Where could I find the 2520 op amps??? I am thinking of purchasing the ADK AP-2... I just want to be sure That I can get plenty of Op Amps. I really like the way the 2520 sounded in the Listening Sessions, especially with the Lundahl... Big difference over stock op amp...

Good luck! API will not sell you them without a trade in of an old one. On ebay they come up fairly regular, but seem to now be hitting the $90 each mark. Ouch!

There are quite a few OPAMPs that were manufactured using that configuration. New ones are the Millenia 990, Hardy 990 and variants. Those are about $50 each. I just came accross a pair of Analog Devices opamps that are like 2520 on Steriods. Just huge. Think API meets NEVE.

Or you can do like I do, and roll your own. The 2520 opamp is discrete. It is not an IC. So that means you could theroretically take the cover off of it, and see each transitor, resistor and caps. A group I hang out with, backwards engineered the original 2520 and made some PCB's for our own enjoyment.

These are not mine, but I used the same boards.


That is what is under the hood of a 2520. The 990 are very simular, but cleaner sounding. Most others, are IC chips, placed under a cover to look like a 2520.

JD

This is what is under the hood of a Melcor 1731. Which is what the 2520 was designed from. Melcor engineers designed the 1731, and left to open API. They used a sligtly modified version, and called it 2520.



Melcor 1731 is very smooth and open
API 2520 is agressive and punchy
990 are very clean and uncolored

Hope this helps

JD

I see this topic was reposted in the studio tech/design area....

Did I get to technical for the Recording section again? Sorry!

JD

I just hooked up with some 20 sumthin wizz kid that has this pretty cool studio above his dad's shop. Very modest setup but very very nice, tuned and treated rooms - he's a drummer.

Anyways, he showed me a 2 ch API 312 clone he made. I asked him about the opamps and he said he got the parts list and made his own. I heard some drum eg's and they sounded great...So, peeps are making their own 2520's it appears.

Kid also modded some Marshall 603's that "he'll put up against any SDC for OH's". Did his own mods on his 460, similar to the AA mods I posted awhile back and modded his YSMp's for $350 CDN. I forget the speakers he replaced, but the tweeters were the same as the ones in one of the Dynaudio apparently. Having YSM's myself and being very familiar with them, the upgrade was huge....I want...anyways, I'm rambling. Just wish I had the tech skillz and patience to do that kind of stuff.

MJM, this is were things get "sporty". You can't buy 2520 opamps from API. The newer 2520's we have are in a 3124. And the older, handmade "vintage' 2520's we have came out of an API console that we chopped up and sold off the individual channels. And the older 2520's we have aren't for sale.

If you're looking for real 2520's I'd suggest looking on Ebay, and/or getting into circles of API owners who might have - or might know of someone - who's selling API 2520's.

A place to start might be calling up http://www.brentaverill.com/ and talking with Avedis. He might be able to throw you a bone.

My Melcor 1731 PCB designs pops up in the strangest of places.....

The above descriptions of the various opamps are pretty much on the money, a nice variety of tones.

MJM, if you want to try some of the 1731's, I still have some left. Send me an email peterc(at)onwe.co.za

Regards
Peter

Hey Peter. I am guessing you are Peter C from prodigy? Very cool to see you here. I did not put two and two together. (I am jre productions from prodigy).

I would not mind getting hooked up with some melcor boards. The ones I have from Gustav do not have any supporting documentation. I am trying to backwards figure them out with your schematic.

Look me up if you have some 1731 or other opamps available!

Joe

Hi Joe

Are you after boards or finished opamps?

Send me an email, I can give better details there....

Peter

Email sent...

quote:

Dot said "If you're looking for real 2520's I'd suggest looking on Ebay.

Ah Man! You just couldn't wait until after I won the opamps to do that. Now could ya?

Seventh Circle Audio makes and sells their own version of the 2520s. Based on some hearing tests done by Michael Wagener and others, they're very close to the API.

ADK is making an the Vint-Op-M (US Sound similar to early API and Vint-Op-N (British Sound - similar to early Neve).

I have the Vint-Op-M here and will be taking it for a spin this weekend (along with the Jensen and Lundahl transformers).

I'm hoping to get the Vint-Op-N at some point and will be getting a John Hardy 990c (which should pair nicely with the Jensen).

In any case, ADK will have at least three opamps (and their original opamp sounds good to me) and three good transformer options (Jensen, Lundahl, Cinemag). Mix them all up and you have a good amount of options, I think.

Hey guys, I certainly appreciate the info... I have not purchased the ADK... I just found the concept interesting... I wish that I was more knowledgeable on the technical aspects of designing and building my own equipment... Do you guys think the ADK could be considered as a highend Pre? I want 2 channels with 4 extra Transformers. That's going to cost $1500... I could buy a nice 2 or 4 channel for that price or just a little more. I already own a UA6176... Do you guys think my money would be better spent on a Highend Pre that would contrast my 6176 or would the ADK provide me with the versatility and quality to be worth the investment???

If you want my opinion, I would spend the money differently. I would consider buying a few different preamps beforr I would buy adk.
1) 4 channel Focusrite ISA430 ($1500)
2) 2 channel Pacifica ($1600 ish)
3) 2 API cards and rack ($1500 ish)

I think that would be a better compliment to what you have. I think the ADk is fine, and for the most part "can" be comprable to API, but for my money, I'd rather own the API. And if you get the 4 space rack, you can add another channel for $500 ish. Also OSA, Pacifica, John Hardy and Purple all have cards that fit into that box as well. Kind of a grow as you need it basis.

Yeah its true you can convert the Adk, but you can an API too. With good soldering skill, you can place a socket on the api card that will alow you to swap opamps just like the ADK.

Just my 2 cents.

JD

Not to be a jerk, but has anyone seen schematics for the ADK opamp? Is it descrete? I am 99% sure the OSA opamp is IC based under the cover. I have not heard about what ADK uses, but I have not heard the words descrete either. To me there is a big difference in sound.

JD

I really like API!!! I didn't know about all of the other quality brands that could be combined with API... I was kind of skeptical about the ADK...It seems that when something is designed to do everything, it compromises the quality of the product in some way... Thanks for the input...

quote:

Vint-Op-N (British Sound - similar to early Neve).

I say this without having heard the ADK unit, but here are some experiences on Neve sounds.

One thing I have found when doing Neve style preamps is that the input transformer is critical for "that" sound. I have built Neve clones with Lundahl, Neutrik, St Ives, Marinair & one other brand (I forget), all with the correct output transformer, & the only ones that sounded like the real thing were the St Ives & Marinair transformers. Magical stuff.

Peter

Agreed Peter. The Neve preamp is just a different breed. I would find it hard to believe that by changing the opamp in the ADK you could realistically make it sound like a NEVE. Vintage yes...NEVE no.

That is not to say different OPAMPS don't sound different. They do sound different. But they all the 2520 opamps also have simular qualities too. Like nice tight sound fields, solid botton ect. I think that is the nature of the design.

quote:

New ones are the Millenia 990, Hardy 990 and variants.

The Millennia op-amp is now known as the MM99, a name change that took place a few years ago (although the photograph on their site still shows the "MM-990" model number). It is a completely different circuit than the JE-990 that was designed by Deane Jensen of Jensen Transformers, and the name change helps to make that clear. My thanks to John LaGrou of Millennia for making the change.

The MM99 uses field-effect transistors, the JE-990 uses bipolar transistors. The latest version of the JE-990 is the 990C, which is available from the John Hardy Company in an API-2520 compatible package.

http://www.johnhardyco.com/pdf/990.pdf

Thank you.

John Hardy
The John Hardy Co.
www.johnhardyco.com