B1 with Korg Triode

[jakefromstatefarm]

pot wipers to GND

no need for resistors in mute route, just switch from wiper to GND , manual or relay

Got it, I think I'll go this route. Thanks.

 

[DQ828]

The plan is to take the PSU out and feed it from the power amp with a seperate supply.



I will rewire the ground like the images, for the moment I'm going to leave the Korg where it is and see how things go.

 

[Sagen]

Hi, start up the Nutube today. The value I got was.

T1 - 23.99 V
T3 - 22.33 V
T4 - 9.15 V
T5 / T6 - 0.668 / 0.684 V
T7 / T8 - 15.2 / 15.3 V

Adjusted T7 / T8 to 12.0 V.

Looks ok to me, hook up and test it ( :

Frank

 

[cubicincher]

to Sagen #5664

Hello Sagen,



you can start with a T7/T8 setting at 12 V and then turn down.
Nelson Pass suggests a starting voltage at T7/T8 of 9.5 - 10 V
in his article.



Greets
Dirk

 

[Sagen]

Yes I will try that. I was at a friend last night testing his B1K.
He ran it at 12v, is sound very good. He plays on Teak CD, DDdac, Hiraga 8w class-A and Sonus Faber Extrema clones.


12v is the null point right? Pass also say that the pos/neg 2 harmonic is a psycho-acoustic trick that not everyone can hear or like. Or am I wrong?


I will play with the voltage for sure.


My source is Marantz SA15S1, two way electronic filter (LR), Hiraga 30w class-A / Dynamic Precision 6.1 140w and 3way selfmade speakers.

 

[dtaylo3]

Board version

Ha, I was going to tell you to check which version of the board you have, as I recalled the jumper required on your PCB. Glad you found it!

 

[safesphere]

All JFETs with corresponding resistors that come in each bag, are they all the same and interchangeable or do I need to measure and select them somehow? Thanks!

 

[Soundhappy]

All Q2 jfets are interchangable they ready was measured and selected.
Don't mix them with Q1 🙂 Best regards

 

[Knuds1]

Her is my Korg b1
It sounds god with my new f5 turbo 😉

- Academy audio vcu volum pot
- Elena slimic 2 10uf bypassed On the underside with Cornell Dubilier Polypropylene caps.
- Amtrans signal wire
- neutrik connectors
- separate psu case whit amb sigma 11
- modulshop case

 

[Soundhappy]

Her is my Korg b1
It sounds god with my new f5 turbo 😉

- Academy audio vcu volum pot
- Elena slimic 2 10uf bypassed On the underside with Cornell Dubilier Polypropylene caps.
- Amtrans signal wire
- neutrik connectors
- separate psu case whit amb sigma 11
- modulshop case

High quality build , some great components inside too 😉
Bypassing Elna Silmic II with polypro that is the best imho.
This B1K preamp is one excellent compagnion for F5 Turbo.
Congratulations

 

[cubicincher]

to Knuds 1

Hello Knuds 1,


very good work! Another nice B1-NUTUBE-pre! 😀


I am sure, that sound is delicious....


Skâl!

Dirk

 

[Sagen]

Hi, I played for 4 days now. Still run it at 12 vdc, it sound so good. Just another world from the B1.
But I get a high pich sound in right canal after 1,5-2,0 hour playing, sound as a 5k.
Starts low then just go higher and higher until I switch it of.
I can tap the card and it plings but that goes away after some seconds.

 

[Soundhappy]

@ Sagen

Great news, congratulations
Put them now inside of the sealed enclosure and the high pitch sound will disappear.
For example : B1 with Korg Triode and B1 with Korg Triode

Still run it at 12 vdc, it sound so good. Just another world from the B1..

Yes is another world even if compared with more classic tube preamp's.
BTW your B1K have some interesting mixture of passive components

Do you have try play with other voltages and polarisation (+)(-)change of power amp speaker outputs ?

 

[Sagen]

Soundhappy:

I have no enclosure yet, working on it. Does it have to be metal or is wooden cage with thin copper inside also good?



Yes the components are a step up from oem, if its make night and day I dont know but it makes me sleep better ( :



I have not played with other voltage yet, want to have control on that pitch first.


Frank

 

[Soundhappy]

@ Sagen

Nova days modern homes have a lots of magnetic field waves in the air with smartphones, wi-fi, tv or computer screens etc.
Maybe quick and cheap wood enclosure with copper do the job..
but Modushop or similar are the best for such nice preamplifier look at Knuds1 example.

Get some logarytmic volume potentiometer(s)?
Again bravo very well DIY build with care to the signal quality

 

[avdesignguru]

Hi, I played for 4 days now. Still run it at 12 vdc, it sound so good. Just another world from the B1.
But I get a high pich sound in right canal after 1,5-2,0 hour playing, sound as a 5k.
Starts low then just go higher and higher until I switch it of.
I can tap the card and it plings but that goes away after some seconds.

Sagen:
5KHz ringing is typically the NuTube filament ringing which can become self sustaining since there is no negative feedback in this design. Have a look at damping the tube glass. Here is 6L6's remedy:
Post #4344 and 4346
B1 with Korg Triode

 

[citronone]

Hi, this is my first post in the forum.
I built the Korg B1 Nutube preamp. I connected everything and I have no sound/no output.

My measurements are:
T1: around 24V
T4: around 9.5V

T5 and T6 are at about 0.6 VDC.

The values from T7 and T8 are not right.

T7 changes from 000,1mV to 000,0mV and back again.
T8 is at 000,1mV constant.

The Nutube lights up blue. Both sides.

I dont know but, can it be that there is a warm up time for the Nutube thats longer than 30 minutes? And then T7 and T8 will show a normal VDC? I had it running 30 minutes and still no sound/no output but didn't meassured T7 and T8 then.

I testet it with two Amp Camp Amp Mono first, then with one ACA, and then with my active Computer Speakers. No Sound.

I attached Pictures for T7 and T8 and front and back side of the PCB, maybe its the soldering.

I hope you can help me. Thank you.

 

[dBel84]

The middle pin of JQ1(top left of your board) is not soldered

 

[citronone]

Yes, i also recognized it after posting and viewing the pictures. Soldered the pins again and now it works.

Music is playing.

Thank you.

 

[Sagen]

Soundhappy: I will look at modushop for shure.
I use a TKD logarytmic 50K, way to much gain so ordred a 10K pot. Maby 25K also good but try 10K.


avdesignguru: I look at that, have already some damping on Nutube but maby need moore.


Frank