3U Warbler IV issues

[mattrico]

Hi all, I recently bought a 3U Warbler IV and it was having issues from the get go (the guy I bought it off didn't admit it had issues, so lucky me I get to try and fix it!).
Anyway, there are 2 main problems I've noticed:
1. The V switch does nothing. Flicking between the 3 voices, even waiting a while, seems to have zero effect on the sound.
2. It slowly loses gain over time. So when I plug it in, it has strong gain, but over time you can see it losing gain until it hits a point that it doesn't drop anymore. I think this is also related to the pad switch, which seems to behave sometimes and not others.
Short of ripping the capsule and transformer out to use in another project mic, what can I do? If it's too much mucking around to fix it, I think I will just get the capsule and transformer and buy another apex 460 style mic to drop them into, which is much more within my means than the real technical stuff that might be required to fix this.
Any help is appreciated!

 

[pucho812]

have you contacted 3U about it?

 

[micolas]

Hi all, I recently bought a 3U Warbler IV and it was having issues from the get go (the guy I bought it off didn't admit it had issues, so lucky me I get to try and fix it!).
Anyway, there are 2 main problems I've noticed:
1. The V switch does nothing. Flicking between the 3 voices, even waiting a while, seems to have zero effect on the sound.
2. It slowly loses gain over time. So when I plug it in, it has strong gain, but over time you can see it losing gain until it hits a point that it doesn't drop anymore. I think this is also related to the pad switch, which seems to behave sometimes and not others.
Short of ripping the capsule and transformer out to use in another project mic, what can I do? If it's too much mucking around to fix it, I think I will just get the capsule and transformer and buy another apex 460 style mic to drop them into, which is much more within my means than the real technical stuff that might be required to fix this.
Any help is appreciated!

Has anyone made any changes, interventions in the microphone?
Was it defective and did he partially repair it?

 

[mattrico]

have you contacted 3U about it?

Not as yet. I didn't think Guosheng would be too interested in a faulty used mic, even though I have bought a couple of capsules off him in the past. But I guess it's probably worth a shot!

 

[mattrico]

Has anyone made any changes, interventions in the microphone?
Was it defective and did he partially repair it?

Not that I can see. Everything looks stock.
The guy I bought it off didn't do anything to it by the looks of things. And if he did, he didn't admit anything to me when I told him that it wasn't working properly.

 

[micolas]

Not that I can see. Everything looks stock.
The guy I bought it off didn't do anything to it by the looks of things. And if he did, he didn't admit anything to me when I told him that it wasn't working properly.

Then it's worth trying to fix it

 

[mattrico]

Then it's worth trying to fix it

Yeah it was too long ago now (late last year). I don't think the guy would care. Best to fix it myself and reach out to Guosheng to find out his thoughts.

 

[micolas]

Yeah it was too long ago now (late last year). I don't think the guy would care. Best to fix it myself and reach out to Guosheng to find out his thoughts.

I was referring to the possibility of repairing it yourself.
I would start with cleaning the high-impedance entrance area with isopropyl alcohol, very carefully.
Then with testing the capsule in another circuit, or testing another functional capsule (of any type) in the Warbler.
Check switches
Then measuring the voltages at the relevant points, the BIAS of the jFET, checking the DC/DC converter, check, replace coupling or filtering capacitors
etc., etc.
Possible causes of incorrect operation must be methodically checked and eliminated one by one.

 

[Voyager10]

Can you post pictures of the insides, especially the circuit boards?

 

[mattrico]

Can you post pictures of the insides, especially the circuit boards?

Sure thing, here are a couple of photos. I'll have to unscrew it to take some photos of the backs of the boards.

 

[rock soderstrom]

I wonder if the hot glue over the high impedance area does anything positive?

 

[micolas]

I wonder if the hot glue over the high impedance area does anything positive?

In the case of Rode, Neumann, etc., it protected the area from contamination over time.The glue just needs to be of good quality

 

[rock soderstrom]

The glue just needs to be of good quality

How do you know that beforehand? Adhesives tend to change their properties over time as they dry out. I am not an expert on materials, but I would be careful at this point, as this can lead to problems over the years.

 

[micolas]

How do you know that beforehand? Adhesives tend to change their properties over time as they dry out. I am not an expert on materials, but I would be careful at this point, as this can lead to problems over the years.

You don't know now, just by visual inspection.
But I wouldn't start with removing the protective glue. Maybe later, after some measurements, test.
Before doing anything else, I would measure the phantom voltage supplied by the preamp or audio interface.
Then I connect the microphone and measure the voltages everywhere, starting from the output of the microphone, go to the PSU Board, note everything on a summary sketch.
Then I would measure the audio PCB.
If you have the skills it would make sense to draw the schematics, if not relevant pictures of the traces part of each board should be posted.

 

[micolas]

Hi all, I recently bought a 3U Warbler IV

On the audio pcb it says Warbler MKII Rev1
Are you sure the microphone model is MKIV?

 

[Khron]

On the audio pcb it says Warbler MKII Rev1
Are you sure the microphone model is MKIV?

Would the electronics have needed to change between "generations"? Could just be capsule differences, or even just component value differences (not necessarily warranting a new board revision).

 

[micolas]

Would the electronics have needed to change between "generations"? Could just be capsule differences, or even just component value differences (not necessarily warranting a new board revision).

@Khron you are perfectly right!
That's exactly what I was thinking right now.
Technologically, it is a current, profitable practice to use subassemblies, platforms, etc. for several models from the same family, class.
Of course, this PCB is used for several models, changing only the capsule, possibly the transformer, etc., especially if it is a linear circuit.
They don't even have to be different generations in time, just with a different sound character.

 

[mattrico]

Hi all, thanks for the extra input. I do believe the above to be true, that it's a "one size fits all" board, that is just adapted depending on what the final mic needs to be. It has Warbler MK IV on the body, and it has the side terminated capsule, so I would never assume otherwise that it wasn't this mic.
So with regards to the above, I was mainly using it with an SSL2 interface, as part of my travel voiceover setup. I never checked the phantom power voltage on this unit as I hadn't had issues with other mics, only this one, so figured it wasn't an interface problem.
I've emailed Guosheng but I know he can take days to get back to emails so I'll post in here once I hear from him. Otherwise, I'll probably need to fully disassemble all the PCB's to really have an understanding of what's going on, and when I do that I can post some more pictures.

 

[micolas]

Hi all, thanks for the extra input. I do believe the above to be true, that it's a "one size fits all" board, that is just adapted depending on what the final mic needs to be. It has Warbler MK IV on the body, and it has the side terminated capsule, so I would never assume otherwise that it wasn't this mic.
So with regards to the above, I was mainly using it with an SSL2 interface, as part of my travel voiceover setup. I never checked the phantom power voltage on this unit as I hadn't had issues with other mics, only this one, so figured it wasn't an interface problem.
I've emailed Guosheng but I know he can take days to get back to emails so I'll post in here once I hear from him. Otherwise, I'll probably need to fully disassemble all the PCB's to really have an understanding of what's going on, and when I do that I can post some more pictures.

We are all curious what Gousheng will tell you. He is a respected name in the field with an impressive contribution in DIY and beyond.
I doubt it will give you the schematic though.

 

[Khron]

I'll probably need to fully disassemble all the PCB's to really have an understanding of what's going on, and when I do that I can post some more pictures.

I doubt it will give you the schematic though.

Well, the audio board miiiiiiiight be a U87A clone type deal, possibly? Since the transformer is a 12:1, it shouldn't need that second transistor as an emitter follower for low-impedance drive, so that might be a capacitance multiplier?

The "PSU" board is more interesting though. The pair of inductors and capacitors near the bottom edge must be between the transformer secondary and the XLR output. Otherwise, it kinda-sorta looks like a Schoeps-type oscillator, but i'm only seeing ONE inductor, instead of the usual two

That being said, manual labor must be dirt-cheap in China - i wouldn't exactly call this "design(ed) for manufacture", with those dozens of wires flying all over the place...