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

The Lounge A place to talk about almost anything but politics and religion.

John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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
Closed Thread
 
Thread Tools Search this Thread
Old 17th December 2012, 11:11 PM   #31541
kgrlee is offline kgrlee
diyAudio Member
 
Join Date: Nov 2011
Location: Cooktown, Oz
Quote:
Originally Posted by bcarso View Post
But whether even it is significantly better overall, given the other noise sources like Brownian motion of air and thermomechanical noise of the structure of the capsule is questionable.
Well I do have a small interest in capsule design.

With evil 21st century digits, it's possible to re-visit some of the compromises we had to make in da previous millenium. Excuse me for swearing
 
Old 18th December 2012, 01:52 AM   #31542
scott wurcer is offline scott wurcer  United States
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: dorchester ma
Quote:
Originally Posted by bcarso View Post
The 862 is fine except for the rather high current, given one of Scott's constraints being battery operation. But whether even it is significantly better overall, given the other noise sources like Brownian motion of air and thermomechanical noise of the structure of the capsule is questionable.

Which reminds me: I wonder if Wave ever tested those photonic mic capsules?
2SK222 of Sanyo is the best because the Idss is only around 1mA. There is no need to run a FET in a mic at Idss so this does not matter anyway.

In any case I stated my case in my articles and have tired of correcting the misconceptions. The JFET in a large capsule mic has little or nothing to do with the noise performance. The obsessive Neumann rebuilders search for authentic 1960's 2N3819's for goodness sake.
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."
 
Old 18th December 2012, 01:54 AM   #31543
Nelson Pass is offline Nelson Pass  United States
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
John Curl's Blowtorch preamplifier part II
Quote:
Originally Posted by wayne View Post
That Sony looks very nice shame you can't get them.
I would bet that you could.

 
Old 18th December 2012, 02:13 AM   #31544
Triodethom is offline Triodethom  United States
diyAudio Member
 
Triodethom's Avatar
 
Join Date: Dec 2009
Location: Newnan GA
Smile Oh contra mon ami

Quote:
Originally Posted by wayne View Post
That Sony looks very nice shame you can't get them.
Try this 2sk152 Sony FET 15V .05a .3W DSG | SONY *SS | Distributed By MCM at 1.52 or 147 for four each .
 
Old 18th December 2012, 03:36 AM   #31545
wahab is offline wahab  Algeria
diyAudio Member
 
Join Date: Nov 2009
Location: algeria/france
2SK150.
 
Old 18th December 2012, 04:04 AM   #31546
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
John Curl's Blowtorch preamplifier part II
Quote:
Originally Posted by Esperado View Post
Mr Marsh, Error correction works in comparing two signals. I am afraid there is noway to use that kind of thing on an oscillator, where there is nothing to compare.
I was hunting for something along the lines as conceptual... --- Demian has suggested the method Amber uses which phase shifts the harmonics and feeds it back somewhere/how to cancel them. I'll look into that. Thx-RNMarsh

Last edited by RNMarsh; 18th December 2012 at 04:15 AM.
 
Old 18th December 2012, 04:14 AM   #31547
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
John Curl's Blowtorch preamplifier part II
Default 2SK152

The 2SK152 device may still be around... just have to go to Texas to get it at InterFET Corp. They say the 2SK152 is same process as their IF1320 and IFN152. Also, same process as 2N6451,2,3,4 (process NJ132L). Thx-RNmarsh
 
Old 18th December 2012, 04:38 AM   #31548
Esperado is offline Esperado  France
Banned
 
Join Date: Jul 2011
Location: Portugal
Quote:
Originally Posted by RNMarsh View Post
I was hunting for something along the lines as conceptual... --- Demian has suggested the method Amber uses which phase shifts the harmonics and feeds it back somewhere to cancel them. I'll look into that. Thx-RNMarsh
The two problems i had encountered with this kind of cancellation is both phases and levels. Hard to be better than 60db in the best situations (low frequencies <1000Hz).
I used this kind of canceling circuit to evaluate dynamically (With musical signals) the distortion of amps (and listen to-it). It is the base of my protection circuit.
Levels are hard to set too.
Did-you want to design an analog distortiometer ?
 
Old 18th December 2012, 04:45 AM   #31549
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
John Curl's Blowtorch preamplifier part II
Quote:
Originally Posted by Esperado View Post
The two problems i had encountered with this kind of cancellation is both phases and levels. Hard to be better than 60db in the best situations (low frequencies <1000Hz).
I used this kind of canceling circuit to evaluate dynamically (With musical signals) the distortion of amps (and listen to-it). It is the base of my protection circuit.
Levels are hard to set too.
Did-you want to design an analog distortiometer ?
I'm trying to get the oscillator in an HP339A as low in H2 and others as is humanly possible. It allows for multiple freq and the built-in analyzer is a bonus (I have picked up an ShibaSoku AD725D anaylzer). They use a jFEt for agc and it is the limitng factor -- espec H2. Thx-RNMarsh
 
Old 18th December 2012, 05:00 AM   #31550
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
John Curl's Blowtorch preamplifier part II
FYI -- anyone else buy one of those nano scopes? i just got one (4 channel DSO: DS203) cause its so cute. And, it takes up zero space on the crowded work bench and good for following a signal around to see where it gets lost or goes wrong. Size of deck of cards and 1/2 the thickness. Nice color display rez, too. USB and signal gen port output. www.minidso.com -RNM

Last edited by RNMarsh; 18th December 2012 at 05:10 AM.
 

Closed Thread


John Curl's Blowtorch preamplifier part IIHide 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


New To Site? Need Help?

All times are GMT. The time now is 08:37 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki