RB500 ribbon mic transformer update?

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inputhone

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Joined
Aug 17, 2010
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53
hey there, i read a lot about people thinking about improving their cheap ribbon mics with new transformers but i never found anyone who really did it (with a Lundahl for example) and if it would improve anything besides maybe nois floor. Anyone here did that?

After improving the headbasket and and popfilter garbage inside there i was thinking about also having a go for the tranformer to make them more useful (even though i already really like them on bass amps and more).

Anyone?  :)
 
Hi Inputhone
i'm in the process of modding an SE mic. i'm no expert, there are folk on this forum who are, but I've learnt a few things in the process. maybe some of this will help..
Firstly you need to decide what you don't like about the sound of the mic, that question will then lead you to the correct answers, rather the thinking about generic improvements based on brandnames.
The most important part of a ribbon mic is the Ribbon. you need to start with the ribbon when modding. the alloy is important plus the thickness. for example my SE mic ribbon was plastic with a metal coating (we didn't know this until we removed it!). it just sounded cheap with mid freq emphasis. no warmth or detail. my new ribbon sounds much better and has a different iron content, which means the output is lower, so now i'm looking into a new transformer to increase the step up.
so you can see from this example how important it is to start by checking out whether the ribbon cqn be improved.
also i'd be careful about what you pull out. it is recommended to leave in the fine mesh which protects your ribbon from damage from high SPLS or singers. the holes in the mesh are probably so small they would only block very high frequency content which you probably don't want anyway if you're using a Ribbon.....
my two cents. enjoy the ride!  :)
Ian
 
yeah, i just took out the outer metalic frame (just more resonating material) and the outer mesh. ripped of the inner mesh (placed on the front and back of the ribbon) from the metallic plates it was attached to and build some new plates out of plastic with bigger holes for better high frequency respond (was a little bit low-pass filtering) but too keep the ribbon save. also put some foam into the empty bottom of the mic and put foam between the motor and the housing to keep the headbasket from ringing to much when fed with high signals.

the ribbon looked good to me. how can i check the thickness? or material? where can i get new ribbons and how can i shape them properly and check the tension? the sound already is nice for guitar and bass (that's what i use it for) but could be more defined in the high mids and low end compared to more expensive mics like a coles 4038. sometimes this cheaper one sounds a bit washy there. levels and nois-floor are fine to me. thanks!
 
mmm. if you like the sound it may be best to leave the ribbon as is. trouble with ribbons is you usually can't put them back in once removed. you can try experimenting with acoustic filtering by placing various thicknesses of felt behind the motor. they did this in the old days. and it reduces the pickup from behind the mic which may be beneficial. I'm afraid i can't help with these other questions....I'm based in the UK and got help from an old school sound engineer friend.
however you can buy DIY ribbon kits online and there are a couple of good sites well worth visiting for more info....
http://recordinghacks.com/2008/11/01/chinese-ribbon-microphone-designs/
http://www.xaudia.com/xaudia/Home.html

have fun  :)

 
inputhone said:
... ripped of the inner mesh (placed on the front and back of the ribbon) from the metallic plates it was attached to and build some new plates out of plastic with bigger holes for better high frequency respond (was a little bit low-pass filtering) but too keep the ribbon save. also put some foam into the empty bottom of the mic and put foam between the motor and the housing to keep the headbasket from ringing to much when fed with high signals.
DON'T DO THIS!

The mesh on either side of the ribbon isn't just for protection.  They are an important part of the damping system and replacing them is likely to give VERY wonky jagged response.

BBC Engineering Memo no4 which describes the design of the 4038 explains what they do.
 
hey there, i read a lot about people thinking about improving their cheap ribbon mics with new transformers but i never found anyone who really did it (with a Lundahl for example) and if it would improve anything besides maybe nois floor. Anyone here did that?

After improving the headbasket and and popfilter garbage inside there i was thinking about also having a go for the tranformer to make them more useful (even though i already really like them on bass amps and more).

Anyone?  :)

Hi  inputhone,
There is little point replacing the transformer alone as the the biggest problem with China mics is the ribbon material and it's implementation then once you sort that out the transformer upgrade would be worth it!
Use the search feature you should find loads of great info on ribbon mics
 
ricardo said:
DON'T DO THIS!

The mesh on either side of the ribbon isn't just for protection.  They are an important part of the damping system and replacing them is likely to give VERY wonky jagged response.

BBC Engineering Memo no4 which describes the design of the 4038 explains what they do.
really?

i was referring to this mod i found online i've been told should work fine. http://moonroomrecording.blogspot.de/2010/06/shinybox-ribbon-mic-mod.html

this guy there took away the whole plates because they should be likely to ring when fed with high signal. assuming that i replaced them with a plastic frame with almost no plastic matiral in the way (just the mesh) to keep protextion without the metal plates (they had quite tiny holes).

you think that is still a bad idea? let me know!
 
Not sure about RB500, but other Chinese rebranded versions of that mic I ever seen don't have damping screens. Most likely OP talks about gaze glued to resonator plates.

As a side note, longer ribbons much less prone to resonances, as opposed to short ones. The 4038 which BBC memo refers to is a 1" short ribbon, while the RB500 ribbon is ~2.5" long. Would be loading air enough to damp 6um thick ribbon used in Chinese mics is very questionable, but this is already completely different issue...

Best, M

ricardo said:
inputhone said:
... ripped of the inner mesh (placed on the front and back of the ribbon) from the metallic plates it was attached to and build some new plates out of plastic with bigger holes for better high frequency respond (was a little bit low-pass filtering) but too keep the ribbon save. also put some foam into the empty bottom of the mic and put foam between the motor and the housing to keep the headbasket from ringing to much when fed with high signals.
DON'T DO THIS!

The mesh on either side of the ribbon isn't just for protection.  They are an important part of the damping system and replacing them is likely to give VERY wonky jagged response.

BBC Engineering Memo no4 which describes the design of the 4038 explains what they do.
 
this guy there took away the whole plates because they should be likely to ring when fed with high signal. assuming that i replaced them with a plastic frame with almost no plastic matiral in the way (just the mesh) to keep protextion without the metal plates (they had quite tiny holes).

you think that is still a bad idea? let me know!

The resonator the plates induce reflections and are there to boost high frequencies but they also effect other parts of the sound weather you feel the effects are desirable or not is up to you.  Try both! :)
 
inputhone said:
i was referring to this mod i found online i've been told should work fine. http://moonroomrecording.blogspot.de/2010/06/shinybox-ribbon-mic-mod.html
If you think this guy knows more about ribbons than Shorter & Harwood, go ahead.

See fig 10 of http://downloads.bbc.co.uk/rd/pubs/archive/pdffiles/monographs/bbc_monograph_04.pdf

That mod is seriously dodgy.

Does it change the sound?  Absolutely.  For the better?  :eek:

Does it make the mike more fragile?  Absolutely.

Your choice.
 
Speaking of resonator plates, let's not forget the same 4038, as well as RCA44, B&O, Melodium, vintage Oktava, and quite a few other, rather revered ribbons in one or another form did have resonator plates (which BTW, also do serve as an additional protection). That was for a (good) reason.

As for the using the foam... depending on its origin and quality expect it to start deteriorating in anywhere between 1-5 year. Ever seen Beyer M500 (the one with grill lined with foam) with all the gunk sticking to the ribbon and magnetic gap? I am not even talking about condensers, where electrostatic attraction nicely pulls all that stuff right on membrane...

I'd listen to good advises from the folks in this thread and first do quite a bit of reading before you start busting your mic following the mods you read on internet.

Best, M
 
Hello !!
I also use 2 RB 500 and after I removed the silky mesh and the inner Frame with the wiremesh i  can hear a little improfment in terms of Resolution and Dynamic,after i damped the whole  lower Body with (non rottening) Dampingmatrial i hear a little less ringing at 3-6kHz ,after removing the  Metalholeplate it was lacking high Frequencys, over 8 k so I put it back. In Terms of the Transformer it is good to know if they have the declaimed 600 ohm or if they are more in the 2 k Ohm Range.A Friend of me has a few older Rb500 from i think 2009 and they were  at 2,3 k Ohm (Agilent Meter).After the change to the Lundahltranny,the Sound was worse, probably a Impedancemissmatch between the Ribbon ,Premierwinding,Secondarywindind and the Inputimpedance of the V72a which is even quiet high at 4k Ohm .We were not able to change the Ribbon yet, so we put everything back like it was .When these mics were plugged into a vintage,low Impedance Micpre,they sounded horrible,of course but when plugged into a modern Steinbergmicpre with a Inputimpedance of 2,5k Ohm the Sound was quiet good. Probably there  happens a current instead of voltage coupling.Funny but if you keep the Cable short it works.When my 600  ohm Mics were plugged into the Steinbergmicpreamp they sounded worse, dull ,boring,and  and zissy.With my V76 they sound great.(600  Ohm Mic into 600 Ohm Input,currentcoupling) So without a prof. Analysis of the Mic you have,i would not change the Tranny.Some Folks change the Lamination of the Tranny with better high Nickel one s ,but that changes the Impedance of the Tranny ,too,so thats not easy done.
I have a high respect for those who can crinp and attatch a Ribbon in the Motor of a Ribbonmic.I tried it a few Times,........... All the best,Lothar .
Greetings from Berlin and sorry for my bad written English
 
That mod is seriously dodgy.

Does it change the sound?  Absolutely.  For the better?  :eek:

Does it make the mike more fragile?  Absolutely.

Your choice.

I wouldn't say the mod is seriously dodgy...let's not throw the baby out with the bath water :)...It does address the ringing base of the mic as long as a good damping material is used! As for resonator plates take em or leave em it's up to the user and depends on how and where and how you use the mic ..Yes it's more fragile in some ways but as long as you are aware of the fact and use caution it's a non issue in fact I've seen quite a few mics with ribbon corrugations flattened out from the ribbon contacting with the plates.
 

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