Author Topic: ¿Same output as input in the clon 1176?  (Read 1333 times)

moybm

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¿Same output as input in the clon 1176?
« on: August 10, 2012, 06:51:44 AM »
Hi, I'm Moses and is the first time I write in this forum, I am Spanish so excuse my translations.

Have mounted a clone of 1176 rev J and performs the functions of the input compressor but mcarca distrust than VU.

My query is:
If I put 0dB input 1khz (0.775Vrms) with the switch in VU if I adjust the potentiometers for the 0dB VU mark in the output should also be 0dB?

Another problem I get is that there are no differences between 4:1 and 20:1 (with audio meters in the mitda lso) and I did calbración process correctly.

thank you very much  :D


mac

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Re: ¿Same output as input in the clon 1176?
« Reply #1 on: August 10, 2012, 08:13:27 AM »
Hi Moses,

Have you worked your way through the calibration process as documented on Mnats website?

http://mnats.net/1176_revision_d.html#videos

Unless you do the Q bias adjustment, your GR FET may not be going into conduction....

Mac.
Barclaycon: The client said 'That sounds great, what are you using on it?'
The engineer's reply was: '30 years of experience'.

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #2 on: August 10, 2012, 09:48:53 AM »
Hi mac, I have reviewed many times and once set calibration always get the same result set, that the VU does indicate movement but not the dB should be. I'm thinking that has components in poor condition, and will discuss the results will change. Mac thank you very much for responding.

gyraf

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Re: ¿Same output as input in the clon 1176?
« Reply #3 on: August 10, 2012, 10:10:11 AM »
A standard VU-meter like the one recommended for G1176 (and the original one for that sake) will indicate 0VU for a steady signal of +4dBm

Jakob E.
..note to self: don't let Harman run your company..

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #4 on: August 10, 2012, 07:42:11 PM »
Thank you for your answer  gyraf :). Well I'm using this VU

http://www.ebay.es/itm/130384936913?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

and compression makes me correct data but the VU meter mark wrong, I was checking the voltages of the transistors and are within the margin, resistors too. From the list of COMPONENTS found one that not to put it:

65 1 8.2K resistor R50 (Not Used in Gyraf version)

because I don´t know where and I make the J rev.

¿Can this be the problem?

mnats

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Re: ¿Same output as input in the clon 1176?
« Reply #5 on: August 10, 2012, 09:11:22 PM »
Thank you for your answer  gyraf :). Well I'm using this VU

http://www.ebay.es/itm/130384936913?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

and compression makes me correct data but the VU meter mark wrong, I was checking the voltages of the transistors and are within the margin, resistors too. From the list of COMPONENTS found one that not to put it:

65 1 8.2K resistor R50 (Not Used in Gyraf version)

because I don´t know where and I make the J rev.

¿Can this be the problem?

It's right there in the ebay posting you linked to: "no external resistor,diode required,"

These are probably the stock Nissei meters that don't conform to the normal VU standards. So you'll have to modify your build to accommodate it.

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #6 on: August 11, 2012, 09:25:39 AM »
Then I have to do is change the resistance ratio of the switch right?
They are: R23, R24, R2, R26 and R25?

If complication is not much I could tell as I have to calculate the resistors for adjusting the level meter?

Very grateful in advance.

ln76d

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Re: ¿Same output as input in the clon 1176?
« Reply #7 on: August 14, 2012, 09:29:00 AM »
It's right there in the ebay posting you linked to: "no external resistor,diode required,"

These are probably the stock Nissei meters that don't conform to the normal VU standards. So you'll have to modify your build to accommodate it.

What's needed to modify?
I bought the same VU meters, from the same ebayer, i didn't paid yet.
Buy them or look for something different?

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #8 on: August 15, 2012, 07:25:26 AM »
I look a diference of the hairball audio and th ebay's:

Hairball:
Configured to read 0db at 1.228V through an external 3.6k resistor +/- 10%
Internal Resistance: 3.9K ohms +/- 10%
Built in germanium diode bridge rectifier


Ebay:
Panel VU Meter TN-73 0dB=1.288V 76x59mm LED lamp NISSEI
Complete set, directing use.
no external resistor,diode required,
0dB=0.8Vrms(actual=0.775Vrms),+/-10%(factory setting, calibalated)
Base on dBu(dBv)=20log(E/0.775Vrms)
or you can change to 0dB=1.228Vrms, but you need external a 1/2W 3.6KΩ resistor


as I have to mount the resistor in parallel or in series with the VU?
Thanks.
« Last Edit: August 15, 2012, 07:47:43 AM by moybm »

ln76d

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Re: ¿Same output as input in the clon 1176?
« Reply #9 on: August 15, 2012, 07:57:43 AM »
I found this topic:

http://www.groupdiy.com/index.php?topic=1996.0

Some useful information but i just started to read it.
Maybe together we find the answers :)
On nissei site i didn't find anything useful.


ln76d

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Re: ¿Same output as input in the clon 1176?
« Reply #10 on: August 15, 2012, 08:25:11 AM »
Maybe it's stupid question but it results from language barrier  ;)

Resistor and diodes are required or  resistor and diodes are no required?

"Complete set, directing use.

no external resistor,diode required"

I understand that as: resistor and diodes are no required

I'm right?

If so, it's only 3.6KΩ in series to add.

Before i understand that conversely, so i was thinking that these meters needs to build in  rectifier and resistor ;D

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #11 on: August 15, 2012, 10:32:35 AM »
I found this topic:

http://www.groupdiy.com/index.php?topic=1996.0

Some useful information but i just started to read it.
Maybe together we find the answers :)
On nissei site i didn't find anything useful.

Thanks for the info, my vague and difficult to understand English I find these things, I'll get to read, that looks interesting and try to understand.

abechap024

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Re: ¿Same output as input in the clon 1176?
« Reply #12 on: August 15, 2012, 11:13:04 AM »
The ebay meter needs a 3.6k resistor to read 0db = 1.23V ; to make it calibrate correctly...hope that helps?
AC Sound - some DIY circuitboards

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #13 on: August 15, 2012, 11:17:39 AM »
If so, it's only 3.6KΩ in series to add.

The schemes have put a resistor of 3.9 is it a mistake? In what capacity is the capacitor?

I discover the metter have a diode rectifier and a resistor of 1,5k but I think the assembled components are of poor quality and no resistance when combined with the 3.6-k

ln76d

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Re: ¿Same output as input in the clon 1176?
« Reply #14 on: August 15, 2012, 11:47:49 AM »
If so, it's only 3.6KΩ in series to add.

The schemes have put a resistor of 3.9 is it a mistake? In what capacity is the capacitor?

I discover the metter have a diode rectifier and a resistor of 1,5k but I think the assembled components are of poor quality and no resistance when combined with the 3.6-k

On schematic 3,9K is instead Your 1,6K (5%).
If i'm not mistaken with series connection, You can put 5,2K (1%) instead 1,6K, if You find some.
Simplest way it's only add 3,6k.

If someone knows what germanium diodes, filtering capacitor and resistor add, to rebuild these meter please let us know.

For now i must go, tommorow or late today i'll look for some info.

Biggest problem is that we don't know, what's uA of these meters.

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #15 on: August 15, 2012, 11:57:51 AM »
Thank you very much for your help, I will try now to see the results that I get with the strength that you show me.

Otherwise misunderstandings apologize for my translations.

thanks

ln76d

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Re: ¿Same output as input in the clon 1176?
« Reply #16 on: August 15, 2012, 05:42:38 PM »
My english sucks too ;)

For excuse I have only that i never learned the language.
I do not know grammar at all.

I found answer!
3,6K in series to 1,6K resistor or 5,2K (hard to find) instead 1,6K or 3,6k external to (+)  point.
That's all ;D

It's right there in the ebay posting you linked to: "no external resistor,diode required,"
These are probably the stock Nissei meters that don't conform to the normal VU standards. So you'll have to modify your build to accommodate it.

When i've read mnats post for the first time, i was confused and i was thinking that these meters needs to be modified in much complicated way.

cheers!

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #17 on: August 15, 2012, 11:36:39 PM »
Jajajaja... don't worry I understand you very well!.  ;D

I'm revised the boards and in the Switch from the VU (Mants Rev J) the R51 is a resistor of the 3,6k and it's in series width the Meter VU... it neet to put one more in the terminal + of the VU?  ???

ln76d

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Re: ¿Same output as input in the clon 1176?
« Reply #18 on: August 16, 2012, 08:49:15 AM »
Yes, I think You should use an external 3.6 K. The PCB is part of the regular circuit, which is used with meters, that have 0dB = 1.23V. You need an additional 3.6k, to  get the 0dB = 1.23V.

moybm

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Re: ¿Same output as input in the clon 1176?
« Reply #19 on: August 16, 2012, 02:15:09 PM »
Yes, I think You should use an external 3.6 K. The PCB is part of the regular circuit, which is used with meters, that have 0dB = 1.23V. You need an additional 3.6k, to  get the 0dB = 1.23V.
Ok, thanks for the aclaration, I will try tomorrow an test it.

Greetings!!


 

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