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6J1 China preamp thoughts
6J1 China preamp thoughts
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Old 5th June 2019, 02:26 PM   #151
avtech23 is offline avtech23  Australia
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6J1 China preamp thoughts
I tried to add the resistance into the heater circuit by changing out the R1 (2.2 ohm) with first a 39 then 33 ohm, 5 watt but it seems the current isn't dividing as nicely as I'd hoped.

With the 39 ohm, I did not get the V2 heater to operate.
With 33 ohm, I got V1 looking normal and a faint glow out of V2.

Schematic_Heaters.png

So I think I'm going to need to drop in a regulator (got some buck converters on the way).

Do I still need to have a higher value at R1 then R1->regulator->V2;
or revert to the 2.2 ohm;
or remove R1 altogether?
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Old 23rd June 2019, 04:21 AM   #152
nymeria96 is offline nymeria96
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Hey guys. I pretty much got the FX Audio Tube 01 preamp. Added the GE JANs and it sounds nice. Is there any mods that I can do to further enhance the sound? Maybe PSU, or changing something on the PCB? I am quite handy with soldering.

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Old 15th September 2019, 07:32 PM   #154
Soundengine is offline Soundengine
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Just finished to build the kit, fun project and nice sound but 2.2 ohm 2 watts is getting very hot like I cannot let my finger on it...Is it normal or it's pooly designed ? I would like to use this preamp safely.
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Old 17th September 2019, 12:12 AM   #155
avtech23 is offline avtech23  Australia
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6J1 China preamp thoughts
That resistor is dropping around 1.8W in my build so I changed it out to a 3W resistor to increase the longevity and decrease the temperature load.

It was running a little too close to limit for my liking.

If you are uncomfortable with how hot it gets, try increasing the power rating of the resistor to 3 or 5W.
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