B1 Korg Preamp

Having mentioned the B1 preamp in the "What did you do with your stereo today" thread, I thought I would post what it is. My latest build is based on a Nelson Pass design found on the DIYAudio forums. Even though it doesn't look like it, this is a tube preamplifier. What looks like a glass IC is actually a Korg Nutube 6P1 Dual Triode. I purchased the PCB and NuTube from DIYAudioStore. The mini "Pass Labs" chassis is from China.

I love the sound of this pre. It is dead quiet. The high end is crisp and clean. The mids smooth. The bass is tight. I get the "tubey" goodness without the high voltages and heat, as it runs on a 24v wall wart.

r4001k3abt7h.jpg

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Comments

  • Conradicles
    Conradicles Posts: 6,010
    Great job! Beautiful.
  • treitz3
    treitz3 Posts: 18,230
    Which one of your rigs do you currently have it running in?

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
  • Wardsweb
    Wardsweb Posts: 899
    treitz3 wrote: »
    Which one of your rigs do you currently have it running in?

    Tom

    This one is in the sun room.

    x89lrv72zzrh.jpg


  • Clipdat
    Clipdat Posts: 12,557
    Can you post a pic of the rear?
  • Wardsweb
    Wardsweb Posts: 899
    Clipdat wrote: »
    Can you post a pic of the rear?

    v02qgcf1iy4c.jpg
  • Clipdat
    Clipdat Posts: 12,557
    Thanks, appreciate it!
  • JayCee
    JayCee Posts: 1,474
    Nice creation. Always appreciate your work. Interesting volume control with all the resistors surrounding it.
    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streaming: Roon ROCK on wifi'd NUC, TP-Link WAP, & Uptone EtherREGEN, AfterDark, Emperor Double Crown Clock, Black Modernize LPS, PS Audio AirLens⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • Wardsweb
    Wardsweb Posts: 899
    JayCee wrote: »
    Nice creation. Always appreciate your work. Interesting volume control with all the resistors surrounding it.

    It is a stepped attenuator. Each level of output is regulated by a different resistance.
  • treitz3
    treitz3 Posts: 18,230
    Wardsweb wrote: »
    This one is in the sun room.
    Ah, didn't see it sitting on the plinth. I was trying to figure out what that was...

    Tom

    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
  • JayCee
    JayCee Posts: 1,474
    Wardsweb wrote: »
    JayCee wrote: »
    Nice creation. Always appreciate your work. Interesting volume control with all the resistors surrounding it.

    It is a stepped attenuator. Each level of output is regulated by a different resistance.

    My PSA BHK Pre is stepped. Never popped the hood far enough to look but assume it's a similar implementation. Other stepped vol's I've seen are enclosed with a metal cover and not so apparent. Cool looking. Saw the new Star Wars movie last night and yours could've been used as a death ray prop!
    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streaming: Roon ROCK on wifi'd NUC, TP-Link WAP, & Uptone EtherREGEN, AfterDark, Emperor Double Crown Clock, Black Modernize LPS, PS Audio AirLens⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • EndersShadow
    EndersShadow Posts: 17,517
    Your work makes me want to try and emulate it!

    That rig is very simple and classy, and the size makes me think I want one in my work system lol....
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
  • joecoulson
    joecoulson Posts: 4,943
    Wow. That looks fantastic. Well done.
    Curious, how much $$ (sans labor) do you have in it?
  • Wardsweb
    Wardsweb Posts: 899
    The kit can be purchased at many levels from DIYaudiostore

    The basic has the PCB and matched Jfets for $25. The Nutube is $50. The parts list for the PCB with power supply from Digikey runs around $25. You would need to source a chassis, wire, volume control and connectors.

    The full blown turn key kit is $300.

    My build is very different, in that I sourced a lot better parts for my PCB from Sonic Craft. It also means I had to do some modding to fit parts that were not made to fit the PCB. I already had wire, volume control and connectors. The chassis I got from China. I didn't track cost, but most likely total parts were more than the full blown kit but I have a next level pre over the stock kit.
  • Wardsweb
    Wardsweb Posts: 899
    The stock kit looks like this. You can see mine is very different. That is the beauty of DIY, you can make it your own way.

    s7da887mhex3.jpg
  • mhardy6647
    mhardy6647 Posts: 32,926
    ahh, the Korg VFD "NuTube" :)
    https://korgnutube.com/en/

    How do you like the sound of it?
  • Wardsweb
    Wardsweb Posts: 899
    mhardy6647 wrote: »
    ahh, the Korg VFD "NuTube" :)
    https://korgnutube.com/en/

    How do you like the sound of it?

    It is very nice. Good high end without being shrill. Smooth mids and good bottom end. It is second only to my 6H30 custom build.
  • mhardy6647
    mhardy6647 Posts: 32,926
    edited December 2019
    neat-o.

    In the days before Korg commercialized those things, there were crazy ;) hobbyists repurposing old VFDs as triodes... just because... they could.

    Kinda gotta admire that spirit. :)
    It's the kind of thing that makes guys (and they do tend to be guys) mount jet engines in the beds of their pickup trucks.

    B)

    (and I do mean that as a compliment, at least to the VFD repurposers... not necessarily the P/U jet engine-ers, though)

    ;)

  • ZLTFUL
    ZLTFUL Posts: 5,640
    Do you happen to have a link to the volume control and case you used?

    I am very interested in replicating your work for a living room 2 channel rig with a single source...
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • Wardsweb
    Wardsweb Posts: 899
    ZLTFUL wrote: »
    Do you happen to have a link to the volume control and case you used?

    I am very interested in replicating your work for a living room 2 channel rig with a single source...

    Go to AliExpress.com and search 1506-PASS. There are many vendors selling this chassis. Look at both the price and the shipping cost together, to see which is the best price for you. Note it is made for an IEC connector. I had to make a block off plate to cover the hole, so I could install the DC input connector.

    I don't have a link for the attenuator. It was something I got off Ebay 5 years ago. For plug and play, I would order an Alps RK27 in 50K or 100K. Always a great volume control.
  • ZLTFUL
    ZLTFUL Posts: 5,640
    Thank you sir. Got a case on the way and found several sources for the volume pot.
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • CoolJazz
    CoolJazz Posts: 569
    Here is my NuTube headphone amp build. Rechargeable battery powered.

    nf3aotjykkdv.jpg

    CJ
    A so called science type proudly says... "I do realize that I would fool myself all the time, about listening conclusions and many other observations, if I did listen before buying. That’s why I don’t, I bought all of my current gear based on technical parameters alone, such as specs and measurements."
  • verb
    verb Posts: 10,176
    CoolJazz wrote: »
    Here is my NuTube headphone amp build. Rechargeable battery powered.

    nf3aotjykkdv.jpg

    CJ

    Nice! Love CAO flatheads too! :smile:
    Basement: Polk SDA SRS 1.2tl's, Cary SLP-05 Pre with ultimate upgrade,McIntosh MCD301 CD/SACD player, Northstar Designs Excelsio DAC, Cambridge 851N streamer, McIntosh MC300 Amp, Silnote Morpheus Ref2, Series2 Digital Cables, Silnote Morpheus Ref2 Series2 XLR's, Furman 15PFi Power Conditioner, Pangea Power Cables, MIT Shotgun S3 IC's, MIT Shotgun S1 Bi-Wire speaker cables
    Office: PC, EAR Acute CD Player, EAR 834L Pre, Northstar Designs Intenso DAC, Antique Sound Labs AV8 Monoblocks, Denon UDR-F10 Cassette, Acoustic Technologies Classic FR Speakers, SVS SB12 Plus sub, MIT AVt2 speaker cables, IFI Purifier2, AQ Cinnamon USB cable, Groneberg Quatro Reference IC's
    Spare Room: Dayens Ampino Integrated Amp, Tjoeb 99 tube CD player (modified Marantz CD-38), Analysis Plus Oval 9's, Zu Jumpers, AudioEngine B1 Streamer, Klipsch RB-61 v2, SVS PB1000 sub, Blue Jeans RCA IC's, Shunyata Hydra 8 Power Conditioner
    Living Room: Peachtree Nova Integrated, Cambridge CXN v2 Streamer, Rotel RCD-1072 CD player, Furman 15PFi Power Conditioner, Polk RT265 In Wall Speakers, Polk DSW Pro 660wi sub
    Garage #1: Cambridge Audio 640A Integrated Amp, Project Box-E BT Streamer, Polk Tsi200 Bookies, Douglas Speaker Cables, Shunyata Power Conditioner
    Garage #2: Cambridge Audio EVO150 Integrated Amplifier, Polk L200's, Analysis Plus Silver Oval 2 Speaker Cables, IC's TBD.
  • msg
    msg Posts: 9,307
    edited January 2020
    What a CAO flathead?
    CoolJazz wrote: »
    Here is my NuTube headphone amp build. Rechargeable battery powered.
    Is that the same as this? Curious since this is a headphones piece.
    https://www.head-fi.org/threads/portable-headphone-amp-kit-with-korg-nutube.892146/
    I disabled signatures.
  • CoolJazz
    CoolJazz Posts: 569
    msg wrote: »
    Is that the same as this? Curious since this is a headphones piece.
    https://www.head-fi.org/threads/portable-headphone-amp-kit-with-korg-nutube.892146/
    Nope. I bought this board from Pete Millett.

    pmillett.com/nuhybrid.html

    CJ
    A so called science type proudly says... "I do realize that I would fool myself all the time, about listening conclusions and many other observations, if I did listen before buying. That’s why I don’t, I bought all of my current gear based on technical parameters alone, such as specs and measurements."
  • msg
    msg Posts: 9,307
    Hehe, turns out that head-fi thread cites Pete Millett as the kit source :)
    I'm gonna look into this. That looks like a fun build.

    CJ, for yours, am I correct in understanding that you have the little kit set up inside that cigar box?
    I disabled signatures.
  • CoolJazz
    CoolJazz Posts: 569
    msg wrote: »
    Hehe, turns out that head-fi thread cites Pete Millett as the kit source :)
    I'm gonna look into this. That looks like a fun build.

    CJ, for yours, am I correct in understanding that you have the little kit set up inside that cigar box?

    Yes sir. It's a pretty small board. I had room for a pair of batteries, the 1/8" trs audio in jack on the left side and the pot and 1/4" trs HD jack on the front.
    CJ
    A so called science type proudly says... "I do realize that I would fool myself all the time, about listening conclusions and many other observations, if I did listen before buying. That’s why I don’t, I bought all of my current gear based on technical parameters alone, such as specs and measurements."
  • mhardy6647
    mhardy6647 Posts: 32,926
    edited January 2020
    Pete Millett is a wonderful resource to this hobby; roughly in the same league as Nelson Pass.

    :)

    http://pmillett.com/
    http://www.tubebooks.org/

    pelexqc49x7u.png
    One of the Pete Millett low-voltage space charge tube hybrid headphone amps I built some years back.

    Now back to your regularly scheduled programming...

    :#
  • verb
    verb Posts: 10,176
    Nice full bodied sticks! Love em! :smile:
    psmd6znhel31.png
    Basement: Polk SDA SRS 1.2tl's, Cary SLP-05 Pre with ultimate upgrade,McIntosh MCD301 CD/SACD player, Northstar Designs Excelsio DAC, Cambridge 851N streamer, McIntosh MC300 Amp, Silnote Morpheus Ref2, Series2 Digital Cables, Silnote Morpheus Ref2 Series2 XLR's, Furman 15PFi Power Conditioner, Pangea Power Cables, MIT Shotgun S3 IC's, MIT Shotgun S1 Bi-Wire speaker cables
    Office: PC, EAR Acute CD Player, EAR 834L Pre, Northstar Designs Intenso DAC, Antique Sound Labs AV8 Monoblocks, Denon UDR-F10 Cassette, Acoustic Technologies Classic FR Speakers, SVS SB12 Plus sub, MIT AVt2 speaker cables, IFI Purifier2, AQ Cinnamon USB cable, Groneberg Quatro Reference IC's
    Spare Room: Dayens Ampino Integrated Amp, Tjoeb 99 tube CD player (modified Marantz CD-38), Analysis Plus Oval 9's, Zu Jumpers, AudioEngine B1 Streamer, Klipsch RB-61 v2, SVS PB1000 sub, Blue Jeans RCA IC's, Shunyata Hydra 8 Power Conditioner
    Living Room: Peachtree Nova Integrated, Cambridge CXN v2 Streamer, Rotel RCD-1072 CD player, Furman 15PFi Power Conditioner, Polk RT265 In Wall Speakers, Polk DSW Pro 660wi sub
    Garage #1: Cambridge Audio 640A Integrated Amp, Project Box-E BT Streamer, Polk Tsi200 Bookies, Douglas Speaker Cables, Shunyata Power Conditioner
    Garage #2: Cambridge Audio EVO150 Integrated Amplifier, Polk L200's, Analysis Plus Silver Oval 2 Speaker Cables, IC's TBD.