IC's get hammered - Page 3 - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

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

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 23rd April 2013, 04:51 PM   #21
diyAudio Member
 
Join Date: Jan 2013
Excuse me gentlemen, although I find much about Burson´s to be nonsense there is some truth in the page in post 1 which I also believe can make a difference. The part about transistors being inferior is nonesense and actually the opposite is quite true but resistors and capacitors inside ICs are. Resistors not much of a problem but do you know how caps are formed in ICs ??. They are not caps like we know them in discretes but are reverse biased mosfets (in some cases and this was the best solution some years ago). Looking at their performance and properties they are of similar performance to disk capacitors and not the COG type. Would you use such caps as say compensation ??

Some proper research is in order although modern techniques are much improved.
  Reply With Quote
Old 23rd April 2013, 04:59 PM   #22
GoatGuy is offline GoatGuy  United States
diyAudio Member
 
Join Date: Dec 2012
Location: SF Bay Area
What's particularly funny about the "hammer the ICs" argument is that their very unique "feature" is turned into a bug. The feature being, with modern manufacturing (circa 2000), that the transistor-matching and passive-component matching are within 0.1% on a chip! That is really hard to achieve in discrete circuits (not too hard with the passives, but just TRY to come up with a dozen or two 0.1% matched semiconductors!)

Moreover, when I had my "automatic double-blind" A/B/C switch rig, a whole room full of us (some self-proclaimed golden-ear types) couldn't tell the difference between a bog-standard op-Amp, a super-duper ultra-high end one, and a discrete module. Provided the output trim pots were adjusted so that the gain overall was exactly the same. But this is what digital multimeters are good at, especially when outfitted with a small zero-crossing-point A-law dU meter with good Zener references, and independently battery powered. Easy to adjust to 3½ digits. 0.1 dB accuracy.

Oh - if you were listening for cues like "noise" ... sure. But that's with no signal coming through. Even the IMD on noise+signal is inconsequential when there's a 100 dB difference between the two. I'm quite happy with modern FET input opAmps, even the cheaper ones. The $0.99 wonders (mouser) have 15 nV/√Hz ... and the more expensive ones (such as TI OP1642 at $4/ea) come in at less than 7 nV/√Hz. Amazing devices, really.

Ah well. There are people that think that letting power cords sit in a jug of liquid nitrogen for a few hours (until it boils off, one presumes), then installing them on little risers to avoid capacitive effects of one's carpet, and of course "burning them in" for a few days ... is the cat's meow. My little A/B/C completely-anonmymous (therefore unimpeachable) vote-box got rid of that silver-plated bias!

GoatGuy
  Reply With Quote
Old 23rd April 2013, 05:37 PM   #23
godfrey is online now godfrey  South Africa
diyAudio Member
 
Join Date: Nov 2009
Location: Cape Town
Quote:
Originally Posted by GoatGuy View Post
with modern manufacturing (circa 2000), that the transistor-matching and passive-component matching are within 0.1% on a chip!
OTOH, getting the value you actually wanted, within a factor of two, still seems to be a challenge.
  Reply With Quote
Old 23rd April 2013, 05:54 PM   #24
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally Posted by qusp View Post
burson are known for speaking nonsense on this issue and 'their' discrete regs and opamps are not exactly known for their high performance by discrete standards. they are forever posting ridiculous, biased so-called research and technical results on their pages
I purchased a pair of the Burson regulators for the Linear Audio Magazine review -- they were pretty simple devices -- and for some reason (inexplicable in the statistical analysis, or by any measure of PSRR, noise and Zout) they sounded very nice!
  Reply With Quote
Old 23rd April 2013, 06:02 PM   #25
GoatGuy is offline GoatGuy  United States
diyAudio Member
 
Join Date: Dec 2012
Location: SF Bay Area
Quote:
Originally Posted by godfrey View Post
OTOH, getting the value you actually wanted, within a factor of two, still seems to be a challenge.
Uh, huh ... though not really. Chip passives (resistors) now are within tolerances of 20% wafer to wafer. Doesn't sound terribly impressive, but consider: virtually ALL designs are set up to be insensitive to significant overall variation in Hfe, gm, R ... so long as the RELATIVE values remain closely matched. (This is exactly analogous to high-end tube and discrete amplifier design, where carefully matched, but not absolute-value precise components are used)

The reason why discrete amp makers use high-precision resistors is because they're comparatively cheap now, and because this gets them 'matched' without having to actually 'test-to-match' them. Capacitors are notoriously imprecise, yet, in their slated "duty", their absolute precision is in no way meaningful. Amplifiers are "happy" (and many after-market DIYdesigners "play around") with +20%, +50% caps. ... except for equalization where more precision is necessary ...

But even discrete amp makers "sigh and deal with" the imprecision of their discrete active transistors, and especially tubes. They will match them, and so on ... but REALITY sets in: this is why fine amps have trimpots onboard to allow "bias point" and operating points to be adjusted. All those 0.1% precision resistors are for naught ... when you need to adjust the trimpot 25% to account for a Soviet-manufactured 12AX7 not having as much mu as the GenElec equivalent.

So... the analysis of ICs was fatuous and bogus. Not much more to be said.

GoatGuy
  Reply With Quote
Old 23rd April 2013, 06:05 PM   #26
diyAudio Member
 
Join Date: Mar 2004
Location: At the output stage
Send a message via Yahoo to mr_push_pull
Quote:
Originally Posted by jackinnj View Post
I purchased a pair of the Burson regulators for the Linear Audio Magazine review -- they were pretty simple devices -- and for some reason (inexplicable in the statistical analysis, or by any measure of PSRR, noise and Zout) they sounded very nice!
so, are you telling us that the most reasonable way of altering the signal is by adding a power rail modulating device with absolutely unpredictable behavior in a circuit? and we should be surprised that whatever effect it had in your application sounds good, because, well, it altered the signal in some way?
hmm.
__________________
we all love a good ol' stereotype until it's against us
  Reply With Quote
Old 23rd April 2013, 06:12 PM   #27
GoatGuy is offline GoatGuy  United States
diyAudio Member
 
Join Date: Dec 2012
Location: SF Bay Area
[its interesting - this idea of modulating the power rails]

As far as EFX boxes go - and especially older tube-guitar-amps go - this is exactly what is done in their power-supply rail, to deliver distortion that is considered musically interesting. Long chains of high-value resistors, modestly small capacitors ... ostensibly to form LP networks blocking stage-to-stage feedthrough, but in reality also drooping and rising in seconds-long RC periods; delivers interesting macro effects all by itself to guitar signals.

Could be a similar effect in output amplifier stages: changes in a nonlinear way, the maximum output slew rate and gain. Kind of like a nonlinear low-cut filter? But more complicated.

Amps as EFX boxes! DF96's most favorite chiding-point topic.

GoatGuy
  Reply With Quote
Old 23rd April 2013, 06:13 PM   #28
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally Posted by mr_push_pull View Post
so, are you telling us that the most reasonable way of altering the signal is by adding a power rail modulating device with absolutely unpredictable behavior in a circuit? and we should be surprised that whatever effect it had in your application sounds good, because, well, it altered the signal in some way?
hmm.
Did you read the article?
  Reply With Quote
Old 23rd April 2013, 06:18 PM   #29
diyAudio Member
 
Join Date: Mar 2004
Location: At the output stage
Send a message via Yahoo to mr_push_pull
Quote:
Originally Posted by GoatGuy View Post
Amps as EFX boxes! DF96's most favorite chiding-point topic.
would you be amazed if I told you that I'm using such amp?
yes, I really am because it sounds better. am I being a hypocrite? no. because it was cheap, looked nice and for some reason makes my system sound engaging.
it has "custom vibration isolation" on the transformer, uses "special treated RCA connectors", custom capacitors and there's some putty on one of the RCAs on the inside. LOL do I care? no. do I think it sounds good because of them? no.
__________________
we all love a good ol' stereotype until it's against us
  Reply With Quote
Old 23rd April 2013, 06:20 PM   #30
diyAudio Member
 
Join Date: Mar 2004
Location: At the output stage
Send a message via Yahoo to mr_push_pull
Quote:
Originally Posted by jackinnj View Post
Did you read the article?
which of them? there are many links on this thread.
__________________
we all love a good ol' stereotype until it's against us
  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
TA2022 IC's Available HarryK Swap Meet 12 14th April 2008 07:15 AM
IC's vs Discretes Bonsai Solid State 9 19th September 2007 04:41 PM
Need IR2010s IC's maxzimum Class D 0 21st March 2007 08:54 AM
IC's for 2.1CH O/P bimbla Chip Amps 8 28th November 2005 10:54 PM


New To Site? Need Help?

All times are GMT. The time now is 12:48 PM.


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