TS-1 ..ribbon mic*IT WORKS!! **HORAY**pics / completion info

[ToobieSnack]

thanks consul

however i do have a lil update:

the output is about half the output my RCA 74 has...

it does sound good ... just low output...

any suggestions???
ts

 

[Consul]

Based on conversations Marik and I have had, I believe one way to increase your output would be to increase the flux of the magnets, which means swapping out your current magnets for more powerful rare-earth types. That probably isn't a practical solution.

You might be able to slip in a couple of pole pieces (to focus the field) and then put in a thinner ribbon... ?

Don't listen to me. Just wait for the experts.

 

[bcarso]

Neodymium magnets are wonderful but oh are they hard to handle!

 

[PRR]

> what if you took a large ring magnet (like what's in a speaker) and cut a slot through it and used that gap for the ribbon?

A) good luck cutting that stuff

B) the direction of the flux is wrong. A speaker ring-magnet has faces on front and back. If you managed to cut a slot in it, the flux would flow from the front to the back. In a ribbon-mike, we want the flux to flow sideways across the gap.

C) about 99% of the total flux is wasted, even if you had some strange sideways ribbon. Flux is flowing front to back over the whole surface of the ring, not just in the gap.

Even in speakers, where front-back is translated with pole-pieces to inside/outside of the voice coil gap, ceramic magnets are very very wasteful. If even half the theoretical flux passes through the voice coil, you have done fantastic. Ceramic has been popular in speakers because it is cheap, the pole-structure is cheap, speakers need heat dissipation and a big hunk of ceramic is an OK heat sink, and because buyers get excited by phrases like "80 Oz Magnet!". I know magnet technology has made great strides, while speaker magnets have gone unchanged in 30 years: the goals of a speaker designer are NOT always "efficient magnet design" but cost and looks.

It would be possible to re-magnitize the ring for circular flux, and then saw a gap. That might not be a bad design (at least I don't see any real flaw). Remagnitizing ceramic to maximum flux (speakers generally do NOT go to maximum) is hard work with heavy electricity.

And even at maximum magnetization, the flux at the surface of a ceramic magnet is much less than you can get with polepieces to concentrate the flux. Consider: a big speaker has a 4" magnet, magnet face area about 10 square inches. This is concentrated down to a 1.5" diameter 1/8" tall voice coil gap, about 0.6 square inches or over 10:1 concentration of flux. Assuming the very leaky magnetic structure gets 50% of the flux into the gap, and the gap runs 5,000 Gauss, that's maybe 1,000 Gauss at the surface of the ceramic. Efficient electrodynamic motors/generators typically run 5,000-15,000 Gauss in the gap: any less is usually too wimpy to be worthwhile. (Speakers actually don't want maximum efficiency: they would be bass-less. Speaker midrange efficiency is reduced to match acoustic efficiency of a small cone at the desired low frequency cutoff.)

Marik has posted pole-less rare-earth magnet structures that appear to be as good as any other ribbon mike magnetic system. They look strange to my Alnico eyes, but I had a hard-drive motor engineer glance at them and he says that's about how he gets maximum seek-speed (his measure of magnetic strength). As bcarso says, the really hot little magnets are wicked to work with, but it beats the heck out of assembling a good tight low-loss pole assembly.

 

[El Fito]

Toobie, congratulations. Great achievement! :sam: I think there are two likely suspects re the low output: the magnets and the trafo. Small neo magnets like the ones I'm using aren't expensive at all. That said, I haven't tested my beast yet, so can't quite comment on the behaviour of its magnets. Anyway, should you find their strength isn't powerful enough, you can always pile them up like a sandwich (say double rows of magnets on either side) and double their strength. Maybe you could experiment that way, since your design allows for magnet adjustment relative to the ribbon gap.

 

[ToobieSnack]

yes all some neo's are in the near future...

PRR nice to see you here

I know,,,reading through the post I have many questions still to answer.

your explanation of the speaker pole arrangement make things a bit more clear. the one detail

Even in speakers, where front-back is translated with pole-pieces to inside/outside of the voice coil gap

this, in particular, was the detail I have been looking for.

If I understand correctly:

Pole pieces absorb energy (like a sponge) and at the same time provide the shortest path for the energy to flow
THUS encouraging energy flow across the poles ...
max flux is acheived by maximum surface contact area to the magnet structure and distance of the gap.

THEREFORE: i would attach my pole peice to ONLY the respective NORTH side of "magnet A" and the SOUTH side of "magnet B" ONLY and NOWHERE ELSE on the magnet structure.

EG: I wouldn't "wrap my magnet" 360 degrees with this material ONLY attach it to the correct pole area.

please correct or confirm

ALSO:

in a previous post PRR you had stated that
"strapping between 2 magets"
someting about
"laying a peice of a "bottle opener" across the structure???
would give 6db more output"

I guess...... my questions are:
IF the pole peices only attach and face IN toward each other (not touching)

would iron be benificial anywhere else other than "facing the gap"......
eg: strapping the magnet structures... and the effects of other coincidental metal adjacent to the magnet structure ...(W/ W/O air gap??) ..... or in the immediate area (body of the mic and other parts)

anyway I sincerely appreciate the info and your visit to my post.
looking forward to your next visit.
thanks
ts

 

[ToobieSnack]

Fito

thanks for offering this "sandwich" info.

I had previously posed the question here at this post about
"turbocharging" my ceramics with a neo in a "sandwich" configuration.

I can fit 1 (maybe 2) of those thin neo's you are using of the outside of my magnets.

and hey

SINCE: my magnets ARE my pole peices....couldn't I add magnets to my pole peices?
I mean: just becuase my pole pieces "happen to be magnets", attaching another , stronger magnet to it should be OK....right?

I beleive el fito has confirmed this...

thanks fito :sam: :guinness:
ts

 

[ToobieSnack]

hey agian all
here's MORE pics...

enjoy ts

OH...BTW
...a white athletic sock is a "tube sock"(in the usa..anyway)
the black sock ....in the last pic is a "toobie sock" ?get it? lol
a "toobie sock"hahahhaha anyway enjoy ts

ps the sock is clean lol (new actually)

 

[ToobieSnack]

hey peeps
I scrapped the "toobie sock" and made a nice brass grill top and sides.
funny/lucky story:
I ran to the ACE hardware store between several frantic errands...asked about the screen material...i asked "whats the least you can sell me i just need a small"sample"" answer...welll 1/2 a foot x 3' $2.50
OK fine I'll be right back....went out for more money and as I was coming back in the guy stopped me and said "here you can HAVE this" as he hande me about 1.5' x 3' peice of slightly crumpled brass screen...nice..I brought it home ..formed and soldered it...
....looks nice...pics later...
now it's off to find some neo's

After marik informed me my magnet strength woud be insufficient, i changed my construction game plan a bit and allowed for the eventuality of this change.
I can remove and replace this motor easily .
so conversion shold not be that difficult.
especially considering the extra space the smaller neo's will provide.

I would... like to try this "tubocharged sandwich" idea before completely scrapping the whole motor.

may very well prove to be the answer. opinions?

ALSO:BTW i have a nice new body and a "super cool" base mount I just can't wait to build something on.
"the toobie 2b" hehe ..... get it (or not 2b...yeeess 2b...of course)
ooooo..."stainless steel and high polished aluminum" ....OOOOO
this might be a problem with a tube mic but ....since the body and base are not used as grounds in a ribbon mic this will be ok. (no soldering to the body or base needed)

I'll rebuild this motor and build the other at the same time.

this may take a while so... look for the "toobie 2b" soon (i hope)
later
ts

 

[ToobieSnack]

hey here are some grill pics and the first pic of the "toobie 2b" coming soon...and
OH yeah my RCA 74b is there too (signed by janis ian a wonderful influence to my current guitar style...all acoustic baby...)
I'm kinda embarrased by the slack in the ribbon of my RCA but i fugured I'd show it anyway...the 2b will be designed very similar to my RCA.
After a few more projects maybe I will get up the nerve to adjust my RCA ribbon..and install a new trafo..

BTW: is it possible/necessary to recharge the magnets of my RCA while there still in the frame?
I have never seen one of the devices and I'm not sure if it's even possible.

anyway here are the pics

enjoy
ts

 

[Svart]

thanks PRR, I can always count on you to teach me something new! :thumb:

 

[ToobieSnack]

hello again people,
I am just updating this post a little
I left out some helpful info at the end
just wanted to add more info about my grill work ok?

one thing i did that was recomended in another post regarding the soldering of the screen material...

I had a tube of extremely similar proportions so i inserted and piece of grill material inside the tube and trimmed an re-fit it until it matched perfectly with ...no overlap ...of the screen...
I then re-inserted it and let just the smallest bit of material extend past the end othe tube.
this holds the material in place quite nicely. (great suggestion whover posted this originally)
i then tacked the edge with a few drops of solder

then I removed the material ...flipped it to the other side and positioned as described above and tacked the other side with a few drops of solder

OK now we have screen cut to exact proportion and tacked at the seam on the 2 ends.

after this i slipped the screen a out a little more and continued to solder about half way then i flipped it again and did the other side..

I must mention be careful that your solder or flux doesn't drip onto your screen anywhere...the flux is easily removed but un-necessary if you are careful. a solder drip could be horribly disasterous if you want everything really pretty..
i leaned the tube and screen at different angles to prevent drips and encourage the proper flow of the solder..

ok now we have a soldered screen ... shaped like a tube with a single seam.
this seam proved to be a bit of a problem for flush placement within the mic body because of a few solder "bumps" so.....

after dry fitting it into the mic i removed it and simply sanded the soft lead solder until it was nice and straigh and it fit tightly..and evenly right up against the inside wall of the mic body. the grill screen is not soldered to the mic body...it fits tight inside and doesnt move..this makes the grill removabe and replaceable as well as modify-able (like painting it black or someithing) i think this was a better altenative to soldering "inside the mic body" even though it was a bit tedious...if you try this out...i think you will be pleasantly suprised.

the top grill was super simple
cut a round peice of material ... pressed it over an asprin bottle and just inserted it after forming....my mic body is threaded at the top so a trim ring will complete the top ring installation and make it pretty/
one thing..the asprin bottle had an indention in the bottom which helped to definge the edges when the middle of the screen was pressed into the indention on the bottom of the asprin bottle while holding the edges firmly.

i hope this info was helpful to someone

and OK BTW ther are some questions in this post that remained un-answered mysteries...I will condense them for discusion at a later date and continue to search for the answers. (to post)
In the mean time if anyone can answer a question not already answered here please ...please... please... feel free...:ush push:: ::nudge nudge::haha

this mic will be on the back burner for a while untill I can get the neos I plan to use to boost my flux.
Until then I have started a new mic based on the RCA 74b. look for this new topic soon...tomorrow maybe.... when I can get the pics out of my daughters digital camera......
she hogs the camera alll the time hahahaha
but hey she can have anything she wants...and that's why I have nothing...ok not really nothing but.....arggg....

I'll update this post when I have the results I am looking for. ( or if all efforts fail...which I don't expect considering my output wasn't too bad) I may try some differnt trafo ratio's too. (funds permitting)

anyway bye for now
enjoy life
ts

 

[ToobieSnack]

hi all

soon I will finish my other mic and compare output using the same magnets, ribbon and the same trafo..

I have had a realization lately:

the optimun output ribbon mic that xvlk had offered us is similar in design to this mic
the design involves a circular magnetic return rings (disks)

quite by accident this mic has ..on top and bottom... circular steel which provides this circular circuit..

this may explain the unexpected level of energy I have currently produced...

ALSO: the mic had the ability to test without the top "ring" in place and testing was done "without" this top ring...
next testing will have all available assistance in design.

I will try to add some more circular disks around my magnet structure or some other material within compliance to increase efficiency of the magnetic return circuit (which was previously thought to be non-existant) ...possible a combination of the top disks and a U shape magnetic return from the back of the magneet structure. steel wire is also a consideration.

It would take considerable effort to add pole peices to this mic so...
this will be a last resort...
stacked booster magnets may also be implemented on the outside magnet surfaces.

later
ts

 

[ToobieSnack]

OK...I have my other mic working wonderfully with only a re-designed grill cover to fabricate and some mounting issues. :grin:

I have some neo's on the way (about a week) and
now I will begin some imrovements to this mic that should have been addressed initially.

this improvement is the addition of a more efficient magnetic return circuit
it was previously assumed that I have NO MRC but...
after further reading and a design offered by xvlk ...
i realized i did have a small but inefficient MRC....
you see ...the top and the bottom mounts I have used are high grade steel "plugs"

these plugs seved as a circular MRC ( as I said inefficiently...well to some degree... it was predicted that i would have a much lower output)

this circular design MRC, offered by xvlk, is THE best MRC obtainable! period!
therfore ..my plan is as follows:

I will add 1' iron straps to the outside surface of my magnets and use conductive epxoxy to join the side MRC material to the top "plugs"

I will then add metal straps across the back of the magnet structure ...at the the extreme top and bottom.... and joining to the side MRC material.

i may also add some intermediate rings between the top and the bottom of my plugs.
almost as if they were circular heat sinks but they will act as MRC components.
i will have a complicated design for the front of these rings (adjacent to the ribbon) which will be better explained with the pics...

the addition of pole peices may not be necessary or convenient at this time.
suggestions welcome.
i though maybe razor blades across the front.. and move the ribbon forward slightly to allow it to be positioned between the blades.
of course this would change my ribbon width and proportionally my length ( at a ratio of 1:11 ribbon length:width)
a thinner (width) ribbon will most likely improve output as well.
It's a lot of work and to tell you the truth...the ribbon really looks cool the way it is now...between the 2 flat magnet ends. :grin: it's just pleasing to the eye....hopefully my ears too.
possible pole peice options will be considered throughout the process.

however:
information on the operation of the existing design with the addition af an improved efficient MRC will be collected and analysed to determine if further effort is necessary or desired.

my measured output with my current configuration was about 65% of nominal desired output. if I can get an increase of 25-30% this may be acceptable.

I will post my results as they become available.

I hope everyone has enjoyed this thread and find the information useful or at least entertaining... it has been a long journey but well worth it..
i've had a lot of fun and I hope all of you did too. :grin:
thanks for everyones help

later
ts