• 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.

JLTI Tube Preamp

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JPannell

Member
2004-10-12 6:43 pm
Hi guys,
I am currently constructing a preamp based somewhat on the JLTI tubed gainclone. http://www.customanalogue.com/diytubegainclone/index.htm
I am building the front end of this circuit to feed my power amp. For reasons purley of aesthetics I am using one tube per channel. This will leave me with an extra triode on each channel. I have read that the triodes simply be paralelled together, and this may actually provide better performance. Is this the best way to take care of these extra triodes. I am blindly assuming that you don't want to leave the pins floating. Any help would be very appreciated, I really don't know much about tubes.
Thanks,
Jason
 
You can leave one side unused. No B+, no cathode or grid connection. Apparently the heater will run more or less forever. If you wire one channel for one section and the other channel for the opposite section, you can switch the tubes between channels after a long time and get fresh sections on each side.

Or, you can do the full Joe Rasmussen treatment and use one tube each side in this configuration:

http://www.diyaudio.com/forums/attachment.php?s=&postid=546300&stamp=1105035450

I think Shoog did this one. Search and you can probably find the original thread.


Sheldon
 
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