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Bugera Fake Valve Glow


King Tut

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I had a sneaking suspicion all was not as it seems, so I took the top off of my Bugera Veyron Tube and switched it on.

So, it seems that the very lovely valvey glow that shines through the front of the amp isn't the valves glowing at all, but three orange Led's, cunningly set on a dimmer so they gradually fade in after you've turned the amp on.

What's that all about then?

I don't know much about valve amps - maybe someone could enlighten me as to why the actual valves dont glow? I can feel heat coming off them so they appear to be real and not just for show!

IMG_20191215_192058078.jpg

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1 minute ago, Newfoundfreedom said:

I could have saved you the bother of removing the lid. I've got the MOSFET version and it still has a red glow, so I was never under any illusion that it came from valves. 

It sure looks purdy though. 

Hahaha that's funny, I thought only the valve one glowed!

Edited by King Tut
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On 15/12/2019 at 20:45, wateroftyne said:

It's pretty common practice. Preamp valves don't glow, 'cos there's not enough power involved.

Power amp valves do.

And I'm not sure there is 200 to 300 Volts to make them work properly...

Here is the data sheet of a typical preamp valve (or tube), a 12AX7 aka ECC83 aka 7025 :

ecc83s_popis_001_v.jpg.d7da17a7f9436cbc5f0834fdcbb77e42.jpg

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23 hours ago, Hellzero said:

And I'm not sure there is 200 to 300 Volts to make them work properly...

Here is the data sheet of a typical preamp valve (or tube), a 12AX7 aka ECC83 aka 7025 :

ecc83s_popis_001_v.jpg.d7da17a7f9436cbc5f0834fdcbb77e42.jpg

Surely the glow comes from the heaters, not the amount of power being dissipated within the device? The last valve amp I had was fitted ECC83s and I am sure they glowed.

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27 minutes ago, Chienmortbb said:

Surely the glow comes from the heaters, not the amount of power being dissipated within the device? The last valve amp I had was fitted ECC83s and I am sure they glowed.

Indeed, they glow first because of the heater, then the electrons begin to flow from the cathode to the anode through the grid on a triode, but there must be enough tension at the anode to work properly otherwise you won't get the amplification expected (the gain) as the grid will block the flow of electrons.

It's the simpliest way to explain how a triode works.

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I love the orange glow from my MOSFET Veyron. It's only window dressing but there's nothing wrong with that. Sounds pretty darned good too. 

Shoulder and back playing up so the Veyron is picking up a bit of work right now. Dare not risk the all valve or the Trace bi-amp with a dodgy back. 

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4 hours ago, stewblack said:

I love the orange glow from my MOSFET Veyron. It's only window dressing but there's nothing wrong with that. Sounds pretty darned good too. 

Shoulder and back playing up so the Veyron is picking up a bit of work right now. Dare not risk the all valve or the Trace bi-amp with a dodgy back. 

It's all I ever use.

I still can't get over how good it sounds. 

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Orange leds are common, I have a Vox effects pedal with a valve and an orange led under it.

It has nothing to do with how much power it is using, the heater of a valve works about 6v. Valves can be run without the heater, (cold plate), which is I assume what is done here.

But as every fool knows, a valve that doesn't have an visible orange glow doesn't sound anywhere near as good!

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5 hours ago, Woodinblack said:

It has nothing to do with how much power it is using, the heater of a valve works about 6v. Valves can be run without the heater, (cold plate), which is I assume what is done here.

The applications of cold cathode devices are limited to low currents or those where heating is provided in other ways. I haven't come across cold cathode power amp valves.

In some valves the heater is separate from and shielded by the cathode, that's probably the case in amps where they don't glow much.

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55 minutes ago, Stub Mandrel said:

The applications of cold cathode devices are limited to low currents or those where heating is provided in other ways. I haven't come across cold cathode power amp valves.

No - but the valves in the OP aren't power valves, they are preamp valves.

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