[JohnActon]

Jude,

That's a good question - I do hear a whooshing sound as well when I turn off the amp. I don't know about the turn-on pop, as I don't have the headphones on yet when I turn on the amp. Jeez, I hope there is nothing damaging about this practice. So far, so good, I guess.

Has anyone experienced any headphone failures that they think they can directly attribute to turn-on/turn-off transients (besides the Audio Valve RKV II, that is)?

That would suck to blow out a nice pair of cans like that!

 

[Tides]

Quote:

Originally posted by jude Maybe someone can comment on turning on and off the amp with the headphones plugged in. With almost every amp I've used, there has been a "whooshing" sound through the headphones after the amp is turned off. ....

Jude~

That is EXACTLY why I unplug my Hd600 from the amp before I turn the amp off. I do not like that weird sound coming out of my hd600. Dont know if it is some sort of electric current or whatnot passing thru

I also turn on my amp before I plug in the hd600.

Tides

 

[aos]

Pops when turning on the headphones are the consequence of capacitors needing to be charged. Many amps are AC coupled, meaning that there is a (usually large electrolytic) capacitor between stages or between output stage and headphones/speakers. Some more advanced amps have the ability to disconnect the headphones/speakers for the first few seconds (or even minutes!) to allow the amplifier to achieve its stable state. DC amps can have the same problem, due to the voltage rails not coming up from 0 to whatever they are synchronously, as the capacitors in power supply and on rails are being charged. Even with DC servos this still can happen as the regulating opamp in servo does not receive stable and symmetrical voltage either.

Oh yeah, this DOES mean that the (potentially) large current is flowing through speakers/headphones. This has probably destroyed many speakers in the past or reduced their lifespan. I don't know about headphones. Most amps have protection circuitry that makes that tump less damaging. You can still hear it but it's probably not too dangerous. I wouldn't bet my life on it though.

 

[dhwilkin]

Thanks for that explanation, aos. So is the same amount of current always generated starting up? As in, is the damage potential the same no matter what volume the amp is set for?

 

[aos]

The volume pot setting is not going to make any difference. It's not the signal that is generating the "thump" current, it's the process the amp goes through before it settles down into operating state.

 

[jude]

Well, I guess I'll continue to unplug my headphones before I turn the amp on or off.

aos, would you kindly explain the whoosh sound at power off?

 

[Tides]

aos~

Thanks for the explanation.

What you said was pretty much what I had in mind. which is why I always turn on amp first then plug headphone in.
I disconnect Headphone while the amp is on, put it back to the case then shut off Amp

( and cdplayer)

Tides

PS. gotta love an informative forum!

 

[Dusty Chalk]

My MF X-CANv2 makes rude "farting" noises when I shut off the X-PSU. It sounds like a bias frequency oscillator generator losing its cycles (I know this, because I used to have a tape deck that did the same thing when you left it in Record-Pause mode, and then powered it off)...two questions: is that good or bad, and what causes it? Any thoughts would be appreciated...

 

[aos]

I also get all kind of whoosh noises when I turn off my amps. I have no idea what's causing it but I would guess it's not as simple as turn-on since, unlike thump, noise is an oscillatory process.

 

[jude]

Quote:

Originally posted by jim Hey Jude, does wiping the plug with the micro-cloth help very much? I always figured that the jack itself would cause more damage than any dust on the plug, but maybe I'm wrong.

Heheh. Yeah, you're probably right, Jim. But the whole idea behind that (other than the fact that it's just a weird habit) was to prevent any buildup of dust or grime residue on the contacts.

 

[lini]

Yup, I favour disconnect/reconnect, too - 3 reasons:

- My speakers are less efficient, so a disconnected headphone means a safe headphone.

- The tweeting of the headphone disturbs me, when I listen with speakers.

- Else it would be simply in my way.

Greetings from Munich!

Manfred / lini

P.S.: For cleaning contacts I use isopropanol (99%) and a clean piece of cotton cloth.

P.P.S.: Disappearing gold layers on connectors: Apart from wear & tear there's also an electrochemical reason behind this. A gold connector usually has 3 layers: The material beyond (copper, brass...), a layer of nickel (is that the same in english?) and the gold layer. On cheaper plugs, both the gold and the nickel layer are not thick enough, so the plug will both wear off faster and the gold will diffuse faster through the nickel layer, which should act as an anti-diffusor (the current drives the gold atoms into the material beyond...).

 

[aos]

Thanks for the info Lini. I was thinking that my plugs were good quality since the shop also carries WBT but it seems like I'll have to *actually* ask for WBT

. On the other hand, DIY experimenting is not a typical use so I can't complain, those CDN$10 lasted a whole year.

I don't disconnect my headphones. a - too lazy, b - my amp(s) is on most of the time anyway (there's idea for another poll, as some people suggest that they sound better if they're left on), c - I like living dangerously (kidding), d - when you're doing DIY you get sick of connect/disconnect and don't have time or patience to do that every time you pull the plug, e - if the headphone dies, it was time to replace it anyway

.

 

[raymondlin]

WBT plugd are quite expensive, cost around $55 just for 4 midline plugs. Most people don';t even spent that much on the whole cable, but I think it's worth it, that's why I bought some for my DIY i/c.

 

[lini]

Yup, WBT - good stuff. They seem to think before they produce something...

Manfred / lini

 

[BenG]

After you clean w/ 99% alcohol, use a conditioner. This will lubricate the plugs, smooth over plate imperfections, and prevent oxidation buildup for 6 months or so.