Warm Audio WA-67 - Teardown

[andYz00m]

I'm pretty sure if your Neumann "67 reissue" was compared to pucho812 "vintage u67's" it would be obvious as to which was which in an unlabeled audio listen test...

Totally agree. In fact, we did just that before purchasing the reissue. It's arguably overpriced and you're right about the components and design being well known.

Some people (myself included) just wanted the badge and the confidence (misplaced or not) that goes with it.

Dont get me wrong, I have plenty of DIY, noname, clone and weird stuff that nobody cares about that SOUNDS great. But sometimes a brand, and the experience that offers, can be worth the cost.

 

[Tim Campbell]

Neumann uses similar approach with their TLM103 capsule, reduced count and altered size of the holes.

Yes it is 3U audios capsule. Like most other WA models.

I have a stack of these 3u backplates, real Neumann K67 backplates as well as those I manufacture. A well made K67 can sound much better than this design.

 

[Gus]

Whoops

Do you have the history of the microphone and are you sure the capsule has not been changed before you looked at it?
I bring this up because you are posting something on the forum that will be read by many.
Did you check the history or facts about the microphone?

The 67 circuit is not that simple and the parts used matter. How many people understand how the high pass filter works in the 67 etc.?

 

[Spiritworks]

I wonder how many of these clones will improve simply with changing the capsule with one, say, by Tim Campell? When changing a capsule do other components need to be changed as well? Or, is a drop-in capsule change a noticeable performance improvement?

 

[Tim Campbell]

I wonder how many of these clones will improve simply with changing the capsule with one, say, by Tim Campell? When changing a capsule do other components need to be changed as well? Or, is a drop-in capsule change a noticeable performance improvement?

Well It hasn't been determined yet if the circuit has been altered to work with this capsule.

If you ask anyone here they will tell you that I am so busy that I am not currently producing my K67. I hope this situation changes as I have learned to love this capsule. I will also add that I am not here to promote any products, just to join in a conversation about capsules, a real love of mine.

Generally a better capsule always improves a mic unless in as may be this case, the mic is optimized for a darker one.

 

[amplexus]

This squares with almost every bit of Warm gear i’ve been in. Had their WA-47 on the bench a few weeks ago from a client who had literally had it a week. Unsoldered joint from the factory. And the same shitty pcb, no solder mask.

They’re not quite as bad as Stam but they do seem like they’re in th same race to the bottom.
They sell you with fancy component brand names “lundahl, wima, sowter, solen, panasonic, styrene caps!!!” But then basically cut every single other corner they can to hit the price point.

in my experience they basically have “engineers” who figure if they throw enough brand name components in the box it will magically sound good and be reliable.

Hilariously- the best Stam product that was ever produced (imo) was the very first run of their U87 clone- and it was dany/poctop PCBs- not even remade, literally screened like the diy boards/kits- and Eric’s capsules with a sowter output. (This was before they switched capsules, and I believe PCBs…)

At least Warm seems to build their own pcbs…..

 

[Whoops]

Some people (myself included) just wanted the badge and the confidence (misplaced or not) that goes with it.

I totally understand that, I also feel the same, we don’t listen with our Ears, we listen with our brain and the brain is influenced by a lot of different things when perceiving a sound. A mic that gives us confidence will sound better for our brain that’s for sure.
It gives confidence also to the Clients, but I’ve found that it’s changing now, if a client trusts you a lot as an engineer you can put a no brand mic and tell them it’s great and they will trust your choice.

Latelly I had a recording session with Piano and Electric guitar, the client really wanted me to Engineer because he loved my previous work, so he paid an higher fee to take me to the studio as an outside Engineer.
I used on his guitar a cheap TBone lollipop ribbon mic and a Sen MD409, they wanted a Darker Piano sound, so I used 2x cheap TBone Ribbons (the bigger model) and put also a pair of U67 just in case.
In the end he loved the sound and asked links to order the 3x cheap ribbon mics I used…
I think the fact that he trusted me made him accept the cheap mics and listen the end result without prejudice.
But the same doesn’t happen with all clients and some of them have expectations of being impressed with the badges

 

[Whoops]

Whoops

Do you have the history of the microphone and are you sure the capsule has not been changed before you looked at it?
I bring this up because you are posting something on the forum that will be read by many.
Did you check the history or facts about the microphone?

Yes, I know all the facts that’s why I’m posting, If there was any doubt I would not post because I don’t want to bash any company based on second guessing.

The microphone is completely new, only had 1 owner and for a short period of time, I was the first person to use it and open it.

thanks Gus, I also think it’s important to be clear about this

 

[Bo Deadly]

COol. Nice breakdown. If only Warm Audio didn't have a dumb name and even dumber looking logo, I might have bought something from them.

 

[kingkorg]

Btw, the fact capsule lacks some goldplating shouldn't be a dealbreaker. It might have slightly lower output, and that's it. Take a look at "golden drop technology" from JZ. One might even argue that capsule behaves "faster" with less mass on it. Just listen, if it's good it's good.

I think that mic needs some measurement, at least comparative against something you are familiar with. U67 should basically be almost dead flat with some roll off starting above say 10-12k. It should be a 87 without any bump in the high end.

Last mic from WA audio i played with had loosely soldered polystyrene gate cap. The whole mic was ringing and resonating like a church bell. A perfect example of how blind usage of "fancy" components can obliterate mic performance. By just resoldering the componen so it sits tightly attached to the board, and hot glue improved performance radically.

This was 47jr, so imagine using the mic in front of kick drum with that loose cap!!! Otherwise, quite nice mic. It has a smaller diameter of the grille so it creates a dip in FR at wrong frequency, so not a real u47 or u47fet replacement. Pad is created by reducing pol.voltage which is a nice feat. The while mic has a 3u audio board. So it's basically a Warbler mic.

Personally i would just change that cap for c0g, even glued to that board it still transfers a lot of sound. And this is not negligible amount, it behaves as aditional capsule.

Update:
I don't know WTF is the deal with that 4.7uF output cap?!?!? Larger is not always better, and that component is a key in a tube mic. One should do a propper measurement of that tube-cap-transformer combo. While that mic might sound and perform like a dream, it doesn't seem to have anything to do with a 67.

 

[Whoops]

While that mic might sound and perform like a dream, it doesn't seem to have anything to do with a 67.

I will check the schematic and the components values against the original one and post it here, then it would be clearer how close or how far this is from the original U67 circuit

 

[HP200CD]

Whoops,
Thanks for this informative post. And for confirming that the subject piece was factory direct and in "as built" condition.

 

[Whoops]

Whoops,
Thanks for this informative post. And for confirming that the subject piece was factory direct and in "as built" condition.

Yes it was, I guarantee I was the first person to open the microphone.

I still have some hope that the circuit is true to the original with the De-emphasis circuit in place and that this capsule was fitted as production mistake.
Let's see

 

[Whoops]

I was preparing the mic for the future circuit tracing and I first noticed a solder point that is almost touching the side case brackets, soldering is a bit sloppy for sure. I will have to re-touch all solders just in case.

 

[Ike Zimbel]

Interesting thread. Some PS caps have both leads at one end, IOW, radial leads. Are you sure that's not the case here?

 

[Whoops]

Interesting thread. Some PS caps have both leads at one end, IOW, radial leads. Are you sure that's not the case here?

Thank you Zimbel, you were correct, I unscrewed the board to have a better look, and it seems both legs of the cap are at one end.
I was not aware of that as all the Styrene caps I have and used all were axial.

Thanks for letting me know, I will delete my post

 

[Whoops]

BODY RINGING

I found why the microphone had an horrible mechanical ringing, it's due to the tube parte of the body, it rings like a Bell.
I did a video showing the ringing and comparing it to a U87 body (same body as U67).
There's terrible ringing in the WA67 tube, I don't know if this presents a problem while recording or not, but I will try to dampen the body.
With the U87 there's some resonance, lower in volume but no Ringing, it sounds dampened.

 

[Whoops]

This is the WA67 PCB right next to a home etched Bo Hansen DI PCB I’ve made.
The PCBs look the same,
I find it strange Warm Audio didn’t do a professionally made PCB, even though quality PCBs are pretty cheap, it makes me think there’s someone in a basement in China home-etching these pcbs by hand.
Really strange

 

[Ricardus]

This is the WA67 PCB right next to a home etched Bo Hansen DI PCB I’ve made.
The PCBs look the same,
I find it strange Warm Audio didn’t do a professionally made PCB, even though quality PCBs are pretty cheap, it makes me think there’s someone in a basement in China home-etching these pcbs by hand.
Really strange

View attachment 88329

That's REALLY weird.

 

[Khron]

This is the WA67 PCB right next to a home etched Bo Hansen DI PCB I’ve made.
The PCBs look the same,
I find it strange Warm Audio didn’t do a professionally made PCB, even though quality PCBs are pretty cheap, it makes me think there’s someone in a basement in China home-etching these pcbs by hand.
Really strange

View attachment 88329

Makes one wonder just how they made the (what are usually plated) through-hole vias, to connect the top and bottom copper layers...

Not that PCB's don't cost literally merely CENTS to have professionally made, even (or especially) in bulk quantities.