Thread: Auditronics 501 console modules

Remy,
Do you still have these modules available? are there differences in the 501 consoles? I have one loaded with 14 inputs that I am considering rebuilding and would want to fill it up. It is also missing a couple of bus modules. I'm also interested in any schematics/documentation you have.

Michael Stucker
Wolfgang Michael Sound
Wolfgang Michael Sound: console restoration and studio maintenance services

Sorry I'm so delinquent in this answer. I've been heavily ensconced in a documentary film.

Yes I still have 40+ modules of the inputs and bus switches and I have the additional 2 you'll need with the output amplifiers.

There were two versions of the 501. The original release had a yellow colored microphone transformer and monitoring switches labeled " L-C-R " with white colored pushbuttons. The later release had the silver colored Dean Jensen 110 series microphone transformer. The secondary modification were monitoring switches that were silver in color labeled simply " L-R " along with a programmable mute switch. These two particular different versions are not interchangeable and one should not substitute one version with the other in the same frame. Doing so can actually cause some extensive damage.

You'll be happy to know, I have both versions. I modified the later version strips to disable the programmable mute switch. Doing this made them fully compatible.

The microphone preamp IC chip was an uncompensated National Semiconductor LM709. A factory recommended upgrade was to replace that chip and the others with Signetics 5534AN's. Since the outputs of those chips were buffered with a pair of push-pull output transistors, to enable the outputs to drive up to +24 DBM into a 600 ohm load, I'd still recommend staying with the 5534's. Though others that are hiring performance by today's standards may be able to be swapped out with the 5534's, I personally have not yet attempted that. Though I don't think there should be a problem? It could be though since the output buffer transistors may present a fairly low impedance load to the chip? Something on the order of 1000-3000 ohms? Newer chips probably don't want to see more than 10,000 ohm loads? But I have not personally look into other possibilities. Part of the classic sound of those desks were the 5534's. Not much different from some of the later Neve consoles that also incorporated the use of 5534's in the BA 638-640 operational amplifiers. In comparison to the earlier all discrete versions of the BA 438-440 operational amplifiers, that were utilized in nearly identical earlier Neve's.

I know I have at least one complete 501 manual and schematics along with the recommended factory upgrade sheets. And I think I also have the schematics for the later version as well. Not in front of me at the moment. Though I most likely do?

One of the nice things about these 501's is that they were quadraphonic. When I acquired these desks 21 years ago, I was going to modify the quadraphonic Panner. My intention was only for a stereo mix bus and then utilizing the rear channel pan control for use between odd and even bus switching. But today, I would keep it quadraphonic so that you could also utilize the 16 channel bus outputs where you would utilize only one bus output for the LFE " .1 " for 5.1 mixing. Not sure if that's completely tenable? It might not quite be that easy and straightforward? It might require the use of more than one output bus into a sub mixer? Otherwise you might not be able to vary level of your LFE sends in an artful way? You should know that's a huge issue with 5.1 surround mixes. Thankfully I have as yet to surround myself with anything like that issue.

I've thought about using toilet paper for that?
Mx. Remy Ann David

PM'd you about this! Hope you still have some!

Actually I still have more than 40 of them. I've been slammed with a whole lot of other crazy BS going on here. Three moves in one year. So, yeah. Both versions. As many as you want. Earlier versions going for 200 per channel. Later version going for $250 per channel. The difference is merely the microphone transformer & a programmable mute circuit (now disabled, for interchange compatibility purposes). And they all have virtually brand-new 5534's. Guaranteed in working condition. I've hardly used these desks since I got them 21 years ago. Nary a scratch. Some of these modules have your name on them. PM me. Or call me at 202-239-7412 and leave a message on my answering service. I'll get back to you.

Would you also like the 16 channel router modules with those input modules? Is this for an existing 501 or are you going to rack these up? Documentation will be included. You must purchase your own ± 15 V regulated power supply. And a couple of cables will be all you need for rack mounting these. Title, taxes and tags, not included. See your dealer for details.

46 mpg (musicians possibly good)
Mx. Remy Ann David

Hi, I pm'd you about some of your auditronics modules. Would like to pick some of those up if they're still available.