Michael Joly MXL 991 mod mic

[skmando]

Hi all,

New to this forum. The reason I'm here is I was recently gifted a Michael Joly modded mic, a small D based around a MXL 991. From the few posts I could find about it online, I believe it sonically sits 'between' the km84 and km184.


The mic is fantastic! It's quickly become my fav Small D for a number of sources, including mandolin (my main instrument). I don't have access to a km84, but we have km184s at work, and this sounds very similar, with slightly less push around 5kHz. Very, very happy with it.

It's my first 'modded' mic, and has got me really interested in maybe modding a few mics myself. I have an old AKG C1000 with the grill snapped off sitting at the bottom of the mic cabinet doing nothing, so I'll be attempting my first mod soon...

One question I did have in regard to the Michael Joly mic and thought someone here might be able to answer; is this mic transformer based output like a km84, or transformerless like a km184?

Thanks in advance,

Sean

 

[Khron]

One question I did have in regard to the Michael Joly mic and thought someone here might be able to answer; is this mic transformer based output like a km84, or transformerless like a km184?

http://recordinghacks.com/microphones/MXL/991

The capsule, and in fact the circuit design, match the MXL 603S,

 

[Migs 31]

Hi all,

New to this forum. The reason I'm here is I was recently gifted a Michael Joly modded mic, a small D based around a MXL 991. From the few posts I could find about it online, I believe it sonically sits 'between' the km84 and km184.

View attachment 135924
The mic is fantastic! It's quickly become my fav Small D for a number of sources, including mandolin (my main instrument). I don't have access to a km84, but we have km184s at work, and this sounds very similar, with slightly less push around 5kHz. Very, very happy with it.

It's my first 'modded' mic, and has got me really interested in maybe modding a few mics myself. I have an old AKG C1000 with the grill snapped off sitting at the bottom of the mic cabinet doing nothing, so I'll be attempting my first mod soon...

One question I did have in regard to the Michael Joly mic and thought someone here might be able to answer; is this mic transformer based output like a km84, or transformerless like a km184?

Thanks in advance,

Sean

Well...

Since it is a modded mic, there could be ANYTHING in there!
MJ might have changed a few crucial components or simply replaced the PCB for one of his own, who knows?

Since you have one just there, why don’t you open it (three small screws) pop it out and take pics of it. Many knowledgeable old grumpy folks here can tell you exactly what is the “secret sauce” and if yes or not it’s close to a Neumann KM84 or 184. Who knows maybe you can replicate it and have a pair

PS: Mandolin player hey? Good, good.

M

 

[skmando]

Hey Migs,

Thanks for the reply. I don't have a screwdriver small enough to open it myself, but next time I bring it to work I'll ask one of the technicians to open it and take a photo.

In some ways it doesn't really matter - the mic sounds great and that's the main thing.

S.

 

[Migs 31]

Hey Migs,

Thanks for the reply. I don't have a screwdriver small enough to open it myself, but next time I bring it to work I'll ask one of the technicians to open it and take a photo.

In some ways it doesn't really matter - the mic sounds great and that's the main thing.

S.

Cool!
MXL991 is readely available still now (just saw one for £30 in a London shop).

Get them open (screws are countersunk if I remember well) take good pics front and back. Peeps here can tell you exactly what MJ did - you can repeat that. Get a pair for stereo image/depth. Great on Mandolin, fiddle etc.

I now use SDC in pairs on acoustic instruments of all sorts (these older Neumann my favourites-see pic )

You (or a friend) can do it !
It’s not rocket science, believe me!
Just need good soldering skills.
Welcome to DIY, my friend !

M

 

[skmando]

Cool!
MXL991 is readely available still now (just saw one for £30 in London shop).

Get them open (screws are countersunk if I remember well) take good pics front and back. Peeps here can tell you exactly what MJ did - you can repeat that. Get a pair for stereo image/depth. Great on Mandolin, fiddle etc.

I now use SDC in pairs on acoustic instruments of all sorts (these older Neumann my favourites-see pic )

You (or a friend) can do it !
It’s not rocket science, believe me!
Just need good soldering skills.
Welcome to DIY, my friend !

M

Wouldn't it be difficult to replicate the capsule MJ used? Thus making it v difficult to use as a stereo pair? I wouldn't be willing to take the head of the mic apart... Also the head of the mic looks different to the stock 991, so perhaps that's custom and again difficult to replicate.

I get what you're saying about a pair, but for the moment I'm happy to have this as a single mic. I've a bunch of pairs of mics at present (414s, 451s, NT5s). But this MJ 991 is my fav on mandolin.

I'm gonna dip my toe into this mic mod malarkey slowly. From this forum I found the mod for the AKG c1000. And someone on gearspace posted saying it's their fav mic on mandolin after the modification, above a km84. I'm very dubious of this, but just so happens I've a fully working c1000 and a broken one someone gave me (grill missing), so that's gonna be my first project. Mod the broken one. Do some shootouts on various mandolins between the two. Nice way to start the modding journey

 

[k brown]

The best mod to the MXL SDCs is shaving off the front of the capsule, so that the diaphragm isn't so deeply recessed. This tames the big peak at around 7-8kHz.
https://www.pr.com/press-release/126633

https://audioimprov.com/AudioImprov/Mics/Entries/2012/12/5_Modifying_the_MXL_991.html

 

[skmando]

The best mod to the MXL SDCs is shaving off the front of the capsule, so that the diaphragm isn't so deeply recessed. This tames the big peak at around 7-8kHz.
https://www.pr.com/press-release/126633

https://audioimprov.com/AudioImprov/Mics/Entries/2012/12/5_Modifying_the_MXL_991.html

Thanks for this!

Mine isn't shaving down, more tapered in, so the grill is almost flush with the casing at the point of contact. Photo attached...

 

[k brown]

Thanks for this!

Mine isn't shaving down, more tapered in, so the grill is almost flush with the casing at the point of contact. Photo attached...

Unfortunately, I think Joly was trying to make it look like a KM84, the mic he was inviting comparison to.
The rounded-off edge is much better, whether it sounds more like a KM84 or not, IMHO.

You'll notice that the beveled edge on the Neumann is much narrower/shallower than that.

This is what some of us have done with the Pronomic SCM1/Takstar CM-60; tests by @kingkorg showed that most of the peakiness of that capsule was due to how deeply recessed the diaphragm was; not nearly so much the slotted grille, as was originally thought. Many fine-sounding mics have had slotted grilles like that; though not as deep):

 

[Di_Sousa]

One question I did have in regard to the Michael Joly mic and thought someone here might be able to answer; is this mic transformer based output like a km84, or transformerless like a km184?

Transformers are expensive, small components aren't (transistors, FETs, resistors, diodes...) , Joly had a business run for profit so it was much easier to achieve profit by replacing some cheap components in an existing circuit than to change the complete circuit for a transformer based one. (the last scenario would make the modified microphone cost more than an original KM184)

Be careful with Joly's words and marketing gibberish, take it with a pinch of salt,
but here are his words on the MXL991 mods:

"
Complete Rebuild -

To deliver these benefits your stock CM-90, 603, 991, GXL-1200 etc. will completely disassembled and rebuilt. The PC is board removed and upgraded with superior components. All capsule parts (screen, diaphragm, spacers, backplate, tuning chamber and retaining ring) are removed and replaced with my upgraded parts.

The capsule housing is re-machined with the MJE “DirectSound” mod to eliminate diaphragm set back resonance and coloration. A new diaphragm, hand-selected for flattest HF response is installed. The new advanced-design MJE backplate is used to build up the modified capsule. Once re-assembled, the entire capsule is tuned to an ideal capacitance for greatest sensitivity and output.
"

you can still view his full page about these mods here:

http://web.archive.org/web/20160731...d=238&osCsid=fe919eae6e5d47d1a84c429cb5863db8

 

[RuudNL]

One of the well known LDC mods was replacing the capsule with an 'MJE-K47' capsule. (In fact a K47-style capsule,)

 

[skmando]

Transformers are expensive, small components aren't (transistors, FETs, resistors, diodes...) , Joly had a business run for profit so it was much easier to achieve profit by replacing some cheap components in an existing circuit than to change the complete circuit for a transformer based one. (the last scenario would make the modified microphone cost more than an original KM184)

Be careful with Joly's words and marketing gibberish, take it with a pinch of salt,
but here are his words on the MXL991 mods:

"
Complete Rebuild -

To deliver these benefits your stock CM-90, 603, 991, GXL-1200 etc. will completely disassembled and rebuilt. The PC is board removed and upgraded with superior components. All capsule parts (screen, diaphragm, spacers, backplate, tuning chamber and retaining ring) are removed and replaced with my upgraded parts.

The capsule housing is re-machined with the MJE “DirectSound” mod to eliminate diaphragm set back resonance and coloration. A new diaphragm, hand-selected for flattest HF response is installed. The new advanced-design MJE backplate is used to build up the modified capsule. Once re-assembled, the entire capsule is tuned to an ideal capacitance for greatest sensitivity and output.
"

you can still view his full page about these mods here:

http://web.archive.org/web/20160731...d=238&osCsid=fe919eae6e5d47d1a84c429cb5863db8

Thank you very much for posting this. Great to read the original blurb about the mic. Thanks. S.

 

[Di_Sousa]

Thank you very much for posting this. Great to read the original blurb about the mic. Thanks. S.

His mods maybe really made the microphones sound better, I just don’t know because I never used his services.

What I never liked was his marketing approach and exaggerated descriptions.

 

[callgrlmusic]

if you do get a chance to pop it open, i’d also love to see the guts. i’m fascinated by what joly wrote on his site versus what he was actually doing. i’ve poked around on this and other forums for years and aside from extremely polarized opinions and a few really weird gooey headbasket/capsule sections, i’ve not seen many of his circuit mods.

an important note—on those 991s, the screws holding the body together actually screw further into the body to release the xlr section and board, not out. (that was my first mistake messing with one)