B1 with Korg Triode

[Nelson Pass]

When you have dual mono pots without any clicks to ensure same setting of both pots then you have to do the "tracking" by "eye and/or ear"?

I would have thought, but I find that separately dialing them up makes
you more aware of the balance. It doesn't bother me at all.

Perhaps Mark Levinson's preamp had something.....

 

[Zen Mod]

-aha , now is semi loud enough

-aha , now is in a middle ..... and loud enough

 

[xrk971]

After building the Korg 6P1 preamp I realize that the NuTube is nothing more than a vacuum fluorescent display (VFD) with two active elements. Has anyhow ever tried to make an amplifier triode from a run of the mill 1980’s calculator/VCR/appliance display?

10-Bit Vacuum Fluorescent Display VFD Display LCD Nixie Tube Display Module | eBay

Seems one could parallel enough 7 digit segments to get the plate current that was desired.

Wikipedia says that some ham radio people made amps with a VFD device (not Korg NuTube).

 

[6L6]

How would you modulate the signal...I .E., how would you make the digits a triode instead of the diode that they already are?

 

[xrk971]

They are triodes - All VFDs are triodes not diodes. They are switchable on/off per segment.

VFD As A Sound Amplifier | Hackaday

 

[6L6]

Been looking since your posting bringing it up - hop diggity dog, they are triodes! I stand corrected. 🙂

Look here, somebody has already dome some work on the idea -

A VFD Receiver (Triodes in Disguise)

VFD as an audio/RF amplifier? | Electronics Forums

 

[xrk971]

Now we can play with these for $6 instead of $50. 😀

What’s neat is that the VFDs with many segments can be used as various stages of triodes in a network and all on one “tube”.

 

[AKSA]

WOW, X, never knew this but it makes sense.........
The only issue might be linear operation, like a Trench mosfet these VFDs are set up as switches so you might have to take care about plate dissipation, just the same issue as the Korg.
Generally distortion from triodes seems to follow the loading. It should be around 2-3 times the plate impedance, and that's probably the reason the distortion dropped markedly when you increased the plate load from 270k to 470k.

Terrific find and much cheaper.........

Hugh

 

[avtech]

Looks very interesting..

Anyone up to the challenge of presenting a schematic..? 😉

 

[indra1]

... Anyone up to the challenge of presenting a schematic..? 😉

Done, Pascal Nguyen showed exactly that December 16, 2018 in LateSit. 😀

 

[avtech]

Done, Pascal Nguyen showed exactly that December 16, 2018 in LateSit. 😀

Nice 🙂 thanks for the link!

 

[sov]

I can imagine a project with nixie tubes.

 

[xrk971]

Nixie is triode?

 

[sov]

I guess not but they make a nice display.

 

[xrk971]

Pascal’s design is for “tube” VDF (nixie like):

I think flat calculator/VCR style - a la Korg would work better due to closer proximity of cathodes under each grid. There may be an electron cloud time smear with so many cathodes stacked axially in same path with cylindrical Nixie tube.

 

[indra1]

Just ensure the one used displays the auspicious good luck of 88 to warm the heart of audiophiles of the Far East. 🙂

 

[Steve Luck]

One of the first electronic kits I built was this clock from Adafruit. I bought a spare tube too. I love tubes and valves Out of production now I think all the kits where designed around NOS they acquired.

 

[brian92fs]

Korg makes an accessory kit to aid in mounting. RS has a listing for it: NUTUBE ACCESSORY KIT 01

Can't tell from the pics if it would be useful with the B1K boards or if you'd need to design a PCB that could accommodate it.

I put an order in for this to see what it looks like. I'll post some detailed pictures of it whenever it arrives.

 

[Steve Luck]

Finished for now:





Swapped out all the cables and the ALPS for TKD pot and put the Elma switch in. I've mounted the Korg on 6mm perspex strip with foam sandwiched behind it using double sided tape. I've put that whole assembly behind the front window using standoffs.

The gold plated solid core is a pain in the bum to use but that and getting shot of the Alps pot has this thing kicking ***. Feet are really moving all by themselves.

FYI I'm listening to Tidal from Nativ Streamer and my Sugden SDT1 CD player via Cambridge DAC Magic.

Thanks Nelson - 106db Horns and single ended class A transistor Amps and Korg Triode what fab mix🙂🙂🙂

 

[rhing]

Very nice work Steve! With the Perspex bottom chassis where you have mounted the B1K board, do you no longer have electrical continuity between the board mounting holes and the metal portion of the chassis? I ask as I want to insert some vibration-isolating stand-offs to mount my B1K board to reduce Korg Triode microphony. Some on this thread have mentioned that the board requires a connection to chassis ground via the mounting holes and stand-offs, but there is no earth ground for the chassis using the pioneer kit-supplied wall wart power supply.

Also, was the switch from the Alps to TKD volume pot worth the extra expense? I really like the B1K as-is with the kit-supplied Alps pot, but some have said that a better pot or stepped attenuator should improve the B1K’s performance.