Telefunken/TAB U73 compressor question

echorec · 31st January 2004, 01:13 PM

Hi,

I have a TAB U73b tube compressor.

At first it worked and sounded great then after a while it stopped working (dead silent). I replaced the input transformer - it worked for a while but then silence again.

I am feeding it with a V77 preamp. Could the problem be that the signal from the V77 is too hot? Is it that easy to damage a transformer? Should I build something that reduces the signal before it hits the U73? If so, what do you suggest? It would be nice to have something with a volume pot so I can use it as a threshold control.

Thanks.

gyraf · 31st January 2004, 02:27 PM

What was wrong with the input transformer you replaced? Pri or sec?

Is the replacement one also broken? In the same way?

Jakob E.

volki · 31st January 2004, 02:47 PM

echorec,

check http://www.shinrock.de/inold.html
ingo is one of the german persons to ask when it comes to v7x technology. you might of course ask at www.tab-funkenwerk.com , too. they're even doing an (extended) reissue of the u73...

as far as i know, the u73 has an input impedance greater than 20k, so for attenuation it might be worth a try get a good dual log. pot of, say, 47 or 100k, and hook it up to the ins of the u73. it might interact with the rlc-network before the input xformer, though, so you might get an altered freq. response!

you could also attenuate the in's of your v77, maybe you even have the required gain switch (w77)? noise performance will be worse then, of course...

but maybe that's not the issue anyway, so better check with shinrock or funkenwerk.

hey, what's your full recording chain like?

btw. jakob, big up's to you for your supercool and informative diy stuff!! i'm one of the first in line for the next load of ssl-comp pcb's from steve... =)

cheers!

echorec · 31st January 2004, 06:41 PM

Thanks for the replies.

Jakob, I´ll check the transformer. I assumed that the replacement transformer is broken too, I´ll check that too.

BTW, I had the chance to test your products for a few days, great stuff!

Volki, thanks for your advices. I have different recording chains. One would be Neumann U48, U89 or KM84 - V77 - U73b if the U73 worked. I also use Studer 962 and Neve 3126 preamps and various outboard compressors (& the 962 compressor - great if you want transparent compression or limiting).

volki · 31st January 2004, 07:43 PM

btw almost all v7x/u7x gear is compatible in terms of headroom. one exception is the very v72 itself - unlike the v72a/b, it can only take up to +16dbu. almost all others can take up to +22dbu.

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31st January 2004, 01:13 PM	#1
echorec Lives for gear Join Date: May 2003 Location: Europe Posts: 966	Telefunken/TAB U73 compressor question Hi, I have a TAB U73b tube compressor. At first it worked and sounded great then after a while it stopped working (dead silent). I replaced the input transformer - it worked for a while but then silence again. I am feeding it with a V77 preamp. Could the problem be that the signal from the V77 is too hot? Is it that easy to damage a transformer? Should I build something that reduces the signal before it hits the U73? If so, what do you suggest? It would be nice to have something with a volume pot so I can use it as a threshold control. Thanks.

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31st January 2004, 02:27 PM	#2
gyraf Lives for gear Join Date: Jun 2002 Location: Denmark Posts: 500	What was wrong with the input transformer you replaced? Pri or sec? Is the replacement one also broken? In the same way? Jakob E.

31st January 2004, 02:47 PM	#3
volki Gear Head Join Date: Jan 2004 Location: berlin, germany Posts: 64	echorec, check http://www.shinrock.de/inold.html ingo is one of the german persons to ask when it comes to v7x technology. you might of course ask at www.tab-funkenwerk.com , too. they're even doing an (extended) reissue of the u73... as far as i know, the u73 has an input impedance greater than 20k, so for attenuation it might be worth a try get a good dual log. pot of, say, 47 or 100k, and hook it up to the ins of the u73. it might interact with the rlc-network before the input xformer, though, so you might get an altered freq. response! you could also attenuate the in's of your v77, maybe you even have the required gain switch (w77)? noise performance will be worse then, of course... but maybe that's not the issue anyway, so better check with shinrock or funkenwerk. hey, what's your full recording chain like? btw. jakob, big up's to you for your supercool and informative diy stuff!! i'm one of the first in line for the next load of ssl-comp pcb's from steve... =) cheers!

31st January 2004, 06:41 PM	#4
echorec Lives for gear Join Date: May 2003 Location: Europe Posts: 966	Thanks for the replies. Jakob, I´ll check the transformer. I assumed that the replacement transformer is broken too, I´ll check that too. BTW, I had the chance to test your products for a few days, great stuff! Volki, thanks for your advices. I have different recording chains. One would be Neumann U48, U89 or KM84 - V77 - U73b if the U73 worked. I also use Studer 962 and Neve 3126 preamps and various outboard compressors (& the 962 compressor - great if you want transparent compression or limiting).

31st January 2004, 07:43 PM	#5
volki Gear Head Join Date: Jan 2004 Location: berlin, germany Posts: 64	btw almost all v7x/u7x gear is compatible in terms of headroom. one exception is the very v72 itself - unlike the v72a/b, it can only take up to +16dbu. almost all others can take up to +22dbu.