Woo Audio Amp Owner Unite
May 10, 2015 at 11:39 PM Post #33,496 of 42,298
  As far as I know and just recently learned all tube amps should have a load on the transformer all the time. Either speakers or headphones. If not it can ruin the transformer or transformers. If they are ruined then ya might as well throw the amp away as they are the most expensive part of a tube amp. I have read that the Woo amps have some tolerance to not having a load however the best practice is to always have something connected. When I have just rolled new untested tubes I always just plug in crappy headphones until I am satisfied the new tubes are safe. Usually after 5 minutes.
 
I'm not a expert on this so there can be some mistakes in the above statement so other more experienced members could probably tell us more.

 OK, so I'm now going to start practicing powering on my WA6 up with the HP's plugged-in. 
Now what about when powering off…should I leave the HP's plugged in also, then after the amp is powered off un-plug the HP's?
Another thing is, I've mentioned the way I power-on/off the WA6 many times before when this question was asked…I hope this hasn't caused any potential damage to anyones WA6! 
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May 10, 2015 at 11:51 PM Post #33,497 of 42,298
   OK, so I'm now going to start practicing powering on my WA6 up with the HP's plugged-in. 
Now what about when powering off…should I leave the HP's plugged in also, then after the amp is powered off un-plug the HP's?
Another thing is, I've mentioned the way I power-on/off the WA6 many times before when this question was asked…I hope this hasn't caused any potential damage to anyones WA6! 
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Yip. I would leave the headphones in until it is completely drained of power. 20 seconds or so. I do this. My understanding is you must have a load. Headphones or speakers. I think you can be safe for a lot longer with the volume turned right down. I also do this as well. So I lower the volume then turn off, then remove headphones. To turn on I plug headphones in with the volume down, turn on then once the Woo has done its warmup and the LED signals all is okay then adjust volume.
 
As far as damage. I really don't know.
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Like I said. I was doing it wrong for months. I couldn't hear things going bad and right now the amp sounds incredible. There could be a chance damage was done to the internals tho. Transformers and capasitors. I really don't know.
 
May 10, 2015 at 11:57 PM Post #33,498 of 42,298
  Yip. I would leave the headphones in until it is completely drained of power. 20 seconds or so. I do this. My understanding is you must have a load. Headphones or speakers. I think you can be safe for a lot longer with the volume turned right down. I also do this as well. So I lower the volume then turn off, then remove headphones. To turn on I plug headphones in with the volume down, turn on then once the Woo has done its warmup and the LED signals all is okay then adjust volume.
 
As far as damage. I really don't know.
confused.gif
Like I said. I was doing it wrong for months. I couldn't hear things going bad and right now the amp sounds incredible. There could be a chance damage was done to the internals tho. Transformers and capasitors. I really don't know.

I always have the volume down upon power on/off.
Here is a post I found about the WA6 with Jacks reply too this question and more, so I"m going to be practicing this being it is his amp design. Thanks for your input! 
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Thread: So whats the "correct" way to turn on tube amps with headphones?
Page:3
Post#:37
 
 

 
May 11, 2015 at 12:12 AM Post #33,499 of 42,298
  I always have the volume down upon power on/off.
Here is a post I found about the WA6 with Jacks reply too this question and more, so I"m going to be practicing this being it is his amp design. Thanks for your input! 
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Thread: So whats the "correct" way to turn on tube amps with headphones?
Page:3
Post#:37
 
 


Can you post Jacks reply? I can't find it.
 
May 11, 2015 at 12:18 AM Post #33,500 of 42,298
  Can you post Jacks reply? I can't find it.

 
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.
 
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
 
May 11, 2015 at 4:03 AM Post #33,502 of 42,298
New WA22 owner checking in, would anyone mind telling me what tubes provide the most impact on sound ? Rectifier, Driver or Power tubes ? Trying to figure out which ones to upgrade first 
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May 11, 2015 at 4:41 AM Post #33,503 of 42,298
  New WA22 owner checking in, would anyone mind telling me what tubes provide the most impact on sound ? Rectifier, Driver or Power tubes ? Trying to figure out which ones to upgrade first 
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Drivers IMHO. The heart and soul of the tube trinity.
 
I have tried many of the NOS, and just about all the new production. I can recommend only 2 - both NOS - the Tung Sol Round Plate (TS RP) and National Union (NU). TS RP is little more detailed and accomplished, the NU is a little warmer/sweeter. Either will give sonic goodness.
 
NU requires a 6F8G adapter. TS RPs can be crazy expensive.
 
May 11, 2015 at 8:00 AM Post #33,504 of 42,298
  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

 
Thanks for posting that... I don't recall reading anything like that in the manual, so good to know.
 
May 11, 2015 at 8:54 AM Post #33,505 of 42,298
I have a pair of ts rp for sale if you're interested.
 
May 11, 2015 at 9:16 AM Post #33,506 of 42,298
  New WA22 owner checking in, would anyone mind telling me what tubes provide the most impact on sound ? Rectifier, Driver or Power tubes ? Trying to figure out which ones to upgrade first 
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In my system, Power >= Driver > Rectifier.
 
May 11, 2015 at 1:17 PM Post #33,509 of 42,298
   
I should point out that my amp is the WA5. In that amp the driver is definitely king in terms of tube influence vs the other 2.
 
WA22 could well be different.

I found that on my WA5 the order is: power > rectifier > driver
When I was using the WA22, the order that I found is: driver > rectifier > power.
 
guess the standard ymmv applies here, what a hobby, haha.
 
May 11, 2015 at 1:22 PM Post #33,510 of 42,298
  I found that on my WA5 the order is: power > rectifier > driver
When I was using the WA22, the order that I found is: driver > rectifier > power.
 
guess the standard ymmv applies here, what a hobby, haha.

 
That's so different to my experience. Once I found the TS RP and NU drivers it lifted my SQ much more than improved 300Bs and rectifiers.
 
Really interesting how folks hear things differently
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