B1 with Korg Triode

[avtech]

Thanks

Curious question: what's the 1/2 switch on the front used for? I only see 4 RCAs on the back.

Very observant

This board has switchable input but I couldn't fit 3 pairs of RCAs on the back. Instead I've drilled out for a 3.5mm jack in between those 2 visible pairs, only I've run out of jacks and didn't want to show the hole..

 

[Marra]

I had a listen through the stunt speakers before properly casing things up.



[/ATTACH]

 

[Marra]

All cased up and time for a proper listen.

 

[LUX35]

I have T5 / T6 too high with 0.64V.
T1=24V
T3=23,2V
T4=9V

To go down to 0.6V what should I do?
1 / put a zener diode of 8.9V
or
2 / put R1 of 270R instead of 180R.
note: I have J113 Q1 / Q2 rated at 7.4 mA

Thank you for your answers

 

[cubicincher]

to LUX35

Hello LUX35,


in my B1 NUTUBE - build the voltage is at:


T5: 0,66 V
T6: 0,653 V


(check my post #1908 in this thread with the other values)


and all is working / sounding fine.


But perhaps some of the more experienced members can answer this?


Greets
Dirk

 

[Nelson Pass]

.64 is fine. If it makes you nervous, you can reduce it by increasing the
value of the 475 ohm resistor - 510 ohms is a common value at Digikey.

 

[cubicincher]

to Mr. Pass

Thanks for clarification.


Greets
Dirk

 

[LUX35]

.64 is fine. If it makes you nervous, you can reduce it by increasing the
value of the 475 ohm resistor - 510 ohms is a common value at Digikey.

OK
Thanks Papa

 

[Marra]

Wow this thing really is microphonic; my clunky Valab stepped attenuator causes whistles through the right speaker. I need to find a better means of damping the Nutube. Sounds good though

 

[MEPER]

Therefor I used Blue Alps for this one…….they are so smooth…..especially with a 40mm knob

 

[cubicincher]

I fully agree with MEPER -


ALPS RK27 (blue) works great in my B1 NUTUBE (with 44mm knob).
Smooth feeling when turning this pot.

Some claim about reproduce channel unbalance - you can measure it -
but I normally don't hear it....

And affordable price.



Greets
Dirk

 

[Marra]

Thanks guy that would be by far the simplest and possibly cheapest solution.

 

[Erlend Sæterdal]

Signal Capacitors

Hi does everybody use the Silmic 10 uf Signal coupling capacitors? Is there DC at output without. How is sound with electrolytics compared with film capacitors?

 

[6L6]

Yes, you need the coupling capacitors.

I've used Nichicon as well as Silmic, both sound wonderful. You may use film, if you have the room.

 

[Zen Mod]

.....if you have the room.

YouTube

 

[MEPER]

I tried to knock quite hard on my Nutube chassis but no "ringing" in speakers (and it was with power on both Nutube and power amp!). So damping of chassis using 4mm bitumen sheets works.

 

[cjfrbw]

There simply could be batch variation in microphony susceptibility in NuTubes. That is certainly true with standard vacuum tubes and nuvistors, which I have rolled on other devices. My NuTube is blissfully insensitive, but I would imagine some are not so lucky.

 

[cubicincher]

I have used the NICHICON greensleeves / 10 µF / 50V in my B1 NUTUBE.
Sounds very good.
In my M2X I have changed the coupling cap from the NICHICON greensleeve to
a MUNDORF cap (C2 between EDCOR and follower stage). The differences
are marginal but audible. The discrepancy in the price is not marginal!
There is more difference changing the inputboards in the M2X. But they all sound good - each inputboard with its own 'character'.



Greets
Dirk

 

[cubicincher]

Some pics of the NICHICONs in the B1 NUTUBE.
And in the M2X (the coupling cap is screwed in a screw terminal block -
easy to exchange - no soldering).


Greets
Dirk

 

[laverda]

Wow this thing really is microphonic; my clunky Valab stepped attenuator causes whistles through the right speaker. I need to find a better means of damping the Nutube. Sounds good though

The xmas gift board from Mr P rings like a bast**d. I'm not blaming the board rather the Nutube itself or the way its mounted??.
The DIYstore board and the second Nutube is very quiet. Both were built with identical components and both tubes purchased from RS here in the UK but at different times some weeks apart.

The xmas tube it fixed (soldered) directly to the board where as the DIYstore board tube is on flying leads and on a foam suspension arrangement.

I'll be having a look at the xmas tube and detaching it from the board and mounting remotely with flying lead and a suspension kit. Not sure how much heat the tube will take for a de-soldering exercise. ??