Discrete vs. Non-Discrete

[cpsmusic]

Hi Folks,

I recently had a chance to watch this instructional video: https://www.groove3.com/tutorials/Microphone-Preamps-Explained.

Now, I'm no electronics expert, but from my (limited) understanding, there's some information in this series that's just plain wrong. In Part 5 ("You Get What You Pay For") the narrator compares 3 mic pres - a MOTU UltraLite, a GA 73 and a Chandler Germanium. He says that because the first two pres are "non-discrete" and so they have more noise, increased distortion, lower headroom, and less gain. In contrast, the Chandler is "discrete because it's built from individual components as opposed to a printed circuit board" (!) (as a Neve clone isn't the GA discrete?). It has a faster slew rate and therefore a better transient response...etc.

Anyway, there seems to be a lot of misinformation here - I think op-amps are being confused with the use of PCBs, etc. Over at <https://nwavguy.blogspot.com.au/2011/08/op-amps-myths-facts.html> the author states that "For audio use the op amp’s main competition is a fully discrete amplifier made out of transistors, resistors, etc. Which is better? It turns out, for nearly all applications for which IC op amps are suitable, they easily outperform discrete designs in the following areas..."

Are IC op-amps really the problem here?

If anyone is interested I can put the clip up on dropbox (it's probably a copyright infringement but in the interests of truth I'm prepared to take the hit).

Cheers,

Chris

 

[iampoor1]

Audio is filled with people misattributing the reasons for sonic differences that are clearly audible.

It doesn't help that a layperson's understanding of electronics is simple enough to not understand the mechanism involved, or how they have been duped into some silly marketing terms that "explain" why gear sounds different.

 

[Andy Peters]

I recently had a chance to watch this instructional video: https://www.groove3.com/tutorials/Microphone-Preamps-Explained.

Now, I'm no electronics expert, but from my (limited) understanding, there's some information in this series that's just plain wrong. In Part 5 ("You Get What You Pay For") the narrator compares 3 mic pres - a MOTU UltraLite, a GA 73 and a Chandler Germanium. He says that because the first two pres are "non-discrete" and so they have more noise, increased distortion, lower headroom, and less gain. In contrast, the Chandler is "discrete because it's built from individual components as opposed to a printed circuit board" (!) (as a Neve clone isn't the GA discrete?). It has a faster slew rate and therefore a better transient response...etc.

It's not like we can't buy an op-amp for a couple of dollars that has a slew rate that will beat a discrete design. It's not like we can't buy for a couple of dollars an op-amp that has bandwidth which will put a discrete design to shame.

Anyway, there seems to be a lot of misinformation here - I think op-amps are being confused with the use of PCBs, etc.

It's because the author of that article has an axe to grind and he doesn't know what he's talking about.

Are IC op-amps really the problem here?

No, and for starters, an op-amp is a general building block and a mic preamplifier is a specific design with specific goals.

 

[PRR]

> ...some information in this series that's just plain wrong. ...., there seems to be a lot of misinformation here -

On the INTERNET?? Wrong? I'm shocked, so shocked.

 

[ruffrecords]

> ...some information in this series that's just plain wrong. ...., there seems to be a lot of misinformation here -

On the INTERNET?? Wrong? I'm shocked, so shocked.

What really annoys me is this is a paid for service that appears to denigrate the wealth of free information available on the net. It has the gall to state:

"Looking for pro-quality studio video tutorials done right? Tired of looking through endless free videos and ads only to wonder if you’re getting correct information? "

Cheers

Ian

 

[JohnRoberts]

Hi Folks,

I recently had a chance to watch this instructional video: https://www.groove3.com/tutorials/Microphone-Preamps-Explained.

Now, I'm no electronics expert, but from my (limited) understanding, there's some information in this series that's just plain wrong. In Part 5 ("You Get What You Pay For") the narrator compares 3 mic pres - a MOTU UltraLite, a GA 73 and a Chandler Germanium. He says that because the first two pres are "non-discrete" and so they have more noise, increased distortion, lower headroom, and less gain. In contrast, the Chandler is "discrete because it's built from individual components as opposed to a printed circuit board" (!) (as a Neve clone isn't the GA discrete?). It has a faster slew rate and therefore a better transient response...etc.

Anyway, there seems to be a lot of misinformation here - I think op-amps are being confused with the use of PCBs, etc. Over at <https://nwavguy.blogspot.com.au/2011/08/op-amps-myths-facts.html> the author states that "For audio use the op amp’s main competition is a fully discrete amplifier made out of transistors, resistors, etc. Which is better? It turns out, for nearly all applications for which IC op amps are suitable, they easily outperform discrete designs in the following areas..."

Are IC op-amps really the problem here?

If anyone is interested I can put the clip up on dropbox (it's probably a copyright infringement but in the interests of truth I'm prepared to take the hit).

Cheers,

Chris

Repeating information even to debunk it can still have the unintended consequence of spreading it. I have been trying to debunk stuff since my old 1980 "audio mythology" magazine column and the old myths are still around.  :

Audio technology is pretty mature, even digital is several decades old, so not a lot of new ground to cover.  It is safe to assume when people say they hear a night and day difference in something that you should put one hand on your wallet and back away slowly to leave the area.  8)

JR

 

[pucho812]

We have  a test we did some time ago on a circuit that due to a 1:1 balancing output X-former, we were able to swap the single opamp gain stage with discrete opamps,  and then IC's We recorded a  short clip of guitar in the daw and the did reamping so that the source was the same. From there we recorded 4 X different versions with IC's and discrete opamps. I dare anyone to spot the discrete in there vs the IC's

 

[JohnRoberts]

I like null testing to prove lack of difference, but it will reveal phase shift and other minor errors. With  digital you need to tweak fine time delay issues too. 

Old cheap CD players used to have a small time difference between L and R. 

JR

 

[user 37518]

With the risk of being flamed, I always thought you really cant do much better than a NE5534/NE5532 considering its price, although nowadays I mostly use the nearly extinct LME49720. Yes there are faster opamps with less noise, but can you actually hear a night or day difference? are +-120V DC supplies really necessary? or even +-24V for that matter?, the amount of API discrete opamps I've seen die is simply staggering, even more often than vacum tubes, most of the time I've seen clients replacing them with 990s just to get things going. So, considering today's integrated opamp technology, remind me, why do we need discrete opamps ?

 

[pucho812]

Discrete is just another way to skin the cat.

 

[living sounds]

Not entirely sure about preamps, but in a console or in mixing outboard I also think properly implimented NE5532/NE5534 with adequate decoupling are very hard to beat.

 

[mjrippe]

I have mentioned this elsewhere, but it bears repeating.  We have a Neve 5316 board here loaded with 33114 input modules.  These modules can be fitted with 438 & 440 discrete transistor amps OR 638 & 640 IC based amps (TDA 1034 = 5534 type ICs) OR any mix of the two types.  None of the engineers know which modules have which amps and none of them care because they all sound great. 

In fact, here is a quote from Dan Alexander's web site (https://danalexanderaudio.com/2017/09/05/funny-stories/)

"I sold a pair of Neve 33115 modules to a very good engineer friend of mine. Seriously, he’s an excellent engineer….so a year and a half later, he calls me up and says a tech has opened his modules to fix something, and has discovered that one module was all IC amps (600 series IC amps instead of 400 series discrete amps). I had no idea, and I exchanged amp boards for him, but he used them as a pair, for 18 months without noticing any difference! As a result, I did a comparison myself and the difference is slight; very subtly noticeable in the low end.

The most influential elements of the Neve designs seem to be the transformers and the simplicity of the circuits themselves, not the particular amplifiers."

 

[JohnRoberts]

Discrete is just another way to skin the cat.

Actually the older more expensive way to skin the cat, that gives merchandisers a hook to talk about.

JR

 

[user 37518]

Discrete is just another way to skin the cat.

Don't get me wrong, I would love to design a DOA and play around with transistors and such, but it would be more of a hobby rather than a necessity. I know an NE5534 is not as sexy as an API 2520, but it works.

 

[madswitcher]

Don't get me wrong, I would love to design a DOA and play around with transistors and such, but it would be more of a hobby rather than a necessity. I know an NE5534 is not as sexy as an API 2520, but it works.

Hi user 37518,

Last time I looked, the 5534 data sheet didn't have a 'sexy' specification, or for that matter the API version of the 2520.  How could we describe such amplifier functionality.   

Insert snake-oil comment here - keep it clean to keep the mods happy

Regards

Mike

 

[Seeker]

We have  a test we did some time ago on a circuit that due to a 1:1 balancing output X-former, we were able to swap the single opamp gain stage with discrete opamps,  and then IC's We recorded a  short clip of guitar in the daw and the did reamping so that the source was the same. From there we recorded 4 X different versions with IC's and discrete opamps. I dare anyone to spot the discrete in there vs the IC's

Pucho, would you be able/willing to upload these files?  I enjoy listening to these kind of tests, esp when I don't have to do the work to set it up. 

 

[Matador]

Maybe there are arguments to be made for discrete when dealing with driving very low impedances, or when you need a circuit that can swing very large voltages.  But a) these don't come up so frequently, and b) there's often IC's to accomplish these tasks anyways.  8)

In my last batch of listening tests on an API-512 type circuit configuration, I preferred the cheap IC op-amps in almost all cases.

 

[pucho812]

Actually the older more expensive way to skin the cat, that gives merchandisers a hook to talk about.

JR

well they got that going for them

 

[Spino]

We have  a test we did some time ago on a circuit that due to a 1:1 balancing output X-former, we were able to swap the single opamp gain stage with discrete opamps,  and then IC's We recorded a  short clip of guitar in the daw and the did reamping so that the source was the same. From there we recorded 4 X different versions with IC's and discrete opamps. I dare anyone to spot the discrete in there vs the IC's

here's another request for null test for the sake of curiosity.

 

[Spino]

but is it correct to say that those capi preamps cannot be used with a 5534 in it because it cannot drive the output trafo and such?