the active channel vs black lead in the idle channel. If you read something like 2 volts, then you have a BTL type. If you read something close to zero volts, it is probably safe to consider it non-BTL.

Am I missing a simpler way?

 

[BYRTT]

...Am I missing a simpler way?

One could be plug out all cables including mains, now measure resistence (DC) number from cold speaker terminal to chasis or one of the RCA grounds, if number reads near being zero ohms output should be non BTL.

 

[restorer-john]

99.9% of common ground amps will have continuity between any RCA outer (or less than 10 ohms in some cases due to a resistor) and the negative speaker terminals.

Caveats being a few NAD power amp models and a few others I can't remember the brands right now, where they ran one channel opposite polarity to the other to allow better usage of the power supply under heavy load conditions. They are few and far between.

Just put your DMM on continuity and check the two negatives beep and beep to chassis. Then you'll be fine to play null games.

 

[PuX]

fantastic video.

still gonna use decent wires though for aesthetic/convenience/whatever reasons, but nothing too expensive.

btw it would be cool to find an especially bad cable where the difference would exist. i.e. thin, extra bad materials and connectors.

 

[amirm]

btw it would be cool to find an especially bad cable where the difference would exist. i.e. thin, extra bad materials and connectors.

Good suggestion. Always good to have such a control.