Otari MK-III 8 track - op amp upgrade?

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plexi

Active member
Joined
Feb 7, 2006
Messages
36
Location
St. Louis
Hi,

My first post on the site so please go easy on me. I have a small analog project studio, Otari deck, Soundworkshop 1280 board. I always seem to get the same "sound" from my rig. It is not quite as sharp and open as I'd like. I have upgraded all the opamps in the desk from 4741's to TL074's, considering re-capping it as well, but my main question regards the tape machine.

I noticed there are 4559's and 1 4556 in the Otari amp cards...in some cases (line output and record head output) it seems like they may be getting loaded down. I don't know what the head impedance is, but it is almost directly connected so the op amp would have to drive an inductive load...the line out could also be getting taxed especially when I run into older 600 ohm passive eq's, etc...

I am cosidering the good old 5532 in a few key locations. Keep it to a minimum to not tax the power supply too much. Maybe also something a little better but not so much of a current hog in the other spots. These are duals so I have more options than in my board which uses a quad 14 pin...I'm kinda stuck on that one, I tried some OPA4132 but they oscillated and I didn't want to mess with it at that point, so I stuck the TL074's in it......

One of the opamps is an inline HA12017 and it is in the repro amp, first stage. I could not find any specs or subs for it yet...may not be quite as critical, but every little bit helps I guess.

Am I wasting my time with this? Should I just do a little lighter bias and tweak the top end of the machine and live with it? I have many decent mics (421,441,57,MXL,GTMD1,D19,Shinybox,77DX) and pres (V372D,1272,MX-10) and even outboard (Langevin eq's, la-3a's, altec 436) and I always bypass the board and go straight in to the deck but the "color" of the deck is always the same...a little on the cloudy side.

Thanks for listening and I welcome your comments and suggestions.
 
I thought I would revive this thread since i'm getting ready to do the same on the 4-track version of this machine. Anyone have any thoughts?

thanks,
Brad
 

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