Studer 089 and the a101 opamp

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hyde maintenance

Active member
Joined
Nov 22, 2008
Messages
37
Location
Guelph
Hey everyone.

I am working out the details on purchasing an 089 mk2 console which has probably never been recapped. Understandably it has been described by the owner as somewhat noisy which I have attributed to all the old caps. In researching the ins and outs of this console I have come across the a101 as a topic and was wondering if this should be considered a contributing factor to the noise floor?
What are the signs of a failing opamp anyhow? Noise? Dead channel? Smoke?

I have recently recapped another small console so I think I can handle doing the basic maintenance, but if this is significantly more more involved of an undertaking I hope to know ahead of time.

Originally I was going to check out the console in person and now this doesn't look like a possibility. Regardless I'm moving ahead with the deal, albeit prudently. It's not a screaming deal, or a burn. Just pretty fair market value on a console that has always caught my eye.
Does anyone have any experience with these boards they care to share?

Thanks
 
The 089 is a lovely sounding desk! The headroom is a bit on the low side, but it sure craps out in a musical way.  :)
Be prepared for a recapping job that is a bit trickier than usual, espacially the "plug-in amp"-boards, of which there are quite a few. Once it's in good shape, you can improve upon the original noise specs a bit by swapping the BC179/BC109 transistors for BC560/BC550 in the plug-in amps and the A101s.
 
Hey thanks for the info. I think that the mkII utilizes more a101's in lieu of the daughter boards found in the 1st 089's.
I was actually hoping this console used the daughter boards because the they seem much easier to rebuild than procuring or building a boatload of a101's would be. $40 buck a pop is the cheapest I have found so far for them.
At any rate, it sounds like the a101's aren't a major concern unless they're failing so I think I'll proceed as planned.
Has anyone heard of a a101 pcb available anywhere?
 
I had a 289 and a 189 wich I had to sell because of storage problems, but I finally found a nice 089 wich I'm going to keep. I always loved the sound and even if you are a little limited in the eq section, I find the eqs very useful and musical. The main problems I had with those decks was the noisefloor. The output of the modules is -15dB unbalanced, this signal goes through half of the console toe the line amps for summing and balancing. I did replace the psu of the 189 with an external unit and could immediatly reduce the noise. So I would go for the caps, leave the 101 in as long as they work and experiment with an external psu, wich also keeps the heat out of the console. O have all sorts of documents for the unit, please contact me if you need any further informations.
Peter
 
The post fader out apparently gets you to -9dB...a bit better. But can the line amps not be used to achieve +4 balance direct outs? Basically patching the preamp insert signal through them on the way to your converters/tape deck? If this is the case, the 089 I'm buying is loaded with 8 channels of them, and if the board can support 2 more cards I'll track them down and be good for 12 direct outs.
I've also heard of people bumping the supply up a bit from 22v (I believe) to 24v to help with the headroom.
I would love to see any documentation that I haven't stumbled across yet. I'll shoot you a PM.
Thanks Peter!
Chris
 
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