Api 2520 and MM990 how different do they sound ?

[andre tchmil]

I'm planning to make an extra 2 api 312 pre's, one with the 2520 and he other with the MM990 amps.
how different will they sound?
And cn I make the Hamptone with a mixture of 2520 and MM990 ?

 

[Bjorn Zetterlund]

The fet hamptone uses an inverting gain amplifier block, and as such isn't really one to put op-amps in. It's a bit of a different animal...

Bjorn

 

[Fletcher]

Realize that 2520's run on bi-polar 16vdc and 990's runon bi-polar 24vdc... you'll want to run different power supplies when running different op-amps. The two aren't really interchangable.

Peace

 

[soundguy]

this is not accurate at all.

the two can be completely interchangable from a single supply.

the 2520 running at +/- 16v is, according to the hardy website, completely interchangable with a 990C which is spec'd to run between +/-12V to +/-24V. There are also versions of the 990 and 990A spec'd for +/-15v or +/- 18v, either of which you could use interchangably with a 2520 if those are still available from hardy. I run all the old API amps that Ive racked up with +/- 18V and have no problems and those all have original 2520's which are spec'd up to +/-18V although I think the API lunchbox is +/- 16V.

dave

 

[tk@halmi]

Dave,

As I understand they were talking about the MM990 a JFET opamp and not the JH990C. Somewhere along the conversation the MM designation dropped off. The MM990 works best off 24V rails, and I don't think it will do well with anything less than 20V.

Tamas

 

[Fletcher]

That's great... I run my 990's at bi-polar 24... wanna bring your 2520's over with a package of hotdogs and have a weinie roast?

 

[soundguy]

blech, my mistake!

why the F does everyone call their **** 990??

too confusing...

Well, if you wanted to use the hardy 990, you could...

dave

 

[Moby]

Ok, and how different they sound?

 

[trenchfickler]

It's kinda like how everyone with an old mixer module on ebay compares it to Neve. It's the point of reference that people use because people have swapped 990's into mixers for decades. Pretty much everyone has redesignated anything that isn't a faithful 990 at this point.

Dunno how the sound compares.

tf

 

[Flatpicker]

[quote author="Moby"]Ok, and how different they sound?[/quote]Here's a link to a thread over at Studio Forums covering the subject. Dan Richard's comments about the sonic differences are down in there somewhere. Peter C's involved in this thread too.

http://studioforums.com/eve/ubb.x?a=tpc&s=1436041581&f=3756015614&m=7566015614

 

[John Hardy]

It seems that folks decided to call their op-amps "990" because it was in the same or similar package as the 990 that I make, even though the circuit was completely different. This did not make sense to me, and I said so.

"990" is a CIRCUIT, not a PACKAGE. The original circuit was, of course, designed by Deane Jensen of Jensen Transformers. The "A" and "C" versions were developed by Deane and Steve Hogan.

If we follow the "package" concept, every op-amp that is introduced in the future in an 8-pin DIP package should be known as a "741" or "5534", which makes no sense either. Anyway, thanks to all who changed their part numbers to avoid any confusion with the actual "990" product.

As mentioned earlier, the 990C can be run anywhere from +/-12VDC to +/-24VDC. The earlier "990" and "990A" are designed to run at a specific voltage, with the +/-15VDC and +/-24VDC versions being the most common. I think that the API 312 and API 325 cards usually have a diode in series with each supply, so the cards are supplied with +/-16VDC which is dropped down to +/-15.3VDC or so (the diode-drop). Thanks.

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

 

[John Hardy]

Regarding the 990 used by K-Disc, that was made by ME! Back then (early 1980s) I made my 990 op-amps in a clear epoxy package using silicone molds. K-Disc requested a black epoxy package, so I used black potting shells filled with black epoxy. The overall dimensions were the same, although the potting shells had square corners, while the silicone molds had rounded corners. K-Disc put their own label on it so it looked like it was their product.

K-Disc used my 990 op-amps for an upgrade card that replaced the stock line-output cards on some of the Studer machines that were popular then. I was told it was a major improvement over the stock cards (at least, in part, because the stock card was poorly designed).

It is possible that K-Disc had some other version of the 990 that was made in-house or by someone else, but I do know that they used mine in regular production.

Another piece of trivia: Bonneville Productions in Utah made a distribution amp product for broadcast applications that also used a black-shell version of my 990.

Sony also used the clear 990 in the PCM-1610. I think they charge a small fortune for replacements, so if anybody still uses a PCM-1610 and needs a 990, they will save a bundle by getting it directly from me.

Thank you.

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

 

[Kev]

once again,
thanks to John for keeping us in tune with the facts about this stuff

as the chef would say,
head down

 

[rafafredd]

Just curious...

Do you think the Melcor clone (with the different transistors) could run on +- 24vdc?

Should I try it?

 

[tony dB]

give it a try, what do you have to loose? :grin:

:sam: :sam:

 

[SSLtech]

erm... a Melcor clone?

:wink:

Keef

 

[tony dB]

in search of the Holy Grail, many young Melcor's die to soon...

Remove the killed parts and proceed... always fun :twisted:

:green:

tdB

 

[dukasound]

On simple questions.
I would like to test Jon Hardy 990C op-amp.
Can I use same circuit like on ARI with 2520 or
I must exchange parts like on JH circuit.
I will use 1:8 input transformer and Profile 1:2 wired.
Duka

 

[CJ]

Try the killer Jensen input that John uses-the 16b or whatever.

 

[dukasound]

[quote author="cjenrick"]Try the killer Jensen input that John uses-the 16b or whatever.[/quote]
Chris I ask can I use 990 with same circuit. Also 16B have ratio 1:2 and that cant work with api circuit.