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    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

6N16 12x preamp srpp/cathode follower with printed circuit board design.

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Hi folks,

Last month i designed/build a small preamp/buffer on a dutch forum. I like to share my experience also on this forum. I used the 6N16 miniature tube in a srpp/ cathode follewer setup. Further i designed a circuitboard and try to use cheap and simple parts for preamp and powersupply.

Some features :

Input voltage: from 10 to 1000mV
Amplification: 12x
Anode voltage rimple: <0.1mV
Output power on delay: 20 seconds.
Printed cicuit board: 100 x 160 mm (eurocard format)

Usable for Dac I/V conversion, CD player output buffer, Preamp, inputbuffer for Hypex class D amps.



Below see printdesign in the pdf file. Powersupply can be seperated from preamp.


Have fun with this schematic.


Hey Koifarm,
Nice tube!
Why are you running the 6N16 at so low Ua and Ia? One also wonder why you have the CF at the output of the SRPP? The CF runs at about the same Ia as the first stage. If you want to go CF it would be better to use a CCS on top of the first 6N16, but then gain would almost double.
Hey Lars,

You are good in asking the right questions.
I shall try to give the right answers.

Normal a srpp is optimized for a curtain impedance. But this srpp has the lowest distorsion at a very high impedance. If you then like to drive lower impedance inputs you need a conversion, there the CS cums in.

About the low anode currents and voltages, i have treid a lot of voltages but at 140V( +/- 3 mA) this schematic sounded best with the lowest distorsion at a 10k input.

It replaced all my 6n6 buffers with the 6n16 i have build in the past. I use it now in my shanling cd t100 se for I/V conversion and as driverstage for unbufferred Hypex UCD amps.

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Today i build a headphoneamplifier with the 6N16 tubes.And it sounds realy good. Below the schematic and some specs.

An externally hosted image should be here but it was not working when we last tested it.

You can bypass/remove U1 and U3 if there is enough input voltage(1 to 5V).


Freq. = 10hz to 100Khz +/- 1 db.
Output power= 5 to 30mW a channel, depending on inputvoltage and headphone impedance.
Output impedance = 16 to 500 Ohm.
Total anode current = 27mA
Total heater current = 1580mA

Very nice. I liked how you put them on IC sockets.

Do these tubes need to be matched? oh, what's with the timing circuit and relays?
I also use 2 sockets with one tube, i solder one socket on the tube and one on the PCB. Now they can be connected and removed very easy.

Matching is always better, but until now i have only very small variations within my batch of tubes.

The output delay( 20sec) is a build in security for as the cicuit behind the preamp does not like or can not handle the DC voltage sweep when the tubes are warming up.
Remove couple of capacitors from cahtodes. You don't need them in reverse polarity, it is always + on cathode in respect to ground.
The reason i use two capacitors in the output from the headphoneamp is the size of them. one 50v capacitor is higher them 2 x 25v capacitors. Now the PCB fits in a 50mm high housing. Futher i parallel them with a 4,7uf MKP wima capacitor. This is a personal preference.

Ivo, there is also a thread regarding the 6n16 preamp on a dutch forum.
In case you do not know.

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