Gabriella conceptual cabinet for Mark I?

Posted: 10/20/2013 5:58:45 PM

From: Salem Oregon, USA

Joined: 2/15/2011

Hi folks...

Looking in the file area (in the yahoo groups) under the Mark I (which is what I am trying to build)  I see the pdf file for a cabinet called "Gabriella conceptual cabinet". 

Is this cabinet build correct for the Mark I, or is this a reproduction of a cabinet for the original RCA theremin?  My understanding is that the original RCA cabinet is not correctly sized for the Mark I.

I have a good friend who turned his garage into a woodworking/cabinet shop.  He builds things for his house.  He has many woodworking tools and machines.  He tells me that he would be happy to cut my wood and give me a hand.  So I will have professional guidance for this part of the build.

If the Gabriella conceptual cabinet is sized for the Mark I, can anyone who has built this give me any tips before I start?  Do any of you have a better suggestion, or is the Gabriella a good choice? 

What wood was the original RCA cabinet made of?  Looking at Lowells and Home Depot, I see that I can buy 4X8 sheets of plywood with a oak, or other finish on top. I would like to buy the finish that mimics the original wood of the RCA  if I could. Should I buy 5/8th inch plywood, or 1 inch?  Suggestions welcome.

What do you stain or rub onto your cabinet once it is cut and assembled?

Sorry for the many questions. 

I do not know if this will cross post to Theremin World, so I am going to cross post this email to that forum as well as the yahoo groups Mark I group.  I am not sure if this is needed or not....  (??)

Thanks my friends.


Portland Oregon


Posted: 10/20/2013 6:49:01 PM
RS Theremin

From: 60 mi. N of San Diego CA

Joined: 2/15/2005

Hello mraroid,


If you have not invested much in your theremin journey yet please tell me why you chose this fine theremin design.

My question is which would you prefer if you had to choose one, an original looking theremin on the inside or a theremin with an original sound that might get Clara Rockmore's attention. The outside of the cabinet can still look the same. (-'

My advice is to always get sound samples of any theremin model you have interest.

Good luck on your journey.


Posted: 10/20/2013 7:49:13 PM

From: Salem Oregon, USA

Joined: 2/15/2011

Thank you for your post Christopher.  I decided on the Mark I maybe two, or three years ago.  I knew that I wanted a vacuum tube theremin, and I wanted one that would closely mimic the RCA theremin.  So, at the time, after looking all over the net, I decided on the Mark I. 

I am quite busy, and I am a slow poke when I work.  Mostly I have been assembling parts for the Mark I as I could afford them.  I now have the two chassis, the coils, the transformers, the vacuum tubes, the sockets, the aerials, and other odds and ends. 

About a month ago, I made a big order with mouser (  I picked up all the caps, resistors, and about 95% of all the little electrical odds and ends I needed to finish the build. I have an electronics friend who is helping with the build of the two chassis.  I hope that part will be finished with in the next 6/8 weeks now that I finally have all the parts together.

So I thought I had better look ahead at the cabinet.  I have a good friend who live near me who I worked with for many years before we retired.  His hobby is building book cases and other fancy things from wood for his home. His garage is set up to be a wood working shop with a lathe, heat, all manor of saws, and a vacuum system to remove dust from cutting.  I sent him the conceptual design pdf file.  He said he would be happy to help me.

I am trying to connect with anyone who has built this wood cabinet for the Mark I to see if they can give me any advice before we start.  Looking at the pdf file (on the yahoo web page), I think it is for the cabinet only (?).  It looks like in addition to this, I need a tabletop and 4 legs.  Or maybe just 4 legs.  I like the idea of detachable legs - like being healed on with a big wing nut. I think it would make the Mark I more safe when it travels if I could remove the legs.

So if you or anyone has any feedback for me on this wood part of my build, I would be happy for any advice or suggestions.

Thanks for your interest.  Did you build a vacuum tube theremin, or perhaps the Mark I?
Mark lives here in Portland Oregon where I do.  I try not to abuse him, but if I get really stuck behind the 8 ball, I'll post for some help.  Maybe I can bribe him with lunch or dinner. :-) 



Posted: 10/20/2013 8:13:28 PM
RS Theremin

From: 60 mi. N of San Diego CA

Joined: 2/15/2005

Hello Jack,

hypergolic will be along, he has built one of the finest versions of your theremin.

Have I built a tube theremin, yes over and over and over. I like to think I am on my final build and have invited an East Coast long time friend to join me on my last ride. It is my own completely original design as well as the physical aspect will be something original from my long time TW friend SewerPipe.

You might view SewerPipe engineering the enclosure here. I do not know what the future for all my research is, over the last ten years I have helped hundreds of University students reach their theremin goal.

The landscape for theremin interest has been rapidly drying up over the last few years, we need an awakening!


Posted: 2/20/2015 2:40:48 PM

Joined: 11/13/2013

How about use wood like a panel from used door. I have some type of door that know need to replace. As far as I know it was made from Caldwells store which is similar to this one at I am seeing this is perfect one to modify to use as the device cabinet.

Posted: 2/20/2015 10:35:53 PM

From: Brooklyn,NY

Joined: 12/1/2009

RCA cabinets were made from solid mahogany 1x12's save for the bottom and the rear doors.  - you can get this at any 'real' lumberyard ;)         The height of the chassis-mounted osc coils make it tough to fit the kep in RCA box.    If you wanted to keep the panel-mount controls, and make it all fit - the vertical front part of the RCA cabinet has to be increased by about 2-3" to make enough room mount the chassis inside against the front panel  w/o the coils touching the sloped part  and still have enough space for the shelf and PS chassis below.    Make sense?


 Oh , just a heads up: the RCA cabinet dimensions posted on this site are just slightly incorrect-   They are close, but there are some errors.  Little things like, a 1/8" discrepancy that makes it so the shelf cannot pulled out  w/o taking off the doors.

 The closet doors that Im familiar with would make horrible anything;well maybe a desk- if you didnt cut it.  They are usually hollow  made from two sheets of thin ply (or worse) to a solid wood outer frame.   If you cut off part of the frame it looses all strength.   Use some nice interior grade  3/8"-3/4"  if you want to use plywood - available at home depot or lowes.  


Posted: 2/21/2015 1:33:16 AM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

"Oh , just a heads up: the RCA cabinet dimensions posted on this site are just slightly incorrect-   They are close, but there are some errors."

Sorry about that, but what do you expect when you are being fed the information by another party.  Believe me, if I had access to one (or the two different versions, so I've been told) the drawings would have been as accurate as humanly possible (disregarding manufacturing tolerances, of course).  Unfortunately, no one was willing to send me their RCA theremin.  I don't know why.  :-)

At the time, I also made a drawing of a variation of the RCA cabinet that could accommodate the Keppinger MK-I.  It has never been released or posted.

Posted: 2/21/2015 5:05:42 PM

From: Brooklyn,NY

Joined: 12/1/2009

Ah Jeff-  I didnt mean to come across as picky. I certainly owe you a big thanks for all the your (and Mark's)  work.    

  All things considered, your drawings are pretty damn good- in fact, they are the best RCA cabinet drawings publicly available.    Whats an 1/8" between friends?

Do you still have the Kep drawing?   Id like to see how you got it all to fit.

Posted: 2/25/2015 3:49:49 AM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

Mr. Hobbs,

No problem - I didn't (mean to) imply that you were.  I was excoriated far worse by another expert for producing flawed drawings and told to simply hand over my work to him.  It didn't happen.  I have yet to see an "accurate", quality set of drawings from him.

I just had to load AutoCAD on my new computer to verify, but yes I do have a basic concept drawing of an RCA cabinet made to fit the Keppinger MK-I components. I also attempted to design it so the body could be lifted out of the legs/frame.  Basically, to fit the larger coils I made cut-outs in the upper chassis shelf so that the coils would sit on a "sub-shelf" attached to the underside of the upper shelf.  The biggest problem is that the lower chassis power switch and power lamp would need to be mounted remotely from the chassis to maintain the classic RCA cabinet size and profile.

I also made basic outline drawings of the original Keppinger cabinet.

I will send you my email if you wish to discuss this any further.

Posted: 11/3/2020 7:17:25 PM

From: Richmond Hill, Georgia

Joined: 9/18/2005

I designed the cabinet from scratch using Autocadd at the time. It was a fresh start that only resembled the RCA in general appearance. The enclosure was built by a master cabinetmaker with Chapparalle boats near Nashville, Georgia (my father in law retired from the company in the early 2000's). There is not a single nail or screw in the cabinet, exclusive of the hinges used to hold the doors on.

The antennas, however, are almost exact reproductions of the original RCA aerials. The exception is that I chose brass as a color to go with the overall appearance. The full width antennas make the instrument very responsive.

The pitch oscillators work at around 192 KHz. The volume oscillators run at around 425 KHz, if memory serves. You MUST be careful in setting up the two freeks so they are not integral multiples or you WILL get unwanted overtones. There is a Kepp on Youtube right now that sounds awful....almost like a chainsaw. I recognized it from my early troubleshooting prior to encasing the thing in a proper cabinet.

Unfortunately, I alternate betwixt three hobbies; ham radio, astronomy, and theremin playing. So this is why I have not been around in awhile. But, I still have the knack and I still play entirely by ear. And if folks hate my playing/technique, I just say "hey, I'm only an electrical engineer, not an artist".

Be good/safe.


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