# Amp Mod's



## stompy (Jul 7, 2009)

Hi there,

I have a Garnet Gnome G15T. I found this mod, and I wanted to know people's opinions and also, where can I find good quality parts such as resistors/cap's. 

Here is the mod.

http://www.kilback.net/homebrewtweaks/amps/amps.htm

Half way down the page... 

Here is the schematics from the website...


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## stompy (Jul 7, 2009)

OH! And I forgot... I would like to replace my tubes as I've never replaced them and I've owned the amp since about 94.. I figure its probably about time. I used to play it pretty hard from when I bought it to about 97.. So a couple years where it had an overdrive pedal with its gain at max, and the amp at max...

My point, where do I find tubes for a reasonable price... At long & mcquade in town here they said they would have to charge me about $65 for a matched set of 6v6GT's, when I only need 1... and have seen them in the US for like $15!

If I do the mod, would like to buy tubes and all components from the same online place.... Just to make it easier.


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## greco (Jul 15, 2007)

Have you looked at this Canadian supplier ?

http://thetubestore.com/

I'm not sure if they supply resistors...but probably have everything else you will need.

Cheers

Dave

PS bagpipe and I were posting at the same time


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## bagpipe (Sep 19, 2006)

I've been very happy getting my tubes from the Tube Store. And they're in Canada! They're also very helpful if you have questions:

http://thetubestore.com/


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## Guest (Jul 8, 2009)

Nice tunes man!


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## StevieMac (Mar 4, 2006)

I have NOS 6V6GTs singles if you need just 1 or 2. LMK.

Steve


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## Ripper (Jul 1, 2006)

The Gnomes are a fantastic amp. Before modding the circuit itself, I'd do a tube change to some better tubes and change the SPEAKER. The Garnet speakers are not known for their great sound and response. You might be amazed at what you can get out of that little amp with a speaker change.
I've put Weber's in some and they sound fantastic.


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## stompy (Jul 7, 2009)

Should I stick with the 8", or upgrade to a larger speaker as well and mod the cab to fit? I know very little on speakers/price.. What/where should I look for?


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## Ripper (Jul 1, 2006)

stompy said:


> Should I stick with the 8", or upgrade to a larger speaker as well and mod the cab to fit? I know very little on speakers/price.. What/where should I look for?


What kind of sound are you going for? What type of music do you play? An upgraded 8" in a larger cab like the Gnome can actually sound really good. You could have the baffle cut bigger for a 10".

Look to eminence or Weber they are both fine speakers for that application. What type/style is also going to depend on what kind of sound you're going for.


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## parkhead (Aug 14, 2009)

stompy said:


> OH! And I forgot... I would like to replace my tubes as I've never replaced them and I've owned the amp since about 94.. I figure its probably about time. I used to play it pretty hard from when I bought it to about 97.. So a couple years where it had an overdrive pedal with its gain at max, and the amp at max...
> 
> My point, where do I find tubes for a reasonable price... At long & mcquade in town here they said they would have to charge me about $65 for a matched set of 6v6GT's, when I only need 1... and have seen them in the US for like $15!
> 
> If I do the mod, would like to buy tubes and all components from the same online place.... Just to make it easier.


got to L&M and ask the guy to order you a "jj-6v6" I get mine at L&M 

p


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## Ripper (Jul 1, 2006)

You could also give the tung-sol 6V6 a try. They are a very sweet sounding tube as well. A little less harsh than the JJ, more bluesy.


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## parkhead (Aug 14, 2009)

Ripper said:


> You could also give the tung-sol 6V6 a try. They are a very sweet sounding tube as well. A little less harsh than the JJ, more bluesy.



good point and also sold in singles at L&M 

p


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## mhammer (Nov 30, 2007)

If you're in a modding mood, consider the following:

1) A 220pf cap straddling the input lug and wiper of the volume pot makes a nice bright function. In fact, that is exactly what a "bright" switch does. Lower values will have less apparent effect but only let higher frequency content bypass. Larger values will let more upper mids through.

2) The 5600 ohm resistor to ground in the tonestack is normally a 10k resistor in Fender amps that use the full B/M/T tonestack. It determines how much of the shaped signal is bled off to ground. As the value of that resistor/resistance increases, more mids are retained. Funny thing, though, when there is NO connection to ground at that point, enough mids and upper bass are retained that you get an appreciable volume boost. It is NOT a "gain" boost since no gain stages are altered. However, since the next tube gets hit with a harder signal, it mimics the impact of a gain change. I installed a mod that would lift the ground connection on an old blackface Tremolux I owned and it was a nice boost for solos. Just note that because there is no bleed-off to ground, you effectively lose the functionality of the mid and bass controls, although you can still tone-shape a bit with the treble control. And just so we're clear, it's not my idea. I got it from Steve Morrison (AKA t-boy), the webmaster of the Music Electronics Forum(formerly Ampage).

3) The 10k feedback resistor from the transformer back to the driver stage before the power tube, linking up with the 150R resistor to ground, provides negative feedback. The negative feedback was intended to, ulp, _keep distortion in check_. If the 10k resistance is reduced, there is more negative feedback and less apparent treble bite. If the resistance is increased, there is less feedback applied and more bite. If you simply lift that 10k so there is infinite resistance (open circuit), you get icepick-thru-the-forehead tone. Doing that in tandem with #2 above can get you noticeably more overdrive and balls.


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