MXL V69 repair job

PhilGood

PhilGood

Juice box hero
I am trying to repair my out of warranty V69 and have just one question. Does anyone know what the 12 pin IC chip is? Is it an op-amp? It's wider than any op-amp I've seen.

Anyone? Anyone?

Bueler?...
 
It is a custom made chip. Who knows what they squize inside?
Are you sure it is fried? I'd contact MXL for a replacement. On the other hand, a nice transformer might be a solution.
 
No, I'm not sure that it's fried. Its making the 'wind noise' and I suspected a bad capacitor. I've replaced every stinkin' capacitor in the mic and it didn't help! The last thing besides the caps are the FET's and that chip. I've had enough with it! I may just gut it and build a circuit with a transformer. Any suggestions on a good circuit with a 12AY7? I've already done an ELA M circuit. How about one with an EF86?
 
Keep in mind, I really liked the way it sounded and would like to keep it as close as possible to the original sound...
 
mrface2112 said:
.....and i assume you've already done the "dry the capsule out" trick?

(sometimes the obvious has to be asked)


cheers,
wade
Click to expand...

Yeah, and I've got silica gel packs in the case. Thanks!

The problem is I live in California. Not alot of humidity here.

Just to make sure it wasn't the capsule, I disconnected it and it still made the noise.
 
PhilGood said:
No, I'm not sure that it's fried. Its making the 'wind noise' and I suspected a bad capacitor.
Click to expand...

My V69me's been doing the same thing on and off, and I think I'm done with it. It's too bad, cause I to really liked the way it sounds, when it's working properly that is. :mad:
 
PhilGood said:
No, I'm not sure that it's fried. Its making the 'wind noise'
Click to expand...

Try instead of capsule to connect a 50pf capacitor. If the problem still there, try to replace the tube? Just in case I would check the caps in the power supply. If the mic still makes noise, then may be the problem is in the chip.
 
Marik said:
Try instead of capsule to connect a 50pf capacitor. If the problem still there, try to replace the tube? Just in case I would check the caps in the power supply. If the mic still makes noise, then may be the problem is in the chip.
Click to expand...

I've replaced the tube. My next thought is to check the power supply caps. Any chance it's the FET's? I just want to eliminate them as a possibilty before delving into the power supply, even though that'll be easier...
 
Clit Torres said:
My V69me's been doing the same thing on and off, and I think I'm done with it. It's too bad, cause I to really liked the way it sounds, when it's working properly that is. :mad:
Click to expand...

If I figure this out, you'll be the first to know...
 
PhilGood said:
If I figure this out, you'll be the first to know...
Click to expand...

Thanks, that would be much appreciated :) .

I'm just really suprised that this topic hasn't been discussed in more depth before. Considering how many people around here have this mic, I see this issue come up every now and again, yet it's never really solved.
 
It's the tube

I've had the same problems. Replace the tube and all probably will be well.

There are so many things that can go wrong with tubes.

I wouldn't rule out a loose tube/PCB connection. Check and re-check all of your connections between the tube 'legs' and the PCB. occasionally there is a bad solder joint. That will make the wind noise too.

If it's new enough, see if Marshall will foot the bill. Often a few kind words to a cust. serv. agent and you'll get your way. Just as often, you will pay extra for getting something from the company too, so keep an open mind and shop around if you end up buying parts and DIY'ing it.
 
PhilGood said:
No, I'm not sure that it's fried. Its making the 'wind noise' and I suspected a bad capacitor. I've replaced every stinkin' capacitor in the mic and it didn't help! The last thing besides the caps are the FET's and that chip. I've had enough with it! I may just gut it and build a circuit with a transformer. Any suggestions on a good circuit with a 12AY7? I've already done an ELA M circuit. How about one with an EF86?
Click to expand...


That "wind noise" is a bad capsule or capsule wiring. Check the solder joints carefully under a microscope. Sometimes one is cracked.
 
MCI2424 said:
That "wind noise" is a bad capsule or capsule wiring. Check the solder joints carefully under a microscope. Sometimes one is cracked.
Click to expand...

OK, to reiterate what I've done, I have unsoldered the capsule wires from the circuit board and it still makes the noise. It is not the capsule. I've replaced the tube with 3 other tubes. It is not the tube. I've replaced every single capacitor in the mic. It is not the capacitors.

It happens as soon as power is applied, so it's either an FET, that 12 pin chip, (maybe a resistor, though I doubt it) or the power supply itself.

I have already wired up a board with an Ela M circuit that is ready for when I give up on it. Then it'll be an Ela M69!
 
News

Well, I thought I'd follow up here a little. I replaced every component within the mic except that 12 pin chip and it still made the noise!

I fainally said "screw it" and tore the guts out and replaced it with the ELAM circuit! It sounds really friggin' good now!! The heater voltage is a little high, but I can fix that in the power supply.

So, my guess is the noise was coming from that proprietary chip in the mic!
 
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