Foam-ing at the mouth . . .

[MicMaven]

Good Morning Microphone Mavens !

Looking for what to call, and how to obtain, a small quantity of what I believe is called open cell, low density, foam. You know - the type that is used inside and outside microphone head shells and inside the Shure Super55 and to pack glassware and other fragile items. It is sorta like the foam they use for soft, low cost acoustic wall squares ... but much thinner. Searching eBay, AliExpress, and other sources typically leads to hundreds of listings for thicker, denser, EVA foam sheets (like what craft stores sell) or much too thick, medium density upholstery foam. I guess a useful form factor would be 25mm x 25mm x 2to5mm sheets or strips, rolls, etc. Of course, I only need a small quantity, which likely makes it more difficult to obtain.

Any ideas? Thanks! James

 

[abbey road d enfer]

Have you googled filtration foam? Comes in all sorts of PPI (pores per inch).

 

[MicMaven]

Yes I have. It is a bit expensive, yet air conditioner filter foam is the closest material to what I am looking for and is 1/4 inch thick. Local fabric stores carry thicker, denser foam in a bilious green color. I do not think it would look good peeking out between the fins of an Elvis style or other microphone! I suspect I will end up with air conditioner filter foam, and pay the price for a big enough sheet. My last batch packed a bit of ham radio gear, but nobody packs with it any more - I suspect it costs more than alternatives material.

Thanks for the uptake. Perhaps someone knows a low cost source for it. James

 

[abbey road d enfer]

https://www.mcmaster.com/foam-air-filters/I don't think it's outrageously expensive.

 

[MicMaven]

I don't think it's outrageously expensive.
__________________________________________________________

Agreed.

THANKS for the direct link. I am embarrassed to say I missed that particular product line when searching the McMaster-Carr site, myself, finding mostly much thicker, more dense fish tank filter foam. (I need to go back to Search and Rescue School !!)

Previously I found 8 x 5 inch sheets on eBay for $11 shipped ! That seemed a bit much. I also found modest-size air conditioner filter foam for $9 and more.

The material you found appears appropriate and much more affordable. Thanks for the lead. James

 

[Whoops]

Good Morning Microphone Mavens !

Looking for what to call, and how to obtain, a small quantity of what I believe is called open cell, low density, foam. You know - the type that is used inside and outside microphone head shells and inside the Shure Super55

Mate that foam for the 55 microphone is available from Shure,
you can buy it in a lot of different places, I buy it from here:

https://www.thomann.de/gb/shure_internal_foamshield_sh55_front.htm
https://www.thomann.de/gb/shure_internal_foamshield_sh55_back.htm
I use in on microphones and also use it for headphones

 

[13engrsapper]

https://www.mcmaster.com/foam-air-filters/I don't think it's outrageously expensive.

I LOVE McMaster

 

[MicMaven]

Mate that foam for the 55 microphone is available from Shure . . .

Quite right, and I have some of that on hand, and ... ahem ... (not intending to sound contrary) it is not large enough to fully cover my original vintage 1947 Unidyne 555. It is also very thin and already cut to purpose, so it does not always fit the bill on other projects calling for thicker, larger pieces. For example black foam makes a nice speaker grill cloth, and so forth. As an amateur radio operator, I often make stuff for other hams, and that that type of foam solves a lot of problems, so larger, thicker sheets are specified for various tasks. Aquarium filter foam is similar, and easily found, but too thick and dense for many projects. Air conditioner/ humidifier foam should work much better, especially in larger sheets (as located by Mr. Abby Road.) Oddly, this stuff is more difficult to find, and more expensive, compared to, say, EVA foam or Neoprene sold in craft stores. I just could not bring myself to pay $11 for a single 8x5 inch sheet! So I am glad to find a good source on the cheap.

I truly appreciate the assistance provided herein. James

 

[GeorgeToledo]

https://www.ebay.com/itm/152908812478
This is a great substitute for the thin grey stuff and I think also very close if not identical to what some manufacturers use. It’s also good if you need to make a windscreen in a pinch.

There is some other product that’s a little thicker grade open cell, grey, specifically made for mics…but again, it’s for thicker foam replacement. Sold in sheets. Usually sold at B&H, places like that. I can look and see what the name is later.

 

[Whoops]

Quite right, and I have some of that on hand, and ... ahem ... (not intending to sound contrary) it is not large enough to fully cover my original vintage 1947 Unidyne 555.

Aren't the Unidyne 555 and the Shure SH55 the same size?

I fixed some of those mics in the past, but I don't remember if the model was 555 or 55S.
The mics I fixed were exactly the same size as the new SH55 and the Foam fitted perfectly.



Maybe the 555 is the same size of the 55A (Fathead) which is bigger than any of the other later models

 

[MicMaven]

Right again. I believe my model is the Unidyne 55C High Impedance "fathead" model, vintage 1947 (possibly 1948) which I cleaned and Frankensteined into a modern model with a modern low impedance dynamic cartridge. I acquired mine from a ham operator who considered it old junk for just $16, so it lives on, albeit with a new cartridge. My wife likes its retro look. It arrived in pretty rough condition until I cleaned it. I still have its original "guts," and would probably sell those parts for next to nothing to someone who could use them. I do not know if it worked when I received it, but I believe I have all the internal parts in a big plastic bag. Photos of my iteration below.

 

[MicMaven]

Thanks for the additional lead, George. / James

 

[Tubetec]

I didnt read the whole story so far ,
but I got the gist of it ,
why not try a mobile phone shop for the soft foam in thin sheets thats often parts of the packaging . There going to have stacks of the stuff out back from the display models , get in there my son Mickey boy ,use your charm with the girl at the counter and walk away with a smile on your face and a pile of foam under your arm ,not comming out of your mouth FFS , maybe a hot date dinner date later if you play your cards right with the girl at the counter .

 

[Whoops]

Right again. I believe my model is the Unidyne 55C High Impedance "fathead" model, vintage 1947 (possibly 1948)

Well, in any case the foam Shure sells for the SH55 is pretty good, it's transparante enough for the use in microphones and headphones.
If you don't find exactly what you looking for don't ditch the possibility of buying 2 units of each of the foams I showed (2 front and 2 back), and use them to cover all the inside of the mic, you can easily make it work.

Good luck

 

[Whoops]

By the way if I remember correctly the mic you have used a thin layer of cloth/fabric between the case and the foam, in the case of the photo I showed is that Red fabric on the 55A.
If you or anyone knows a source for that type of mesh/cloth/fabric please let me know, thanks

 

[MicMaven]

why not try a mobile phone shop for the soft foam in thin sheets thats often parts of the packaging . ... maybe a hot date dinner date later if you play your cards right with the girl at the counter .

Good idea. I already have my wife scouting her own (retail clothing) store for some - but a date with the chick from the cell phone outlet might be fun. I hope she likes older men. ... Hmmm... I wonder what other stores may have it lying about waiting for trash day ... maybe shoes ... somebody should have some. Happy trails to you. James

 

[Tubetec]

Computer games on CD/DVD rom often come with a thin low density foam insert in the box .the game shop might be another good place to try , I'll be sussing out local sources who are getting rid of this stuff next oppertunity .

Ive seen silk mesh on some of the older 55's around the frame then a metal screen with some kind of silk mesh closer to the capsule , the outer screen rots out on the older models, I have a pair, one the older one with the blue badge , one a later model with a different logo . The HML impedence switch makes it a versatile mic with all kinds of preamps , I do like them in the low Z position into a 50 ohm to grid transformer ,with 30 or 50:1 step up ratio.
I picked up a pile of old Vortexion amps that were retired from eccumenical pa duties in churches and community halls over the years , they have big Mu metal sheilded input transformers , bandwidth is around 15khz but your getting stacks of level into the grid of the tube so even quieter close mic'd sources arent so noisey as to be unusable . The pinched Shure sound can add quite a bit of presence on certain sources and really make the sound jump out and grab you by the ears , a great tool to have in the mic locker .

A English guy brought a Shure '55 into into my workshop for repair one time , he didnt have the oddball three pin connector ,
I was able to modify it with an xlr insert so a standard mic lead did the job , in the end he decided just to leave the mic with me for the ingenuity I had shown making it work again , I humbly accepted his kind gesture and ended up with a working pair .

 

[MicMaven]

Ive seen silk mesh on some of the older 55's around the frame then a metal screen with some kind of silk mesh closer to the capsule , the outer screen rots out on the older models,

Right! That describes my example exactly. This is the only image I have of the inside of the front grill. I worked hard to remove it and clean the rest of the shell, but a few mystery chemicals, elbow grease and various brushes, it turned out like new in the end. // James

 

[Tubetec]

Thats a nice mix of old style and modern sound with the LDC capsule in there ,
Rockabilly needs a big chrome mic up front , a 58 just doesnt look the part .
I got three '55's over the years , the two working ones and a third with a smashed capsule ,
Im not sure what became of the case of the broken one ,but I do have the transformer around somewhere .
I also have a handful of the Amphenol plugs ,sockets and spring cable strain reliefs that solder into the mic itself , I might be willing to let one go if anyone has chrome skull mic they want to bring back to life .

Dave.

 

[Tubetec]

Ive seen '55's with red blue or black mesh depending on vintage , a wide mesh light silk scarf might be the best job if you want to get it looking close the original .