[plonter]

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif Keep the headphones unplugged when you turn the amp on and off. About 30 seconds to a minute is plenty of time between when you turn the amp on and plug in (once the tubes are obviously glowing). Plug the headphones in and you can immediately set the amp to your normal listening level. I usually turn the amp on, and then pick what Im going to listen to. Even if I already knew what I wanted to hear it still takes enough time for me to get everything set up. If you want to wait (however long) before you listen critically why not warm your ears up with some music too? much better. There is no time requirement between unplugging the headphones and shutting the amp off. Pull the headphone plug and instantly flip the power switch. The output level from the back of the amp is the same as from the front of the amp, your power amps just need more voltage swing into them to get equal sound compared to the HD650. Everyone likes to go on and on about how much voltage swing the 650's need... they really dont need it to run, its just nice to have 40db of voltage overhead/headroom (and the 650's really need lots of headroom).

thanks nikongod,it seems like I was doing ok when powering the amp on and off without headphones plugged in than? I noticed that you said that I can plug the headphones 30 seconds until minute after I turn on the amp,but is it harmful to wait more than that before plugging them in? let's say...30 minutes, hour?

 

[GreatDane]

Quote:

Originally Posted by DynaMike /img/forum/go_quote.gif I´d like to specify the "preamp question" - is the use of a tube amp which keeps the signal on both the preamp & headphone without a headphone plugged in harmful to the tubes / the amp in any way?

I use a Woo 3 mainly as a preamp and don't keep 'phones plugged in. I never gave it a second thought until I read this thread. So far no problems. I can only assume that my amp was designed to operate safely for use as preamp only.

 

[HeatFan12]

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif Its been my experience that VERY few amps require a headphone be connected at all times. The few that do give DIRE warnings in their product manuals(and very few people own them anyways), so you would probably know. That leaves us with the other 2 options of "no different" or "possibly bad" So I tend to leave stuff unplugged when turning on. the idea of short term DC offset, and turn on thumps scares me too much to leave stuff plugged in if I can help it. I guess the 4'th hidden option is amps which cant have the headphones plugged in/out while playing. again, hopefully you would know about this issue.

Thanks nikongod...



Quote:

Originally Posted by DynaMike /img/forum/go_quote.gif I´d like to specify the "preamp question" - is the use of a tube amp which keeps the signal on both the preamp & headphone without a headphone plugged in harmful to the tubes / the amp in any way?

Quote:

Originally Posted by GreatDane /img/forum/go_quote.gif I use a Woo 3 mainly as a preamp and don't keep 'phones plugged in. I never gave it a second thought until I read this thread. So far no problems. I can only assume that my amp was designed to operate safely for use as preamp only.

Never really gave this much thought honestly. I use my WA2 as a pre too and when I do, I don't plug in any 'phones either. I sent Jack a message in reference to this...

Thanks guys...

 

[Redcarmoose]

One really dumb thing I did was shortly after W5le was turned off I made an effort to unplug the power supply from the cord that goes from the power supply to the amp. Even as it had been off for 15seconds power was still being produced and I felt a nice tingle! I am so small minded at times, maybe all the time.

 

[Silenced]

people talk about contacting the manufactures... what if you have a diy

 

[Uncle Erik]

Quote:

Originally Posted by Silenced /img/forum/go_quote.gif people talk about contacting the manufactures... what if you have a diy

You can usually find the designer hanging around here or HeadWize. A quick PM would get your question answered. You can also look through build threads for your amp. If the answer isn't there, you can post and someone who knows should respond.

 

[K_19]

Speaking of contacting the manufacturers, I got a response back from Jack of Woo Audio. I want to thank Jack for getting back to me in a timely manner and taking time to answer my questions.

Anyways, here's his response to my questions regarding WA6:

1) What's the proper way to turn on WA6 with headphones? I ask this because I've read some stuff about it being harmful to the tube amp to turn it on without headphones in? Is this true? So far, I've turned on the WA6 without any headphones inserted (when I turn it on with headphones in, it gives the loud startup tube hum then goes away after about 5 seconds; I wasn't sure if this is harmful for headphones or not, so just to be on th safe side I unplugged it from there on), but plugged it in about 20 seconds later when the tube startup is done. So should I turn it on with headphones in or out (or does it even matter)? Just in case you may be concerned, yes, I always make sure the volume is down to zero when I turn it on or off.

J: It is recommended to switch on the amp with a headphone on. This would avoid the amp being open circuit - not a good thing for any tube amps. You will not harm the amp at all if you leave an open circuit for a short period of time. The loud noise/abnormal sound is normal the tubes are warming up to get into the working state. A proper way to use the amp is 1) plug in your headphone, 2) mute the volume or stop your source 3) switch on the amp and let it warm up for at least 10 seconds, and that's all.



2) I know the length for tube warmup for amp varies, but what I was wondering was; is it actually harmful for the amp/tube if I crank up the music right away without warming it? I realize the sound won't be optimal in the beginning but just wondering if this is actually a harmful practice to not warm it.

J: No harm at all.



3) If I'm understanding correctly, the headphone should be plugged in at all times when warming up the amp, or else it's harmful. Is this correct?

J: Same as 1. So again, it is a good practice when using a tube amp.



4) Is it safe or unsafe to flick the impedence switch in the back while the amp is on/while the music is playing? I always thought no, so I've been turning it off every time before I do so, but wanted to make sure.

J: You can change the impedance setting while the amp is on and music is playing.

So I guess the way Jack recommends it is that I keep the headphones in the jack when I am turning it on, but apparently you won't harm your amp if you leave it as open circuit (without headphones in) for a short term.

 

[plonter]

thanks for the useful info K-19. by what jack says, it is not advisable for any tube amp to be switched on without headphones plugged in. I guess I should start doing it just for case.

 

[WooAudio]

Just to clarify, the problem of open circuit in an OTL tube amp is not as serious as output transformer (OT) coupled tube amp. In an OTL amp as the WA2, there is a pseudo load on the headphone output, which means you can switch on the amp without the headphone plugged in.

As for the OT coupled amp with custom pre-amp, there is a switch to enable/disable the preamp. When it is enabled, the pseudo load connects to the headphone out, making the amp safe to use without headphone plugged in.

Hope that help,
Jack

 

[GreatDane]

Quote:

Originally Posted by WooAudio /img/forum/go_quote.gif Just to clarify, the problem of open circuit in an OTL tube amp is not as serious as output transformer (OT) coupled tube amp. In an OTL amp as the WA2, there is a pseudo load on the headphone output, which means you can switch on the amp without the headphone plugged in. As for the OT coupled amp with custom pre-amp, there is a switch to enable/disable the preamp. When it is enabled, the pseudo load connects to the headphone out, making the amp safe to use without headphone plugged in. Hope that help, Jack

I'll assume that the WA3 works the same as WA2 in this regard.

 

[ford2]

Quote:

Originally Posted by K_19 /img/forum/go_quote.gif Speaking of contacting the manufacturers, I got a response back from Jack of Woo Audio. I want to thank Jack for getting back to me in a timely manner and taking time to answer my questions. Anyways, here's his response to my questions regarding WA6: 1) What's the proper way to turn on WA6 with headphones? I ask this because I've read some stuff about it being harmful to the tube amp to turn it on without headphones in? Is this true? So far, I've turned on the WA6 without any headphones inserted (when I turn it on with headphones in, it gives the loud startup tube hum then goes away after about 5 seconds; I wasn't sure if this is harmful for headphones or not, so just to be on th safe side I unplugged it from there on), but plugged it in about 20 seconds later when the tube startup is done. So should I turn it on with headphones in or out (or does it even matter)? Just in case you may be concerned, yes, I always make sure the volume is down to zero when I turn it on or off. J: It is recommended to switch on the amp with a headphone on. This would avoid the amp being open circuit - not a good thing for any tube amps. You will not harm the amp at all if you leave an open circuit for a short period of time. The loud noise/abnormal sound is normal the tubes are warming up to get into the working state. A proper way to use the amp is 1) plug in your headphone, 2) mute the volume or stop your source 3) switch on the amp and let it warm up for at least 10 seconds, and that's all. 2) I know the length for tube warmup for amp varies, but what I was wondering was; is it actually harmful for the amp/tube if I crank up the music right away without warming it? I realize the sound won't be optimal in the beginning but just wondering if this is actually a harmful practice to not warm it. J: No harm at all. 3) If I'm understanding correctly, the headphone should be plugged in at all times when warming up the amp, or else it's harmful. Is this correct? J: Same as 1. So again, it is a good practice when using a tube amp. 4) Is it safe or unsafe to flick the impedence switch in the back while the amp is on/while the music is playing? I always thought no, so I've been turning it off every time before I do so, but wanted to make sure. J: You can change the impedance setting while the amp is on and music is playing. So I guess the way Jack recommends it is that I keep the headphones in the jack when I am turning it on, but apparently you won't harm your amp if you leave it as open circuit (without headphones in) for a short term.

Very informative,Thankyou for taking the time.

 

[plonter]

thank you jack very much for the further explenation

so in the end I can turn on my earmax pro (OTL) without headphones in.

just for the record,I tries to turn it on today with a headphones inside,and there was no sound whatsoever when i turned it on...or off. just makes me curious. no hum,nothing.

 

[WooAudio]

Quote:

Originally Posted by plonter /img/forum/go_quote.gif thank you jack very much for the further explenation so in the end I can turn on my earmax pro (OTL) without headphones in. just for the record,I tries to turn it on today with a headphones inside,and there was no sound whatsoever when i turned it on...or off. just makes me curious. no hum,nothing.

I cannot speak for other manufacturer's design. You may find out about it just to be sure.

 

[kenratboy]

For my X-CAN V8, I am guessing since the manual really does not even mention this is even a tube amp - there is nothing special I need to do.

However, I leave my phones plugged in all the time. I only amp for 1 power cycle per day. I let it warm up for a few minutes before playing.

However, I am not smart, and I am thinking the preamp is tube, and the amp itself is solid state. This means it is much less fussy?

 

[audiogeekery]

Thanks for this! Longtime lurker, first time poster, here.

I have a question:

1) I will be using a Tube Croft Micro preamp out to my Schiit Asgard v1 for my HD650 headphones. So for what I gather it would still be safe to sequence the startup like this

- Croft preamp (wait 5 mins) volume to 0
- Asgard WITHOUT headphones in
- after 10 mins plug in headphones?

Will this damage the Croft?

Thanks in advance for any replies!