# Garnet Gnome Reverb Speaker Question



## dtaylorl (Mar 19, 2011)

I recently acquired a Garnet Gnome Reverb. I'm looking to add an L-Pad attenuator, but I don't know what the speaker impedance is. I'm thinking either 4ohm or 8ohm, but I can't seem to find a definitive answer anywhere. Can anyone guide me in the right direction?


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## greco (Jul 15, 2007)

Welcome to the forum. Hope you enjoy being here......Post often. This is a great and friendly forum.

You can use a multimeter to get a reasonable estimate.
Put the meter at the lowest ohms setting and take a reading across the speaker terminals (with the connector wires off). 
You should get a slightly lower reading than the actual impedance.

For example...I just measured an 8 ohm speaker and got a reading of 7.1 ohms

Cheers

Dave


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## dtaylorl (Mar 19, 2011)

Thanks for the welcome Dave. Not sure how active I will be around here as I am already involved with another online guitar community. This does seem like a good place though and it's always good to connect with fellow Canadians.

Unfortunately I don't own a multimeter, so I was hoping that someone who knows Garnets might know where to find this sort of info (or someone with a Gnome would already know the specs on their speaker). If not I may have to break down and buy one...


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## bcmatt (Aug 25, 2007)

I have the schematics for that amp, but they don't specify the expected impedance. I would guess 4 ohms if I was forced to, but I really don't know.
I would rather recommend simple VVR as a better alternative to an attenuator:
http://www.hallamplification.com/main.html?src=/#2,2

Only 30 bucks, and much more transparent than most attenuators. It also greatly increases the longevity of your tubes.

Here is the schem if you need it.


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## dtaylorl (Mar 19, 2011)

Never heard of the VVR, but I'll definitely check it out.

I had also thought the speaker would be 4ohm since my understanding is that the Gnome is essentially a Fender Vibro Champ which, as I understand it, has a 4ohm speaker. I did find online one person though, who seemed to think that their Gnome was an 8 ohm which is what made me doubt myself...


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## greco (Jul 15, 2007)

There is a way of determining the output impedance of the amp, from the speaker jack backwards...but it requires both a meter, a very low AC source and a formula (which I have). 

A very inexpensive meter would answer your question in minutes. 

Any friends or neighbours with a meter ?

BTW Is the speaker the original stock speaker sold with the amp? 

Cheers

Dave


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## dtaylorl (Mar 19, 2011)

Yeah, I've been racking my brain to think of anyone I know that might have a meter... Unfortunately I don't know many people who do any sort of work with electronics.

I'm assuming that the speaker is the stock speaker, but I don't know that 100%. It does say "Made in Canada" on the speaker which seems to line up with that assumption. There is nothing on the speaker to identify it as being of any particular brand.


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## bcjek (Oct 29, 2010)

Here is a link to a Gnome schematic that was hand-drawn by Nanaimo's own Sean Kilback that seems to show the output impedance at 8 ohm [8R]

http://www.kilback.net/homebrewtweaks/amps/gnome/197xgarnetg15tgnome-sk.gif


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## greco (Jul 15, 2007)

bcjek said:


> Here is a link to a Gnome schematic that was hand-drawn by Nanaimo's own Sean Kilback that seems to show the output impedance at 8 ohm [8R]


Well done !! Congrats on finding this "needle in the haystack"

Cheers

Dave


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## dtaylorl (Mar 19, 2011)

Wonderful. Thank you so much!

Edit: Now that I know the impedance, does anyone know where I can buy an L-Pad without ridiculous shipping charges to Canada? It would be nice if I could buy locally (Calgary), but online is fine too.


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## bcjek (Oct 29, 2010)

Active Tech in Calgary should have what you need. 

1-2015 32 Ave NE
Calgary, AB T2E 6Z3
(403) 291-5626

61-111-0 MODE ELECTRONICS MONO L-PAD 4-7 days (Lead time may vary by Supplier) 
$5.92

61-111-1 MODE ELECTRONICS MONO L-PAD 4-7 days (Lead time may vary by Supplier) 
$6.33

61-112-0 MODE ELECTRONICS STEREO L-PAD 4-7 days (Lead time may vary by Supplier) 
$9.87

61-112-1 MODE ELECTRONICS STEREO L-PAD 4-7 days (Lead time may vary by Supplier) 
$10.37 



If they only have lower wattage L-Pads, you can parallel two halves of a stereo pad [keeping in mind the impedance] and double the wattage rating. If they have a 25-watt Stereo L-Pad, for example, take the 16-ohm version, connect the two pots in parallel, and you will have an 8-ohm unit at 50 watts. 

Does that make sense to you?


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