MEASUREMENTS

The Lampizator badly needed the measurement section, to confirm its performance to the non-believers.
So here it goes.

I hooked the lampizator to the generator, oscilloscope and some meters on the input and output. I run a set of rather extreme tests which confirmed it's stellar performance.

We operate the lampizator in very safe region  below all it's limits.

1. Voltage amplification limits.
Tube 6H1P
Output connected to a typical pot of an amplifier - 47K Ohm.
The maximum input signal which is reproduced without distortion is 3,3 V AC sine wave at 400 Hz - giving 46 V AC at the output.
Very clean signal. Considering the standard CD output being around 2 V AC, this is 23 times bigger !!!
Considering the typical output of voltage DAC - 2 V - our limit is 1,5 times over the CD. Using the signal from DAC being converted to voltage by a resistor (which is around 50 mV, this is 70 times bigger).



PICTURE: 46 VAC output into 47K load at 400 Hz


2. Standard signal of input (DAC) at 1 V AC pp - lampizator responds with 20 V giving amplification factor of 20x

Square wave signal is also reproduced almost perfectly.


3. Square wave - the most difficult signal to amplify - on the picture there is shown a 20 Hz wave at 47 kOhm load. The change of power supply caps gives no improvement. However the addition of 10 uF cap to the existing 2uF output cap shows a big improvement in the bass. So output caps should be bigger than already big 2 uF. Probably 10 uF will do well.


PICTURE: 20 Hz square at 1 V input, 20 V output, 47k load.

4. This measurements shows the stability of the power supply (unregulated !!!) at maximum volume of amplification of square wave 40Hz at 30 V output.
No distortion or  problems detected. The supply remains FLAT without any pulsation even at extreme load of bass square wave. And maximum amplification. So the normal conditions should easily result in perfect flat supply voltage.



PICTURE: 175 V DC output to anode at extreme power and pulsation of square wave amplification.


This flat power phenomenon is due to GENIUS nature of SRPP circuit. Because two identical tubes sit on top of each other, one forming an active anode resistance and second being an actual triode, if musical signal is applied, the top triode goes "up" the same degree as the bottom tube goes "down" Overall current remains unchanged, and musical signal is amplified.
Imagine two men, one standing on the other's shoulders.
They make sit-ups out of phase - when one stretches up, other sits down. To the external observer the top man's head remains on the same height, but the shoulders of the bottom guy move up and down.

Isn't is great design?
That's why we do not need to regulate the anode supply at all.





PICTURE: 20 kHz triangle wave at normal level.


5. Current:
6H1P has a 2 mA DC current  with the 680 Ohm resistors in SRPP system.
6H6P has 4,5 mA. Well within their respective limits.

6. Cross talk. One channel was loaded to the max, with the biggest signal possible in square wave, and the power line to the second channel's anode was measured. It remained FLAT.  So dual mono power supplies are unnecessary (transformer, bridge and filter).
Resistor-split-caps are adequate and simple.




PICTURE:  40 KHz Square without load. (!) Extreme frequency demand ! IDEAL output.


7.  Frequency response
Sine wave was presented to the inputs , producing 5 V pp AC wave at the outputs (rather typical scenario). 
The amplitude was flat and even from 4 Hz to 90 kHz. (!!!) 
This is two octaves below and above usable range. Well done Lampizator !

Pic 6.


PICTURE: 4 Hz reproduction of sine. PERFECT.


Above the high limit, at 200 kHz the signal is still good and pure, but only some 6 dB lower.

Pic. 7







 
Testing 6H6P - it has voltage amplification factor of 9 (versus 20 in the case of 6H1P) This difference is only 3dB on logarithmic scale.
This was achieved at 7 V AC pp  of input (!!!) producing 54 V pp AC at the outputs of clean sine wave.
The power supply to the anodes showed at this extreme load only 0,01 V pp pulsation. This is only 1/5000 th of the output signal, or in relative terms - 0,6 % of the supply voltage (180 V DC)


Overall, I think that these measurements prove, that the Lampizator - its tubes, tube circuits, operating points and power supplies are more than adequate for the job.


PICTURE: 6H6P reproducing 10 V AC at the output into extreme load of 5 kOhm.
10 times lower than the lowest amplifier load. 20 times lower than most amps (100 K pot).





PICTURE: 6H6P into 200 Ohm load of headphones.

Lampizator DIY step by step for beginners