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 Post subject: Gilbert portable.
PostPosted: Mon Aug 07, 2017 3:38 am 
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Victor II
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 496
Location: Italy
I have desired to own a Gilbert gramophone, with its distinctive "trumpet" tonearm, since I knew of the existence of this make. Gilbert's past ads shown a portable in their production line, which was perfect for me as I don't have much room left for floor machines, but it was possibly even scarcer than bigger machines, which are themselves pretty much uncommon. I thought I could wait my whole life and another for one to pass by on international sales. However, in July I could finally put my hands on one.

Of course I had to take whatever was available, and the conditions of the machine were only so-and-so, but it shows potential and I think it will come out nicely with some hard work. Good news is that the machine is functional, although not well sounding.

The first step is to rehaul the soundbox, which needs some urgent care. It is the model named by Gilbert "Sound Reflector", with its distinctive mother-of-pearl front plate. The soundbox seems stuck in place and I can't figure out wether it is bayonet-mounted or just tight fitted in the arm's collar. There is no visible bayonet key or slot. Can someone who owns a Gilbert machine give some hints about how the soundbox can be removed?

Also, the motor runs quite well, but when it is cranked up the mechanism emits a strange "whirrrrr" sound which is uncommon to all of my other gramophones. Is this normal with Gilberts?


Attachments:
File comment: Mother-of-pearl "Sound Reflector" soundbox.
IMG_3532.JPG
IMG_3532.JPG [ 326.97 KiB | Viewed 266 times ]
File comment: Soundbox mount.
IMG_3531.JPG
IMG_3531.JPG [ 367.95 KiB | Viewed 266 times ]
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 Post subject: Re: Gilbert portable.
PostPosted: Mon Aug 07, 2017 8:53 am 
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Victor III
Joined: Sun Mar 15, 2009 6:18 am
Posts: 562
Marco, I have a cabinet Gilbert with the trombone arm and the same soundbox, but its connection to the arm utilizes a rubber ring, it is not a metal-to-metal connection. The soundbox has no pins nor threads, so it should be just a pressure fit connection to the arm in the case of your machine. Concerning the motor, mine is quiet, with no extraneous noises, but probably it is a different motor than the one on the portable.

I don't know about the portable, but this cabinet I have has a very loud reproduction, even with soft tone needles. It also has a battery-powered lamp that switches ON when the lid opens, to assist the owner in playing somber records in a dim-lit boudoir. I never installed a light bulb or battery though.


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 Post subject: Re: Gilbert portable.
PostPosted: Mon Aug 07, 2017 9:29 am 
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Victor III
Joined: Mon May 13, 2013 2:04 pm
Posts: 898
The soundbox is held in place by a rubber fitting , these are often perished and` I have seen ones where the soundbox has been glued in place making removal difficult . Looking at your picture though it doesn't seem to have the proper rubber fitting as this comes out over the tone arm and should be visible , you can see the rubber in this picture below

The gaskets on these soundboxes are extremely thin rubber , the motor shouldn't make a noise , the whirring noise can be caused by dried grease on the governor hitting the speed control pad , this can be very noisy indeed


Attachments:
gilbert.jpg
gilbert.jpg [ 26.29 KiB | Viewed 233 times ]
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 Post subject: Re: Gilbert portable.
PostPosted: Mon Aug 07, 2017 9:39 am 
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Victor II
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 496
Location: Italy
CarlosV wrote:
playing somber records in a dim-lit boudoir

Add an elegant, charming lady to the scenery, and count me in the deal!!! ;) :D

Carlos, thanks for your notes. Unfortunately the soundbox HAS to be removed, otherwise the needlebar screw is inaccessible. I suppose the rubber ring you mention has dried up and is sticked to the arm and the soundbox back. Are you perhaps aware that the soundbox' back is made of a fragile alloy, or is it robust and will bear the use of some force? Can you think of any liquid, solvent, etc. that may help? Also, do you know of anyone reproducing these rubber rings?

I also figure that your floor model should have a different motor. Will post some pictures when I will open the machine.

I can't comment much about sound at this stage (the soundbox is really knocked out) however I have the impression that the horn is too short and will cancel out the advantage of the extra-long "trombone" arm. Just by placing the arm on any other corner, at Gilbert they could have had a longer horn path without compromising the space for the motor. Also, at the bottom of the case there is a quite useless records compartment that limits the mouth of the horn. Add to this an unbelievably high top cover, and you'll get the almost-cubed shape of the portable when closed! It's never a good sign when I can devise many ways to improve a gramophone just by looking at it... ;) I figure that, in the end, it will play well, although not better than others. But looking at the arm alone is a real pleasure! 8-) Fortunately the arm is in very good conditions, possibly the most well preserved part of the gramophone.

One final question: the Gilbert came with a tobacco/brown velvet turntable. Describing this colour as "uninspiring" would be a compliment. As the velvet is spotted and ripped and I may want to change it anyway, do you have any idea about which colours would be "legitimate" for a Gilbert machine?

Should you have pictures of your Gilbert machine uploaded anywhere, please post a link to them!


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 Post subject: Re: Gilbert portable.
PostPosted: Mon Aug 07, 2017 9:46 am 
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Victor II
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 496
Location: Italy
soundgen wrote:
The soundbox is held in place by a rubber fitting , these are often perished and` I have seen ones where the soundbox has been glued in place making removal difficult. Looking at your picture though it doesn't seem to have the proper rubber fitting as this comes out over the tone arm and should be visible , you can see the rubber in this picture below.

Thanks for the details. I suspect this might also be the case. Do you remember how you could remove the soundbox in that occasion?


Quote:
the motor shouldn't make a noise , the whirring noise can be caused by dried grease on the governor hitting the speed control pad , this can be very noisy indeed


The motor is actually OK when playing a record (it will possibily be the quickest work to be done on this gramophone: some oil here and there and voilà); the whirring noise occurs when cranking it up. Perhaps the anti-unwinding mechanism is made with a latch-and-teeth gear, with very fine teeth. I will inspect the motor when I will open the case.


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 Post subject: Re: Gilbert portable.
PostPosted: Mon Aug 07, 2017 9:47 am 
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Victor III
Joined: Mon May 13, 2013 2:04 pm
Posts: 898
Marco Gilardetti wrote:
CarlosV wrote:
playing somber records in a dim-lit boudoir

Add an elegant, charming lady to the scenery, and count me in the deal!!! ;) :D

Carlos, thanks for your notes. Unfortunately the soundbox HAS to be removed, otherwise the needlebar screw is inaccessible. I suppose the rubber ring you mention has dried up and is sticked to the arm and the soundbox back. Are you perhaps aware that the soundbox' back is made of a fragile alloy, or is it robust and will bear the use of some force? Can you think of any liquid, solvent, etc. that may help? Also, do you know of anyone reproducing these rubber rings?

I also figure that your floor model should have a different motor. Will post some pictures when I will open the machine.

I can't comment much about sound at this stage (the soundbox is really knocked out) however I have the impression that the horn is too short and will cancel out the advantage of the extra-long "trombone" arm. Just by placing the arm on any other corner, at Gilbert they could have had a longer horn path without compromising the space for the motor. Also, at the bottom of the case there is a quite useless records compartment that limits the mouth of the horn. Add to this an unbelievably high top cover, and you'll get the almost-cubed shape of the portable when closed! It's never a good sign when I can devise many ways to improve a gramophone just by looking at it... ;) I figure that, in the end, it will play well, although not better than others. But looking at the arm alone is a real pleasure! 8-) Fortunately the arm is in very good conditions, possibly the most well preserved part of the gramophone.

One final question: the Gilbert came with a tobacco/brown velvet turntable. Describing this colour as "uninspiring" would be a compliment. As the velvet is spotted and ripped and I may want to change it anyway, do you have any idea about which colours would be "legitimate" for a Gilbert machine?

Should you have pictures of your Gilbert machine uploaded anywhere, please post a link to them!

The soundboxes are I think aluminium so not fragile like MAZAC


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 Post subject: Re: Gilbert portable.
PostPosted: Mon Aug 07, 2017 1:47 pm 
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Victor III
Joined: Sun Mar 15, 2009 6:18 am
Posts: 562
Marco, as requested here are the photos of the Gilbert and the soundboxes. I show three sound boxes, two are almost identical, BUT their backs are different, as you will see. The third is fitted in the arm, I used a compliant piece of plastic, because the original rubber (shown in one photo) is mushy, as soundgen mentioned.
I also took a photo of the light and its switch, and the turntable, which is a drab brown typical of the period (like all HMVs from that time)

Ah, the soundbox is made of aluminum, and the screwed back on one of them is steel. All three have the same diameter cylindrical interface. It should be safe to exert reasonable force to turn your stuck soundbox around the arm and release it.


Attachments:
Gilbert turntable.JPG
Gilbert turntable.JPG [ 128.61 KiB | Viewed 194 times ]
Gilbert soundboxes front.JPG
Gilbert soundboxes front.JPG [ 91.84 KiB | Viewed 194 times ]
Gilbert soundboxes  back.JPG
Gilbert soundboxes back.JPG [ 93.4 KiB | Viewed 194 times ]
Gilbert soundbox with rubber.JPG
Gilbert soundbox with rubber.JPG [ 104.63 KiB | Viewed 194 times ]
Gilbert soundbox back.JPG
Gilbert soundbox back.JPG [ 110.08 KiB | Viewed 194 times ]
Gilbert light switch.JPG
Gilbert light switch.JPG [ 121.37 KiB | Viewed 194 times ]
Gilbert gramophone.JPG
Gilbert gramophone.JPG [ 105.2 KiB | Viewed 194 times ]
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 Post subject: Re: Gilbert portable.
PostPosted: Tue Aug 08, 2017 9:44 am 
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Victor II
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 496
Location: Italy
Thanks for the pictures Carlos, I wish mine was in the same conditions as yours!


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 Post subject: Re: Gilbert portable.
PostPosted: Tue Aug 08, 2017 10:17 am 
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Victor III
Joined: Sun Mar 15, 2009 6:18 am
Posts: 562
You're welcome Marco, I hope the photos help in fixing yours. As I mentioned, it probably only takes some twisting to remove the soundbox.

One design flaw of this kind of tone arm is its pivot axis, which is approximately aligned with the disc grooves. As a consequence, the soundbox and the needle only track perpendicularly to the disc surface when the needle height plus the disc height are at a fixed given measure. A shorter or longer needle or thicker or thinner disc will make the soundbox cant and the needle will mistrack as well. I like to use thorn needles, which get shorter with each sharpening, progressively canting the needle, with no way to adjust it other than adding another record under the one that is being played. This is why I don't use this machine very frequently, despite its unique features and nice reproduction.


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 Post subject: Re: Gilbert portable.
PostPosted: Wed Aug 09, 2017 3:00 am 
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Victor II
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 496
Location: Italy
Thanks Carlos, I remember talking about this in another old thread. You could perhaps craft a gauge that will help you to fasten the needle at the correct height. Something made with a coil-like material that will hold the needle in place at the correct height, and that could be slip off once the needle has been fastened into the chuck.

Unfortunately, the pivot point of the arm in the portable model is a "restyled" (=cheaper) version of yours. It doesn't have that nice collar reinforcement, and as a result the moving part of the arm wobbles. I have to see if I can make it fit a little better into the threads.

Removing the soundbox is proving to be a major problem indeed. (I suspect, by the way, that the lack of a bayonet mount as well as the strange pivot point were all "engineered" in order to avoid previous patents, as both don't make much sense.) I think I've tried to pull and rotate the soundbox up to the limit to which there are serius risks to crack the back flange. I would try to dissolve whatever keeps it in position with "nitro" solvent, but quite obviously the solvent would drip into the soundbox possibly doing some damage there. I don't even know if mother-of-pearl is a material resistant to solvents.

Working on gramphones previously tampered by people with no manual skills is always awful. :|


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