600 ohm T attenuators?

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kdawg

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Joined
Jun 9, 2004
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Location
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Has anyone found a good source for these? I know Purple Audio has a new 3 deck pot they are using (I have an email out). I've also seen that Mallory has a T600 attenuator, but it seems hard to find - and expensive maybe?

Thanks
-kdawg
 
I'm looking for something similar to the pots used in the earlier 1176s, to keep the impedance load on the transformer.

Purple Audio quoted me $70... I'm not sure if that is good or not because I don't know what kind of pot it is.
 
[quote author="kdawg"]I'm looking for something similar to the pots used in the earlier 1176s, to keep the impedance load on the transformer.

Purple Audio quoted me $70... I'm not sure if that is good or not because I don't know what kind of pot it is.[/quote]

That's about what I paid JBL/UREI for one (dual AB) about ten years ago.
 
I really need the finer adjustment unfortunately... plus wouldn't a good stepped rotary switch cost just as much?

I read that BLOO's 1176 was using an NOS military attenuator, are those available anywhere anymore? What does UA use nowadays? There has to be some manufacturer making a decent one that is affordable...

-kdawg
 
Get a copy of schematic for the 1176LN D, or F and copy it.
The ends you tie to the pots are critical for function. Ideally would be to get a pic of the wiring on the pot from a 1176 or a Purple, so you can get the orientation correct.
 
If you are going to do this I would get a nice enclosure big enough for a 600 ohm line transformer and XLR connectors and lay it out before hand, so it will not only be a useful pad but will look nice as well.
My .02 cents
 
A good size for this would be a Hammond 1590c, Digikey # HM-153
You can go to my web site WWW.jmkaudio.com and click on JM-410 Re mic and that is the same box. I know you can't tell from a pic how big it is but I have a nice size transformer and extra room inside. Just a thought....You can also get these boxes from LMB Heeger, a little better price...
 
tattenuator.jpg


So R1 can be a 1K dual linear pot for this setup?
 
Mike K;
You suggested it so you need to finish it.
Audio or linear taper 1 K dual?

After your answer this someone may post
that have an issue with the implementation
of this method. I got that feeling.
 
I'm afraid you're mistaken about the dual linear pot. You would need a "special" dual taper that is not available as a standard item. To get a feel for what I'm talking about, look at the resistance values in this diagram. It shows a 0 to -27dB (plus "off") bridged-T attenuator I designed for the output of a customer's Altec 436 compressor. As you can see, a 1K dual linear doesn't even come close.
 
He was looking for a LOW cost solution. The 1K linear pot will work...
It is as you say a custom reverse log, going in opposite directions, no doubt why they are asking $90.00 ea
 
[quote author="kdawg"]Has anyone found a good source for these? I know Purple Audio has a new 3 deck pot they are using (I have an email out). I've also seen that Mallory has a T600 attenuator, but it seems hard to find - and expensive maybe?

Thanks
-kdawg[/quote]Try this link. http://rocky.digikey.com/WebLib/Clarostat/WEB%20DATA/308%20-309%20Series.PDF
You will need 2- 500 ohms, and 1- 1k ohm.
Configuration 500-1000-500 ohm
 

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