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The Tone Generator or Virzi Plate ~ ya right!


The Virzi plate was standard issue for the top of the line F5 mando, and optional on all of the rest of the F5 mandos as well as L5's.

They look like this.



Supposedly invented in the early 1920s, by the Virzi brothers and used primarily
in the violin family or shall we say the Virizi brothers got a patten for the "tone generator"
even though there is evidence that the ancient Chinese Gu-Qin of 3,000 years ago had such plates in them.



Me is installing one in the 17inch Jazz Arch top me building.

If you wanna see the making and installation ...go here.

http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=32415&p=439500#p439500

Now by now you have probably gotten it that me after tone quality, not volume...want volume...go buy an amp is what me say .

The Virzi plate is a small, ovular, very thin plate (0.06) or so of spruce with a very wide grain (6-12 /inch) suspended from the top plate or its bracing. Most have "C" shaped sound holes.

They lower the volume some what but boosts the harmonics by 2 to 4 maybe even 5 partials for them that has the ears to hear it. Mellows out the sound, helps greatly in elimination of wolf tones.

Some like , most don't, those that don't, usually have Marshals, Peavies or Traynors pushing 100 gazillion mega watts of deafness at you.
Them that do, can usually tell the difference between a $100 and $150 bottle of wine.

They are not very common. Nor are really gooder trained ears.

Lloyd Loar installed them in his F5s, and offered them as an upgrade on the rest of the Gibson line..

Most have since been cannibalized by the deaf to feed the volume demon. Although they are regaining popularity in the last decade.

from a 1923 Gibson F5 mando


Gibson's L5 guitar



So if you wanna see the making and installation if one...go here.

http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=32415&p=439500#p439500


blessings
Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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Really interested to hear how this turns out my friend. That lower Siminoff pic almost tempted me to try a Virzi when building my L5 interpretation, but I chickened out & stopped at the asymetrical bracing. Curious... what's it weigh?? BTW that's the only pic I know of showing a guitar installed virzi. Have you found others??

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Dave
Milton, ON

the total weight is between 35 and 40 grams. cheap scales.

Thats the only pic of an L5 I know of with a plate.

Ya, me vacillated a good long while before me decided to go for it although I have used them before on mandos and zookies. I like the mellowness of them. And the curendero who is getting the instrument would appreciate that quality.

Umm Dave, me was just gonna PM and ask you .... what type of bolts do you use for attaching the neck with? The time is coming for me to thinks about that.


blessings
Padma

_________________
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Audiences and dispensations on Thursdays ~ by appointment only.


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I use big flathead KD bolts (1/4"x20 X 1 1/2") and barrel nuts (3/4" long) ... all HD available. I also glue a 3/8" dowel into the tenon for additional strength for the barrels to pull against. You can see the hardware/procedure in tutorial
viewtopic.php?f=10117&t=16049

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Dave
Milton, ON

Awesome! I want to do a bolt on for my Selmer build and have been scratching my head for weeks trying to come up with something.

Very interesting, Padma. Looks like the applciation is only for archtop guitars. What are your thoughts on an application for a flattop guitar?

Dave - thanks for that tutorial on M&T process - that's a cool little jig for locating the barrel holes precisely and consistently! Consider it stolen!

When I grow up I wanna be like the Padma.

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"Act your age, not your shoe size" - Prince

Dude! NO! NO you don't! Believe me!

Gonna paraphrase Rickie Nelson here

" 'n' it's all right now, learned my lesson well
You see, ya can't please everyone, so you got to be yourself "


blessings
Padma

_________________
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Audiences and dispensations on Thursdays ~ by appointment only.


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Yo, Corky

Naw... its only a plate hanging down from a top plate...curved, flat, con vexed , concaved no matter.

These plates work really well in violins and violas, especially well if all the mandos in al mando orchestra have them. THere is no reason why one coulden't be installed in a flat top.

Guitars and mandos arn't realy build like a violin that you can pop the back off in 1 min. to access the inside for working on. So an axe that has the back HHGed and has not been trimed and banded yet would be in order to experiment with such plates. Then if one likes what it does, the back can be trimed , banded and finished accordingly.

And yes Daves bolt on technique is how me gonna do this build.

blessings
Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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Keep up the good work Pad

Steve

I've been pondering a similar concept after attending a workshop with Bob Benedetto and he discussed carving the re-curve and how it affects the overall sound of the guitar. If you hold the back against the body it will dampen the sound. My thought was why not suspend a secondary thin plate raised around 1" above the back plate allowing it to freely vibrate and flex without outside influence. After seeing what Padma posted I thought I might try a scaled back version and mount it on the heal and tail blocks. The plate is a piece of very light mahogany about 3/32 - 1/8 inch thick. Has anybody tried this? Am I wrong in thinking this could enhance the sound? Any thoughts, ideas, or comments good or bad would be greatly appreciated. I have a lot to learn!

My initial gut reaction is that it just might be too much mass for the guitar strings to drive well enough to make the enhanced tone production to be worth the loss in power that will be experienced. I know that yours is not directly attached to the soundboard, which would not tax it anymore as far as vibrations being turned into sound, but I don't know if being attached to the sides will halt too much of the energy being reflected back at the soundboard through the back and sides. It looks like a killer idea though if it works. And at worst case scenario if you used HHG to attach the back plate you could remove it should the sound quality be too compromised. If it weren't for experimentation the world would not have the things that it does, so give it a crack and make changes down the road if necessary. Good Luck, and post some pics and details once it's done.

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http://www.sixgunguitars.com

This rather lovely mandolin has a "false back" over a carved spruce plate. The top is walnut. I hear it sounds incredible, and in fact there are videos of it being played and compared to a Lloyd Loar mandolin.

There is a device called a "Tone guard" that suspends the instrument away from you in order to allow it to vibrate more freely. Obviously padma's device is a different concept altogether.

Thanks. I wish the back wasn't already glued on. This is a low cost build for practice using material I had on hand so this is perfect for experimenting. I'm going to sand the plate a little thinner and I'm also going to make another one that flares out into the upper bout area. There will also be a slight recurve at the contact points to minimize dampening. I still might carve a full size insert that would have a 1/2" gap from the sides and have only few contact points to attach it to the sides to minimize any dampening. I think it's time to pick up some more inexpensive oak and start another back so I can compare the difference between the partial and full plate designs. I'll try to keep everything else the same so the plates will be the only variable. This will also give me the practice I need to try to improve my skills which are still few and not destroy the expensive wood! Hopefully this will produce favorable results.

That is interesting. It looks like it has a port on the back. That could be food for thought if I try to do a full plate insert!

Interesting! Is the "Tone Guard" essentially a false back? If so, is the port on the back to allow the inner back plate to vibrate freely without being constrained by a fixed air mass?

You hearda Google, right?

The Tone-Gard is a patented device that is made of plastic wire. It is attached to the back of the instrument to keep it away from your belly somewhat. Didn't know they came in so many cool designs. Reminds me of wrought iron stairwells or trellises. This is what they look like.....



The innovation on the mandolin is the same concept but it's a far more elegant solution I think, and the engineering and design goes way past what the other device was made for. There's a lot more going on on that mandolin. More info can be found by searching for the Brian Dean Grand Concert Mandolin on the interweb. I think the sound port is just to let some air out. It has soundholes on the top as well. Real pretty thing. Brian's working on a ten string model that is even prettier.

Keep on working on this double back stuff. Make it your own thing somewhat. People like that sort of thing.

You might want to contact Tim McKnight. He's been doing double backs for a while now. He may be able to give you some pointers on what he's been doing and how he feels it has affected the sound.

Now why would I go to all the trouble of Googlin' it if I can just ask you?

Thanks for the info Ian.

For classical guitars, Jose Ramirez III "invented" a system in which he basically took a second back, cut out the center, so that he had perhaps a 2" guitar shaped donut, and then glued it to the sides half way between the top and the back, using tentallons (or dentallons, or whatever). It became a continuous fin projecting internally from the sides. He claimed considerable improvement in tone, which I think he attributed to the redirection of waves inside the guitar, as opposed to the fact that the insert itself vibrated. HOWEVER, the Ramirez factory does not list this feature on any models, nor as a option. I corresponded with the Ramirez factory, and they said that they do install this feature if requested. So, my hunch is that the Ramirez invention is not really as spectaular as Jose once believed, or else they would install this very simple device as a standard feature, at least in the top line guitars.

The old man who guided me through building my first dulcimer (bout 40 years ago) talked of seeing double back dulcimer as a youngster ( 1900 or so). Google Galax dulcimer( No need fur possum board).

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