[Atdiy and Whisker], the team behind [The Tymkrs] YouTube channel, are at it again with a tombstone guitar amp project.(YouTube playlist link) Their amp began life as a Philco Tombstone radio which had seen better days. By the time [Tymkrs] got their hands on it, it was just a shell of its former self, as someone had already stripped all the electronics.
The amplifier itself is a disused Leslie tube amp [Tymkrs] had on hand. An LM386 serves as the pre-amp, making this a hybrid solid and vacuum state machine.
The tombstone speaker is especially interesting. [Tymkrs] went with an electrodynamic field coil speaker. Field coil speakers have no magnets, instead using a high voltage (approx 90V DC) coil to create a magnetic field for the voice coil to push against. This sort of speaker was commonplace in the 1930’s, as large magnets couldn’t be made lightweight enough to be used in a speaker. As magnet technology improved, permanent magnets became a staple in speakers.
[Tymkrs] paid special attention to the finish of the amplifier. They brought the tired old radio back to a high shine, then added a Metropolis inspired overlay from aged copper-clad board. The result is an amp that looks great and sounds great!
Most awesome! I have thought about putting a guitar amp into an old radio cabinet. Just love the look of those. +1 for sure!
Thank you for starting with an empty cabinet!
So many hacks and case mods that use an old radio start with throwing out the chassis and destroying parts that haven’t been made in 80 years.
Yea, +1 for not gutting a potentially working radio, and it’s nice this “tombstone” got a new life instead of staying in the grave.
The one piece of critique I just have to offer is the screw holding the speaker showing from the front you should paint the heads of those screws brass or a color that matches the finish of the wood. It will look spectacular regardless I just thought it might enhance the overall detail.
four screws* <- had to correct that
Hi Heatgap – do you mean the washers that’re holding the speaker to the baffle from the back? There aren’t any screws on the front?
If you want to get some work done today, you’d better not start watching until after you get home :-)
Using an LM368 as a preamplifier I suppose sounds great is in the ear of the beholder. The original circuit isn’t mine, but I modified it to use easier to source parts
http://www.instructables.com/id/Transistor-Amplifier-Build/
Using a vintage JRC4558 as a preamplifier it sounds pretty nice if you like the hard rock sound too. I made another and put it into a cabinet but I don’t feel like finding a picture of it right now.
Yep, we have plans on working on a tube pre-amp for Tombstone eventually!
I’m sorry to hear that. Solid state is where it is at today. Get with the times. I’ve had the whole tubes vs. transistor conversation too many times now so I’m not going to go into it here too. I’m just going to figure you’re an idiot and leave it at that.
Do the knobs go to 11?
Naturally :)
What are you doing?? If you’re going to put silicon in there, at least use FETs, sticking an opamp in there would get you jail time where I come from… Damn noobs.
You’re right that the LM386 isn’t appropriate for such a project, and during tests, we used our Art Tube pre-amp with this with pretty good success. Luckily, it’s easy to desolder the LM386, avoid jailtime (and the damn trolls), and like I mentioned before, work on a diy tube pre-amp for this in the future.
Google JRC4558 tube screamer. Enough said.
That so beautiful.
no so big, I think it’s very useful for me.
http://www.baroni-lab.com/pedals/distortion-pedals