Tascam TM-180 as mod platform?

[MicMaven]

The LD-74 definitely is a ready made DIY platform, whereas the TM-80 would require a lot of finessing (i.e. fabrication..). But not a bad mic as is?

Thank you for the kind words on my photos.

Both microphones sound OK, especially considering their low cost. The TM-80 sounds nearly the same as the LD-74. I believe it is well worth the $29 US (including shipping) I paid for it. It is a nice body with a bit of heft (weight/mass) to it. Looks good, too.

The TM-80 MIGHT be an easy donor body, notwithstanding it lacks an internal frame like most other condenser bodies have. The replacement circuit board could "float" inside the body, perhaps suspended or wrapped with cloth, packing foam, or other appropriate material, being sure to ground the XLR Pin 1 to the body.

The only tricky bit is to make a 40mm circle of metal, plastic, circuit board, or other material for mounting the replacement saddle and capsule. Or, one might carefully remove the original saddle, and devise a way to secure the replacement saddle to the original circuit board, but that might damage the original circuit board. Therefore, I would cut a 40 mm metal or plastic disc to replace the original circuit board. One MIGHT make it from triangular piece of plastic, metal or even PVC board, drilling the mounting holes just inside the three points, as it may be easier to cut three straight lines than to cut a 40mm circle. It all depends on what tools and materials you have. I think this is the only tricky aspect to using the TM-80 body. (Easy to do than say it!)

So ... um ... it may not be as difficult as it first appears ...

Just thinking aloud. Good luck. James

 

[svyet]

The circuit inside of my TLM 193 is floating as you say. Not impossible as you say, but definitely tricky. Nonethless, it's some good food for thought! Thanks again for your thoughtfulness!

 

[svyet]

I'd recommend an iSK BM-600 for a donor mic/mod project. But that's because it's fairly U87 shaped and has 3 patterns.

That, and apart from the PNP follower and low-ratio transformer, everything else is a pretty accurate copy of the U87Ai circuitry. It's also branded as the Devine BM800 btw.

Now that I'm giving these Tascams a closer look, it seems like the TM-180 might be the same body as the iSK and Devines that came up in search..those have two switches for cutoff and pad versus the Devine that has one switch for pattern select despite sharing the same model number. The Devine with two switches seems like some kind of update. The Tascam TM-80 looks an awful lot like the Devine BM-100 as well.

Additionally, this other mic that both @Icantthinkofaname and @Khron discussed has the same exact transformer as what's in the TM-180 if the labels are to be trusted. So it seems like despite a few differences you may have spotted (U87ai / AKG Perception family), the Tascam could possibly be a re-brand. It's funny, because in that same thread, you guys are also reporting differences in switch setups in the iSK/Devine's (i.e. cutoff/pad models vs pattern select models).

 

[soliloqueen]

Would you change those two things or anything at all on the iSK/Devine, or would a good capsule be "good enough" by your estimation?

3d print an insert so that there's no hollow space in the basket below the mesh, then raise the capsule as high as you can without shorting the backplate to the basket

 

[svyet]

3d print an insert so that there's no hollow space in the basket below the mesh, then raise the capsule as high as you can without shorting the backplate to the basket

That's a pro tip, thanks! I assume the insert is for allowing reflections to escape more immediately rather than bounce around inside the bottom of the headbasket (which I assume also contributes to resonance), and raising the capsule minimizes the amount of reflections that actually reach the capsule?

Would you also recommend this for any mic that has space below the mesh? Same question for raising the capsule.

 

[soliloqueen]

That's a pro tip, thanks! I assume the insert is for allowing reflections to escape more immediately rather than bounce around inside the bottom of the headbasket (which I assume also contributes to resonance), and raising the capsule minimizes the amount of reflections that actually reach the capsule?

Would you also recommend this for any mic that has space below the mesh? Same question for raising the capsule.

It depends on the geometry of the basket but generally yes. It's not about minimizing reflections so much as minimizing the boundary effect of the mount plate. The u47 doesn't have the capsule where it is because they weren't aware of the acoustic effect of the beam on the head basket as I've seen said before. They were probably aware. It's just that the acoustic effect of the beam on the head basket was much less important than the gain that came from getting the capsule as far as possible away from the plate

 

[svyet]

Wow, thanks @soliloqueen. Never really looked at a U47, but now I see what you're talking about. I'll be adding your suggestions to my notes for my first build, whatever that ends up being.

 

[svyet]

3d print an insert so that there's no hollow space in the basket below the mesh, then raise the capsule as high as you can without shorting the backplate to the basket

Any tangible benefits to a dome-shaped insert (and to what degree) as opposed to an entirely flat one?

 

[soliloqueen]

Any tangible benefits to a dome-shaped insert (and to what degree) as opposed to an entirely flat one?

a dome is nice. so is a cone. it breaks up the mode a bit