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Author Topic: Help:troubleshooting noise floor.Chain:Hedd+OCL2+Ibis  (Read 1213 times)

Alécio Costa - Brazil

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Help:troubleshooting noise floor.Chain:Hedd+OCL2+Ibis
« on: November 12, 2008, 10:09:49 pm »

Hi!

Just a few questions:
a) pentode and tape are pretty cool.
However, triode seems to bring an offset, a weird trace is shown at my Waves PAZ as I engage it.
IS this normal?

b)Pentode and tape seem to raise the noise floor, where I see something similar to a little snake/dither figure dancing towards 15khz.
I have substituted the OCL2 tubes but this  boring noise is always present.

Noise figure  raises as I increase OCL2 output gain, engage Ibis with colour at 3 + a few band boosts (no more than 0.5 to 2db).

Cabling is fine.
Noise floor oscilates between -73 and -55(!!) without dither.

Hedd: Master Clock
PT HD 192 I/O DIgital:slave, enabling AES ENCL.

Signal flow: PT HD 192 Digital AES outs >>Hedd 192 AEes>>
Hedd D/a >> OCL2 unbalanced >>> Ibis Balanced ins >> Hedd A/D >> 192 I/O AES Digital ins.

Thanks





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Alécio Costa Studio
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dcollins

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Re: Help:troubleshooting noise floor.Chain:Hedd+OCL2+Ibis
« Reply #1 on: November 12, 2008, 11:27:46 pm »

What's the noise with the OCL-2 bypassed.


DC

zenmastering

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Re: Help:troubleshooting noise floor.Chain:Hedd+OCL2+Ibis
« Reply #2 on: November 12, 2008, 11:58:43 pm »

Al
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Zen Mastering
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Alécio Costa - Brazil

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Re: Help:troubleshooting noise floor.Chain:Hedd+OCL2+Ibis
« Reply #3 on: November 13, 2008, 12:11:17 am »

Many thanks, Zen. I will do the tests you mentioned.

Balanced connections are the standard: 1 ground 2 Phase 3 Rev Phase.

Connections between Hedd D/A and Ocl2 input is unbalanced, as unit demands.

DC, even with OCL2 bypassed, seems I get some considerable noise floor. I will measure everything and post 3 JPGS, before and after each module being engaged.

There were a couple of songs I had to do an eq automation to minimize the boring noise at the very end of a song: enabling LPFs.

The least noise figure is when (of course) everything is flat, no colour functions enabled ( from Ibis or Hedd) and OCL2 output gain is at Zero.

Greg commented something about adjusting internal trims, but if output gain is lowered, S/N will go too. SO, no cure in there...
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Alécio Costa Studio
High-end Mastering, Music Production
http://www.aleciocosta.com

Listen to my album at:
http://www.audiostreet.net/aleciocosta

MySpace:
http://www.myspace.com/aleciocostamasterizacao

Alécio Costa - Brazil

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Re: Help:troubleshooting noise floor.Chain:Hedd+OCL2+Ibis
« Reply #4 on: November 13, 2008, 07:20:36 am »

I realized there is a word clock cable going from hedd to clock in of 192 I/O Digital, but clock is set at PT HD to AES ENCL, which was the way PT accepted the sync.

There is an adat bridge at the legacy port of the 192 I/O Digital. I will eliminate it either.
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Alécio Costa Studio
High-end Mastering, Music Production
http://www.aleciocosta.com

Listen to my album at:
http://www.audiostreet.net/aleciocosta

MySpace:
http://www.myspace.com/aleciocostamasterizacao

tom eaton

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Re: Help:troubleshooting noise floor.Chain:Hedd+OCL2+Ibis
« Reply #5 on: November 13, 2008, 12:13:21 pm »

My HEDD has done some VERY strange things... on occasion if I'm using it as an analog front end under internal clock it will make strange quiet buzzing sounds when there is wordclock present at its word input.  Pulling the wordclock cable immediately resolves the issue.  I have also had issues with it responding on some level (generating noise) to AES clock, when using the a/d.  Switching the digital source switch from AES to SPDIF has resolved the issue every time.  

Not sure what the issue is, but the thing sounds so good (excepting, as you mention "triode" which is 99.9% useless), that it's worth the occasional oddball behavior.

tom
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