kdawg

600 ohm T attenuators?
« on: October 10, 2005, 09:09:37 PM »
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


drpat

600 ohm T attenuators?
« Reply #1 on: October 11, 2005, 12:27:32 AM »
What range and resolution are you looking for? Do you want balanced or unbalanced?
I use the LA2a on very hot signals like lead vocal.

CJ

600 ohm T attenuators?
« Reply #2 on: October 11, 2005, 12:35:52 AM »
d...d..d..d..d...d..Davens are......... n...n..n..n...n...n...n...nice.
If I can't fix it, I can fix it so nobody else can!
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kdawg

600 ohm T attenuators?
« Reply #3 on: October 11, 2005, 02:42:05 AM »
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.

Bryson

600 ohm T attenuators?
« Reply #4 on: October 11, 2005, 03:17:24 AM »
Quote from: "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.


That's about what I paid JBL/UREI for one (dual AB) about ten years ago.

Brian Roth

600 ohm T attenuators?
« Reply #5 on: October 11, 2005, 03:45:15 AM »
Or perhaps build up a stepped attenuator with a rotary switch and a bunch of fixed resistors?

Bri
Brian Roth Technical Services
Salina Kansas, home of the best vinyl on the planet!

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kdawg

600 ohm T attenuators?
« Reply #6 on: October 11, 2005, 03:57:09 AM »
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

Mike Keith

600 ohm T attenuators?
« Reply #7 on: October 11, 2005, 09:15:43 AM »
Get a Clarostat 1k dual gang linear pot and 2 620 ohm resistors and start soldering...
mike keith

Svart

600 ohm T attenuators?
« Reply #8 on: October 11, 2005, 09:19:42 AM »
Mike, how would you hook that up?
Welcome to the GroupDIY leper colony! when something falls off, we just replace it with a tube!
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Mike Keith

600 ohm T attenuators?
« Reply #9 on: October 11, 2005, 09:40:19 AM »
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.
mike keith


Mike Keith

600 ohm T attenuators?
« Reply #10 on: October 11, 2005, 09:46:23 AM »
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
mike keith

Mike Keith

600 ohm T attenuators?
« Reply #11 on: October 11, 2005, 10:03:21 AM »
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...
mike keith

Svart

600 ohm T attenuators?
« Reply #12 on: October 11, 2005, 01:23:11 PM »
Thanks!
Welcome to the GroupDIY leper colony! when something falls off, we just replace it with a tube!
occupation: General Electron Mayhem

Alesis X2 information repository:
http://www.theopiumdenproductions.

kdawg

600 ohm T attenuators?
« Reply #13 on: October 11, 2005, 02:22:35 PM »


So R1 can be a 1K dual linear pot for this setup?

adrianh

600 ohm T attenuators?
« Reply #14 on: October 11, 2005, 04:11:18 PM »
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.

Mike Keith

600 ohm T attenuators?
« Reply #15 on: October 11, 2005, 04:16:33 PM »
linear..
mike keith

soundguy

600 ohm T attenuators?
« Reply #16 on: October 11, 2005, 04:37:41 PM »
I have a pair of T attenuators that Im probably not gonna use at this point, pm me if interested.

dave

chips are good with dip...

NewYorkDave

600 ohm T attenuators?
« Reply #17 on: October 11, 2005, 04:56:47 PM »
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.

Mike Keith

600 ohm T attenuators?
« Reply #18 on: October 11, 2005, 05:35:11 PM »
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
mike keith

EP

Re: 600 ohm T attenuators?
« Reply #19 on: November 10, 2005, 11:40:42 PM »
Quote from: "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
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