Can someone please point me at a schematic for the kit (and maybe a BOM)? I got just the PCB, JFETS, and tubes, as the full kit did not seem to be available.
Also, the JFETs seem to have come with some resistors, 4 221K ones, if I'm not mistaken. Why? I do not see these on the board, unless these are the otherwise unmarked R1.
Apologies if this info is somewhere on these 500+ pages.
Also, the JFETs seem to have come with some resistors, 4 221K ones, if I'm not mistaken. Why? I do not see these on the board, unless these are the otherwise unmarked R1.
Apologies if this info is somewhere on these 500+ pages.
Guide is very helpful! Thanks for that.
I could produce a BOM for inclusion as I order the parts, if that would be helpful (and maybe even a Mouser BOM for single-click ordering). Quick question, though: What voltage rating for the 10uF caps? Looks like 50V in the kit, if I can see them properly in the pix. Do we need that much? (I'm assuming the resistors are the usual 1/4W Dales.)
I could produce a BOM for inclusion as I order the parts, if that would be helpful (and maybe even a Mouser BOM for single-click ordering). Quick question, though: What voltage rating for the 10uF caps? Looks like 50V in the kit, if I can see them properly in the pix. Do we need that much? (I'm assuming the resistors are the usual 1/4W Dales.)
Here's a simple BOM for the Pass B1 Korg parts completion kit (Nutube, transistors, R1s not included)
Resistors
(6) 332K 1/4W
(4) 33.2K 1/4W
(1) 7.5K 1/4W
(4) 1K 1/4W
(2) 475R 1/4W
(4) 100R 1/4W
(1) 10K 1/4W for LED
(2) 10R 3W
(1) 270R 3W
(2) 10K trimmer potentiometers
Capacitors
(8) 1000uF 25V
(6) 10uF 50V (doesn't need to be 50V, but the nice Nichicon gold-wrapped audio grade are 50V in that size)
Diodes
(1) 1N4739 9.1V zener
(1) Green LED
Chassis mount
(1) 50K Audio stereo volume potentiometer
(3) RCA jacks Red
(3) RCA jacks White
(1) DC power barrel jack
(2) DPDT on-on toggle switches
(4) M3 screw
(4) M3 nut
(4) M3 standoff
Other
(4) 24”/63cm twisted pair wire
(1) volume knob
(1) 24V 500mA DC power supply
Resistors
(6) 332K 1/4W
(4) 33.2K 1/4W
(1) 7.5K 1/4W
(4) 1K 1/4W
(2) 475R 1/4W
(4) 100R 1/4W
(1) 10K 1/4W for LED
(2) 10R 3W
(1) 270R 3W
(2) 10K trimmer potentiometers
Capacitors
(8) 1000uF 25V
(6) 10uF 50V (doesn't need to be 50V, but the nice Nichicon gold-wrapped audio grade are 50V in that size)
Diodes
(1) 1N4739 9.1V zener
(1) Green LED
Chassis mount
(1) 50K Audio stereo volume potentiometer
(3) RCA jacks Red
(3) RCA jacks White
(1) DC power barrel jack
(2) DPDT on-on toggle switches
(4) M3 screw
(4) M3 nut
(4) M3 standoff
Other
(4) 24”/63cm twisted pair wire
(1) volume knob
(1) 24V 500mA DC power supply
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Powersupply.
Hi, we have tested the regulated powersupply from Twisted Pears + 23vac transformator ( Radionette from the 1960s ).
It is spot on 24.00vdc.
Hear that people have getting their printboard and Nutube.
When is the complett kit ready for us customers?
Frank
Hi, we have tested the regulated powersupply from Twisted Pears + 23vac transformator ( Radionette from the 1960s ).
It is spot on 24.00vdc.
Hear that people have getting their printboard and Nutube.
When is the complett kit ready for us customers?
Frank
Attachments
I've had two different sources of microphonics. My chassis was picking up the natural vibration of the stand it was on. That issue is now gone. However, the airborne transmission issue still exists. A sneeze, clap, or other loud noise will initiate ringing that dies off soon thereafter. My microphonics issues have drastically dissipated over time, not sure why--nothing has changed. I would like to figure out some type of removable glass or plastic cover for the NuTube to prevent loud noise shocks but keeps the NuTube visible (I have seethrough mesh top on my chassis).
When having initially set up the recently Loaned KB1, which had approx no more than 10 Hours run time when I received it.
I detected a High Pitch consistent ringing noise I believed was the reported Microphonic of the Nutube.
I had heard two different build guises of the KB1 in my system prior to the Lock Down and having received this recent loan model, but had not recollected a Microphonic Ring that was a consistent ring and a detractor during the listening experience.
The Loaned KB1 Pre' set up at present has been supplied with a Chassis that has a 20mm/ 3/4" inch Acrylic Base as an additional attachment.
Following the noticed ringing, I felt the Acrylic base was a measure put in place by the builder, to help reduce the presence of the Microphonic, as this loaned model is their 'Third KB1 Build'.
I knew there was a need to mount the KB1 in a way that was considerate to the potential production of the Microphonic, as when I had the other two KB1's demonstrated in my system, they had a purposely placed Sorbofoam Sheet, placed under the Shelve in use.
My set up for the Loaned KB1 was similar, it was sitting on a Two Tier Shelving/Sub Plinth with a Sorbofoam isolation separator between the Tiers.
The Shelves are sitting on a stand with a Floor Spiked Base, and Timber Pillars and Timber Top Shelve.
This Top Shelve has a Two Tier Isolated Sub Plinth seated on it.
I thought this Stand Set Up was reasonably thought out and was a usable Mounting for HiFi Devices.
The loaned KB1 had shown it as, 'not so good' for its own purpose, as over a period of use a consistent Microphonic was detected.
For weight absorption, I put Cork Pads between the Lowest Shelve and the Timber Stand.
The Microphonic Crept back to an audible distraction over a period of time.
I had as a material to hand, a Black Foam 18mm/3/4" Pipe Lagging which is called Armaflex in the UK.
These were already cut to 300mm/1' Foot pieces were heavily deformed/compacted as a result of a long period of a previous purpose of use as footers for a Granite Slab.
When two of the pieces were placed under the KB1, the effect was almost instant, as there was also a noticeable change to the frequency extremes,
there was a slight move away from the High Frequencies, and it was being perceived that a little more weight was on the delivery.
Over a period of time, there was not any Microphonic detected.
As I have spent a lot of time with using different materials to attempt to attenuate my system to my preferred SQ, I was keen to see what could be done.
As a result, put a additional Shelve on the Armaflex Foam, and then placed the KB1 on this, again the perception was that the High Frequencies were becoming more prominent.
I put Cork Pads between the KB1 and extra shelve in use seated on the Armaflex.
Each small change to the Sub Plinth made a change to the SQ that I believed was perceivable to myself.
Using a KB1 with very little usage time, my findings are in my set up,
that when a KB1 is Seated on Hard Materials, it will elevate the High Frequencies and produce a leaner sound, as well as increase the possibility of producing a noticeable Microphonic Ring.
As stated earlier, I have had experiences with attempting to produce a attenuation with different devices to suit my listening tastes.
A material that has left a Good Impression as a Isolation Separator is a very soft foam, with a Brand Name EKI Foam, I have been using their EKI 420 Acoustic Sheeting in 40mm thickness.
It has proved to be extremely good as a Multi Layer Suspension design I have been using on a TT Sub Plinth assembly of materials.
My Gut Instinct was as this is extremely soft with a memory, it might be the perfect material to try out as the opposite of a Hard Support.
To my ears my instinct come good, this is the material I have stuck with, I tried it as direct contact material with the Acrylic Base and then with other materials separating it.
The BK1 sitting on the EKI Foam with no other materials has proved the best to date, I can knuckle tap surrounding materials, to try and force a ring,
but can't achieve a audible sound ring.
Another important finding is that this has allowed for the KB1, to be perceived as it has more weight to the presentation, much more than the earlier perceived changes, and this new perception is much more to my liking.
As of today, I am aware of the changes in the KB1's SQ just through allowing it to have a longer period of usage and burn in, I feel confident that when it is completely settled, a revisit to the Sub Plinth will have further possibilities to the attenuation of a preferred SQ.
A Sub Plinth Material Investigation would be a valuable practice to all KB1 users.
I have used the KB1 to support a 6SN7 Tube Rolling experience on my power amps, and have come to the conclusion that this Pre' is extremely revealing and is a perfect partner for such a endeavor.
All the above has reinforced my thought process for a casing.
I have access to Permali Wood, and have the intention to use this to produce most of the Casing.
I also intend on having a 15mm thick Lead Platform inside to place the NuTube PCB on.
As I have both of the materials to hand it seems like the properties of these materials may be valuable to the Nutube.
It is looking like my KB1 Parts are soon to be returned to me.
When my own KB1 is built and has approx 200 Hours of usage, I will be revisiting all the above investigations to see what can be created.
I detected a High Pitch consistent ringing noise I believed was the reported Microphonic of the Nutube.
I had heard two different build guises of the KB1 in my system prior to the Lock Down and having received this recent loan model, but had not recollected a Microphonic Ring that was a consistent ring and a detractor during the listening experience.
The Loaned KB1 Pre' set up at present has been supplied with a Chassis that has a 20mm/ 3/4" inch Acrylic Base as an additional attachment.
Following the noticed ringing, I felt the Acrylic base was a measure put in place by the builder, to help reduce the presence of the Microphonic, as this loaned model is their 'Third KB1 Build'.
I knew there was a need to mount the KB1 in a way that was considerate to the potential production of the Microphonic, as when I had the other two KB1's demonstrated in my system, they had a purposely placed Sorbofoam Sheet, placed under the Shelve in use.
My set up for the Loaned KB1 was similar, it was sitting on a Two Tier Shelving/Sub Plinth with a Sorbofoam isolation separator between the Tiers.
The Shelves are sitting on a stand with a Floor Spiked Base, and Timber Pillars and Timber Top Shelve.
This Top Shelve has a Two Tier Isolated Sub Plinth seated on it.
I thought this Stand Set Up was reasonably thought out and was a usable Mounting for HiFi Devices.
The loaned KB1 had shown it as, 'not so good' for its own purpose, as over a period of use a consistent Microphonic was detected.
For weight absorption, I put Cork Pads between the Lowest Shelve and the Timber Stand.
The Microphonic Crept back to an audible distraction over a period of time.
I had as a material to hand, a Black Foam 18mm/3/4" Pipe Lagging which is called Armaflex in the UK.
These were already cut to 300mm/1' Foot pieces were heavily deformed/compacted as a result of a long period of a previous purpose of use as footers for a Granite Slab.
When two of the pieces were placed under the KB1, the effect was almost instant, as there was also a noticeable change to the frequency extremes,
there was a slight move away from the High Frequencies, and it was being perceived that a little more weight was on the delivery.
Over a period of time, there was not any Microphonic detected.
As I have spent a lot of time with using different materials to attempt to attenuate my system to my preferred SQ, I was keen to see what could be done.
As a result, put a additional Shelve on the Armaflex Foam, and then placed the KB1 on this, again the perception was that the High Frequencies were becoming more prominent.
I put Cork Pads between the KB1 and extra shelve in use seated on the Armaflex.
Each small change to the Sub Plinth made a change to the SQ that I believed was perceivable to myself.
Using a KB1 with very little usage time, my findings are in my set up,
that when a KB1 is Seated on Hard Materials, it will elevate the High Frequencies and produce a leaner sound, as well as increase the possibility of producing a noticeable Microphonic Ring.
As stated earlier, I have had experiences with attempting to produce a attenuation with different devices to suit my listening tastes.
A material that has left a Good Impression as a Isolation Separator is a very soft foam, with a Brand Name EKI Foam, I have been using their EKI 420 Acoustic Sheeting in 40mm thickness.
It has proved to be extremely good as a Multi Layer Suspension design I have been using on a TT Sub Plinth assembly of materials.
My Gut Instinct was as this is extremely soft with a memory, it might be the perfect material to try out as the opposite of a Hard Support.
To my ears my instinct come good, this is the material I have stuck with, I tried it as direct contact material with the Acrylic Base and then with other materials separating it.
The BK1 sitting on the EKI Foam with no other materials has proved the best to date, I can knuckle tap surrounding materials, to try and force a ring,
but can't achieve a audible sound ring.
Another important finding is that this has allowed for the KB1, to be perceived as it has more weight to the presentation, much more than the earlier perceived changes, and this new perception is much more to my liking.
As of today, I am aware of the changes in the KB1's SQ just through allowing it to have a longer period of usage and burn in, I feel confident that when it is completely settled, a revisit to the Sub Plinth will have further possibilities to the attenuation of a preferred SQ.
A Sub Plinth Material Investigation would be a valuable practice to all KB1 users.
I have used the KB1 to support a 6SN7 Tube Rolling experience on my power amps, and have come to the conclusion that this Pre' is extremely revealing and is a perfect partner for such a endeavor.
All the above has reinforced my thought process for a casing.
I have access to Permali Wood, and have the intention to use this to produce most of the Casing.
I also intend on having a 15mm thick Lead Platform inside to place the NuTube PCB on.
As I have both of the materials to hand it seems like the properties of these materials may be valuable to the Nutube.
It is looking like my KB1 Parts are soon to be returned to me.
When my own KB1 is built and has approx 200 Hours of usage, I will be revisiting all the above investigations to see what can be created.
Last edited:
Thank You Mr. Nelson
It's done! I've been baking the B1 for hours. No smoke! The T7-T8s are at 9.5V. Please share your wisdom on what your sweet spots are.
The sound is balanced. The low, the mid, and the high are "appropriate" and the low is plenty. As many of you have reported it, the sound is clean and at time revealing. I love it.
In the past years, I've put together different types of preamps based on 12au7, 12ax7, 6dj8, and settled with 12sn7gts. But the B1 preamp is definitely a keeper.
As I was listening to the B1, I turned to my wife and said, "what do I do with all the tubes that I've collected?" She said, "sell them!" we will see.
I ended up using 10fu polyprop/film caps. The preamp does not found bright or harsh at all. I may be bypass them with pios later. But I am very happy with the way it sounds.
I can't wait till pairing it with F6 which is also completed. That would have to be waited till next days.
Thanks Mr. Nelson, for your generous spirit.
And thanks everyone for your help.
It's done! I've been baking the B1 for hours. No smoke! The T7-T8s are at 9.5V. Please share your wisdom on what your sweet spots are.
The sound is balanced. The low, the mid, and the high are "appropriate" and the low is plenty. As many of you have reported it, the sound is clean and at time revealing. I love it.
In the past years, I've put together different types of preamps based on 12au7, 12ax7, 6dj8, and settled with 12sn7gts. But the B1 preamp is definitely a keeper.
As I was listening to the B1, I turned to my wife and said, "what do I do with all the tubes that I've collected?" She said, "sell them!" we will see.
I ended up using 10fu polyprop/film caps. The preamp does not found bright or harsh at all. I may be bypass them with pios later. But I am very happy with the way it sounds.
I can't wait till pairing it with F6 which is also completed. That would have to be waited till next days.
Thanks Mr. Nelson, for your generous spirit.
And thanks everyone for your help.