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Passive iPhone / Victrola Amp

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So I’ve been thinking about how my old Victrola works by passively amplifying the vibrations from the diaphragm through a simple box and how I can control the volume (somewhat) by opening and closing the doors.  I said to myself, “Self, I bet that would work as a passive iPhone amp too.”  I was thinking about how to get the iPhone speaker at the beginning of the sound's path, thinking it was gonna be complex like removing the arm of the Victrola.  I didn’t want to damage the old girl. 
And then, Eureka! I saw that the diaphragm and needle part of the arm come right off easily, revealing a simple way to get the iPhone sound in.  After about an hour, I had this baby working.
 
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Step 1: Materials and Tools

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I used what I had laying around:
-Some PEX plumbing scrap; one piece 4.5” long and another 6” long.
-Some dowel that was just a bit too big to fit in the end of the PEX
-A bit of electrical tape

Total cost: $0

I used the tools I had, including a drill press (but I’m sure you could do it with a hand drill), a 3/8” drill bit and some smaller ones, a utility knife, and a handsaw.  Thats it.

Step 2: Made a Plan

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I carefully unscrewed the end of the diaphragm mount on the arm of the Victrola (see picture).  I made some measurements and came up with a plan.
Here’s the basic design in two parts:

The lower part is to redirect the sound from the iPhone speaker (on the bottom) down through Victrola.  It has a slot cut in along it for the iPhone to fit in and a hole that will line up with the Victrola sound path.  The ends of this part are plugged up with dowel to send the sound down through the hole and not out the ends.  Check out the diagram for some dimensions.

The upper part is just to support the iPhone so it doesn’t swivel down to the turn table.  So it just needs a slot cut along one side of it for the top of the iPhone to fit in.

Step 3: Got it Together.

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First, I laid out the slot for each part.  And marked the center for a 3/8” hole at each end of each slot and made a mark for the sound hole too.  Starting with smaller bits to avoid drilling in the wrong spot, I worked up to a 3/8” bit for each one.

Second I scribed a line from one hole to the other for the slot sides with my knife.  To get as straight a cut as possible, I used the molding on a door frame to mark it (see the picture).  The slots were done after carefully cutting successively deeper cuts on the scribed lines.  To finish, I just carved the ends of the slots square.

Thirdly, I whittled down the ends of the dowels slightly, just until they fit inside the ends of the lower part.  I then cut them to about 1/4” long and stuck them in either end of that lower part.

Fourth, I carved out access to the home button after marking it with the iPhone in place.  Upon testing the fit in the Victrola, I found a bit of play so I wrapped a bit of electrical tape around the end to en-snuggen it.

Step 4: Done.

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In use, I find that I still have to be ginger with it as the fit can be a bit unstable.  But overall, it sounds great.  Now I can break open the doors on the Victrola when the party really gets going.
i need my parent's amp. NOW :)
pmn939311 months ago
You deserve another thanks for not destroying it in the process. It disgusts me how much stuff is destroyed by people on this site. You could also go to a hardware store and get some brass tubing for a more authentic look.
Now I have another problem and that is where can I obtain the old record player as my Mother refused me to keep old stuff as she said it was just junk.HMMMMPF!
criggie1 year ago
Thank you for not screwing up a loverly antique in the process.

Have you considered "aiming" the iphone speaker down the horn more rather than making the sound do a U turn? Or try tweaking the distance that the phone sits into its red tube may help with the volume.
theerikjohnson (author)  criggie1 year ago
Some good ideas. I haven't tried tweaking anything yet. But I'll give those a shot when I do.
MCUman1 year ago
Now that's great! I laughed. Good job!
Mistwalker1 year ago
Clever idea. I have a Victrola, though I lack an ipod. I might be able to get some other device to fit it, though. I might have to try this, just because.
bgepp11 year ago
very clever - iPhones are amazing. Do you have a video so we can hear this baby in action?
rancidbry1 year ago
post a video!
alzie1 year ago
Cool!
I like the mating of techs that are a century apart.
Next enhancement - steam punk the ipod part to match.
theerikjohnson (author)  alzie1 year ago
thanks alzie. you're right: it doesn't look like much now. got any specific ideas to dress it up?
Hi Eric
Hmmm . . . ideas?
Well, metallic plumbing parts figure prominently in steam punk,
not to mention lots of sheet metal with rivets.
I think a trip to home depot for plumbing stuff
would be the most straight forward.
It would add a similar look
to what is already the victrola.
Not expensive either, but
needs a good bit of sweat equity to make it work, but
thats true of any art form.
Edison + Steve Jobs !!!!…


How does it sound ?… LOL
theerikjohnson (author)  vincent75201 year ago
It sound okay. It won't take the place of a real amp or stereo. But in a pinch it will do. There isn't a very rich bass sound.
jraiford1 year ago
This seems like a cool way to save records to digital format. Have you tried this, and if so, how were the results?
How can you do that ??? It seems only the amplifier is used here : there is no "music conversion" from digital to analog : the iPod does that.

Or did I miss something : could the iPod take music from the Vitrola and register it ?…
theerikjohnson (author)  vincent75201 year ago
Vincent, do didn't miss anything. You're right only the amplifier is used here. It's simply making the sound from the tiny speaker on the iPhone a bit louder; like cupping your hands around your mouth to shout to someone.
There are RCA to USB units to hook up more modern record players and tape decks. I have one and have started converting my more obscure recordings
theerikjohnson (author)  jraiford1 year ago
I have not tried. This only really works one way: sound out of the iphone made bigger by the victrola, no record involved.

I suppose you could just make a voice memo of a record playing by sticking the iphone in the sound hole...but it wont sound very good.
remendab1 year ago
What software id you use for the 3d cad model in the picture above? It looks quite excellent!
theerikjohnson (author)  remendab1 year ago
Thank you rememdab. I used Blender for the model and Illustrator for the text. Not sure if you're familiar with Blender, but it's pretty great, but it has a steep learning curve. Best of all it's free; open-source.

There are a couple of little tricks I used to get the look of this diagram. I'd be happy to post a tutorial here if there was enough interest.
JerryMoore1 year ago
Awesome idea!!!
remendab1 year ago
Very cool! I love the marriage of old with new.
ssimonsen1 year ago
Cool!
Two questions!
1) Which sexy drawing program did you use?
2) How about a video demonstration? I wonder if the Victrola makes a warm filter to the music?
theerikjohnson (author)  ssimonsen1 year ago
Thank you.

1. I used Blender to make the simple model and Illustrator to add the text and lines. The trick is to export 2 files from blender: one with a grid on the plane you want the text to be on and one without. In Illustrator, I laid the text out with the grid as perspective guides. and then swapped out the image without the grid...still with me? If there's interest. ill put a tutorial up here.

2. I was thinking about doing a video of my iphone playing but realized that i need the iphone to take the video. i'll sort it out and get something up. thanks for the suggestion.
mi1ez1 year ago
Brilliant! You know what the next step would be? A nice brass version! Pity about the Victrola requirement!
mi1ez mi1ez1 year ago
*Pity about the Victrola requirement as I'd be all over this otherwise!
theerikjohnson (author)  mi1ez1 year ago
yeah a brass version would be nice. I was given this Victrola last year. It came with a few records. The only time it got much use was during the 5 days without power from the big storm. Maybe with this i'll use it more.

thanks for the comment.
rimar20001 year ago
Interesting, but the arm of your pick-up must be a little longer, in order to allow the needle to follow the track. It would rotate approx 30 degrees counterclockwise until the edge of the record. When it have its original membrane and prong, its length is the correct.
theerikjohnson (author)  rimar20001 year ago
Thanks Rimar,
I"m not sure I follow you. I'm not using the needle or membrane or the record. As it is now, it works great.
Can you explain what you mean?
MMMhhh, I think I'm misinterpreting your work, you're putting the sound of the iPhone on the Victrola, isn't?

I thought it was the other way, getting the record sound. Pardon. I am not anglophone, this is a truly problem for me.
theerikjohnson (author)  rimar20001 year ago
no problem. thanks for the comment. and nice work on your instructables.
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