Dennis Had Inspire Amps

[cgn-dt-n]

84 drives 84?

Wasn't there even a Japanese tube circuit in which the power triode was driven by the same tube as a driver?

[straitwire]

The driver tube in the picture is an ECC99 Dual Triode, basically a beefed up 12AX7.
The basic circuit is a 12AX7 driver but Dennis likes the "Hot Rod" version of the 12AX7 better.
The ECC99 is taller so it kind of looks like an EL84, it's usually used to drive directly heated Triodes like the 300B, 2A3 etc., but can be used as a power tube in headphone amps and small power amps.
It's also known as the 6N6P.

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Dennis has a box of 6N6P's on the way from Viva Tubes stateside.
He's been shipping them with the PH-1a for use in the output buffer stage.
And there is plenty of filament current for these tubes in the RB84.

[cgn-dt-n]

That's when the memory comes back. It was Sakuma-san driving the 300b with a 300b. That's what he did also with the combination el84 drives el84. But his concept is very controversial.

[Formerly YB-2]

Have also used Soviet era 6N14P (if I've got that right without running downstairs to look) as an excellent replacement for EL84s.

[Isaacc7]

Originally Posted by cgn-dt-n

That's when the memory comes back. It was Sakuma-san driving the 300b with a 300b. That's what he did also with the combination el84 drives el84. But his concept is very controversial.

Huh. I thought the 300b was a bit difficult to drive, at least more difficult than the typical pentode output tube. So what drove the 300b that was driving the output 300b?

[cgn-dt-n]

Here is a report on how someone recreates such an amplifier. Otherwise, you can find a lot on the Internet
https://www.diyparadise.com/sakuma_darling.html
I'm not a technician myself and can't explain his circuit to you

[straitwire]

Finally got around to working on my 6GK6 preamp.
The circuit is the same as the 396a preamp, I just replaced the zener diodes with voltage regulator tubes.

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Fired it up and it worked right off the bat, no sparks, no smoke, and it's not noisy...
Playing it now, this 396a circuit sounds fantastic!
Gonna let it burn in today, then I'll install my remote volume control power supply and control module.

[Formerly YB-2]

Originally Posted by straitwire

Finally got around to working on my 6GK6 preamp.
The circuit is the same as the 396a preamp, I just replaced the zener diodes with voltage regulator tubes.

[IMG][/IMG]

Fired it up and it worked right off the bat, no sparks, no smoke, and it's not noisy...
Playing it now, this 396a circuit sounds fantastic!
Gonna let it burn in today, then I'll install my remote volume control power supply and control module.

Very nice work.

[cgn-dt-n]

nice preamp,
Impressive light show with the Voltage Regulator Tubes.
how does the sound of the 396a compare to the LP2030 or the CJ5?
Is there a sonic advantage to replace the zener diodes with the voltage regulators?

[straitwire]

I installed the power supply and control module in my preamp.
Works great, I just need to redo the knobs using smaller 30awg wire for the LED's so the knobs move more freely.

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The power supply is a 12v 1 amp AC adapter removed from it's housing.

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The control module is a modified RF remote control kit programmed to "jog" mode.

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The panel mount female connector for the WIFI antenna.

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The WIFI antenna.

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The 12v key fob controller with Inspire overlay.

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