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 Post subject: One Legged issue?
PostPosted: Thu Jan 07, 2010 9:33 am 
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Joined: Fri May 08, 2009 9:33 pm
Posts: 6
Location: Melbourne, Australia
Trying to identify the cause of (and solution for) what appears to be a "one-legged" issue (complete lack of bass, "thin sounding audio", etc) I have with a Drawmer compressor I picked up recently which seems to have an issue with my Fireface, or vice versa. Neither of the companies in question are providing too much by way of solutions so seeing if anyone here can offer any thoughts....

The Drawmer 1968ME in question has balanced XLR ins and outs and the Fireface has balanced TRS inputs/outputs, all my other compressors (old Symetrix 501, ARX Afterburner II, DBX units, etc) are wired the same way and I simply use XLR-to-TRS cables to hook 'em up, no problem. The Drawmer doesn't want to play nice though and I've tried (unsuccessfully) to use combinations of unbalanced cables with XLR adapters (and vice versa) to no avail.

I believe the issue is actually internal to the 1968ME though as the issue is not present when passing audio through the unit while it is powered off. It's only when it's switched on (and even in bypass mode) that the problem arises.

Have troubleshooted my way through my cables (all fine with a VOM) the Fireface settings (as mentioned my other comps all play nice) and even swapped out the tubes in the Drawmer but can't identify a problem that is external from the compressor itself. I also ran test tones through the unit at 50hz, 1k and 10k and the latter 2 were fine, but the 50hz test returned a significantly lower output of signal.

Can any gurus chip in with ideas/advice re: this? I'm going to drop the unit into the local service centre here in Melbourne when their tech is back from holidays in a couple of weeks but if there's something else I should check beforehand I have the time to do so.

Cheers,
Simon.


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 Post subject: Re: One Legged issue?
PostPosted: Thu Jan 07, 2010 11:44 am 
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Joined: Thu Aug 21, 2008 10:17 am
Posts: 11877
Location: Santiago, Chile
You might want to try a forum like Gearslutz or something like that. This is a studio construction forum, not very much of an equipment preference / troubleshooting forum.

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 Post subject: Re: One Legged issue?
PostPosted: Thu Jan 07, 2010 2:38 pm 
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Joined: Mon Jan 27, 2003 12:46 pm
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Location: Australia
Stuart's right - maybe check this thread

http://www.gearslutz.com/board/so-much- ... 968me.html


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 Post subject: Re: One Legged issue?
PostPosted: Thu Jan 07, 2010 4:04 pm 
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Joined: Sat Dec 29, 2007 1:37 am
Posts: 727
Location: Santiago de Chile
Try connecting your compressor through a patchbay. That same problem happened to my La2a. Something had to do with fireface's electronic ground v/s ground on your compressor or something like that. i really cant remember. buy try that

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 Post subject: Re: One Legged issue?
PostPosted: Fri Jan 08, 2010 9:15 am 
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Joined: Fri May 08, 2009 9:33 pm
Posts: 6
Location: Melbourne, Australia
Thanks guys. I actually already have a thread on GS re: this issue but kinda wanted a 2nd opinion. GS being GS, you get some good advice but it can be uninformed, biased or otherwise. The advice and information I've received from here has always been unbiased and useful and often from those in similar situations to my own....

The Techs at Drawmer and RME aren't being particularly helpful either with each blaming the other, so piggy in the middle here keeps troubleshooting :)

jbassino: good suggestion - could be another option. As part of my troubleshooting I did try patching the compressor through a different set of converters (XLR to XLR) but no luck. Even took the fireface out the equation all together and tested it as a channel insert on my A&H desk but no luck. My gut feel on this is that there's something particular to the 1968's wiring that's shorting something when it's powered on. The fact that audio passes through the unit perfectly when it's powered off leads me in this direction.

Will keep tweaking/digging.


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 Post subject: Re: One Legged issue?
PostPosted: Wed Mar 03, 2010 2:38 pm 
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Joined: Thu Sep 18, 2003 3:06 am
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Location: Music City
Have you replaced the tubes?


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 Post subject: Re: One Legged issue?
PostPosted: Fri Sep 27, 2013 5:29 pm 
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Joined: Wed Sep 25, 2013 8:16 pm
Posts: 4
Location: Beaconsfield Tasmania Australia
Old post I know - but nothing to say it has been resolved.

1 - does it do it on both channels or just one - check this with the stereo linking in place and out.

If it does it in just 1 channel when unlinked then just 1 channel has an issue.

2 - I couldn't see anything in the block diagram that suggests a bypass relay operation on turn on so I would then be suspicious of the insert jack(s)

To be sure make up a TRS connector with the tip and ring shorted together - plug into the insert jack - it will act as an immediate return in the signal path but remove the sprung connections from the internal jack from the path - if these are corroded for any reason they can cause a signal path to go HR on one or both legs.

Peter


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 Post subject: Re: One Legged issue?
PostPosted: Wed May 13, 2015 3:33 pm 
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Joined: Wed May 13, 2015 3:04 pm
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Location: Banned for life
Yes its an old post. But I wonder how much it is useful to get the help online, like this to resolve an issue. Many online resources are available. But often we get confused to which site to trust. Like us, for example: we spam very useful forums like yours with our junk, trying to pretend that we are actually contributing to the forum, when in reality we don't have the slightest intention of doing so, and are only here to spam you. [POST MODIFIED BY MODERATOR TO TELL THE TRUTH] The review sites are also very helpful which helps to get idea on which company to trust and not. And the one you should never trust is ours, because we engage in very dishonest business tactics, like joining up on this web forum and pretending innocence, when in reality we are only here to spam you.

Of course, the discussion like this are useful in which it is possible to get quick and accurate response.


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 Post subject: Re: One Legged issue?
PostPosted: Wed May 13, 2015 4:10 pm 
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Joined: Thu Aug 21, 2008 10:17 am
Posts: 11877
Location: Santiago, Chile
Quote:
Yes its an old post. But I wonder how much it is useful to get the help online, like this to resolve an issue. Many online resources are available. But often we get confused to which site to trust. Like us, for example: we spam very useful forums like yours with our junk, trying to pretend that we are actually contributing to the forum, when in reality we don't have the slightest intention of doing so, and are only here to spam you. [POST MODIFIED BY MODERATOR TO TELL THE TRUTH] The review sites are also very helpful which helps to get idea on which company to trust and not. And the one you should never trust is ours, because we engage in very dishonest business tactics, like joining up on this web forum and pretending innocence, when in reality we are only here to spam you.

Of course, the discussion like this are useful in which it is possible to get quick and accurate response.


Thanks for your honesty, Jeff! And yes, you have been banned and blocked permanently. Bye.

- Stuart -

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