Modding a Nady RSM-4 Ribbon Mic

[Bow]

Some of you gents might dig this...

Started with the NADY RSM-4

Removed the Inner screens and re-tensioned the ribbon... sounded like this with my fat fingers, 12 String, and the Mic about 10" from the 12 fret, angled toward the Neck/Body Joint:

http://riley-music.com/RSM4/RSM4Mod/RSM4Stock.mp3

Next I dug around and found out about Transformer swaps.
Refusing to pay as much for the replacement transformer as I paid for the Microphone new, I discovered the RMX1 Ribbon Microphone Transformer from Edcor... Priced right at $25 + $5 Shipping to my door UPS Ground

http://edcorusa.com/products/transformers/rmx/rmx1.html

Since I have a soldering iron and very few Morals...



Remove all the screws from the body and baskets to gain entry to the guts...



Remove the ribbon motor from the basket (Watch those magnets and your screw driver or bye-bye Ribbon), and unsolder the old transformer leads...



install new transformer leads through the neck and solder onto the ribbon motor (Red is Common, Blue is Input), Then re-install the ribbon motor into the Basket for its safety and your sanity:





Next, remove the old transformer from the XLR connector and install the RMX1 leads to the XLR jack... don't forget to run the wires through the mic body BEFORE soldering...

Black Wire - Pin 1
Yellow Wire - Pin 3
Green Wire - Pin 2



Next, reassemble the body with all the screws and try out your modded Ribbon mic!



My mic now sounds like this with the same setup...
My fat fingers, 12 String, and the Mic about 10" from the 12 fret, angled toward the Neck/Body Joint:

http://riley-music.com/RSM4/RSM4Mod/RSM4Modified.mp3

Comments welcome

[sweetbeats]

wowwwwwwwww...that is a HUGE difference...the clarity/sparkle on the original is terrible/non-existent, and it sounds so boxy.

The modded version sounds so much more pleasing to the ear and there is so much energy to some of the lower harmonies...the 4ths and 5ths...not boxy or boomy but clear and strong.

what a difference!

[antichef]

nice post - love all the pictures. Changing the transformer in a cheap ribbon mic has been one of the most straightforward and rewarding mod projects I've done, as well. I now have two of them with the Edcor RMX1 and two others with Lundahls. I like the Lundahls better, but you're right - they tend to cost more than the mics

[Bow]

Thanks for the replies.

Yup, I have been told the Lundahls sound great, but I'm a budget minded guy. I am very happy with the way it came out.

[thajeremy]

I guess this would be done the same way with a Nady RSM-5....I have one of those...but not the RSM-4....

[antichef]

I did it with 4 different models of cheap ribbon mic, and there were no surprises.

[thajeremy]

If I were to look for a Lundahl transformer to do this...what specs should I look for?

[antichef]

Fortunately, there's not much variation on ribbon mic transformers for a particular manufacturer, and if they make more than one, the difference is usually in core materials or connector style or something other than ratio.

I used the LL2912 because it has wire leads (the others they make are PC mount, which may be good too, but I knew I could make wire leads work). The form factor of the LL2912 is slightly longer and narrower than the stock tranny that appears in these cheap chinese mics, but I haven't had a hard time making it fit -- I didn't work on one exactly like yours, but I did work on an RSM-4, and one that was similar to an RSM-3, and I bet they have about the same housing size as yours.

The LL2912 has nylon or teflon or something for the coating of the wire leads - they come pre-trimmed, so you don't have to strip, but if you mess up (like I did) and have to cut and re-strip, it can be a challenge, because the coating is really tough (I think there are tools especially for the job, which I didn't have)

[Bow]

The Wire Insulation is teflon.

You can strip it with normal strippers, it is the same type of wire/insulation we use in out aerospace applications.. it is great because teh insulation doesn't melt when you solder.....

[guitar junkie]

ok so I have one of these mics myself, and am really thinking I might just change this bugger out sometime when I get some money to do it with...

Any noise floor improvements?

Mine has a buzz to it

[Bow]

I haven't noticed much of a buzz on mine, before or after...

However, I wouldn't be surprised if yours has a flakey solder joint, the factory solder on mine looked like it was done with a hot rock and a bar of lead...

[sweetbeats]

the factory solder on mine looked like it was done with...a bar of lead...

Butbutbut...that's not ROHS compliant....!

I prefer a hot poker that's been in the fire...I've found the heat to be a little more focused than the rock.

[antichef]

Originally Posted by sweetbeats

I prefer a hot poker that's been in the fire...I've found the heat to be a little more focused than the rock.

You can get an even warmer sound when you just put the mic in the fire

[sweetbeats]

Huh!

Does that work with pre's too?

Per artist request for a "creamier" sound I've been pouring half and half through the little vent slots but my efforts have only been met with limited success...if I can convince the artist that they are really looking for a warmer sound...well we might really be on to something then...

[thajeremy]

somebody pronounce Lundahl!!! record yourself saying it or something...Im gonna call a local electronics store and see if they carry them....its a pretty large store.....also, I spoke to one of the guys in my maintenance dept at work and he said I could purchase it through work and get a pretty nice discount...

[Bow]

Lun-Dal?

That is my Guess

I believe the "H" is silent...

[guitar junkie]

guess I am gonna have to take the blasted thing apart soon and see what happens then....

[antichef]

as far as I know, the only USA distributor for Lundahl is:

http://www.kandkaudio.com/

that's where I got mine. I, um, never had to pronounce it, but I'd go with Bow's instructions.

[lollygagger8]

How does one retention the ribbon w/o breaking it?

I just used an unmodded RSM-4 on electric guitar, and it sounded really good. I can't wait until I mod this!

This mod looks very easy to do, and I'd like to do it myself instead of sending the mics to Oktavamod and save enough $$$ to buy another mic and transformer!

[antichef]

you mean the Right Way, or the not-really-concerned-with-end-result-as-long-as-it-works way?

I don't know anything about the first way, but I think it involves a frequency analyzer.

The second way involves a small screwdriver to loosen a clamp on one end (in an environment with no moving air), and a q-tip that you wetten with spittle so that it'll stick to one end of the ribbon so you can pull it out until it looks good, and then re-tighten the clamp.

If the unclamped ribbon does catch some air, it's weird - it's like a wisp of smoke, the way it moves. But it's not *as fragile* as you might think.

I can only imagine how much better my tracks would sound if I had done it the Right Way! -- in all seriousness, it does make a lot of sense to get it tensioned precisely, and properly, but I didn't go there this time.

now the obligatory disclaimer: POSTER IS NOT QUALIFIED AND HAD NO IDEA WHAT HE WAS DOING AND PROBABLY JUST GOT LUCKY

[Jim Lad]

Nicely done!
I'll come looking for you if I ever need to fix my ribbons.
You think you could start a "Show Me" thread on checking and repairing ribbon tension?

[dgatwood]

Originally Posted by antichef

The second way involves a small screwdriver to loosen a clamp on one end (in an environment with no moving air), and a q-tip that you wetten with spittle so that it'll stick to one end of the ribbon so you can pull it out until it looks good, and then re-tighten the clamp.

In my experience, the ribbons usually end up electrostatically welded to the clamp. I always found that I had to completely remove the top part of the clamp, carefully peel the ribbon loose without tearing it (using a screwdriver inserted slightly into the non-ribbon end of the clamp), tension the ribbon with a wet Q-tip (using moisture to stick it to the bottom half of the clamp), then reinstall the top part of the clamp. YMMV.

I tore a ribbon on the first one because I completely unscrewed the clamp and the top half fell out of the way before I realized the ribbon was stuck to the top half of the clamp. Don't make that mistake. Unscrew it about halfway, then dislodge the ribbon, then finish removing the clamp.

[antichef]

Originally Posted by Jim Lad

Nicely done!
I'll come looking for you if I ever need to fix my ribbons.
You think you could start a "Show Me" thread on checking and repairing ribbon tension?

Yeah - what dgatwood said -- same thing happened to me, but I was lucky enough to notice the ribbon attached to the clamp before I tore it. I gently scraped/pushed/coaxed it off with an x-acto knife blade.

I have to say, I hesitate to post pictures or a how-to guide, because this is really not the right way to do it (IMO) - it's just the cheap/dirty/risky/likely-to-result-in-a-suboptimal-mic (although greatly improved over slack-ribbon) way to do it

[dgatwood]

Originally Posted by antichef

Yeah - what dgatwood said -- same thing happened to me, but I was lucky enough to notice the ribbon attached to the clamp before I tore it.

Me, too. On #2, #3, and #4.

[DrewPeterson7]

How much of a difference does retensioning the ribbon make?

I've got one of these, and while it's not the most transparent of microphones by any stretch of the imagination, it's actually a phenominal lead guitar mic - up close on a Rectifier, it's a very easy-to-place, smooth, full sounding microphone. The slightly attenuated bass and rounded off highs work perfectly for a lead guitar tone, and while I wouldn't want to radically change the way the mic sounds, if a tighter ribbon would help it somehow I'd be interested in maybe taking a crack at it.