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

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Discrete opamps.
Discrete opamps.
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 19th May 2019, 12:46 PM   #11
scott wurcer is offline scott wurcer  United States
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: Belmont MA
Quote:
Originally Posted by canvas View Post
Some of the characteristics are quite impressive.
Like BJT's with 40 pico-amp Ib or 260dB Aol?
__________________
"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."
  Reply With Quote
Old 19th May 2019, 12:57 PM   #12
canvas is offline canvas  Taiwan
diyAudio Member
 
Join Date: Nov 2003
Location: Taiwan
Quote:
Originally Posted by scott wurcer View Post
Like BJT's with 40 pico-amp Ib or 260dB Aol?
Hi Scott,

Yes, these sounds impressive to me. I've only seen few bjt op amps with less than 50pa Ib. And the 260dB Aol? Never heard. Perhaps they are exaggerating. I don't know. You're an expert. Would love to hear your opinion about it.

Poting
  Reply With Quote
Old 19th May 2019, 01:17 PM   #13
scott wurcer is offline scott wurcer  United States
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: Belmont MA
Quote:
Originally Posted by canvas View Post
Hi Scott,

Yes, these sounds impressive to me. I've only seen few bjt op amps with less than 50pa Ib. And the 260dB Aol? Never heard. Perhaps they are exaggerating. I don't know. You're an expert. Would love to hear your opinion about it.

Poting
I meant BJT not FET, 40pA is not possible so it must be a confusion. All the illustrations are CAD drawings so who knows?
__________________
"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."
  Reply With Quote
Old 19th May 2019, 02:01 PM   #14
Mark Tillotson is offline Mark Tillotson
diyAudio Member
 
Join Date: May 2018
Location: Cambridge UK
Quote:
Originally Posted by dreamth View Post
On the other hand i bet they measured its noise with a ne5532/34 based sound card or analyzer as they couldn't get lower than the ne532/34 noise itself.
Input noise measurements are done with decent amounts of gain, so the noise behaviour of the output stage of the device (and of the measuring equipment) will not confound the reading.
  Reply With Quote
Old 19th May 2019, 02:20 PM   #15
dreamth is offline dreamth  Romania
diyAudio Member
 
Join Date: Nov 2010
Which makes for the fact that they could measure much better for a discrete op-amp so they should be thankful for giving them a chance to cheat
It looks like these guys never read this:
http://leonaudio.biz/double.balanced.mic.amp.notes.pdf
Nobody trying to make a hybrid should skip Graeme Cohen's document.
And this too:
http://www.forsselltech.com/media/at...ts/JFETMP1.PDF
http://www.forsselltech.com/media/at...ike_Preamp.PDF

Last edited by dreamth; 19th May 2019 at 02:41 PM.
  Reply With Quote
Old 19th May 2019, 02:51 PM   #16
Mark Johnson is online now Mark Johnson  United States
diyAudio Member
 
Mark Johnson's Avatar
 
Join Date: May 2011
Location: Silicon Valley
Discrete opamps.
FYI, Douk Audio also sells chassis with huge heatsinks, suitable for class A amplifiers, on eBay. I bought one and built a First Watt M2x in it. Good mid-grade quality and corresponding mid-tier prices. Here's the one I bought, the JX085 (link)

What the photo in the eBay listing does NOT show, is that the front panel is engraved with the words "PASS ALEPH AMP CLASS A". I consider this a little misleading; the photos in the listing are carefully arranged so the engraving is out of frame. The one head-on picture is lighted so no shadows fall in the engraving and you can't see it or read it.

Those are the kind of folks you're dealing with when you buy from Douk Audio.

(It turns out I don't actually care very much whether the case is or is not engraved; this has no effect upon the sound of the amp . But I do think it's not a completely honest way to advertise goods for sale).
  Reply With Quote

Reply


Discrete opamps.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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
sound of discrete opamps robmil Analog Line Level 383 7th September 2016 03:57 PM
Are Discrete components better than Opamps ? jsa_ind The Lounge 53 6th September 2016 02:35 PM
low noise discrete opamps robmil Solid State 0 7th May 2010 07:24 AM


New To Site? Need Help?

All times are GMT. The time now is 02:25 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki