• 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.

6N3 Tube Preamp with DC-DC converter

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#23
nige838 said:
I would like to know if anybody can find a schematic on this tube, I haven't been able to...
Click to expand...

Someone said double pentode. Another said the 5670 is a drop in for a 6n6. The 5670 is a twin triode though.

Off another site:
"6N6 (chinese), 6N6P (russian). This tube has NO known direct replacement: the best replacement is another 6N6 - 6N6P. However if you are experienced, and with the proper tools, it could be replaced (given socket rewiring and maybe some circuit tweaks) with 5687, 12BH7, ECC99 or E182CC. This last tube seems to be the closest equivalent."
 
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#25
lazzer408 said:
Someone said double pentode. Another said the 5670 is a drop in for a 6n6. The 5670 is a twin triode though.

Off another site:
"6N6 (chinese), 6N6P (russian). This tube has NO known direct replacement: the best replacement is another 6N6 - 6N6P. However if you are experienced, and with the proper tools, it could be replaced (given socket rewiring and maybe some circuit tweaks) with 5687, 12BH7, ECC99 or E182CC. This last tube seems to be the closest equivalent."
Click to expand...

Wait a minute, this is not a 6n6, this is a 6n3, they are very different.

5670 is in fact a replacement for the 6n3 as is the WE396.
 
#26
I didn't mean to start a war about what type of tube it is and what kind of replacement you can use...I just wanted some input on this, that's all...

I'm still wondering if I could just bypass the step up circuit and give the tube 110v from a 12v inverter?

Thanks,
Nicholas G.
 
#27
You could use an external B+ supply or, perhaps use the attached voltage multiplier to replace the one on the circuitboard.
 

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#31
Thank you for finding the datasheet...

I'm going to tie the left out into the right in, bridging the amp for mono so that i can use it as a guitar preamp...

I still plan on bypassing the step up and just using 110v. for the plates from a cheap DC-AC inverter...
 
#33
Hi, I'm totally new to tubes... I'm interested in modding this pcb so I hope this thread will grow up.
Today I've connected the buffer to a Ta2024 Helder amp, I had a nice feeling after a couple of hours of burn in.
I've noticed some hum particularly while touching the pot, maybe it will disappear when in a metal case with proper grounding.
The 7805 regulator runs terribly hot... I'm planning to desolder it and screw it with some thermal grease on the metal case.
Tonight I bought a Jan 5670 GE tube on eBay.
Also I wonder if different diodes and better resistors could give some improvement.
 
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#34
I don't think so. If you examine the schematic, you'll notice that there is a gain of.....wait for it......ZERO. THis is a cathode follower and doesn't produce any gain what so ever. I found that you absolutely have to use a transformer, not a wall-wart. The heaters need to run on AC power, not DC...Plus it does go up after you rectify it...

I turned this into a guitar "pre"amp. It distorts nicely, and doesnt interfere with anything else. I'm currently building a true tube amplifier, the AA4 (or All American 4)...

Peace,
Nicholas
 
#35
Hi Nicholas, zero gain do it means that it's a buffer and not a preamp? My purpose here is to improve detail and soundstage and to have a more analogic/tubee sound.

Someone recommends Schottky diodes in a heater PSU, it seems that 1N4007s switching noise get into the music.

I'm planning to use a toroidal transformer (12v - 150VA) for both the buffer and the TA2024 amp (the latter after rectification).
 
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