LateSit

[alexberg]

Have Fun. Fluoroscein is toxic and great allergen. We're making it at school, chemistry.
There are a lot of USSR VFD at ebay. One can check parameters at istok2.com. For instance
http://istok2.com/data/1702/

 

[Pascal Nguyen]

Our environment

Have Fun. Fluoroscein is toxic and great allergen. ....

Thanks for a reminder about toxicity of those cyclic compounds. We inhale rosin smoke then rubbing fingers with beryllium dust! hihi.

I remove the VFD out of the board, made by SamSung with printed diagram at the back of the display, will play with it when I am able to clean up my bench.

So far one channel of the line driver BF862 with 6C51H-B nuvistor has been done, I use two trimmer, one for plate current and one for grid biasing by varying cathode resistor, a non educated approach to tube design.

The result is very pleasing with a nice second harmonic on FFT SA.


Cheers
.

 

[Pascal Nguyen]

I remove the VFD out of the board, made by SamSung with printed diagram at the back...
.

Please correct to “ made by SamSung with printed circuit at the back”

Will try it as a Poor Man Korg Triode, at least only on fluorescent effect.

Thanks



.

 

[kasey197]

Cool experiment !!

 

[Pascal Nguyen]

6S51N-V & BF862 Driver

Cool experiment !!

Hi Kasey197

Lot of fun having a nuvistor driver for my Lateral Sit amp with BF862 buffers.
And more to come with VFD.

Cheers

.

 

[Soundhappy]

You get friend video of the similar experiment

DIY NuTube from fluorescent display VFD

 

[Pascal Nguyen]

You get friend video of the similar experiment

DIY NuTube from fluorescent display VFD

Thanks for the link, will watch it when time permits.
I am very interested in the Korg tube, not on the trendy of brand name and price tag, but on the positive voltage bias for the grid, I think this technique will open a door for me to play with starving tube (low anode voltage).

By the way my scoundrelly attitude to go low in money spending, has ripen on a cheap 6j1 preamp kit on EBay.
The driver composed of BF862 as buffer and 6J1 amplifier, is working really nice, I don’t have any landmark for a comparison, only a satisfaction of H2 ratio and negative phase, it is measured good and sounded well.

Salut et bonne semaine.

 

[Pascal Nguyen]

You get friend video of the similar experiment

DIY NuTube from fluorescent display VFD

I finished my “poor man B1-Korg” preamp, with two VFD scored from a certain hamfest.

very poor result at first attempt, the spectrum showed a very high noise floor and 50Hz.

I tried to reduce the exposure to 50Hz by keeping only one grid actif, it yields much better result but still mediocre.

More works need to be done to optimise for best grid voltage and anode current.

 

[Soundhappy]

I finished my “poor man B1-Korg” preamp, with two VFD scored from a certain hamfest....More works need to be done to optimise for best grid voltage and anode current.

B1 Triode was powered by smps but have external rcrcrc filtering in Papa psu circuit = very low noise floor.
Probably Nutube construction materials was optimised by Korg for audio if compare to regular VFD ?

Congratulations Patrick interesting experiment!
Bonne soirée ou Bonne journée

 

[Pascal Nguyen]

B1 Triode was powered by smps but have external rcrcrc filtering in Papa psu circuit = very low noise floor.
...

Many thanks for your input, I think that I should learn more about RCRCRC to avoid embarrassment.



B1 - Korg, the preamp for the poor on YouTube.

YouTube

 

[Soundhappy]

Power supply filter from original B1Triode schematic is efficient against the smps noise

B1 with Korg Triode

Don't expect very low distorion numbers, was generaly recommended for amp's with 20dB of gain and H3 dominant character.

Thanks again Pascal for Your passionate work sharing , descriptions,schematics, photos and video's.
Very well documented thread Have a nice day

 

[Pascal Nguyen]

Power supply filter from original B1Triode schematic is efficient against the smps noise
...

Don't expect very low distorion numbers, was generaly recommended for amp's with 20dB of gain and H3 dominant character.
...

Thanks for your guidance, will keep it in mind.

 

[Pascal Nguyen]

B1 with VFD - Critical Tuning

I imitate the B1&Korg circuit with minor modification to suit the 7 segments VFD.

“Imitation is a sincerest form of flattery”

Thank you Mr. Pass.


YouTube



.

 

[Pascal Nguyen]

YouTube



.

For a fine tuning without notch filter, one can use the Arta with an obsolete computer (don’t use your pc, sooner or later you will kill your soundcard).

Get to the minimum distortion, then back off to CW and CCW for your favourite H2 dosage, take notes of plate voltage (2 voltages, one for -H2 and one for +H2)

Inject some musics in and retune the bias to the plate voltage as noted, the nice sounding is the bias with Positive H2.

My project is nearly done, all four driver have been built and tested, the fifth VFD (sounds nice also) is waiting for some Russian Nixie tubes with very short filaments to replace the Samsung’s.


Cheers

 

[Pascal Nguyen]

...

My project is nearly done, all four driver have been built and tested, the fifth VFD (sounds nice also) is waiting for some Russian Nixie tubes with very short filaments to replace the Samsung’s.

...

Cheers

Set both VFDs for same gain, one is brighter than the other!!!
Without any input, very close to speakers, I can hear the resonance, like some one strikes a gong few minutes ago.

YouTube



Cheers

 

[Pascal Nguyen]

The Sound of an One Aussie dollar Tube

...
My project is nearly done, all four drivers have been built and tested
...

Cheers

My 6J1 à la B1 is sounding really nice:


YouTube


Grid bias and plate current are exactly same from the eBay 6J1 preamp kit.

Only a minor modification at the power supply section had been performed by removing all steering diodes for voltage multiplication.

There is an error from my last schematic diagram of the 6j1 driver.

A grid resistor R11 has been amended.


Cheers

 

[dady]

Hi, why the 33µF coupling cap? you can use one of fraction of this value without low pass effect 1µF is fine or 0.5µF. And this could be non polarized.
Also you can avoid the use of the first buffer. The amplification amount is <1, it has input high impedance, near the same of the valve.
Try to use a cascade buffer without cap between the stages.
Best Regards

 

[Pascal Nguyen]

Hi, why the 33µF coupling cap? you can use one of fraction of this value without low pass effect 1µF is fine or 0.5µF. And this could be non polarized.
...

Simply due to my availability of having many 33µF capacitors at the time of breadboarding.
Fc (33µF — 4.7kOhm) = 1 Hz
That value was noted and used in my drawing.

...
Also you can avoid the use of the first buffer. The amplification amount is <1, it has input high impedance, near the same of the valve.
Try to use a cascade buffer without cap between the stages.
...

Having only low impedance sources (Android phone), I do need a buffer interface to avoid impedance mismatch.
Will do some more reading to build a direct coupling between stages without capacitor.

My appreciation for your comments
Kind regards

 

[Pascal Nguyen]

With Love From Russia, Nuvistor 6S51N-V

From our forum, a mixed bag about 6S51N-V performances hit my search.
Stubbornly I placed an order of 20 nuvistors from Russia, to play with my LateSit.

Quite nice sounding

YouTube



A coupling capacitor C11 is missing from my last drawing, another one C12 is amended to cathode resistor for AC bypassing.

Please change C1 value to 0.01uF or omitting this cap, I need it for avoid RF breaking in due to a kW transmitter is in proximity.

Cheers

 

[Soundhappy]

Quite nice sounding

Excellent Nuvistor preamplifier thanks Pascal for video show.
Salutations