Adcom GFS-3 Speaker selector

Lux Man

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Has anyone had one of these? Does it degrade the signal? Also I'm curious as to what is going on inside if anyone knows.
 
Has anyone had one of these? Does it degrade the signal? Also I'm curious as to what is going on inside if anyone knows.

I own one and have not noticed it affecting the signal or SQ of the speakers connected to it. I downloaded the owner's manual from somewhere on the web at no cost so I am sure if you Google it you might be able to find it and get some details.
 
I found the manual as well but not much for details. I mainly wanted to know it was detrimental to the signal. I'm thinking of using it to avoid my turn on thump. I'll have the speakers on channel A and have it set to B when I turn my amp on.
 
It bugs me. I notice a loss of highs & a loss of stereo image, even when not using the protection resistor.

In addition to the wire you'd normally use, the signal will also pass through the input connectors, then the switch, then the switch for the resistor, then (if switched in) the resistor, then the output connectors, then the extra length of wire.

I have the GFS-6. I also have a Niles, same deal plus two amp inputs and volume controls.

Try it, if you already own it. See if you can borrow one if you don't.

je
 
It bugs me. I notice a loss of highs & a loss of stereo image, even when not using the protection resistor.

In addition to the wire you'd normally use, the signal will also pass through the input connectors, then the switch, then the switch for the resistor, then (if switched in) the resistor, then the output connectors, then the extra length of wire.

I have the GFS-6. I also have a Niles, same deal plus two amp inputs and volume controls.

Try it, if you already own it. See if you can borrow one if you don't.

je

Thank you for your reply. The things you mention are also my concerns. I don't own one but there's a used for sale. I'll report back if I decide to get it.
 
I have the GFS-3...had it hooked up for a little while but took it down last weekend. To my ears, it didnt affect the SQ one bit, I removed it because it just wasnt needed.
 
Thank you for your reply. The things you mention are also my concerns. I don't own one but there's a used for sale. I'll report back if I decide to get it.

This stuff comes up every couple of weeks, I think we really need to get one main thread for selector info. I did a measurement comparison recently of the added resistance of having the selector in line, I'll quote it or link to it if I can find it.

Some day I'll take out the RTA and see if there's a visible display of any loss of frequencies.

Would anybody care to see pics of the innards of the Adcom, Niles and a cheezy Radio Shack selector?

je
 
http://www.audiokarma.org/forums/showthread.php?t=186833

Here's what I just measured on my Adcom GFS-6, tried with two different types of speakers (Celestion ~6 ohm & Canton ~8 ohm)

Celestion direct - 5.6 ohms
Celestion via GFS - 5.8 ohms
Celestion via GFS w/protection - 8.2 ohms

Canton direct - 7.8 ohms
Canton via GFS - 8 ohms
Canton via GFS w/protection - 10.5 ohms

Both spkrs via GFS- 3.6 ohms
Both spkrs via GFS w/protection - 6.2 ohms

...opened the unit up, and found two big 2.5 ohm resistors.


je
 
My Adcom GFS-3 is actually sitting here next to me with the top off. If you want a pic let me know and I'll post.
 
I have the GFS 300 in my upstairs system and the GFS 6 on the one in the basement.

In my upstairs system I never use the protecton because I only use 1 pair of my fronts at a time. I use my Summits for HT and the CLSs for 2 channel.
I hear no difference. I have never tried to run both at the same time for fear of doing damage to my amp trying to drive 2 pairs of electrostatics at the same time.

When playing more than 1 set of speakers at a time in the basement and using the protection you can definatly hear a difference.

If your using it to just switch between speakers I highly reccomend it for the price.
 
BTW,
on the GFX 3 what type are the input output connectors? I really can't tell by the manual.
 
BTW,
on the GFX 3 what type are the input output connectors? I really can't tell by the manual.

They just take bare wire...no bananas or spades.

IMG_1591.jpg


IMG_1592.jpg


IMG_1594.jpg


Insert the bare wire and twist the socket to lock it in place. Its a very secure connection.
 
Great pictures- thank you! So much for using my MIT cables. I don't think that I've ever seen these connectors before.
 
Great pictures- thank you! So much for using my MIT cables. I don't think that I've ever seen these connectors before.

I was totally new to the connectors myself. I just ran 12AWG, put bananas at the speaker end, and bare wire into the selector.
 
hi to all,
is anybody using a GFS-3 or (similar) as amp switch?
i want to use one speaker pair and 2-3 amps
 
Kind of an older thread but I thought about that as well and chosen against it. The possibility of both amps connecting at the same time and shorting out scared me. I'm kind of considering using one between a pre-amp and going to two separate amps...
 
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