M-Audio / Behringer C1 Hybrid
« on: November 18, 2018, 06:01:44 AM »
Hi there,
This is my first post here after being pointed to the GroupDIY board by someone from the Cakewalk board.

I've got an old M-Audio Nova mic which has served me well for over 18 years, but recently it has started to develop noise (like a low static fuzz) which is making my recordings impossible.  I'm guessing the electrics have gone (could be a cap or transistor) but the diaphragm is still good.

Here's my question.
If I put the large diaphragm from the Nova onto a Behringer C1, would it work?  I know this is not the best solution, but it would be a pity to waste a perfectly good diaphragm.
Of would it be better to fix the Nova?

Thanks for any help.

To fill you in on my circuit building abilities - I've done some minor builds such as fuzz pedals, tone pedals, tube amp pedals and I do repairs on my old colorsound Wah pedals.  I'm good at the soldering and following instructions, but know nothing about ohm's law.


Gus

Re: M-Audio / Behringer C1 Hybrid
« Reply #1 on: November 18, 2018, 09:00:06 AM »
Have you tested the capsule so you know it is good? A small amount of dust etc. at the clear edge of the diaphragm can cause a noise issue. Search for capsule cleaning for threads on this.

I would not assume a cap or transistor is bad.

Have you substituted a fixed 47pf to 100pf cap for the capsule and tested for noise? If that does not work try cleaning around the input of the circuit

I like the Nova and Sterling 51 circuit(I clean up the PCb and wiring and change a few parts for EQ). I would fix the circuit if it needed repair.

What PCB(s) are in the microphone? Two with leaded parts or one with a mix of SMDs and leaded parts.

There should be threads about ST/groove tubes/M audio microphones at this forum


















Re: M-Audio / Behringer C1 Hybrid
« Reply #2 on: November 18, 2018, 11:32:57 AM »
Hi there,
This is my first post here after being pointed to the GroupDIY board by someone from the Cakewalk board.

I've got an old M-Audio Nova mic which has served me well for over 18 years, but recently it has started to develop noise (like a low static fuzz) which is making my recordings impossible.  I'm guessing the electrics have gone (could be a cap or transistor) but the diaphragm is still good.

Here's my question.
If I put the large diaphragm from the Nova onto a Behringer C1, would it work?  I know this is not the best solution, but it would be a pity to waste a perfectly good diaphragm.
Of would it be better to fix the Nova?

Thanks for any help.

To fill you in on my circuit building abilities - I've done some minor builds such as fuzz pedals, tone pedals, tube amp pedals and I do repairs on my old colorsound Wah pedals.  I'm good at the soldering and following instructions, but know nothing about ohm's law.

Nope, you can't. C1 is an electret mic, M Audio capsule won't work in it.

Re: M-Audio / Behringer C1 Hybrid
« Reply #3 on: November 18, 2018, 02:41:19 PM »
Thanks guys. I guess I won't be Frankensteinin' the C1.
I'm going to do a good clean of the curcuitboards. I'm swapping out the wires for newer ones. I'm a bit worried about touching the capsule after reading the threads on here.
I'll try and be delicate - though I might already have damaged it.
However, I don't think that is what is causing the hum in recordings - I've tried it with an Edirol Fa101 preamp, and a Behringer tube pre amp and get the same gradual build-up of noise (it's not the preamp as I've tested it with other mics). One clue might be that when I have the mic curcuit board exposed and touch the 1KM ceramic capacitor before the capsule, the noise cuts out for a moment, then starts building up again.
Could that cap be faulty?

Cheers again.

Khron

Re: M-Audio / Behringer C1 Hybrid
« Reply #4 on: November 18, 2018, 03:32:36 PM »
That "cap" is actually a / the 1Gohm resistor (1KM = 1k megohms = 1000 megohms = 1Gohm).

Reflowing the solder joints might not hurt.

I recall having revived one or two mics (that i bought used / dead), and one leg was cracked off one of the 1G resistors.
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

Re: M-Audio / Behringer C1 Hybrid
« Reply #5 on: November 19, 2018, 09:12:05 AM »
Have you substituted a fixed 47pf to 100pf cap for the capsule and tested for noise? If that does not work try cleaning around the input of the circuit

What PCB(s) are in the microphone? Two with leaded parts or one with a mix of SMDs and leaded parts.
Hi Gus,
Thanks for responding.
The circuitboard(s) in my Nova are exactly the same as those in this link: http://cdn.recordinghacks.com/images//mic_extras/m-audio/nova-pcb.jpg
I'm not quite sure which cap you are referring to. There are two 4.7uF caps in position C5 & C6. Should I change both?

I replaced C1 (2A102K) this morning, but the noise remains.
I don't have any substitutes for R2 & R1 around the house, and I think these might be the offending parties. Here's a dumb question: could I swap them out for another value?

Thanks

Re: M-Audio / Behringer C1 Hybrid
« Reply #6 on: November 19, 2018, 09:14:22 AM »
That "cap" is actually a / the 1Gohm resistor (1KM = 1k megohms = 1000 megohms = 1Gohm).

Reflowing the solder joints might not hurt.

I recall having revived one or two mics (that i bought used / dead), and one leg was cracked off one of the 1G resistors.
Thanks Khon,
I reflowed the solder - swapped out some wires - still got noise building up....in fact, it's getting worse.
Could I replace the 1G resistor with something else? (to save me a trip to the electronics store).

Re: M-Audio / Behringer C1 Hybrid
« Reply #7 on: November 19, 2018, 02:21:58 PM »
Always had trouble with electret mics.  Have a pair of Sony ECM22 mics in the (junk) box that haven't worked in years.  The permanent charge of the electret capsule was lost with time and the mic no longer useable.  The noise getting worse is the first sign of this.  Did not disassemble the mic to look inside.  I have since stuck with tube mics...and there are some nice clone kits out there....

Probably take some time and work to convert over an electret mic... no 48 v polarizing voltage to start with unless deriving it from a phantom supply... where is your time better spent?

Gus

Re: M-Audio / Behringer C1 Hybrid
« Reply #8 on: November 19, 2018, 05:19:04 PM »
Hi Gus,
Thanks for responding.
The circuitboard(s) in my Nova are exactly the same as those in this link: http://cdn.recordinghacks.com/images//mic_extras/m-audio/nova-pcb.jpg
I'm not quite sure which cap you are referring to. There are two 4.7uF caps in position C5 & C6. Should I change both?

I replaced C1 (2A102K) this morning, but the noise remains.
I don't have any substitutes for R2 & R1 around the house, and I think these might be the offending parties. Here's a dumb question: could I swap them out for another value?

Thanks

Unsolder the two white wires at the top left in the picture. Solder a 47pf to 100pf cap at the two nodes, make sure the cap is clean and you don't touch it with your fingers.
Check for noise if the noise goes away or has a reduction(you changed a cap and added another unknown) the capsule might have something on it.

If you overheat the cap at the top left red(1000pf, 102, 1nf) in the picture you can cause problems

Don't assume it is the electronics.

Don't heat up the 1 gig resistors

Don't touch the input cap with bare hands (the 100v 1nf cap in the picture) you can form a conductance path with  oils and dirt this can be a noise issue at this section of the circuit.

Re: M-Audio / Behringer C1 Hybrid
« Reply #9 on: November 21, 2018, 10:02:50 AM »
Unsolder the two white wires at the top left in the picture. Solder a 47pf to 100pf cap at the two nodes, make sure the cap is clean and you don't touch it with your fingers.
Check for noise if the noise goes away or has a reduction(you changed a cap and added another unknown) the capsule might have something on it.
I did what you suggested. Placed a 100pf cap at the two nodes - noise went away immediately. So, I guess it is the diaphragm after all. In fact, on closer inspection, it is damaged (probably my fault) and that is what is making the noise. Damn! Let's call this a learning curve.

I'm based in Italy, so I don't know how easy it will be for me to come across new mic diaphragms - any ideas?
In the meantime, I got a cheap offer on a C1 to use as a backup mic for acoustic guitar and I'm holding out for a Black Friday offer on a new mic. I enjoyed the Nova sound, so I hope I can find something similar.


Re: M-Audio / Behringer C1 Hybrid
« Reply #10 on: December 13, 2018, 04:29:09 PM »
Just thought I'd update this thread. I was thinking of getting a new diaphragm for the Nova. I noticed several sellers on eBay, all around £20 mark, based in China. Not sure if it's worth the time and effort getting something so cheap and far. But there is one seller from Hong Kong with 100% positive feedback who seems to specialize in music and electronics, and it won't break the bank.
Anyone ever bought diaphragms from Hong Kong?
Cheers

mhelin

Re: M-Audio / Behringer C1 Hybrid
« Reply #11 on: December 14, 2018, 02:30:07 AM »
Those capsules are usually cheap K67 type capsules you can get them also from Thomann. You better get a K47 style capsule from Wgtcenter, their C12 style capsule is also good but may require higher capsule voltage than is available with Nova. Anyway, Nova propably came with K67 style capsule so the ones you found should have similar sound signature. 
Mikko

mhelin


mhelin

« Last Edit: December 14, 2018, 02:44:14 AM by mhelin »
Mikko

Khron

Re: M-Audio / Behringer C1 Hybrid
« Reply #14 on: December 14, 2018, 05:31:42 AM »
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

mhelin

Re: M-Audio / Behringer C1 Hybrid
« Reply #15 on: December 14, 2018, 06:21:18 AM »
SC 450 is supposed to have 6 micron capsule at least. Also I like the colors of wires more. Actually I've got the mic and kind of like it. Tried CK12 style capsule in it but it was very weak, low output. That mic. has an output transformer, btw.
Mikko


 

Related Topics

  Subject / Started by Replies Last post
27 Replies
15925 Views
Last post December 21, 2004, 09:18:45 AM
by zebra50
2 Replies
1519 Views
Last post November 09, 2005, 11:14:06 PM
by fucanay
0 Replies
1147 Views
Last post August 28, 2006, 09:40:01 AM
by
19 Replies
6743 Views
Last post June 01, 2008, 10:46:16 PM
by skipwave