API Opamp test

[Matt Allison]

On my laptop I heard the SL with more upper, upper mids; more percussive on the 'd' in 'dear' and 'cha' in watcha. For smoother vox, I'd stick w the original myself, YMMV.

[sliebers]

Originally Posted by abechap024

I wouldn't be surprised it the input transistor pair/other components in the SL's aren't matched as closely as the API leading to more of the 2nd harmonic distortion that makes the SLs sound "louder" and more juicey.

Not trying to say this was an accident. Just saying it is probably done intentionally.

I prefer the SLs. But would I want that juicy color on everything?? Yea probably!

It's not the input differential pair. Those are matched to less than 3mv DC offset at idle on every opamp (pretty much the same as a stock 2520) You are correct though, there is intentional distortion (mostly 2nd order) with red dots. They were made to sound like the vintage Huntington and Melville 2520's made in the 70's. Those opamps exhibit the same distortion characteristics. Transistors in the 70's were slower than what is available today. I had to put the brakes on in certain areas of the circuit to match the distortion curves of the old ones. A spectrum analyzer will reveal modern API2520's having less distortion than the older ones. Not that less distortion is a bad thing, but some folks prefer to have some mojo or hair on their sound. The GAR2520 is another fine opamp that has that vintage sound. In Andrew's case with a 3124, he now has two different flavors to choose from within the same box.

[cheu78]

Originally Posted by API Sez...

Don't know where you are getting your information - we haven't seen you in the production/assembly area at API. How do you know API is using cheaper alternatives?

We spend a tremendous amount of time and energy keeping the heritage and tradition of this company as current and accurate as possible. And that includes transformers.

We'll raise your 0.02$

let me first state that I like what api does.. the 2500 is a great and very versatile product, also the preamps, or the eq's...My opinion is that I would like to see better xformers in your products (in the specific the 512). You have a big reputable name in the industry.
In all honesty if I didn't like api, I wouldn't have bothered in trying to have a better performance from it, I'd have just not bought it, and therefore I'd not be one of your customers.

I don't know if I got a lemon or not..I don't think so though..
Btw you don't even need to open up the "hood" on a 512..it's already opened!
When I changed the xformer the difference was apparent to me and to the oscilloscope..

Aren't you also offering a xformer option for the 1608 as well?
So why bashing somebody who want to upgrade a 512..?
You should do a special edition with better xformers on the 512, I'll be very happy to pay 90$ more for that difference, maybe everybody though..
After all it's only a matter of price..

as always my 0.02$,


Btw this thread was about an Opamp test.. so back to the thread..

Bests,

Cheu

[Jonathawkes]

There's really not much of a difference. I wouldn't go through the trouble of swapping out the Op amps of an already perfectly good mic pre.
"Night and day" "Upper-mid clarity" "better bass response" These vague descriptions always seem pop up whenever there's a vague difference. Hehe
I dunno, am I out of line here?

[ScumBum]

I could hear the red dots difference at first listen . Thing is I use that DOA in alot of my gear so I'm familiar with the sound . Its like all gear , when you use it alot , you get to know it better and can hear what it does . It made the sound more round , less hard , harsh . It is subtle , but once you hear it , it stands out . Like a stain on a white shirt , once you notice it , it has your attention .