Threshold NS10 Lineamp PCB - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 30th March 2006, 10:27 AM   #11
mlloyd1 is offline mlloyd1  United States
diyAudio Member
 
mlloyd1's Avatar
 
Join Date: Feb 2001
Location: illinois
lumanauw:

i agree with steenoe; interesting comments on use of JFET.

just curious if you have tried a JFET that has a lower IDSS than the 2SK30 to see that changes the sound for you in a positive or negative way? i don't know the 2SK30 specs offhand - i was thinking maybe a 2N5457 or 1/2 of a U404 (don't rememeber the single version). i think it's possible that a part designed for lower IDSS "MAY" have "better" performance/specs at lower currents in your application...

mlloyd1
  Reply With Quote
Old 30th March 2006, 09:09 PM   #12
diyAudio Member
 
apassgear's Avatar
 
Join Date: Nov 2002
Location: Viña del Mar, Torreon
Lumanauw,

Nice to have you around very interesting experience with the jfet you mention, I would like to test myself some of these ideas as the time comes. Guess, as you say that the load for Q1 (R8) will make a lot of difference since we are changing operating parameters of the device.

I’m quite anxious to start testing this “original” topology and see how much can we squeeze out of it and of course test the jfet at Q1. In your opinion, which of the small signal Toshiba’s would be your first and second pick for Q1?

As you may remember a lot has been discuss around the best type of PSU for the NS10, and Steen did try some different supply’s and in his opinion the shunt reg was by far the best sounding one but he did encounter noise problems with it.

Due to Steen experiences I started following the Blowtorch thread with great interest, mainly on shunt PSU topics to see if I learned something “simple” that could be applied to this stage. On post 598 of that thread Justcallmedad proposed some nice shunt regs that call my attention, specially the second one. It seems to me that one of these could be the ticket to the NS10 psu. Which would be your opinion over these circuits? Did you have an opportunity to test some of those ideas?
  Reply With Quote
Old 31st March 2006, 02:18 AM   #13
diyAudio Member
 
apassgear's Avatar
 
Join Date: Nov 2002
Location: Viña del Mar, Torreon
This is the shunt reg I was referring too on my last post. It’s actually identical to Justcallmedad with some other ideas which were discussed on that same thread and adjusted to give aprox. 24V.

Has not been tested yet but think it has great potential.
Attached Images
File Type: jpg shunt reg for ns10.jpg (25.4 KB, 4132 views)
  Reply With Quote
Old 31st March 2006, 02:28 AM   #14
diyAudio Member
 
apassgear's Avatar
 
Join Date: Nov 2002
Location: Viña del Mar, Torreon
Steen,

I will post the PCB copper side so anyone can duplicate and test this wonderful line stage. I have done some more changes to the layout to add some flexibility regarding the input cap so now you will be able to decide if you want to use a lytic or a MKP cap.
  Reply With Quote
Old 31st March 2006, 03:04 AM   #15
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally posted by apassgear
This is the shunt reg I was referring too on my last post. It’s actually identical to Justcallmedad with some other ideas which were discussed on that same thread and adjusted to give aprox. 24V.

Has not been tested yet but think it has great potential.

according to last 'xperiences from jh6you,when I urge him to try tl431,seems that zenner approach is maybe less noisier....but-try and tell us.....tnx to last playing with Babelfish and Oly's Mini,I didn't tested 431 in shunt reg,as I promised........

btw-nice job with PCB
__________________
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 31st March 2006, 06:13 AM   #16
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
Hi, mlloyd1,

First of all, I wanted to say that they way I use Jfet (in the noisiest area) could be very WRONG from the technical POV. I use it that way for myself, not suggesting others to do so
I've tried some other Jfets, like Electrocompaniet's K117, but to myself, the best sounding one is still 2SK30. Hiraga (or is it Kaneda?) uses 2SK30 about 0.25mA bias.
Maybe other JFET could be good in Q1's position, but I haven't tried very much type.
Quote:
Guess, as you say that the load for Q1 (R8) will make a lot of difference since we are changing operating parameters of the device.
I notice that majority of good sounding preamp seems to have quite low bias for the input transistor (like Q1 here), rather different than for power amps. Input transistor for preamp usually biased below 1mA, while for power amp usually above 1mA. I don't know this is only habit or there is technical reason why?
Quote:
Due to Steen experiences I started following the Blowtorch thread with great interest, mainly on shunt PSU topics to see if I learned something “simple” that could be applied to this stage.
Blowtorch thread? Yes that is very good thread.
I want to write about my own (myself) experience. Something that I do not understand until now, is that why many "good" things in textbook do not result in the sonics that I wanted?
For example, there was time that I build cct's with very good regulators, cap multiplier etc. The sound is just "dead". Now I only use 1 R and 1 Cap forming pi-filter, and to me (myself) it sounds better than using complicated rail filter with many semiconductors. Again here I don't know why it is so to my ears. Using passive components (R-L-C) seems to sounds better to me than using semiconductors for rail filter (again : not for anyone's else's ear )
I make many cct's that will be blamed "wrong" from technical POV. I have books like DougSelf's kind of technical book, have built cct's based on those book's tutorial, but now I just make cct's based on 2 pages of Keith Jarret's Foreword in "Complete Guide to High End Audio" by Robert Harley. It helps me to convince myself when I'm making a "technically-wrong" audio cct's
I still haven't found what is the main guide in designing good sounding audio cct's. NP's recent cct's (ZenV9 with LU1014) makes me thinks harder now about what is tobe pursued
  Reply With Quote
Old 31st March 2006, 07:02 AM   #17
Account Disabled
 
Join Date: Aug 2002
Location: Near to the Pacific Ocean
Quote:
Originally posted by lumanauw

The sound is just "dead". Now I only use 1 R and 1 Cap forming pi-filter, and to me (myself) it sounds better than using complicated rail filter with many semiconductors.

Ah . . . you are a good student . . . got A+

  Reply With Quote
Old 31st March 2006, 09:45 AM   #18
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
What is that Keith Jarret wrote?
page1
Attached Images
File Type: jpg keith1.jpg (44.3 KB, 3624 views)
  Reply With Quote
Old 31st March 2006, 09:46 AM   #19
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
Page2
Attached Images
File Type: jpg keith2.jpg (56.8 KB, 3323 views)
  Reply With Quote
Old 31st March 2006, 09:52 AM   #20
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
Question : what do you read in those 2 pages?

There are no "THD" or "S/N ratio" or "Damping factor" word in it. But for me it gives a clue what the "average ears" are looking for. ("average ears" here = everyone who don't design audio amplifiers or have soldering iron in their hands). If the music is sad, you have to be sad hearing the reproduction. If the music is happy, it has to make you happy hearing the reproduction. It's difficult to approach this, and strangely, this characteristic very often can be achieved with cct or approach that is said "wrong" in technical textbooks.
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
My Take on Threshold NS10 Russ White Pass Labs 583 23rd May 2012 05:05 AM
Threshold NS10 renewed steenoe Pass Labs 54 31st May 2007 07:08 PM
Threshold NS10 ponger Pass Labs 4 12th November 2005 11:29 AM


New To Site? Need Help?

All times are GMT. The time now is 07:24 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2