Low Cut on 1176 ???? Help please!

[t-wurst]

Hello, hope that somebody can help me out. Searched the Forum with no result....

Just finished my first DIY - the g1176 - and first i want to thank Jacob, Kev, Frank and all the forum for the great support and the lot of information.

My unit seems ready now, yesterday i did the the important measurements - got 30V and -10V, 35V at the Meterlight so I decided to put some audio thru to finally test it.

What happens?
The 1176 pass audio. There´s no hum (without the "no-hum-cut") and no heavy distortion (only when Input and Output are full CW) and it seems to compress audio material - the attack and release knobs do what I expect, also the different Ratios affect the sound...

BUT

It sounds like I have an Low cut in my signal. I miss the promised warm sound. everything sounds like going thru an telephone-speaker ???!!!

Ok, its not calibrated yet, cause I miss the SIFAM (the sub. VU-Meter work in GR mode) and i did not all the Q1- Q15 measurements cause it seems to work...
Any suggestions???

(When i try to measure the voltage on output - i put one tip on Output GND and the other one on Signal hot the sound becomes a bit louder and more low frequencies can be heard - thats strange, isn´t it?)

 

[t-wurst]

Sorry, i should have put this in the 1176 help thread....

 

[gyraf]

As this is a transformerbalanced unit, you NEED to connect -in and -out (xlr's pin 3) to ground (xlr's pin1) for correct debalancing.

Make sure that you debalance correctly or use balanced interfacing, and recheck the unit..

Jakob E.

 

[t-wurst]

Thanks Jacob for your quick reply.
I guess it depends somehow on the grounding. And I´m sure I didn´t connect pin3 to pin1 on both XLR...so i use it balanced.
I´ll correct this today and post the result.

TOBY

 

[kato]

Hey Toby, what was the result??

 

[Mark Burnley]

Hi Toby,

I reckon Jakob is on the right track- if you've connected either the input or output connections incorrectly, one end of the transformer floats, and the audio signal is transferred only through the leakage capacitance of the transformer and ground. This causes the sound you describe- tinny and odd. It's easily done and quickly remedied! Just check your wiring at the XLR's.

Glad your project worked out well.

Mark

 

[t-wurst]

sorry guys, forgot to post my results

sure it works now. just corrected the groundings on XLR, did the "no-hum-at-all-cut" and of course it sounds great now.
here are some quick pics :grin:
G1176_1
G1176_2

cheers :sam:
toby

 

[radiance]

Nice one Toby!