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Old 24th November 2018, 12:45 PM   #91
Soundhappy is offline Soundhappy  France
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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
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Old 25th November 2018, 03:08 PM   #92
Pascal Nguyen is offline Pascal Nguyen  Australia
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Quote:
Originally Posted by Soundhappy View Post
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.
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Old 25th November 2018, 03:21 PM   #93
Pascal Nguyen is offline Pascal Nguyen  Australia
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Default 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



.
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Old 30th November 2018, 01:32 PM   #94
Pascal Nguyen is offline Pascal Nguyen  Australia
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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
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Old 3rd December 2018, 01:06 PM   #95
Pascal Nguyen is offline Pascal Nguyen  Australia
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Quote:
Originally Posted by Pascal Nguyen View Post
...

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
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Old 4th December 2018, 12:37 PM   #96
Pascal Nguyen is offline Pascal Nguyen  Australia
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Default The Sound of an One Aussie dollar Tube

Quote:
Originally Posted by Pascal Nguyen View Post
...
My project is nearly done, all four drivers have been built and tested
...

Cheers

My 6J1 ŕ 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
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Old 4th December 2018, 02:01 PM   #97
dady is offline dady  Europe
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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
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Last edited by dady; 4th December 2018 at 02:05 PM.
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Old 5th December 2018, 11:58 AM   #98
Pascal Nguyen is offline Pascal Nguyen  Australia
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Originally Posted by dady View Post
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.

Quote:
Originally Posted by dady View Post
...
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
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Old 7th December 2018, 01:40 AM   #99
Pascal Nguyen is offline Pascal Nguyen  Australia
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Default 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
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Last edited by Pascal Nguyen; 7th December 2018 at 01:48 AM.
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Old 7th December 2018, 01:52 AM   #100
Soundhappy is offline Soundhappy  France
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Quote:
Originally Posted by Pascal Nguyen View Post
Quite nice sounding
Excellent Nuvistor preamplifier thanks Pascal for video show.
Salutations
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