B1 with Korg Triode

[jphabc54]

Since the active regulation in the Nutube is simply the zener diode, I
assume you mean the H2 project?

You need a converter for the led? I just use a resistor to give it a couple mA.

Yup — that’s what I did — added a 1K resistor for the LED and it’s all working great.

On the 2H, the distortion behavior is different on both channels as I adjust the trimmer resistor. One of them dials into 1% 2H with minimum 3rd harmonic at around 9.25v. The other channel does not get below ~1.3% second harmonic but 3H is minimized at ~9.6v.

I am really enjoying listening to this project with my F5! Outstanding imaging and soundstage.

 

[Mrshazbot]

That's awesome, I'm planning on using it for my F5 also and was worried about it matching well.

Does the F5 work okay with the amount of gain from the Nutube or do you find any distortion at higher levels?

 

[Nelson Pass]

On the 2H, the distortion behavior is different on both channels as I adjust the trimmer resistor. One of them dials into 1% 2H with minimum 3rd harmonic at around 9.25v. The other channel does not get below ~1.3% second harmonic but 3H is minimized at ~9.6v.

Not a good match. Unusual, but it happens...

Send me your mailing address and I will give you a pair that do better.

 

[jphabc54]

Not a good match. Unusual, but it happens...

Send me your mailing address and I will give you a pair that do better.

Sir -- your graciousness and generosity know no bounds! I will e-mail you my address, though this really is above and beyond.

 

[jphabc54]

That's awesome, I'm planning on using it for my F5 also and was worried about it matching well.

Does the F5 work okay with the amount of gain from the Nutube or do you find any distortion at higher levels?

More than enough gain. While this gear is in a small listening room, the monitors I'm driving with the F5 are not particularly efficient at 88db (LSA-1s). Volume knob at 40% is the max my ears can handle.

 

[cjfrbw]

Somebody was selling guts of B1 clone passive on ebay with linear 24V power supply and board, so I bought it. I have a chassis with fused AC input and volume knob (old tubed headphone amp), so I am ready to start my VERY FIRST DIY project as soon as these Korg NuTube boards are commercially available. The chassis even has an opening on top to gaze at the tubes. It is big enough to hold the power supply & board. Seems like the nutubes are available from Millet ebay.

Maybe I'll wreck it, but at least I'll give it a try.

 

[Soundhappy]

Seems like the nutubes are available from....

....DiyAudio Store as well
Korg Nutube 6P1 Dual Triode – diyAudio Store

 

[cjfrbw]

Thank you, Soundhappy, I will buy one there.

 

[Nelson Pass]

I am just finishing up the documentation on the DIY Nutube build.

It should be posted shortly.

Also, I am prepping a run of boards + Jfets for the store.

 

[feds27]

Thank you Nelson. I just received the board/kit from Bob today and it looks great. I can’t wait to assemble and test it.

 

[6L6]

I'm expecting my parts order in the next day or two and will get one built up and photographed as soon as I can. I'm very much looking forward to it!

 

[laverda]

Nice one Jim... I’m looking forward to this project.

 

[TungstenAudio]

My kit (board + NuTube) is due to arrive today.

So would I be completely nutz if I were to bolt one of these to the underside of the top cover of my latest ACA build in the Hafler chassis?

 

[Mr. dB]

Package has arrived, for which many thanks!

 

[delecoy]

Got mine! Any reason I couldnt just use the positive side of the regulator I built for my BA3-FE? It puts out 24.2 volts. The negative side would just be sitting there...but does that really mattter?

Itll save me a lot of case work, and with mouser being so close I'd have it running this weekend

 

[jphabc54]

Got mine! Any reason I couldnt just use the positive side of the regulator I built for my BA3-FE? It puts out 24.2 volts. The negative side would just be sitting there...but does that really mattter?

Itll save me a lot of case work, and with mouser being so close I'd have it running this weekend

That’s exactly how I’m running mine right now! Took the +24 from my BA-3 FE.

 

[delecoy]

Nice! Mouser order time.

 

[cjfrbw]

What would be the difference between using a one microfarad input cap on Korg B1(as on standard B1) vs.the 10 microfarad cap?

 

[Nelson Pass]

I expect the 1 uF to give a 2 Hz rolloff.

 

[tleising]

Really looking forward to this board.

I built my BA-3 FE with power and input/outputs all connectorized using JST XH connectors. So I'll be able to swap between the BA-3 and the micro triode B1 fairly quickly.