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
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
Reply
 
Thread Tools Search this Thread
Old 15th January 2020, 03:11 AM   #4011
soundwavesteve is offline soundwavesteve  United States
diyAudio Member
 
Join Date: Sep 2012
Location: Michigan
Could the Quad somehow be allowing DC back into the B1K? What kind of cables are you using to hook up the Quad to the preamp....maybe cables are overly capacitive? Does it make that noise when the Quad is attached but not powered on? Does it change with volume?
  Reply With Quote
Old 15th January 2020, 03:39 AM   #4012
pinholer is offline pinholer  Canada
diyAudio Member
 
pinholer's Avatar
 
Join Date: Mar 2010
Location: Okanagan Valley
Quote:
Originally Posted by soundwavesteve View Post
As a test I lowered the plate resistor of the right channel to 290k (from 330k) but all that did was lower the AC output even more...I went from 2.1Vac to 2.0 . Opposite of what I expected....unless I need to lower the 1K resistor as well. Doesn't less resistance = more voltage in = more voltage out? Even the 1K resistor and Q1 should have been seeing more voltage I thought....
If you plot the load line on the triode curves, you will see that the maximum gain is with a horizontal load line (infinite plate load). This produces the greatest plate voltage swing for a set AC grid input. A smaller plate load (sloped load line) produces a smaller plate voltage swing for the same grid input (and same operating point).
  Reply With Quote
Old 15th January 2020, 06:40 AM   #4013
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
B1 with Korg Triode
Quote:
Originally Posted by KevinHeem View Post
I know, sorry for lack of details...It's just my frustration coming out. I've been trying to track down noise on the mains line for two days now. I don't know where to begin explaining the steps I've taken trying to track this down. I could write a page at least (I will start a new thread somewhere). Using a borrowed Quad 306 was just the last of many steps in trying to isolate the issue. the result of this attempt was a loud siren like noise coming from the tube. I know this because I can put my finger on the tube and make it stop to some extent.
well , K B1's output buffer is buffering ........ so no way that something is coming back from 306's input and unsettling tube ..... amp doing this will long time ago make your ear bleed and speakers cry

must be something with gnd and used supply for K B1
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 15th January 2020, 03:20 PM   #4014
KevinHeem is offline KevinHeem  United States
diyAudio Member
 
KevinHeem's Avatar
 
Join Date: Nov 2007
Location: Hudsonville, MI
B1 with Korg Triode
Quote:
Originally Posted by soundwavesteve View Post
...maybe cables are overly capacitive? Does it make that noise when the Quad is attached but not powered on? Does it change with volume?
I think your on to something there. I use a long run of interconnect from preamp to amp (8 ft). No noise with Quad off. No change with volume.
  Reply With Quote
Old 15th January 2020, 05:03 PM   #4015
soundwavesteve is offline soundwavesteve  United States
diyAudio Member
 
Join Date: Sep 2012
Location: Michigan
So the tube physically makes a sound?? Does it happen if the Quad is on, but you use a cheater plug to break the ground connection on the amp? Or use the cheater plug on the preamp? How about if you physically connect the amp and preamp chassis with a wire? Was there any recent change to the wiring in the house?
  Reply With Quote
Old 15th January 2020, 06:02 PM   #4016
Nelson Pass is offline Nelson Pass  United States
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
B1 with Korg Triode
If you suspect cable capacitance, then higher value of output resistor.
  Reply With Quote
Old 16th January 2020, 01:09 AM   #4017
soundwavesteve is offline soundwavesteve  United States
diyAudio Member
 
Join Date: Sep 2012
Location: Michigan
So far....R channel with a 470K plate resistor is in perfect balance with the left channel using the stock 330K. (shrug). Whatever...lol. I have no explanation. It is still a few mV off at low (more normal) volumes, but I can no longer tell, that might even be normal. At least I can enjoy it now and cross my fingers that nothing else goes wrong with it. Running at 21.06Vdc on the supply side both channels, heater is exactly .6Vdc both channels, bias is at 11.0vDC...just cause that's where it ended up lol.

Listening to my Zaph audio two-ways with the B1K, deep imaging and crystal clarity. There is some hum and noise when I put my ear up to the speaker, but 2 feet away you cannot hear it. Though cover is still off at this point.

Last edited by soundwavesteve; 16th January 2020 at 01:12 AM.
  Reply With Quote
Old 16th January 2020, 01:52 AM   #4018
KevinHeem is offline KevinHeem  United States
diyAudio Member
 
KevinHeem's Avatar
 
Join Date: Nov 2007
Location: Hudsonville, MI
B1 with Korg Triode
That’s great news Steve!!!!
  Reply With Quote
Old 16th January 2020, 03:03 PM   #4019
soundwavesteve is offline soundwavesteve  United States
diyAudio Member
 
Join Date: Sep 2012
Location: Michigan
Thanks to everyone who offered suggestions and support!


How's your project Kevin? Any updates?
  Reply With Quote
Old 16th January 2020, 03:32 PM   #4020
krk25 is offline krk25  United Kingdom
diyAudio Member
 
Join Date: Feb 2018
Location: Cambridge
Quote:
Originally Posted by Nelson Pass View Post
As the DC bias on the grid is adjusted (altering the plate DC) you will
vary the gain as well as the distortion. If you have the ability to measure
gain and distortion you could optimise either of these, and occasionally
both. From my experience the 8% difference in gain is a little more than
average. Of course, mine has twin volume controls....
Thank you Nelson. Thus enlighted, I have tried to find a suitable DC value. Unfortunately I do not have a distortion analyser. I found two points one with R: 13.2V DC and left 18.7V DC giving equal gain at 1KHz. Obviously, this gives a very high distortion and is unlistenably soupy.

I found a different point of R: 9.2V DC and L: 11.3V DC giving equal gain. I will listen to this some more today. Here we should be in negative phase H2 at least for the right channel.

All in all very big changes in DC bias are required to change the gain. If this variation is common in Nutubes, I would suggest to redesign the kit for dual volume controls.

I might try another Nutube at some point as mine is one of the howlers

If anyone has a Nutube that does not ring and has more or less the same gain in both channels, I would love to buy it
  Reply With Quote

Reply


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 24th December 2019 12:33 AM
New tube tech from Korg Newk_Yuler Tubes / Valves 38 15th January 2017 02:55 AM
2 X PIONEER CDJ-1000 MK3 PLAYER, Korg M3 88-Key Workstation / Sampler,Yamaha Korg holocoast Vendor's Bazaar 0 22nd August 2009 08:03 AM
tapping into keyboard of Korg Polysix mashaffer Instruments and Amps 0 5th October 2008 02:06 AM
Just ordered a Korg EMX-1 MikeHunt79 Tubes / Valves 5 19th May 2008 09:34 PM


New To Site? Need Help?

All times are GMT. The time now is 03:23 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki