9000 XL line amp schemo here

Hi all

my two cents:
Input 5532 pair form what Walt Jung calls balanced line receiver using
push-pull feedback. Advantage over simplest design (like GSSL input) is
balanced input impedance. Dissadvantage is high CMRR dependance on
passive component matching (like with GSSL too).

What I find as interesting part is C42 R61 combo. It reminds me of
circuit seen here:
http://www.maxim-ic.com/appnotes.cfm/appnote_number/3171

Basically, this provides AC coupling with small (read super nice poly)
caps=> no electros in signal path. This variation seems to be adaptation
of that topology to balanced reciever. So lower 5532 opamp provides
both balanced Zin and small poly AC coupling for both inputs.

First 052 seem to servo only DC offset "provided" by upper half of 5532
(that is DC caused by Vos and Ios). DC ofset caused by lower 5532 will run wild and free.

Second block is variable gain differential amp. Second 052 will servo out
any DC caused by lower 5532 in input stage and DC caused by 5534.

Using diff amp (built around 5534) for second stage will increase CMRR
(it's like dual stage CM rejection), thus reducing need for fancy ultra
matched resistor pairs in input stage.

Using linear law VR2 not only provides advantages chrissugar mentioned
but gives better resolution around 0dB gain which some (like me) may
prefer(like with cut/boost controll in a.p.i 560 graphic EQ).

VR3 should be CMRR trim. Question is why this configuration .

I have probably made mistakes in analysis so append every
sentence with IMO (and corection is most wellcome)

chiirz
urosh

Thanks recnsci for your analysis (and the link)
That helps a lot to understand things
I guess I will study CMR and servo concept to fully get it though

Thanks again

I am still tryint to get my head around the constant bandwith setting of the E button.

Click to expand...

http://www.groupdiy.com/index.php?topic=8454&highlight=constant++bandwidth

any help?

lookin foreward to some more!!

[quote author="chrissugar"]Pucho, please post some more. If I understand it right the EQ can be separated into two separate circuits, so if you decide you want to build only one of them you don't need anymore those unobtainable multigang pots.

Come on Pucho, let me help you. :green:

chrissugar[/quote]

I plan on posting some more but am trying to find a scanner that will allow me to scan large papers 11" X 17" as those sheets are not regular size but the larger size paper. The eq is not so much to seperate eq circuits but best described as this. It has a button that is E/G.

Standard EQ characteristic is based upon the SSL G Series type.
Pressing the 'E' button selects an EQ characteristic based upon the SSL E Series.

Click to expand...

What it really does is this: when switched to E the badwidth of both Mid frequencies remains constant at all gains. so at a lower gain the curves are somewhat more narrow for a given Q setting. this good cause you can get high Q at lower gain settings. When running a 9000 I usually use the E mode EQ...

I'll be away from my lab for a week when I get back will start scanning those eq's. :thumb:

started a SMD layout. about 10$ worth of parts for a pair of channels using .05% thin film(metal film) SMD resistors..

Now we need the line out schemo!

[quote author="pucho812"]
I plan on posting some more but am trying to find a scanner that will allow me to scan large papers 11" X 17" as those sheets are not regular size but the larger size paper.[/quote]

Thank you man. :thumb: :thumb: :thumb:
Looking forward for your scans.

chrissugar

Chris,
Out of town till july 9. when I am back I'll scan more documents... Less then a few days after I scaned in a 9000 line amp we already got someone who made PCB's for it and is looking for someone to check his work. I have mixed feelings about that. Anyway I'll have them when I get back to Los Angeles.

[quote author="Svart"]Now we need the line out schemo![/quote]

from another large console manufactor:
Balanced Ouput Amplifier Board

[quote author="pucho812"]

I plan on posting some more but am trying to find a scanner that will allow me to scan large papers 11" X 17" as those sheets are not regular size but the larger size paper. The eq is not so much to seperate eq circuits but best described as this. It has a button that is E/G.
[/quote]

A word of friendly advice: remember the axiom "Don't $hit where you eat". I would not want to see the generous host of our public forum threatened by a console manufacturer for being "too public".

I have all the scans of this console, use them to study how it works, and have chosen to share sparingly and privately. More like tech to tech- to learn how to fix problems with the console.

Pucho, the phrase "Shock the Monkey" also comes to mind. . . :green:

[quote author="sodderboy"]A word of friendly advice: remember the axiom "Don't $hit where you eat". I would not want to see the generous host of our public forum threatened by a console manufacturer for being "too public".
[/quote]

I agree. That is the exact reason why I adviced people to act wisely and not mention company names. That way we can learn and also stay out of trouble.

chrissugar

... and when we use $$L instead of the real acronym people bitch about it because they can't search it..

I think that's fine... let 'em bitch.

Personally, the vast majority of the discussions here that I'm drawn to are much more about learning 'how' and 'why', as opposed to copycating commercial designs, anyway.

BTW, thanks for that search tip. :razz:

Seriously tho, I'm not so great at circuit analysis, but I enjoy reading other's analyses because it helps me understand and learn how to piece together, modify and adapt things to suit my own needs and interests... and that's the beauty of DIY!

Thanks!
~ Charlie

[quote author="sodderboy"][quote author="pucho812"]

I plan on posting some more but am trying to find a scanner that will allow me to scan large papers 11" X 17" as those sheets are not regular size but the larger size paper. The eq is not so much to seperate eq circuits but best described as this. It has a button that is E/G.
[/quote]

A word of friendly advice: remember the axiom "Don't $hit where you eat". I would not want to see the generous host of our public forum threatened by a console manufacturer for being "too public".

I have all the scans of this console, use them to study how it works, and have chosen to share sparingly and privately. More like tech to tech- to learn how to fix problems with the console.

Pucho, the phrase "Shock the Monkey" also comes to mind. . . :green:[/quote]

I understand and I agree. I had posted it as someone had mentioned before how beautiful the line in's were. Notice how the first thing I said was "discuss" as opposed to copy this and make some. Might have to rethink posting the eq section...