MXL R144 Transformer Replacement

[saxmonster]

Should I swap it out.  The stock one seems very noisy and picks up Gnd Buzzes RF very easily.

What ratio should I look at?

Thanks
-Scott

 

[tchgtr]

Don't know what ratio you'd need, but the Cinemag 2480 is a humbucking design that should reject the kind of noise you are talking about.
It's been recommended for other ribbon mics.
10:1 ratio

 

[Enchilada]

Have you read this article?

http://www.preservationsound.com/?p=3687

 

[dmp]

The Cinemag 9888 / 9887 are ribbon output transformers with shielding for about $50. Ribbon mics typically have higher ratios. I agree about the buzz with this mic.

 

[tchgtr]

Have you read this article?

http://www.preservationsound.com/?p=3687

Nice article. Might have to try one of those xformers in my Apex 210.

Saxmonster-also check that the wiring from the ribbon to the OT is all in the same plane. If it goes all over the place, it might be picking up some stray noise.

 

[saxmonster]

What is OT?  Thanks for the info guys.

-Scott

 

[tchgtr]

output transformer- I get tired of writing it out.

 

[saxmonster]

DUH. my brain was fried, I just could not get away from thinking OVER TIME, OT.  I might just go for the cinemag 9888 then.

Thanks guys

 

[GregNey]

I put the Edcor RMX1 in mine and honestly did not notice much of an improvement. I'm going to try the Cinemag in the next one I do.

 

[dmp]

I put the Edcor RMX1 in mine and honestly did not notice much of an improvement.

+1
I swapped the transformer in my R144 with a transformer from a better sounding ribbon mic. The R144 sounded the same as before.
lt isn't a very good sounding ribbon mic, in my opinion. Needs more than the transformer anyway. Weirdness in the frequency response.

 

[tchgtr]

I put the Edcor RMX1 in mine and honestly did not notice much of an improvement.

+1
I swapped the transformer in my R144 with a transformer from a better sounding ribbon mic. The R144 sounded the same as before.
lt isn't a very good sounding ribbon mic, in my opinion. Needs more than the transformer anyway. Weirdness in the frequency response.

Do they need a thinner ribbon, or do you think the problem is elsewhere? Seems to me I remember them claiming a 1.8 micron ribbon, but then heard others say that in fact it did not seem to be the case.
Perhaps the ribbon is not even mounted right?

 

[dmp]

Do they need a thinner ribbon, or do you think the problem is elsewhere? Seems to me I remember them claiming a 1.8 micron ribbon, but then heard others say that in fact it did not seem to be the case.
Perhaps the ribbon is not even mounted right?

I'm not an expert but ribbon mics are pretty simple. Unless the acoustics of the body and grill were the problem, it would have to be something about the ribbon I think. I'd like to buy some ribbon stock to try replacing it.

 

[zebra50]

I don't know the MXL R144, but I have seen lot of the china ribbon mics with much thicker foil than claimed - I have seen stuff around the 4 to 6 micrometer mark.

It is really too thick and too stiff for the job, and the extra mass gives a lower output. The problem does not seem to be consistent, with some batches of mics being better than others.

The transformer is then often wound higher to get some of the level back - I have measured some at 1:54.

Changing just the transformer can just expose the limitations of the ribbon, whereas changing just the ribbon can give you an output impedance that is too high (= more noise). Really you need think about replacing both together.

Dirty ribbon clamps can also be a source of noise.

Again, I haven't seen the MXL so can't comment directly on that. But I have repaired & modified a couple of dozen of the t-bones, Apex, Avantone etc.

Stewart

 

[tchgtr]

dmp-I have some 1.8 micron aluminum that I got from the Lebow Company in Goleta, CA. Just under $30 for a piece @ 8" square. Just re-ribboned a Beyer M500 with a normal corrugated ribbon using this material, and it sounds great. Wish I could remember who to thank for the info that led me there, but it's on this forum somewhere. Search "beyer M500".

Will eventually do my Apex 210, but the 1.8 micron foil is like working with smoke, so biding my time, and the Apex doesn't sound too bad after I went thru it and re-tensioned it, and removed all the baffles. The original material in that mic is quite thick, and made me wonder why folks were talking about ribbons being so fragile. I'm sure it would sound better with the thinner ribbon, and probably be much easier to do than the M500.

Stewart-Most likely it was you that I was quoting about the actual ribbon thickness on these mics. Your posts here are a treasure of information, and I will look into replacing the transformer in the Apex after I do the foil. I was careful to remove any old foil/dirt on the M500 clamps as a result of your earlier posts, and I'm sure that is one reason it sounds so good. Thanks for chiming in here!

 

[zebra50]

It is a pleasure. I have learned so much from this place (and the place before)... and am still learning! Probably the info was from Marik or myself - we have both found and posted similar observations.

If you have managed to re-ribbon an M500, then the Apex will be be a doddle. Those Beyer's are a real challenge.

I did a pair of t-Bone 100 Royer rip-offs last week for a customer. They had well over 4 micron foil - you could pull it and it didn't break. The transformer was about 1:55, which is too high for 1.8 foil. With a new transformer (one of our own) and 1.8 foil, they were fantastic, and the owner is delighted.

 

[ricardo]

Swapping transformers and ribbons willy nilly is unlikely to give good results.

The transformer has to be matched to the ribbon. On the electroacoustic side, the 'motor' (ribbon) has to be matched to the air.

Best midrange efficiency [1] is when the mass of the ribbon is about equal to the mass of the air load.  This sets your ribbon thickness and resistance.  The air load is set by the physical arrangements around the ribbon.

The resistance determines the best transformer to use.

Yus Ribbon Gurus, please excuse this simplified explanation which doesn't even touch on LF & HF effects

[1]  Efficiency is not the same as voltage output.  You only get the full advantage if the transformer is properly matched to the ribbon and your preamp too.

 

[dmp]

Great info in this thread!
Thanks

 

[dmp]

I have some 1.8 micron aluminum that I got from the Lebow Company in Goleta, CA. Just under $30 for a piece @ 8" square.

Thanks for the tip - I just ordered a sheet to experiment with

 

[saxmonster]

I have a BV11 transformer laying around. 

What would it do to the mic if I installed that in th R144? 

Would I get more volume out of the microphone with less gain on the preamp?

I think the BV11 is a 5:1 transformer but I don't know what is in the R144?

Just looking for some ideas.

 

[HellfireStudios]

No. In ribbon mics, the ratio actually would be step-up, not step-down. So a "normal" ratio would be like 1:35. A tube mic would use a step-down transformer like your BV11 at 5:1. So, in short that transformer is not compatible, even in reverse, if you want any sort of volume from your mic.

-James-