Altec 1589 Pre- Too hot - Pad?

junomat · Post by **junomat** » Sun Jan 22, 2012 10:02 am

Does anyone else have one of these bad boys?

I am getting tired of only using it for low output mics.

Anything with decent output clips with even just a tiny amount of gain.

Would one of those Shure In-line XLR adaptors alleviate this gain problem? Or is in the output?

Any help would be great!

Thanks!

RodC · Post by **RodC** » Sun Jan 22, 2012 11:31 am

Is it overloading the input if so the 1588B or 1588C have adjustable gain.

Pin 2 is prob connected straight to ground, this is full gain. If you put a pot in between 2 and ground these preamps become much more usable on loud sources. If you see my 1628a mods on this board there has pretty clear instructions.

Mudcloth · Post by **Mudcloth** » Sun Jan 22, 2012 11:38 am

I assume you're using the 1588B or C preamp modules in it. A good way to keep the gain down in these preamps is by using the 15356 line transformer plugs, instead. When I was using mine I'd have one of each in each channel so I could chose without having to take them out of the rack. They pop up on ebay fairly regularly at about $30-$50 each.
Incidentally, do you have any problem with output transformer noise? I started a thread on this a few years ago, planning to bake and re-pot the trannines, but never got around to it. I currently have three of these lying around that I don't really use because of this.

Mudcloth · Post by **Mudcloth** » Sun Jan 22, 2012 11:43 am

Hi RodC. You posted as I was writing mine. Great idea on the 1588B mod, especially if you only use one channel on these. You can use the pot position of the second channel as the trim pot.

junomat · Post by **junomat** » Sun Jan 22, 2012 12:16 pm

RodC wrote:Is it overloading the input if so the 1588B or 1588C have adjustable gain.

Pin 2 is prob connected straight to ground, this is full gain. If you put a pot in between 2 and ground these preamps become much more usable on loud sources. If you see my 1628a mods on this board there has pretty clear instructions.

Pin 2 in the input?

RodC · Post by **RodC** » Sun Jan 22, 2012 12:18 pm

mobtownstudios wrote:
RodC wrote:Is it overloading the input if so the 1588B or 1588C have adjustable gain.

Pin 2 is prob connected straight to ground, this is full gain. If you put a pot in between 2 and ground these preamps become much more usable on loud sources. If you see my 1628a mods on this board there has pretty clear instructions.
Pin 2 in the input?

Pin 2 of the 1588c module.

RodC · Post by **RodC** » Sun Jan 22, 2012 12:20 pm

Mudcloth wrote:Hi RodC. You posted as I was writing mine. Great idea on the 1588B mod, especially if you only use one channel on these. You can use the pot position of the second channel as the trim pot.

I think they both have pin 2 labeled as "Gain Select" They expected you to put a different resistor to ground to affect the gain. Most mixers have it wired to ground, - max gain.

junomat · Post by **junomat** » Mon Jan 23, 2012 6:35 am

So would the Shure Inline Pad work just as well?

RodC · Post by **RodC** » Mon Jan 23, 2012 7:01 am

mobtownstudios wrote:So would the Shure Inline Pad work just as well?

Yes it will prob work, just trying to give you some options to adjust your gain staging.

junomat · Post by **junomat** » Mon Jan 23, 2012 7:03 am

RodC wrote:
mobtownstudios wrote:So would the Shure Inline Pad work just as well?
Yes it will prob work, just trying to give you some options to adjust your gain staging.

Totally. Appreciated.

That said do you have any pictures of doing that mod with pin2? I like the idea of wiring it to the other unused pot in the 1589.

I guess I am a visual person and I need to see it to do it. Heh.

RodC · Post by **RodC** » Mon Jan 23, 2012 7:55 am

mobtownstudios wrote:
RodC wrote:
mobtownstudios wrote:So would the Shure Inline Pad work just as well?
Yes it will prob work, just trying to give you some options to adjust your gain staging.
Totally. Appreciated.

That said do you have any pictures of doing that mod with pin2? I like the idea of wiring it to the other unused pot in the 1589.

I guess I am a visual person and I need to see it to do it. Heh.

Not on the 1589, but if you take a pic of the board where the pre plugs in I could draw a pic. (Bottom side)

junomat · Post by **junomat** » Mon Jan 23, 2012 7:56 am

RodC wrote:
mobtownstudios wrote:
RodC wrote:
mobtownstudios wrote:So would the Shure Inline Pad work just as well?
Yes it will prob work, just trying to give you some options to adjust your gain staging.
Totally. Appreciated.

That said do you have any pictures of doing that mod with pin2? I like the idea of wiring it to the other unused pot in the 1589.

I guess I am a visual person and I need to see it to do it. Heh.
Not on the 1589, but if you take a pic of the board where the pre plugs in I could draw a pic. (Bottom side)

that would be killer. i'll do that tonight or tomorrow...

RodC · Post by **RodC** » Mon Jan 23, 2012 7:59 am

On that model the pre is remoted and there are wires running to the board. A top view may be best, and if you can figure out which one goes to pin 2 of the pre that will help.

RodC · Post by **RodC** » Mon Jan 23, 2012 8:10 am

According to the manual:

http://www.bayoucables.com/altec/Altec- ... xerAmp.pdf

Pin 2 is tied to ground right at the socket. I would cut this loose and wire a pot in there. Should be pretty easy.

junomat · Post by **junomat** » Mon Jan 23, 2012 8:13 am

RodC wrote:According to the manual:

http://www.bayoucables.com/altec/Altec- ... xerAmp.pdf

Pin 2 is tied to ground right at the socket. I would cut this loose and wire a pot in there. Should be pretty easy.

Sounds insanely easy!! Will let you know!!!

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Altec 1589 Pre- Too hot - Pad?

Altec 1589 Pre- Too hot - Pad?

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