• 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.

all dht se PX4

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iko

Ex-Moderator
Joined 2008
What's your I/O voltage ratio on the 26?
I can't hear them at all, even dinged unrespectfully.

At the moment mine are biased at 150V B+, -10V on the grid, 1A through the filament. But I only hear the ding when the volume is very high. Basically, no problem for me. Didn't even bother to mount them in rubber grommets, though I have some nice ones. Oh, and I should add, right now I'm listening to globes.
 
Generally speaking tubes are getting more microphonic at a higher amplification level. Maybe we're both just plain lucky ;)

Outch, you should try the Majestic globes. Does anybody know if Majestics are an original product or rebranded Sylvanias? Haven't enjoyed Ella's voice more, ever.
 

iko

Ex-Moderator
Joined 2008
I have so many 26 tubes (mostly ST) that I have no motivation to get more. I'm a bit curious about a 4P1L preamp, as Ale and Andy built. I got a few of those too. However, I'm not sure the improvement would be worth the effort to rebuild the entire thing. I'm quiet happy with the 26 preamp, plus I haven't even finished tweaking. :)

What I really need to spend more time on is a good power amp. My 4E27 project is moving sooooo slowly! :(
 
Yes, tweaking is a hobby of its own.
Although some die hard technocrats seem to disapprove :tons: :)
One needs the real estate to place transmitter powered amps.
I've seen some impressive sets of over two hundred kilograms.
Sounded impressive, not simply nice ;)



Agreed, to establish a style one should not mix up too many materials and forms.
Perhaps the black paint brush can soften the offending cap and cage.
The idea grew from Italian pottery products from the 1950's: bicolore.
 
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iko

Ex-Moderator
Joined 2008
Yes, tweaking is a hobby of its own.
Although some die hard technocrats seem to disapprove :tons: :)
One needs the real estate to place transmitter powered amps.
I've seen some impressive sets of over two hundred kilograms.
Sounded impressive, not simply nice ;)

These are small transmitting tubes, only 75W max plate dissipation. I'm hoping it will be light! :) Still, it won't compare with your PX4. I'm trying to avoid hard to find tubes.
 
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