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

OK as promised here are some pics.

I started with these tools (I know looks like some Fred Flinstone approach lol ... hey it's lall I had) (for all across the pond.... Fred is a prehistoric cartoon character ... didn't know if you get the flinstones there)



here is what I have...I mocked up the element using 2 jar lids the actual material is the silver piece in the foreground...notice my waste for the mic body has no drill holes....i used a hand grinder...how?...very carefully...I actually got some damage on one of my fingers ...ouch....



here's the element front view..



and a side view




here's a better pic of the mic body (all these pics are before filing ... this is what I had right after the hacksaw and the grinder...I am farther along now and i will update my pics/progress soon



NOT bad for my first mic body attemp huh? (especially considering my limited tool selection lol)
Anyone want a mic body??????hehe

anyway enjoy the pics
all comments suggestions welcome
thanks
ts

hmmm

NO comments????

man...somebody say something ...anything.....

do you like the design? i think it is sleek

i know i have seen the tube mics like this so...
it is nothing new as mic bodies go ... but this will be a ribbon mic...

kind of a cross between an American Ribbon and an RCA 74b

opinions/suggestions/comments welcome
thanks
ts

Hadnt seen this. Looks like a great job.
Im still on the fence about building a G7 cuz of the body work....

Gustav

Toobie,

Nice body!
Unfortuneately, the pics are blurry and it is impossible to say anything about motor design. If you could make better resolution pics we could resume as for refining your design. What magnets do you use?

thanks for your kind comments
I was beginning toi think I was in the "Twilight Zone" with absolutely zero responses.
I'm much happier now :grin:

I was a commercial electrician for 15+ years ... so I have cut a few pieces of pipe in my time.....whoa!

I'd be willing to make mic bodies for anyone...maybe a trade for some la2a trafos or something i need.

I had a lot of fun doing this (even getting my little finger sucked int o the grinder didn't hurt that much..suprisingly...maybe it was adreniline)

Marik:

I know my pics of the element suck...
Fairly unusual for me....
Just that the battery in the camera was low and I had to let the camera rest between pics and I got impatient.
I'll try to get some better pics....(try ....no.... I will)
but in the mean time the magnets measure 1 7/8" x 3/8" x 7/8"

So you see the airspace behind the ribbon is like a corridor (like 2 dominoes on end standing next to each other)
I wanted to try to angle them like a V shape so that the back was a larger gap that the front and the ribbon energy would be directed because the edges next to the ribbon would be a point rather than a flat surface but... my space inside the body just barely permits the configuration I have now.
I might try another one with larger tubing.

One funny idea i had that I will try to implement is:
I'm gonna use safety pins on their sides soldered or epoxied to my mounts for:
ribbon clamps....with a bit of wire insulation or heat shrink over the safety pin t take up the empty space and allow some cushion on the ribbon. the contact is under the ribbon. I really think this is a cool idea ..
after all...when is the last time a safety pin failed on you????? like never..


I used some el cheapo Radio Shack bar magnets ($1.29 each)
my element (motor) is just the 2 bar mag facing each other.
you can see pics of the mags where i show the tools used (laying on the miter box)
the Repro (AEA i think) RCA ribbon mics state that they use alnico magnets... I think a magnetic field is a magnetic field no matter what the source so I don't think that the alnico thing is that big of a deal

anyway just got back from the dentist and I'm in a bit of pain and...
yeah buzzin a little from the meds so i will go for now.
NO GRINDING TONIGHT!!! LOL

ANYWAY
ebody have fun
thanks again
ts

HEY!

some cool news:

I phoned Clarence Kane (TTTHHHEE ribbon mic guru) and he is currently reviewing my ribbon mic and said he would offer any help i needed.
I'm pretty thrilled! :grin:
can't wait to hear his comments and suggestions.
maybe he will becom a member here at the forum
How cool would that be?
TS

Yes, it would be cool if Clarence joined us.

Here what I think.
First, magnets. Your ceramics are big and inefficient. Although I never measured ceramics, from what I read they have about 3 times less flux than Alnico, and 8-10 times than Neodymiums, and magnetic flux is the part of efficiency of the microphone. I have a similar sized Neos, and they show about 6000 Gauss flux in a ¼? gap, so my guess ceramics would give about 600-750 Gauss. Considering saturation in the gap with Neos, you might be up to 1000 Gauss there, which is still very low, and an output of the mic will be low. You can increase magnets efficiency by putting tapered shape pole pieces, or/and magnetic return circuit, and considerably increase the gap flux density, and sensitivity of the mic. Or you could decrease distance between your magnets, but potentially you can run into increased resistance of the ribbon (esp. if you are using thinner foil), and increased ratio between width of ribbon to clearance between ribbon and pole pieces and get a LF loss, as a result.
Go through Meta (its ribbon mics part), and you will find some more info on magnets.

Second, the size of the baffle, created by your magnets. With nice and optimized magnetic strength in the gap, the baffle this large will increase sensitivity of the mic in low-mid range on the expense of HF response. Without taking into account diffractions, theoretically, you?d get a null somewhere around 4KHz, with a fall starting at around 2KHz. It is not spectacular, but in your system, with a condenser as a second element, you could use it as a benefit, crossing these two elements over somewhere in a 2KHz region, and using the ribbons natural fall as a part of x-over. Of course, diffractions, and especially effect of a long narrow tunnel behind the ribbon, will through things way off unpredictably, but at least you have a start.

As for your safety pin idea? It might be cool, but it will not give you a good and safe contact. I?d suggest looking at your RCA, and using clamps?this method was used for decades, and has proved itself.

thanks again marik

great info. I will be using a clamp at the bottom. the top is so crowded i may run into a bit of troubel there. I'll try the pin idea anyway and hope it wil be ok.

I didn't realize there was that much difference in the magnetic flux between the different types of magnets. the element will be removable and could be replaced later down the line after I find some stronger ones.
I'll search google for some of those neo's you talked abou and see if I can find some similar in size.

I have a similar sized Neos, and they show about 6000 Gauss flux in a ¼? gap, so my guess ceramics would give about 600-750 Gauss. Considering saturation in the gap with Neos, you might be up to 1000 Gauss there, which is still very low, and an output of the mic will be low.

Click to expand...

is there a typo here?... just the part "with neo's"... did you mean? "with ceramics" the reason i ask is you started with 6000 Gauss in a 1/4 inch gap.

this lack of magnet power has me very worried. i don't have a gauss meter but maybe ican borrow one. my gap is 1/8" plus 1/32"gap on either side of the ribbon.

You can increase magnets efficiency by putting tapered shape pole pieces, or/and magnetic return circuit, and considerably increase the gap flux density, and sensitivity of the mic.

Click to expand...

hmmm I don't think I have enough room for tapered pole peices. Unless: I might be unclear as to what you mean here....do you mean shaving off a corner of the magnet so it resembles a blade of a knife sharpened on one side only? a diagram might be helpful here.

I am interested to learn more about this magnetic return circuit. I'll do a search here for that.

Do you think the magnets could be assisted by an electromagnet on either side of my magnets? Of corse this would mean powering the mic. I wonder how much I could get from 48v phantom power.

Or you could decrease distance between your magnets, but potentially you can run into increased resistance of the ribbon

Click to expand...

increased resistance just by moving the magnets closer? how does this happen?

Of course, diffractions, and especially effect of a long narrow tunnel behind the ribbon, will through things way off unpredictably, but at least you have a start.

Click to expand...

I hope this unpredictability plays in my favor.

Without taking into account diffractions, theoretically, you?d get a null somewhere around 4KHz, with a fall starting at around 2KHz

Click to expand...

this may be a good thing since that is the frequency range where sibilance becomes a problem. since this mic is being designed as a vocal mic a frequecy response somewhere between 200hz and 2k will be OK. And as a vocal mic proximity effect may may make up for any low end loss.
Also: how did you calculate this null?

in your system, with a condenser as a second element, you could use it as a benefit, crossing these two elements over somewhere in a 2KHz region, and using the ribbons natural fall as a part of x-over.

Click to expand...

yeah ... I'll try to plan for this. looks like I'll have a bit more circuitry than originally planned ..... this this is gonne be tight?

thanks for the info on the META too I'll go there now.
AND thanks for your post .... this info will no doubt impress Clarence and give additional, wonderful credibility to the collective intelligence forum. (for which I am very thankful) At least he'll have some good reading and have some boys (and girls too) to talk shop with.

Looks like I have a bit more research ...better get on it...
1000 thanks
ts

hey i thought i'd add this info from Mr Royer of Royer microphones
if anyone knows this technique for measuring the resonance of a speaker will you plz post it here? i never though i's be researching speaker theory for the purpose of building a ribbon mic. but now that i think of it it make perfect sense.
any way here's the quote

Dave Royer wrote:

Our techniques are somewhat different,
but for a "so-so" microphone, like a Reslo, your approach is
perfectly reasonable. The techniques you describe bring back memories. . .
I have a couple of hints, by the way. . .

1. Many less expensive ribbon microphones will profit from a
transformer replacement-- the RCA Varicoustic has a particularly
good transducer and a particularly bad output transformer.

2. If you are familiar with the technique for measuring the resonance of
a speaker, a similar technique can be used to measure the resonance
of a ribbon microphone's ribbon-- that's how you get consistent results.

3. Ribbon microphones will give their FLATTEST response with a load
that is at least five times the nominal impedance of the ribbon-- RCA
specified that their ribbon mikes work into UNLOADED input transformers.

More Comments from Dave Royer:

1. For corrugating ribbons, get yourself a couple of gears
and make a jig so you can pull the strip of foil between the lightly-meshed gears,
like running a sock through a wringer-- this has been the usual way to do the job.

2. With skinny little ribbons, glue ONE END of the ribbon to the end of
a broom straw; then you can poke the broom straw through the transducer
(prop the clamping blocks up with another broom straw) and pull the ribbon through with less cussing.

3.  With a mike like a Varicoustic, with a pot metal case, use THREE wires to
make the connection to the ribbon-- the BOTTOM of the ribbon connects to the output transformer with ONE wire; the TOP of the ribbon connects to the transformer with TWO pieces of wire, connected in parallel.Twist the three wires
together between the transformer and the bottom of the ribbon, then run the two
wires going to the top of the ribbon ONE ON EACH SIDE OF THE RIBBON.
That way, you will get a hum-bucking effect-- with a Varicoustic, the hum pickup
is unacceptable if it is wired the usual way; it is very satisfactory if wired as I suggest.

Click to expand...

enjoy
ts

Yes, this D. Royer passage is from Larry's website.
Search the Meta--you will find the answers to your questions.

Yes the meta search/reading is an excellent source.
Newbies search and read. I will.
If someone accidentally comes across some info in the meta/forums please point me to that by posting the link here for me. I would be sincerely greatful. Even suggested search criteria would be excellent.

some of the stuff i post here will be repeated in the meta's
this is my way of organizing the things i need to review or feel is related to this subject of designing/understanding a ribbon mic.
there is no history,maintenece,or troubleshooting info here. Just physics and design info.
Also if you have designed or built something a bit different from the commercially available ribbon mics please feel free to post your pics,info and/or specs.

I think the ribbon mic still has some room for some modern innovation.
I'd like to see a Monster/Frannkenstein/Hotrod ribbon mic with every possible innovation that could be applied.
I'd like to see the ubiquitous 48 volt phantom power, which in the past has proven lethal to a ribbon mic, utilized in some way.
i have plans of useing up the phantom power to protect this mic.
this way the mic is protected.
Even if it's just for asthetics...ya know ... a pretty lighted logo would be nice (sexy even ...lol) I have something in mind for my mic and I'll post a pic of my scetch as soon as I can scan it. something a little bit fun.

here's another extremely excellent source of info.
read this about ten times! great physics info.
please feel free to explain in newbie terms or add info to anything posted here.

http://home.vicnet.net.au/~macinc/news9.htm

enjoy
ts

[quote author="ToobieSnack"]
there is no history,maintenece,or troubleshooting info here. Just physics and designe info.
[/quote]

Internet and books are full of history and maintenence info. Physics and especially design info you can find only here.

An interesting text on magnetic maeasurement

http://www.inchem.org/documents/ehc/ehc/ehc69.htm#SectionNumber:2.3

here is an exerpt:

A description of the most common measuring techniques follows,
together with a comparison of their advantages and limitations.
Further details can be found in Williamson & Kaufman (1981),
Grandolfo & Vecchia (1985a), and Stuchly (1986).

The two most popular types of magnetic field probes are a
shielded coil and a Hall-probe. Most of the commercially available
magnetic field meters use one of them. Recently, in addition to
Hall probes, other semiconductor devices, namely bipolar
transistors and FET transistors, have been proposed as magnetic
field sensors. They offer some advantages over Hall probes, such
as higher sensitivity, greater spatial resolution, and broader
frequency response.

For measurements of very weak magnetic fields, such as those
produced by endogeneous currents in biological systems, other
sensors are used. These include fluxgates, optically pumped
magnetometers, magnetostrictive sensors with optical fibres, and
superconducting quantum interference devices (SQUIDS). These
devices are rather specialized and expensive and are not normally
used for the measurement of extraneous fields in biomedical
applications (Stuchly, 1986)

Click to expand...

I think I'll get me an optically pumped magnetometer or a SQUID
lol
enjoy
ts

Great ref!

A gaussmeter ain't that cheap. You don't want to get one for measuring earth magnetic field. It is way to sensitive--you don't want that.
At first, to save some $$$, I was DIYing it, getting different Hall sensors. It was a big challenge to find a sensor with LOW sensitivity, or thin enough for my needs. I was able to find some up to 2000 Gauss, but after that they'd go into nonlinear range. The other problem was calibrating, so finally I gave up and got a meter from here:

http://www.trifield.com/gauss_meter.htm

The company is in Salt Lake, so I just walked in.

Toobie, what kind of trafo are you using? I am lovingly building a ribbon mic (more details of which soon) and have yet to decide on the transformer. I was looking at Sowter's website. They have two there: a 1:10 2 (actually 1 to 3) ohm input and 200 ohm output, and a 1:40 0.25 ohm input and 200 or 600 output.

Which one would you guys recommend?

I personally would go for the 1:40, unless you were planning some sort of active gain stage after the output transformer.

ju

Fum so happy to see you here.
your mics look so lovely :grin:
and WOW it's freaky that this trafo stuff came up today!
I was just about to approch that.
I was sitting here, with my toungue hanging out like the "big bad wolf"
looking at my RCA 74 b like she was "red riding hood"
"come here little red riding hood me and cj want to talk to you ....lol"
I have plans of changing my RCA trafo anyway so ....no....no i don't want to do it....:licks chops:thinks hmmm sour grapes....)
I would like very much to use the sowter trafo's 40:1 mumetal enclosed
I also asked Clarence Kane what he used he said "i use lundahl's" he kinda balked when i asked about sowter and then when i mentioned the lundahl he quickly responded "yeah i use the lundahls"
so these are three choices so far...
one very cheap and at hand ( but damn the RCA is working now so I''d like to leave it that way until i get the RIGHT trafo)
the other 2 considerably expensive for me...waaahhhh
so now for the 4th :
I have this little 1 watt audio amplifier by calectro
it has some pretty little trafo's on it that i think could use or re-wind .... hell i don't know i'm just hoping

it's looking like i can use the little trafo

>>>>pagiing guru CJ ....paging guru CJ.....haha

I have copied here on my hard drive something from the forum on "transformer testing" I'm gonna read throught that and see if I have the means to test these and determine some info.
one is clearly maked:


after looking closer this one is not what i need but read below:

at one end G 4 8 and 16 ohms ...obviously and output trafo..
the other side of the trafo has three connections
the bobbin has no dividers apparent to me
it apperars the lams are E and I with a piece of metal track holding everything together.
the bobbin is 5/8" x 1/2" aprrox
the lams are 1" x 3/4"

hmmmm wait a sec :seems like ther would have to be some kinda division between these coils ...I'm totally lost ......3 in 4 out how could this be wound...i don't think this is my trafo but.........

there is a much smaller trafo:*******
(looks ot be exactly the same size as my RCA trafo hmmmm happy happy?????

one side has three leads the other side 2 leads

JUST LIKE MY RCA

hey i think i may be on to something here....same size same leads ....... an input trafo on a 1 watt amp card????

this could work right?

I'm pullin this little one first.



Anyway damnit i have a nice little trafo and bobbin and some E I lams and some wire
HHHHEEELLLPPP!!!!!

>>>>pagiing guru CJ ....paging guru CJ.....haha (ok but seriously)

I will post some pics of the trafo's in question.
your help is sincerely appreciated.
I look forward to your response.
thanks
ts

I would say don't butcher something that's already working, unless you know for certain it's gonna work slick. :roll:

Ribbon mic traffos tend to be of much higher ratio, and tend to be built specifically for the task. Look at the impedence of the ribbon, it's really really small. Most ribbon mic traffos have input impedences from .2 to 2 ohms!! And they are readily available. The lundahls sound good and can be ordered through K&K audio.

I'm planning on checking out the sowter, to see how it sounds.

Cinemag has traffos that will fit the bill nicely, and dammit, if you just need a frick'n traffo that will work for experimenting, pm me, and I'll hook you up with one from one of my mics. I've got at least one hangin around that doesn't have a home :grin:

Regards

ju

oh how completely kind thank you i think i will take you up on that PM offer.
:grin:
ts

BTW this comes as much need good news....i was using a crappy 14"monitor and decided to hook up my beautiful 20" radius ... all fine happy :grin: happy THEN ......PUFF!!!....:shock: right in front of my eyes OUT went mey precious monitor. .....

now i'm back on my little 14" peice of crap listening to:
ZZ Top "got me under pressure" on the radio quite coincidentally arrrggg.....hahaha

ok going to PM mode
1000 thanks
ts