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Discrete Op-Amp shootout.
Old 23rd June 2012
  #1
Gear Head
 
twitme's Avatar
 

Discrete Op-Amp shootout.

Here's a discrete op-amp comparison.

gar1731
gar2520
Scott Lieber 2520 Red Dot
SGA SOA 1

Uncompressed wavs found here:
Carrier_Flux-Op_Amp_Shootout-wav.zip

All the guitars and basses were re-amped in an effort to get the most accurate and revealing comparison possible. I also wanted to test how tracks stacked using different op-amps and preamps, so for each op-amp there are 5 tracks of guitar and 1 track of bass using only that op-amp, in the context of a full-mix. Basically everything other than the drums are going through each preamp/op-amp to really accentuate the differences. For the op-amp comparison everything is running into a Classic API vp26 with the settings identical for each take/op-amp (gain at 3, attenuation at -4). Some processing was done in the DAW before the final mix, but that processing is identical between the different units. Again the purpose of this test was to compare how they would sound with context.

I also made sure each op-amp was powered on for at least 30 minutes before recording with it, to insure 'burn-in' time in case that's not a bunch of voodoo.

I threw in comparisons for the FMR RNP and Groove Tubes Brick since I had those on hand at the same time and I was super curious how different they sound.

Each guitar is going through an SM57 for one take, and a MD421MKII for another take, in each L/R channel; then one take through the SM57 in the center. The bass is running through an SM7B panned center.
Attached Files

vp26-gar1731.mp3 (2.16 MB, 4900 views)

vp26-gar2520.mp3 (2.16 MB, 4796 views)

vp26-SL_Red_Dot.mp3 (2.16 MB, 4762 views)

vp26-SGA_SOA_1.mp3 (2.16 MB, 4166 views)

Brick.mp3 (2.16 MB, 4019 views)

FMR_RNP.mp3 (2.16 MB, 4023 views)

Old 23rd June 2012
  #2
I think the SL red dot sounds the most clear. gar 2520 is a second
Old 23rd June 2012
  #3
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superwack's Avatar
Quote:
Originally Posted by soundsundergroun View Post
I think the SL red dot sounds the most clear. gar 2520 is a second
Agree but that's why I chose the GAR2520! I tried to phase the SL2520 and GAR2520 with some Huntingtons I have... The GARs, while not 100%, were hair-splittingly close.
Old 23rd June 2012
  #4
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adam_f's Avatar
Quote:
Originally Posted by Jim Williams View Post
I have an old FAX audio DOA, the FA100 from New York City. Anyone ever hear of those?
Jim, do tell!
Old 24th June 2012
  #5
Gear Nut
 

Great shootout

Thanks for doing this shootout, I've been experimenting myself with the gars and red dots. Good stuff.
Old 24th June 2012
  #6
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Frost's Avatar
 

Opamp sound is strongly dependent on the rest of the circuit built around it. There are some I tend to like in many circuits but some that I've grown to dislike until I found them in circuits I like the sound of. Look in an ssl. Lots of less than high end parts, but they sound pretty darn good.

I do tend to try a 6172 in lots of circuits I'm trying to improve.
Old 24th June 2012
  #7
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hasbeen's Avatar
Quote:
Originally Posted by Jim Williams View Post
I know nothing about it, I got it 20 odd years ago from a tech's junk box. I will mount it into a 500 preamp I made and scope it out on the Audio Precision analyzer. Here's a pic of it on my fav mousepad!
Nevermind the OpAmp, where do I get that mouse pad with MY name?
Old 24th June 2012
  #8
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adam_f's Avatar
Quote:
Originally Posted by Jim Williams View Post
I know nothing about it, I got it 20 odd years ago from a tech's junk box. I will mount it into a 500 preamp I made and scope it out on the Audio Precision analyzer. Here's a pic of it on my fav mousepad!
If I was still in Encinitas I swim across the lagoon and snake that mouse pad from you! Lol. Oh well at least another year before I'm back.
Old 26th June 2012
  #9
Gear Head
 
twitme's Avatar
 

After assimilating others' feedback and listening to the clips a number of times I've decided that my favorites are the SGA SOA 1 and the Gar2520. The SGA SOA seems to be a tad bit darker than the gar2520 or Red Dot, but also feels very present. The gar2520 has a well balanced sound to it. A little less presence than the Red Dot, but also a bit warmer to my ears.

I think the SL Red Dot definitely has the greatest clarity, but with this material there's something about the character that I find very slightly grating and fatiguing. I bet I would love that op-amp on acoustic guitar or something else with a little less blanketing of the upper mids than this heavily distorted guitar.

Initially I really loved the gar1731 because it was darker, and I'm looking for a slightly less-bright sound, but after repeat listens to felt more muddy and awkward sounding than the other op-amps. Somehow the stereo image doesn't seem to sit right with the gar1731.
Old 26th June 2012
  #10
Gear Nut
 

Acoustic Guitar

At first I looooved the red dots in my missing links on acoustic guitar so bright, clear and present. But found myself using eq and tape plugs to round off the top to make it warmer more 'analog'. Then I stuck in 2 gar 1731s, nice, warm and thick, take out a touch of low mids to balance it out, man gives me that old school analog feel acoustic guitar. For that type of old school sound was perfect. I would've never guessed I would've like the gar1731s for acoustic guitar. Defintley on bass too!
Old 2nd July 2012
  #11
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dysenterygary's Avatar
 

The gar2520 is the clear winner to me. I'll listen again later and see if I change my mind.
Old 4th July 2012
  #12
Gear Nut
 

Gar2520

Yes, on 2nd listen Gar2520 is the best to me...again at first the clarity and presence of red dot wowed me - but the gar2520 has some warm round tone with some presence. The tone stands apart from the others when the higher notes start playing around 17 secs.
Old 26th May 2013
  #13
anyone have any opamp shootouts on kick or snare? That's what I'm most interested in - especially with the newer CAPI VP28 preamp.
Old 27th May 2013
  #14
Lives for gear
 

Why not include the JE990C? It's a better design than the 2520 (probably won't burn out if you look crosseyed at it, either).
Old 27th May 2013
  #15
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jsteiger's Avatar
Quote:
Originally Posted by tpad View Post
Why not include the JE990C? It's a better design than the 2520 (probably won't burn out if you look crosseyed at it, either).
The 990 is not a good choice for an API style preamp circuit. The input transformer ratio is too high. JH will tell you the same thing.
Old 27th May 2013
  #16
Gear Guru
 
Karloff70's Avatar
 

Quote:
Originally Posted by jsteiger View Post
The 990 is not a good choice for an API style preamp circuit. The input transformer ratio is too high. JH will tell you the same thing.
Any idea if JLM Audio's 99V opamp would run well in your pres, Jeff?
Old 27th May 2013
  #17
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Quote:
The input transformer ratio is too high
What on earth are you talking about? [deleted by mod]

The JE990C is an opamp module. There is no transformer associated with it. The JE990 employs an LM394 input transistor diff pair which exhibits low input current noise and works just fine with a transformer on the input. JH actually shows a mic preamp circuit using a Jensen JT-15 in the data sheet. So don't stand there and claim that JH will tell you not to use a transformer - that's total BS.
Old 27th May 2013
  #18
Gear Guru
 
Karloff70's Avatar
 

Quote:
Originally Posted by tpad View Post
What on earth are you talking about? Or maybe what I should ask do you know what you're talking about?

The JE990C is an opamp module. There is no transformer associated with it. The JE990 employs an LM394 input transistor diff pair which exhibits low input current noise and works just fine with a transformer on the input. JH actually shows a mic preamp circuit using a Jensen JT-15 in the data sheet. So don't stand there and claim that JH will tell you not to use a transformer - that's total BS.
Maybe he meant the transformer ratio in an API pre is unsuitable to match with the 990? In any case I wouldn't be so fast laying into Jeff. Do you really think he doesn't know the 990 is an opamp??
Old 27th May 2013
  #19
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jsteiger's Avatar
Quote:
Originally Posted by tpad View Post
What on earth are you talking about? Or maybe what I should ask do you know what you're talking about?

The JE990C is an opamp module. There is no transformer associated with it. The JE990 employs an LM394 input transistor diff pair which exhibits low input current noise and works just fine with a transformer on the input. JH actually shows a mic preamp circuit using a Jensen JT-15 in the data sheet. So don't stand there and claim that JH will tell you not to use a transformer - that's total BS.
Chill dude, you miss understood my statement. If you read it again maybe you will see what I meant. I did specify that the 990C is typically not a good candidate for the opamp in an API style preamp. Email JH and ask him or use the search function and you will find some info maybe even a quote from him. The API preamps use anywhere from a 1:7 to a 1:10 input transformer. John recommends a 1:2 transformer for a preamp utilizing a 990.

Stick a 990 in a 512C and tell me I am wrong.
Old 27th May 2013
  #20
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jsteiger's Avatar
Quote:
Originally Posted by Karloff70 View Post
Any idea if JLM Audio's 99V opamp would run well in your pres, Jeff?
I am not really sure. Maybe there is some info on Joe's site about them?
Old 27th May 2013
  #21
Lives for gear
 

Quote:
Maybe he meant the transformer ratio in an API pre is unsuitable to match with the 990?
You know the old saying: "say what you mean and mean what you say", neither of which appears to have been the case with what he posted.

[deleted by mod] The 2520 really isn't that great a design, no matter how much you may be in love with it.

Neither is the optimum choice for the lowest noise transformer coupled mic preamp, since you can achieve better SNR with a JFET input stage.

Last edited by [email protected]; 28th May 2013 at 08:32 AM.. Reason: pointlessly aggressive
Old 27th May 2013
  #22
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jsteiger's Avatar
Quote:
Originally Posted by tpad View Post
You know the old saying: "say what you mean and mean what you say", neither of which appears to have been the case with what he posted.

Personally, I was under the impression that he was posting misinformation to dissuade anyone from considering using the superior JE990 design (you did ask for my opinion). The 2520 really isn't that great a design, no matter how much you may be in love with it.

Neither is the optimum choice for the lowest noise transformer coupled mic preamp, since you can achieve better SNR with a JFET input stage.
Read my initial post again, this time slower. I said exactly what I meant the first time.
Old 28th May 2013
  #23
Gear Guru
 
RoundBadge's Avatar
Quote:
Originally Posted by tpad View Post
You know the old saying: "say what you mean and mean what you say", neither of which appears to have been the case with what he posted.

Personally, I was under the impression that he was posting misinformation to dissuade anyone from considering using the superior JE990 design (you did ask for my opinion). The 2520 really isn't that great a design, no matter how much you may be in love with it.

Neither is the optimum choice for the lowest noise transformer coupled mic preamp, since you can achieve better SNR with a JFET input stage.
maybe there's a translation/language issue or dude you obviously don't read very well:
"API style preamp circuit"

love how the anonymous guy above is trying to school the real guy who makes some of coolest preamps on the planet..LOL.
Old 28th May 2013
  #24
Lives for gear
 

Here's what you said:

Quote:
The 990 is not a good choice for an API style preamp circuit. The input transformer ratio is too high.
This what the OP said:

Quote:
I also wanted to test how tracks stacked using different op-amps and preamps, so for each op-amp there are 5 tracks of guitar and 1 track of bass using only that op-amp, in the context of a full-mix.
OP said he wanted to compare opamps.

OP didn't say anything about using them in a transformer couple mic preamp. How you would have 5 tracks of guitar and 1 track of bass going into your transformer coupled mic preamp is beyond me.

OP also didn't say he wanted to use opamps in an "API style" preamp.

JH didn't recommend avoiding transformers with the 990C.
Old 28th May 2013
  #25
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jsteiger's Avatar
Quote:
Originally Posted by tpad View Post
who is the anonymous guy?

I'm not trying to school the guy, just call his bluff. He got caught posting disingenuous information and my replies are the resultant, whether you or anyone else likes it or not!
Haha, this keeps getting funnier. You are a trip!

Thanks Roundbadge. It's time for us to move on.
Old 28th May 2013
  #26
Gear Guru
 
drBill's Avatar
Quote:
Originally Posted by tpad View Post
I'm not trying to school the guy, just call his bluff. He got caught posting disingenuous information and my replies are the resultant, whether you or anyone else likes it or not!


This is too funny. Jeff, you really should do some research or learn about mic pre's, transformers and opamps before posting on the open internet... <j/k of course>
Old 28th May 2013
  #27
Gear Guru
 
drBill's Avatar
Quote:
Originally Posted by tpad View Post
Actually, I thought it was getting more sad. You can't speak for yourself and need to have your buddies come to your "defense"? That's not very funny in my book.
Do you have any clue who you are talking to? Just curious.
Old 28th May 2013
  #28
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sdelsolray's Avatar
 

Try those op amps (among others) in an ADK AP2 preamp, which has swappable input transformers. Even though its basically an API 312 design, the Hardy 990C works great with several of the transformer cards ADK (actually, Jon Ericson) designed.
Old 28th May 2013
  #29
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jsteiger's Avatar
OMG, tpad are you wasted or something? Seriously, read thru this thread tomorrow when you have a clear head.

Here are my bullet points.

I said
Quote:
The 990 is not a good choice for an API style preamp circuit. The input transformer ratio is too high. JH will tell you the same thing.
I said preamp because the OP mentioned the VP26 preamp. That is a little familiar since the VP26 is one of my products!! The input transformer in the VP26 is a EA2622, 1:7 ratio transformer. This is a high ratio for the 990C in a preamp. JH uses a Jensen JT-16-B in the M1. That is a 1:2 ratio transformer. Google "M1 Schematic" and verify the part #. Then Google "Jensen JT-16-B" and check out the data sheet. You will see 1:2 at the top. If you feel this is not a good match for the 990C in a preamp, maybe you should tell JH about it? I personally think he knows exactly what he is doing. That is why he uses a 1:2 input transformer with a 990C.

There. Now read that slow a half dozen times. That is everything I said before only in one place for you.

Peace out, Jeff
Old 28th May 2013
  #30
Lives for gear
Quote:
Originally Posted by tpad View Post
What on earth are you talking about? Or maybe what I should ask do you know what you're talking about?

The JE990C is an opamp module. There is no transformer associated with it. The JE990 employs an LM394 input transistor diff pair which exhibits low input current noise and works just fine with a transformer on the input. JH actually shows a mic preamp circuit using a Jensen JT-15 in the data sheet. So don't stand there and claim that JH will tell you not to use a transformer - that's total BS.
Dude...just stop. You're embarrassing yourself.
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