• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

6BG6-GA

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scott17

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Joined 2009
I did look at the Brimar 807 data sheet. It shows 600V max for the anode. The 6BG6-GA shows 700V max. The plate voltage in my scenario would be about 425V. Although the screen is shown as 350V max for the 6GB6, there is no definitive info regarding the max voltage with the screen tied to the plate or run as ultra-linear. The reason for my question.

Thanks.
 
Miles Prower

Miles Prower

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Joined 2005
dolphin-hsl.com
scott17 said:
Any practical experience running the "standard" 6BG6-GA at 450V in triode or ultralinear for SE operation at 5K?

Looks to be about -22.5V cathode bias at 40mA.

Looks OK to me. Just looking for someone who has done this.
Click to expand...

This involves spec busting so far as the screen voltage rating. It's getting into iffy territory: maybe it works, since the screen and plate are always at the same voltage, and you have more leeway. Then, perhaps, it doesn't, or it could be very dependent on manufacturer types.

I've used these 6L6-oids, but only as pents, and also including parallel local NFB. Used that way, they sound just great.
 
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scott17

Member
Joined 2009
Thanks for the information.

After I typed the original post, I found this thread:
http://www.diyaudio.com/forums/tubes-valves/127710-super-6bg6-vs-6550-a.html

The 6GB6s that I have are the large plate version, Sylvania.

SY is running the screens at 500V. He says his is PP though, I'm guessing triode connected?, I may be wrong on that.

I'll end up trying triode and pentode connected when I breadboard the circuit.

Scott
 
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scott17

Member
Joined 2009
Here is a photo of mine and a link to the photo I was comparing it to.

The plate in mine looks identical to the large plate version, although the getters on mine on on the sides instead of the top.

ImageShack® - Online Photo and Video Hosting
 

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scott17

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Joined 2009
Can someone please help me to verify if these are indeed the large plate variety? I'm beginning to think not.

Although they have the side getters, they have gray plates, and the plates look like the super version. The imageshack link shows the large plate version.

Post #12 in this thread has the photo of mine.

Thanks,

Scott

scott17 said:
Here is a photo of mine and a link to the photo I was comparing it to.

The plate in mine looks identical to the large plate version, although the getters on mine on on the sides instead of the top.

ImageShack® - Online Photo and Video Hosting
Click to expand...
 
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Burnedfingers

Member
Joined 2002
Hi,

Your imageshack photo... the tube on the left is the hefty 6BG6GA. The one on the right I wouldn't trust because I have had them red plate.

I have run the 6BG6GA in both my Dynaco Stereo 70 and my Quicksilver 8417 mono block amps as well as an amp that I built from scratch. I have never run triode with them so I cannot comment on how they sound in that mode. I have run them at almost 500 plate and 55mA without problems.

There is a guy in Missouri that sells the "Good" 6BG6GA's and you should read what he has on his website.

http://www.vacuumtubes.com/6BG6.html
 
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scott17

Member
Joined 2009
I can tell which one the large plate device is in imageshack photo, because it's the one with the large plates.

My question is: Does the one I have shown in post 12 have the large plates? They are grey, and they appear to match, but my tube has the side getters.

I've seen the site selling the large plate variety, thanks.
 
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scott17

Member
Joined 2009
Yes, we've been over that. I understand, but I did not mention post #8.

If you re-read my question very carefully you may notice that I mention the photo of the one I have is in post #12.

Notice that it says post #12, not post #8. It doesn't say post #8.

Maybe another way to ask the question is:
Does anyone know if the large grey plate 6BG6GA were ever made with side getters?
Notice the the upper and lower mica wafers in the the one I have are like the large plate version.

Thanks.


Original Burnedfingers said:
Your post #8 shows the grey plate on the left and the black on the right.

The tube on the left the gray plate one is what you need. At $12 ea from vacuumtubes it only makes sense to buy new.
Click to expand...
 
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