Got some parts with my NIGC kit that I don't know what to do with - diyAudio
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Old 3rd November 2004, 05:02 PM   #1
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Default Got some parts with my NIGC kit that I don't know what to do with

I got what looks like a resistor saying "2.7J 2W" and a small relay looking thing saying "100n CR 63v BC 0423416."

I didn't find them on the parts included on the guide. Any ideas?

Thanks,
Matt
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Old 3rd November 2004, 05:44 PM   #2
Nuuk is offline Nuuk  United Kingdom
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Sounds like a Zobel network to me. If it is, then you connect them in series between the two speaker terminals.
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Old 3rd November 2004, 10:42 PM   #3
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You didn't say if it was the LM3875 or LM4780 GC kit. However, Nuuk is right: they are the Zobel network.

2.7J 2W = 2.7ohm 2W resistor
100n CR 63v BC 0423416 = .1uF cap

There is a spot on the 3875 boards for the Zobel, not sure about the 4780. As an alternative, you can connect the parts in series across the speaker terminals for the same result. Peter and Brian have both suggested to only use the Zoebel if required, and there are many happy GC owners who do not use it. Unless your speakers cables are exceedingly long, or exceptional capacitive, I suggest you leave the Zobel off or at least listen both ways.
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Old 4th November 2004, 12:45 AM   #4
metha is offline metha  Thailand
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Question Order of R/C for zebol- RC or CR ??

About the order of R C for zebol. I am curious. Typically I connect the zebol R (1 ohm) to the speaker out (signal) and the Cap ( 0.22 or 0.1 UF) connect to the speaker ground.

I found some GC board connect the R C reversely (i.e. the zebol R connect to the speaker ground instead). Any difference between both approarch?
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Old 4th November 2004, 01:20 AM   #5
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Quote:
Originally posted by Nuuk
Sounds like a Zobel network to me. If it is, then you connect them in series between the two speaker terminals.

Nuuk, would it be better to actually connect it on the speaker? or on the amp PCB? both?

sorry if it's a stupid question
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Old 4th November 2004, 02:31 AM   #6
Sheldon is offline Sheldon  United States
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Default Re: Order of R/C for zebol- RC or CR ??

Quote:
Originally posted by metha
About the order of R C for zebol. I am curious. Typically I connect the zebol R (1 ohm) to the speaker out (signal) and the Cap ( 0.22 or 0.1 UF) connect to the speaker ground.

I found some GC board connect the R C reversely (i.e. the zebol R connect to the speaker ground instead). Any difference between both approarch?

Nope. The output is AC, so no polarity concerns.

Sheldon
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Old 4th November 2004, 02:33 AM   #7
Sheldon is offline Sheldon  United States
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Quote:
Originally posted by soundNERD



Nuuk, would it be better to actually connect it on the speaker? or on the amp PCB? both?

sorry if it's a stupid question
The normal recommendation is to place it on the board, or near it. That short circuits any high frequency resonances closest to where they would be generated.

Sheldon
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Old 4th November 2004, 07:24 AM   #8
Nuuk is offline Nuuk  United Kingdom
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Quote:
The normal recommendation is to place it on the board, or near it. That short circuits any high frequency resonances closest to where they would be generated.
Thanks to you guys for taking over while we UK chaps took a nap!

Yes, as Sheldon says, the Zobel needs to go close to the amp, ie on the terminals or even on the PCB if there is room.
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Old 4th November 2004, 08:12 AM   #9
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Quote:
Originally posted by Sheldon
The normal recommendation is to place it on the board, or near it. That short circuits any high frequency resonances closest to where they would be generated.

Sheldon
Actually, it's nothing to do with shunting resonances. You place it close to the board because the further away you place it the higher the inductance of the connection, which limits the zobels usefulness (as it is trying to compensate for the phase angle caused by inductive loads).

Quote:
Originally posted by Evan Schultz
Unless your speakers cables are exceedingly long, or exceptional capacitive, I suggest you leave the Zobel off or at least listen both ways.
Not quite. If your speakers or leads present a highly capacitive load, you should add an output series inductor. The zobel is for inductive loads.
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Old 4th November 2004, 10:40 AM   #10
rnoble is offline rnoble  Australia
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Hi,

I noticed this thread and headed down the shop to to add a zobel to my Gainclone to see what the fuss was about. I feel that there's been an improvement in sound, particularly there was a little level difference between LR that seems to have gone - but most noticeably the top end seems less forced and less forward, perhaps less bright? It is hard to put a Zobel on and off with a switch so I can't discount a possible placebo effect, however I do feel it has compensated to the audio quality in some small improvement.

Worth a try.

Cheers
Rod
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