Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Pass Labs This forum is dedicated to Pass Labs discussion.

B1 with Korg Triode
B1 with Korg Triode
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 20th October 2020, 02:43 PM   #5291
morrism is offline morrism  United States
diyAudio Member
Join Date: Sep 2015
I've done some work to help with the microphonics issue. I lined the chassis with Noico 80 mat, and used rubber standoffs to mount the PCB. The mat seems very effective.
Attached Images
File Type: jpg B1 amp chassis.JPG (216.7 KB, 175 views)
  Reply With Quote
Old 20th October 2020, 02:49 PM   #5292
rikiheck is offline rikiheck
diyAudio Member
Join Date: Jan 2020
Location: Providence RI USA
There may be someone in NZ or Australia who sells this stuff. It's pretty popular with professional audio people. The cables I mentioned, e.g., are listed as microphone cables; they make snake cables; etc. So you might check out places like that.
Pronouns: they, them, etc ē System: DIY Turntable, Graham 2.2, Grado Statement Master, XP15 & XP20, Schiit Yggdrasil, Logitech Transporter, Aleph 1.2s, 2s or VTL MB-185s, Dynaudio Contour 60s, Gotham Audio Cables ē DIY Builds: Whammy, SS II, Balanced B1
  Reply With Quote
Old 20th October 2020, 05:58 PM   #5293
ClaudeG is offline ClaudeG
diyAudio Member
Join Date: Jan 2015
I thought I was done with the excellent sounding B1 Korg. However, Mark Johnson recently ę released Ľ an interesting low cost / easy to assemble general purpose SMPS filter. He outlined this could be suited for the B1 Korg PS. More here

PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc

Given Markís reputation and excellent projects, I gave it (of course) a try. In fact several tries as I built 2 of them.
Just to discard one variable, in all my various tests both filters I built sounded identical and this consistency is a credit to its design as that applied with different SMPS for different units.

My B1 Korg is a bit special as it has a low ripple quality SMPS, already an excellent filtering courtesy of M. Pass and on top the PS caps have been doubled in capacity to enhence further the original filtering with some further minor positive effect.

I didnít expect this filter to make any improvement here, given the unit sounds already excellent to me and different PS (such as linear regulated etc.) brought a slightly different caracter (tad more bass etc.) but it was always a trade off and a matter of taste - at the end I prefered to stick to the original PS.

It is not easy to carry out comparisons with the B1 Korg. That is because a) you need it to stabilise, you canít just switch in on and off / listen on the fly, so you need a lot of listening time and effort, but mainly because b) it is so addictive that it is very difficult to concentrate on listening impressions without being carrying away ! J

However, for me the filter worked, althoughÖ I really didnít expect it to work at all ! Basicaly the same as when applied to a cheap chinese unit, but with a much lower amplitude, say 60% of the benefits (say +2 in my scale). It gets harder to find it out, requires careful listening, but the main outstanding figures are IMHO :
- improved drive / punch in the lower bass (and that canít be in that case just the filterís cap increase, something is happening here), very nice flesh and speed
- better resolution overall, more easy to pick in the higher frequencies (those finding this unit somewhat agressive in the treble, something I canít back up at all for myself, should try this filter as it makes the treble more precise and yet more natural)
- a tad wider soundstage and overall better register integration, although the B1 Korg didnít really need any improvement on that and it is was marginal, but still not a negative of course

At the end the most noticeable things are the bass drive and refined treble. But thatís with careful listenings and all IMHO. In terms of gain, I would say the magnitude is similar/slightly more to the PS capacity doubling I did, so overall a small step, on the verge of what is noticeable, letís be realistic. We arenít transforming the unit here, say the cherry on the cake, but who doesnít like an extra J

The small gain in this application is probably due to the power supply being well designed already (of course, Papa did it !), not a big stepÖ but on the other hand it doesnít cost a leg and it manages to enhence a device I thought already close to perfection and consistency, so every increase from there is already incredible. And the gains are somewhere the gains various PS could bring without their trade-offs, so the better.

What about me now ? Well, I will integrate this filter to the B1 Korg permanently and given its low cost and ease of built I can only think that it would be benefical to most B1 Korg owners aswell, especialy those that are not using an extra low ripple with extra caps PS : I can only think that the improvements then are going to be greater while this filter can easily be added as an external device and requires no changes / desoldering on the B1 Korg ! Easy job, easy to try, why shouldnít you ? Of course, and as you can read on its dedicated thread, it does perform even better on normal designs using an SMPS. Thanks Mark, thanks Papa, thanks Konst !

Enjoy music


PS : I like my B1 Korg with negative H2 and less harmonics / spice than suggested as starting point in Papaís paper. Just as a side note, the filter didnít noticeably affect the bias voltage of the B1 Korg, so the effects are not due to bias changes (as this affects the sound)Ö and are anyway very different from what a small bias change would bring around my chosen bias.
Attached Images
File Type: jpg photo 2.JPG (404.8 KB, 151 views)
  Reply With Quote
Old 20th October 2020, 06:45 PM   #5294
konst is offline konst  United States
diyAudio Member
Join Date: Apr 2006
Location: socal
Send a message via MSN to konst
Default Got there first

Nice ClaudeG, I was about to post the same thing here. These things are great and cost just a few bucks to stuff.

If anyone is interested, I have ordered a batch of these and will have around 15 boards available which I am happy giving people for an optional donation for postage of $2/$3 (you can have them free, hence optional, but if you want to contribute that is cool to).

If there is lots of demand I am happy reordering as many as are required)

Please PM me, I can send these out after the election (on an election project), when I get some time.

Below is a pic of the before and after filter "DC" on my Korg B1
IMG_20201017_223706852 (1).jpg
Donít compromise yourself - you are all youíve got. (Janis Joplin, 19. jan 1943- 04. okt. 1970)

Last edited by konst; 20th October 2020 at 06:49 PM.
  Reply With Quote
Old 20th October 2020, 07:20 PM   #5295
dtaylo3 is offline dtaylo3  United States
diyAudio Member
Join Date: Nov 2004
Location: coloradao usa
How do folks mount the rubber anti-vibration standoffs to the floor of the case?
  Reply With Quote
Old 20th October 2020, 08:43 PM   #5296
morrism is offline morrism  United States
diyAudio Member
Join Date: Sep 2015
Use the 3mm screws that come with the kit.
  Reply With Quote
Old Yesterday, 03:33 PM   #5297
dezibaby is offline dezibaby  Germany
diyAudio Member
Join Date: Jan 2017
Location: Bornheim
Originally Posted by dezibaby View Post
Hello dear Diy community,
started with B1 Korg.
I finished Pearl Two, B1, F5 a couple of years ago, I would like "a little hotter".
And I notice that PCB from Diyaudio Store and Schematic from Papa are slightly different.
Haoffe it is not bad.
If this was a topic I would like a link for.
Thank you.
By the way, J113 from Faichild and ON Semiconduktor also have different topologies.Attachment 880899

hello everyone, can someone explain my question to me? I can already see a difference there. And did someone have increased cathode voltage 6.7V despite all remaining exactly right? Thank you.
  Reply With Quote
Old Yesterday, 09:55 PM   #5298
rgolan is offline rgolan  United States
diyAudio Member
Join Date: Sep 2019
Location: Los Angeles, California
Default No Microphonics

I recently completed the build of a B1 Korg using the full kit and it's sounding great with an M2x. I'm a bit puzzled by the lack microphonics of the Nutube though.

After getting it to a working state I connected it in my system and could not produce any ringing whatsoever. The top of the case is not even attached yet. Neither at high volume levels nor by rapping on the case. I did use the iFlight rubber standoffs but that is the only mitigation measure so far. The Nutube is cantilevered in air supported by the pins. I did NOT provide any alternate means of grounding the PC board since the rubber standoffs insulate it. It's just grounded via the power connection.

Is this just a product of my very inefficient speakers (83 dB)? Or just lucky with this Nutube being insensitive to microphonics? I had bought some blu tack putty to dampen vibrations but have not used it yet. Maybe the iFlight standoffs are just very effective.

Should I just close it up and use as it is now or put some blu tack below the Nutube?
  Reply With Quote
Old Yesterday, 11:28 PM   #5299
Paddy Garcia is offline Paddy Garcia  United States
diyAudio Member
Join Date: Apr 2014
If it ain't broke, don't fix it.
Currently enjoying: miro's AD1862 DAC->Korg B-1->3e TPA3251->Kef 104/2
  Reply to this post


B1 with Korg TriodeHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Korg NuTube is now available online pmillett Vendor's Bazaar 156 23rd December 2019 11:33 PM
New tube tech from Korg Newk_Yuler Tubes / Valves 38 15th January 2017 01:55 AM
2 X PIONEER CDJ-1000 MK3 PLAYER, Korg M3 88-Key Workstation / Sampler,Yamaha Korg holocoast Vendor's Bazaar 0 22nd August 2009 07:03 AM
tapping into keyboard of Korg Polysix mashaffer Instruments and Amps 0 5th October 2008 01:06 AM
Just ordered a Korg EMX-1 MikeHunt79 Tubes / Valves 5 19th May 2008 08:34 PM

New To Site? Need Help?

All times are GMT. The time now is 01:07 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio