Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Advice and tips on building a Carvin Guitars kit.

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stickman-393
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Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Tue May 12, 2009 4:17 pm

Meet the Fat Lady:

Image

She's a Carvin HF2, one of my main instruments for the last few years. The parts arrived today for a project I've been planning for some time: installing the GraphTech GHOST piezo bridge and pre-amp. This picture shows her ready for surgery. The two switches are coil taps, which I never use. I'm going to take the switches out, but I think the holes may come in handy. I'll be posting more pictures as the work proceeds.
Last edited by stickman-393 on Wed Apr 24, 2019 12:05 pm, edited 2 times in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Tue May 12, 2009 4:28 pm

My first thought was to order a Resomax bridge that would fit on the existing posts. Careful measuring indicated that the 4mm version would be more likely to fit than the 6mm one:

Image

Funny how the camera shows the dust. Well, it's going to get dustier, so, whatever.

Parts list:
    GHOST Acousti-phonic Pre-amp ($138.95)
    Ghost loaded Resomax 4mm Nickel Bridge ($183.95)

These arrived in the cutest plastic lunchbox, packed inside in individually in foam-padded plastic blister boxes.
Last edited by stickman-393 on Wed Apr 24, 2019 12:06 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Tue May 12, 2009 4:47 pm

Clearly there's plenty of room in the body for the pre-amp circuit and battery, but how am I going to get the six piezo leads from the bridge into the body cavity?

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The bridge (and posts) sit in a solid block of wood. There's a section of the thin top between the pickup and the block:

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Putting a hole at that location is going to be too visible. Ideally I need to drop the hole under the bridge, between the posts, but drill the hole at an angle so that it comes out into the body cavity:

Image

I'm not looking forward to doing that, but I can't see another way.
Last edited by stickman-393 on Wed Apr 24, 2019 12:06 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby jerryv » Tue May 12, 2009 8:14 pm

That's the way to do it ... you just need to find a really long drill bit, which will let you drill the hole almost parallel to the top. Try to find a bit which is about 18" long ..

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Tue May 12, 2009 10:42 pm

Time to see if the bridge was going to install without problems. Having removed the strings, tailpiece, and tune-o-matic bridge, I tried dropping in the 4mm resomax bridge. No go. It was very loose, the posts Carvin uses must be about 3mm. They were, however, exactly the right distance apart (I'd already calculated this but it was good to get confirmation.)

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The point of no return: I extracted the existing posts using a pair of clamping pliers, carefully turning and unscrewing them from the wood. Although I was not looking forward to figuring out how to mount the new bridge posts, I sure admired their solid physicality in comparison:

Image

Basically I was going to have to enlarge the existing post holes to accommodate the push-in post bushings.

At this point I concentrated on not screwing up, and forgot to take pictures, but basically I knew how deep needed to go by measuring the post bushings, and I used a hand-drill and a succession of bits of increasing size until the holes were about 5.5mm in diameter. Then I used a counter-sink bit to carefully grind down the surrounding glossy finish to prevent chances of chipping and cracking when it came time to insert the bushing:

Image
Last edited by stickman-393 on Wed Apr 24, 2019 12:06 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Wed May 13, 2009 12:27 am

Now for the piezo lead conduit. One thing to remember is not only must the hole be wide enough to carry the six leads, but it must be wide enough in which to pass the sixth pin connector after the other 5 leads are already taking up space! This fact was not immediately obvious and required a hole diameter larger than I first imagined.

Also, given that I was going to be drilling at an angle, I was paranoid about the drill bit slipping - hence the guide hole shown below, and the scoring of the perimeter to prevent cracking of the surface finish:

Image

After a number of minutes of very careful drilling, we're done. You can't easily see the angle here but the hole is slanting back, aiming into the body cavity:

Image

You can see where the hole comes out of the block into the body cavity, between the bridge and the pickup:

Image
Last edited by stickman-393 on Wed Apr 24, 2019 12:07 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby Fat-Fingered Jeff » Wed May 13, 2009 6:27 am

Brave soul! :shock:

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Wed May 13, 2009 11:56 pm

Having installed the bridge post bushings with a rubber mallet and a towel for protection, I started feeding through the six piezo leads through the hole, one by one:

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Starting to get cramped! I wasn't too worried - I could always make the hole larger, although I really didn't want to:

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Finally, all done, and the resomax bridge sits snugly on its posts:

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You can clearly see the arc of the 14" radius on the piezo string saddles. The HF2 is a 20" fretboard radius, I think. I have a plan to deal with that, if the discrepancy turns out to be a problem:

Image
Last edited by stickman-393 on Wed Apr 24, 2019 12:07 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Thu May 14, 2009 12:01 am

From the top view, you can't see the leads at all:

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All re-strung, with hardware in place. The nickel bridge actually looks pretty sharp against the existing hardware:

Image

You have to look really closely in order to see the leads:

Image

Next up, time to tackle the electronics from the back side.
Last edited by stickman-393 on Wed Apr 24, 2019 12:07 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby Duke » Thu May 14, 2009 2:10 am

Don't they have the bridge available in black to match the stop and pups?
How does Carvin get them in black?

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby skakid0603 » Thu May 14, 2009 4:02 am

Great work! It's inspiring to see how much you have put into this mod

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Re: re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installat

Postby stickman-393 » Thu May 14, 2009 9:06 am

Duke wrote:Don't they have the bridge available in black to match the stop and pups? How does Carvin get them in black?


Duke, it's not the same manufacturer. Graphtech do sell the bridge in a "black nickel finish" which does not look anything like the existing black hardware from Carvin. To be honest, I thought I had ordered the black nickel version but maybe not - either way I'm not worried, I actually like the end result. I don't think it looks bad. It is obviously a higher-quality component.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby 86general » Thu May 14, 2009 12:11 pm

Wadja do about the radius issue?
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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Sat May 16, 2009 12:21 pm

It would be possible just to tuck the battery inside the compartment using a small metal clip (it comes with the Graphtech kit) , but I have a 9v battery pocket that I'm going to use.

I've checked carefully inside the body cavity - there's plenty of room to place the receptacle, and this looks like the best location:

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It's going to require some more ambitious surgery:

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Arrgghh.

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I hope this works.

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Sweet! Just like a bought one:

Image
Last edited by stickman-393 on Wed Apr 24, 2019 12:07 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby Duke » Sat May 16, 2009 12:25 pm

stickman, Graphtech is the supplier for Carvin's guitars.
Look HERE
Maybe they make black just for Carvin. Yours looks fine. I was just curious as to why they do not offer black to the public. I also want to add that you've got guts to do what you're doing. I'm sure it'll be awesome when you're done. Good work so far!

Where did you get the battery pocket?
Last edited by Duke on Sat May 16, 2009 7:19 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby mike in colorado » Sat May 16, 2009 7:01 pm

Some companies only supply certain parts for guitar companies, like Fishman, try getting a hardtail like Carvin uses...I got one, but it was tricky and I had to go direct through the company.
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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Sat May 16, 2009 9:40 pm

86general wrote:Wadja do about the radius issue?


So far it hasn't been a problem. I understand you can't file down the piezo saddles without damaging them, but I was intending to shim the two E strings to even them up a little. However, in practice, the difference hasn't affected playability. I know that I used to be able to set up the HF2 to have a *really* low action, and right now it is higher than that but it is still darn playable and it just hasn't been an issue.

Duke wrote:stickman, Graphtech is the supplier for Carvin's guitars.
Look HERE
Maybe they make black just for Carvin.


They may supply the electronics for the NS1 model, but I am sure they don't supply regular hardware. The resomax bridge is obviously higher quality than the standard Carvin issue.

Duke wrote:Where did you get the battery pocket?


You can order them from Carvin, or Stewart-Macdonald. I happened to have one left over from an earlier project, originally it was Carvin-sourced.
Last edited by stickman-393 on Tue Jul 26, 2011 7:58 am, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby Duke » Sun May 17, 2009 3:22 am

I can see where a Dremel would come in handy for this.

Image

The 13 pin is going to be a beatch from what I've seen on installation vid's. Should be the last of the major surgery though right? Scares the hell outta me. You should be close to firing that puppy up yes?

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Sun May 17, 2009 10:59 am

@Duke - Yeah, I don't currently own a dremel tool. I seriously debated getting one specifically for this project, but decided it wasn't necessary.

For this project, I decided against the hex/MIDI feature, and part of the reason was I did not want to deal with the installation of the 13-pin socket. The standard jack on the HF2 is a kind of "barrel jack" directly mounted into the wood - it doesn't have a mounting plate. This isn't a great sacrifice for me because I already own a wonderful Godin Nylon SA, complete with the hex/13pin/synth controls.

The instructions that come with the Graphtech GHOST system are comprehensive, flexible, and not 100% accurate. You have many options in how you configure the electronics, and if you are attempting this installation, I highly recommend sitting down and reading everything. The tiny booklet that comes with the kit is, I think, complete but frankly too difficult to use. I went to the Graphtech web site and printed out the PDF version of the instructions on US Letter paper. Much easier to read, and, I hoped, more current. As it turned out, it was exactly the same information, but still, I was able to write notes on the printed out version.

The reason I mention "current" is that the instructions mention a push-push switch for changing piezo tone from dark to bright and back, and the kit I received used a push-pull switch. There were some other minor differences regarding a combined "mag/piezo/mag+piezo" switch that I won't go into detail about. Bottom line: Read the instructions; go over the kit components; and think about how you want to have the controls function.

By default, the instructions assume you are going to use a replacement jack with a built-in switch to control the connection of the circuit to the battery. I was limited to the existing regular barrel jack that came installed with the HF2, and this meant a compromise which I was comfortable with:

Blended signal only. I would not be able to direct piezo and magnetic signals simultaneously to two separate outputs.

For a while I also thought I was going to have to control the power with a separate mini-switch on the top of the guitar! This is not true, however - there is an alternative wiring diagram included in the instructions to allow power-on upon insertion of the jack plug, even on a standard mono jack.

This is why it pays to read through the instructions, as many times as it takes to understand exactly what it is describing. Learning about the options you are not planning to use helps you understand the options you do want to use. This is how it worked for me, anyway.

Image

So basically my plan was this: remove the coil tap switches, move the tone pot, and use the remaining holes for the piezo volume and mag/piezo/mag+piezo mini-switch.

Another tip: It pays to accurately record your current wiring circuit because if you get lost in the middle of all the wiring, it sure helps to remember what was there when you started.
Last edited by stickman-393 on Wed Apr 24, 2019 12:08 pm, edited 1 time in total.

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re: Haunting the Fat Lady (Graphtech-GHOST/HF2 installation)

Postby stickman-393 » Sun May 17, 2009 12:22 pm

I didn't take a lot of pictures of the actual wiring up. The pre-amp board has a tiny trim pot that sets the piezo gain, and I needed to wind it back somewhat because by default, the piezos were much louder than the magnetics.

Here is the control layout before:

Image

And after:

Image

And of course, if I don't add sound samples someone is going to ask for them, so here is a simple lead line and chords, played first on magnetic pickups:
Bridge then Neck Magnetic pickups

Then the piezos:
Piezos, first "bright" mode, then "dark mode"

Upon listening to the second mp3, I admit that the difference between the two piezo modes isn't really represented. It is a subtle difference, most noticeable when you play chords - there is more bass in the "dark" mode. A better description might be a "bass cut" switch, and so far in my experiments, I would usually use the pickups in this mode if I was going for the strumming effect. Lead lines might be better served without the bass cut.
Last edited by stickman-393 on Wed Apr 24, 2019 12:08 pm, edited 1 time in total.


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