Replacing 6N1P' s with 6922s or 7308s

[jon_010101]

You might find that the 6922 oscillates in this circuit, which would lead to the noises you describe. I actually would not advise this switch, since the 6N1P will be more stable in an amp designed for it.

[jonoliew]

From my experience, i would not replace the 6n1 for 6922/e88cc in my yaqin mc-10l. They blow most of the time so far. I'm scared to try anymore and its getting VERY expensive. like 6 philips sq, 3 JJs expensive. Thought i would have learnt after blowing the 1st few... lol

[TheGimp]

If you are blowing tubes, I would recommend doing some checks on your amp before damaging anything else.

(1) Measure filament voltage at the tube pins (4 and 5 DANGER, Potentially Lethal voltages present on other pins!).). It should be 6.3Vac rms +/- 0.3Vrms. I suspect you will find it is higher than 6.6V and probably close to 7.

(2) Measure the B+ high voltage supply and compare this to the manufacturers specification and tube data sheets (Caution do not do this unless you are familiar with HV measurements and comfortable doing so. DANGER, Lethal voltages present!).

The chinese amps are notorious for not being properly made for the mains AC supply that exists in various countries around the world. They run excessive voltage on tube filaments and plates resulting in blown tubes, etc.

There are several ways to reduce the voltage. The best is a 1:1 transformer with taps that allow you to configure the input for the desired output to match your line voltage requirments. Another alternative is a Variac that will allow you to adjust the voltage to your amp.

It is also possible to add a small value resistor in series with the filament supply to drop this down to within spec if the HV is acceptable. (This requires soldering skills, and appropriate safety cautions.)

[jonoliew]

Well it doesn't blow the 6n1 but it does it to the 6922s when i turn them on, see a flash and it stops working. But heater still works. I've sent the amp to get checked but apparently everythings fine.. will check what you've recommended thou. Thanks.

[rotaspec]

6N1 tubes will stand a far higher B+ voltage than 6922/ecc88 tubes. That is their main difference (and high heater current draw). If you have a B+ over 200v I wouldn't put a 6922 in there.

[Wavebourn]

Soviet Union had centralized planning, so it was decided on the top of government stages, which production do people want to consume. The rest was planned in accordance with changed requirements. Octal tubes were called obsolete, and miniature tubes required to replace them.

6Н1П tube was offered to designers as a new miniature tube to replace considered as obsolete octal tube 6Н8С that was equivalent to 6SN7. 6Н2П was offered as a replacement of considered as obsolete 6Н9С, equivalent to 6SL7. 6П1П was offered instead of 6П6С (6V6), and so on.

[Brit01]

What current should I be running the 6N1P at?

I had it at 5.5 mA (240v top tube) and heard some distortion at high levels on a SRPP for headphone amp. (low impedance phones also ).

[anatoliy]

oldradio.qrz.ru/tubes/.../6n1p.shtml

[anatoliy]

Äâîéíîé òðèîä 6Í1Ï sorry this is the right site for lamp 6n1p

[cjkpkg]

Below are some values to consider - courtesy of info found on Broskie's Tubecad journal. One can see that optimizing the idle currents requires a lot of tinkering of the cathode resistors...not a huge deal however.

Looks lik the 6N1P is happiest at 5 or less mA. I had been running 6CG7 at 7mA and then the 6DJ8 at 10mA at 250V. The 6CG7 is very smooth but the 6DJ8's have a little more gain which I prefer - Aikido 5687 pre. Be sure to measure the actual voltage across Rk...it will vary by tube type so dont always assume its 3.1V for example. This will ensure you have your exact idle current.

Tube mu rp Rk Ik(mA) B+ Input Gain Input Gain dBs
6N1P 39.8 12200 328 3.0 200 19.4 25.8
6N1P 36.00 9480 221 5.0 250 17.7 25.0
6N1P 35.00 956 642 5.0 300 17.1 24.7
6CG7 21.10 8960 397 5.0 200 10.4 20.3
6CG7 21.00 9250 626 5.0 250 10.3 20.2
6CG7 20.80 9840 1000 4.5 300 10.1 20.1
6CG7 21.40 8370 470 7.3 300 10.5 20.4
6CG7 21.90 7530 243 10.0 300 10.8 20.7
6CG7 21.80 7680 352 10.0 350 10.7 20.6
6DJ8 30.00 2960 205 10.0 200 14.9 23.4
6DJ8 29.60 3060 291 10.0 250 14.6 23.3
6DJ8 28.60 3980 673 5.0 250 14.0 22.9
6DJ8 28.30 4080 845 5.0 300 13.8 22.8
6DJ8 28.90 3400 481 8.0 300 14.2 23.0