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Hi all,

I was rummaging around in my cellar and I found a couple of GML 8802 discrete op amps. Apparently this stuff grows down there. Anybody know if these are good for audio? I don't know anything about them.

gml_8802_opamp.jpg
GLM 8802 opamp

Thanks,

Seth

Comments

anonymous Mon, 02/23/2004 - 22:22

yeah--

RC they are the discrete opamp found in the majority of Ls stuff...

they sound great! should be 2520/990 footprint... michael jackson's "thriller" was recorded with gml mic pres-- specifically chosen because of the high speed of this opamp. bruce swedien chose them because "they maintain the original transients" (to paraphrase).

so here's a rundown of some of the 2520/990 opamps;

api 2520, hardy 990, jlm--------bipolar transistor
forssell 992, milinea mm-99-----jfet
gml, jonathan little (rare!)------high speed bipolar transistor

be careful with these fast ones-- can oscillate easily and sound like hell when they do. can also torch a power supply if left oscillating for too long...

if you want to reproduce the L mic pres, i believe it's a simple API-ish circuit with this opamp and beyer dynamic transformers-- the later version was transformerless...

by the way, thank you ! just got the AD's today ! what can i send you in exchange ??

anonymous Tue, 02/24/2004 - 10:39

Hmmm I really dont know..I mean George Massenburg may have had different layouts for the GML opamps during the more or less 25 years his been making them, but for the GML 83xx preamps..Let me tell you..they are nowhere near the API/John Hardy..etc opamps !!! I think that George once did mention that his opamps were "based" on the API etc.. topologi..(please correct me if wrong)

The GML pres are all discrete build opamps..both the acturel Gain circuit, and the output driver circuit (which include both conventional transistors and SMD´s)..these are mounted on a real big "main pcb"..there only just about room for 4 of them in a GML 8304 1 unit 19" preamp..with the external GML 8355 +/- 28V powersupply..

I´d like to see those opamps as well...could be fun to see if any changes were made over the years..

Kind regards

Peter

anonymous Wed, 02/25/2004 - 07:42

yeah, seriously brad, it would be awesome to have any more info on the hs-1000. i'm gonna be having a go at fabio's sontec layout soon, and if we could shoehorn an hs-1000 variant in there it would be fantastic. not to mention that it is basically impossible to even get a replacement opamp from sontec if you actually own their products!

ed

anonymous Wed, 02/25/2004 - 08:26

Originally posted by ssltech:
Just send the Sontec down here and I'l take and post all the pictures for you. -Oh, and don't worry yourself even slightly about anything happening like me 'forgetting' to return it to you or anything like that...

hehe, yeah, I'll get right on that...

You know, you guys think API opamps go for a bundle on evilbay, just imagine what this would go for. Somewhere there's a dude with a useless $12k Sontec EQ that would kill his mother for one of these...

anonymous Wed, 02/25/2004 - 08:34

Originally posted by Brad Blackwood:
[. Somewhere there's a dude with a useless $12k Sontec EQ that would kill his mother for one of these... [/QB]

ohhh Brad,

I bet-cha`....even more now when nobody seems to manage to get a hold of Mr. Sontec Burgess himself..over the years I´ve heard about plety of good folks looking for this "old" sontec opamp..

Kind regards

Peter

PRR Wed, 02/25/2004 - 09:46

Image-enhanced. Maybe too much-

(Dead Link Removed)

> as good as it gets from the camera built into my PDA...

Got a scanner? Thin stuff like this often scans amazingly well. Lay the board interesting-side-down, careful not to scratch the glass/plastic, try 300dpi then re-size down to 500-600 pixels wide for posting. Check your contrast: my scanner and your PDA-cam tend to read pure-white as light grey, deep-black as dark grey; it really helps to blow the contrast out to the edges. (If you have Histogram Adjustment, great.)

anonymous Wed, 02/25/2004 - 11:32

Originally posted by Bear's Gone Fission:
Can't really make out whether the outer two points on Brad's are connected. If it is seven pins in use, that's the same count as a 2520 . . . I wonder how the connections would correspond. Interesting prospect here.

It's a 2 sided board. The only pin that's not connected is pin #4 (from left)...

anonymous Mon, 03/01/2004 - 13:29

I'm gonna have to - even the Nikon can't get good pics of it in detail...

The only problem is that apparantly part matching is absolutely crucial on the HS1000 - it's why no one has ever made a copy of it. You have to have many of the parts with a very close (unknown) tolerances or it won't work right, or so I have been told from soe authorities.

anonymous Mon, 03/01/2004 - 14:23

Brad,

You're using the camera in 'macro' mode, -right? (the button with the picture of the little flower by it) and if you (counter-instinctively) hold the camera a little further away and use the optical zoom instead of staying zoomed 'out' and trying to make it focus on something an inch or two away, then you should get nice crisp piccies!

(apologies if you know this already -as you mey very well do!- but these were the revelations which finally made my close-up component pics useable!)

Keith

anonymous Mon, 03/01/2004 - 14:47

The big issue with Canons is the dreaded E18. Error 18 is to do with the lens being unable to retract, and if the governing processor ever senses this it shuts down the camera more or less for good. There is a web page with instructions for how to fix this [[url=http://[/URL]="http://www.ixus-wor…"]here[/]="http://www.ixus-wor…"]here[/], but it's in German...

The best prevention is to buy a case for the camera and USE IT!!! -Grit sand and dust are the suspects for making the lens mechanism fail. I keep mine in it all the time now, when not in use!

I do everything at maximum native resolution then do the image shrinking in Photoshop.

Keith