diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Solid State (http://www.diyaudio.com/forums/solid-state/)
-   -   990 discrete opamp (http://www.diyaudio.com/forums/solid-state/50047-990-discrete-opamp.html)

udip 21st January 2005 08:57 PM

990 discrete opamp
 
Hello all !!;)

I'm kind a new member on this forum, but I must say I find
this forum very interesting. One can learn a lot from people
in this forum.....and it's very good to read as many opinions as possible on a subject. :spin:


I'v read a lot about discrete opamps in this forum, and many
has mentioned the JC-2, Elektor preamp, Great River... but I
can't see a thread about the 990 opamp (The one that is sold
by JH company, and if I'm not wrong was developed by Jensen).

Is there a reason for that? Did anyone buy/build this opamp
or had a chance to listen to it? How does it compare to
other discrete designs?


Udi.

udip 21st January 2005 09:09 PM

I'm sorry...the link:

john curl 21st January 2005 09:32 PM

It is a pretty good discrete op amp, but somewhat dated. Fet's on the input 'improve' the initial design.

udip 21st January 2005 10:02 PM

Hi John,


Do u think that fet's on input will do better?
I suppose it is designed for minimum noise with low impedance
sources, so bipolar inputs seems ok, no?


Udi.

studiotech 21st January 2005 10:11 PM

Don't forget Forssell
 
Check out Mr. Fred Frossell's design here:

[URL=http://www.forsselltech.com/products.htm]

I have a line level pre built with these....wonderful!

Greg

udip 21st January 2005 10:19 PM

Hi Greg,


Are you talking about the JFET-992 or the DLR-1??

studiotech 21st January 2005 10:33 PM

the 992 to be exact.

I could post some pictures maybe tomorrow of my design.

Greg

udip 22nd January 2005 02:39 AM

Has anyone tryied this discrete jfet opamp from forssell??

Simple class a jfet opamp

udip 22nd January 2005 02:41 AM

It looks so simple...I wonder how does it compare to a good
IC opamp like AD825 or OPA627....

studiotech 22nd January 2005 04:39 PM

It IS simple, but the difference is in the power supply that you can operate it from. Being able to go all the way up to +-24v gives LOTS of headroom. The original design for the pre that I built was used in a pro +4dBu environment for a mastering engineer, mine however is only for home use, so maybe it is overkill, but that's what I like!

Greg


All times are GMT. The time now is 01:28 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