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Old 05-15-2019, 08:23 PM   #1
talustalus
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Default Vacuum Tube Headphone Amp crackling--power or preamp tubes, or either?

Hi, sorry it's not a specific Reaper question but I figure there's a lot of good audio brains here.

Is headphone amp crackle more likely the preamp or power amp tubes? Or could be either?

I'm about to purchase some new tubes and need some advice.

Thanks!
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Old 05-16-2019, 02:35 AM   #2
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Quote:
Originally Posted by talustalus View Post
Hi, sorry it's not a specific Reaper question but I figure there's a lot of good audio brains here.

Is headphone amp crackle more likely the preamp or power amp tubes? Or could be either?

I'm about to purchase some new tubes and need some advice.

Thanks!
Could also be capacitors, transformers, something as simple as connections, get it checked out before spending money.
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Old 05-16-2019, 10:38 AM   #3
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That's an unusual symptom.


You can try wiggling the tubes (wear gloves or otherwise protect your hands from the heat) and/or 'flick" the tubes with your fingernail to see if that makes it better/worse and if you can identify the problem with a particular tube. And, try removing & re-socketing the tubes because maybe it's just a bad connection with the socket.


If it's in both channels it's probably from the power supply. If it's only in one side you can swap the left & right tubes (one at a time) to see if the noise switches to the other channel.


Of course, tubes do age and deteriorate but they usually get weak and you get low gain and/or distortion, or they just "die".

..Maybe it's time to get rid of that 1950s technology!

Last edited by DVDdoug; 05-16-2019 at 10:58 AM.
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Old 05-16-2019, 10:59 AM   #4
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Here's a tip to try to figure out if it's a preamp tube or output tube.

Since the volume control is before the output tubes, if you hear the noise increase as you turn up the volume, it's most likely a preamp tube (or something in the preamp section in general, but yeah probably a preamp tube).

If the noise doesn't get louder as you turn up the volume, it's most likely an output tube (or something in the output section...but yeah probably an output tube).

Keep in mind that if there's a phase splitter "preamp tube" being used, that's usually part of the output section. So for what I said above, lump the phase splitter tube(s) in with the output section and not the preamp section.

DVDdoug brings up a good point about the sound being in both L/R sides, too. If each signal path is separate, yet you're getting noise in both sides, it's less likely to be a tube. Although if a preamp tube's two triode sections are being used for L and R, it's possible a single preamp tube can cause noise in both L and R sides. It's just not quite as likely.
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Old 05-16-2019, 07:50 PM   #5
talustalus
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Originally Posted by JamesPeters View Post
Here's a tip to try to figure out if it's a preamp tube or output tube.

Since the volume control is before the output tubes, if you hear the noise increase as you turn up the volume, it's most likely a preamp tube (or something in the preamp section in general, but yeah probably a preamp tube).

If the noise doesn't get louder as you turn up the volume, it's most likely an output tube (or something in the output section...but yeah probably an output tube).

Keep in mind that if there's a phase splitter "preamp tube" being used, that's usually part of the output section. So for what I said above, lump the phase splitter tube(s) in with the output section and not the preamp section.

DVDdoug brings up a good point about the sound being in both L/R sides, too. If each signal path is separate, yet you're getting noise in both sides, it's less likely to be a tube. Although if a preamp tube's two triode sections are being used for L and R, it's possible a single preamp tube can cause noise in both L and R sides. It's just not quite as likely.

Thank you v much for this info. Turning the volume control of the amp all the way down makes no difference to the crackling / static noises I can sometimes hear through the headphones. I guess this means it is not the preamp tubes?
I guess there might be a problem with the power tube(s) or its socket(s).

In order to do my tests, is it OK to handle tubes while the amp is powered ON?

(I assume from what I've read about wiggling/tapping the tubes as a test it implies you do this while the amp is ON so you can hear the result.)
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Old 05-16-2019, 08:35 PM   #6
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I actually insert a Master Effect Module which connects to XLR I/O’s in my project window.
That module is pre Destination Module which is the Headphone/IEM Stereo Out.
Confusing I know.
But it’s basically a way to insert and introduce Tubes to my Ears.
My IEMs are for Mastering as they have 12 drivers per ear, 24 total.
They’re so damn precise sometimes I want something different.
OP obviously knows what Im talking about. It really gives a new dimension to listening.
Fortunately for me this is also my send to a Stage Monitors or FOH, so I can mix to taste, then save.

Here’s the choices I like. Radial is clean to ultra Fire.
RP562 is just incredible grease due to the circa 1956 NOS/NIB RCA Command Tubes.

Fix it, you’re going to love the sound. It can be like 8 Track Tape or colored by Tube choice.
Lots of fun.










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Old 05-19-2019, 09:23 PM   #7
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Monitoring on tube amp is a bad idea. Tubes alter the sound too much.
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Old 05-20-2019, 08:44 AM   #8
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Monitoring on tube amp is a bad idea. Tubes alter the sound too much.
That said some audiophile designs are so clean as to make little or no difference as to whether you are using solid state or a very good push pull tube amplifier. Then again such uncoloured amplifiers generally won't be in DAW audio systems.
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