Warm Audio WA-84

[Emmathom]

Hello everyone.
I have a pair of Warm Audio WA-84s supposed to be "replicas" of KM184... I'm thinking of changing a few capacitors, especially the tantalum ones. I was told that they had placed tantalums in order to remain in the spirit of the original microphone but that the tantalums of the time and those of today do not have absolutely the same characteristics. So, I want to change the 3 x 4.7uF decoupling caps and especially the 4.7uF connection!
Do you think these caps will bring a +++ ?
and that the choice of Elna Silmic II (for decoupling) and Muse BP (for connection) is good?
Best Regards

 

[Migs 31]

Hello everyone.
I have a pair of Warm Audio WA-84s supposed to be "replicas" of KM184...

I believe that would be the KM 84 they tried to imitate, a very different beast and sound.
Before you do anything, could you open your Warm WA-84 and take a couple of clear pictures?
I'm curious to see what they (Warm) actually did in there & I'm sure people here on the forum can advice you better as to what to do and what no to. Share pics first to see all of the actual parts.
My advice.

M

 

[Khron]

Do you think these caps will bring a +++ ?

Probably not. Or at least not as you might expect / imagine, but that only depends how strong your confirmation / expectation bias might be.

 

[Emmathom]

Here are the picts...

 

[Emmathom]

Probably not. Or at least not as you might expect / imagine, but that only depends how strong your confirmation / expectation bias might be.

I hope a Muse BP on the signal would be better than a cheap tantalum... !
For the decoupling one, I agree... it's more for my "piece of mind"

 

[Emmathom]

I also wonder why they put so long trammy wires... ?!? no risk they could bring some hum or interferences ?

 

[Migs 31]

I hope a Muse BP on the signal would be better than a cheap tantalum... !
For the decoupling one, I agree... it's more for my "piece of mind"

If Warm audio followed faithfully the original Neumann Schematic, IF they did...
May I point out that, C-3, 5, 6, 8, 10 are not even in the audio signal path (correct me if wrong).
But C-1, C-2, C-4 on the other hand seem to be getting audio signal through.
Honestly the Styro caps they used and what looks like WIMA (red caps) are good caps.
Better build than what I would expect really. Over all, will changing Caps make a real difference?

I'm always suspicious of the "improving the sound" by only changing few Caps.
I have been down that route and never heard that big of a difference. As @Khron said : "only depends how strong your confirmation / expectation bias might be." If you really want to hear an "improvement" after desoldering-changing caps-resoldering-sweating, your brain will tell you: "Yes, there is a difference!" But measurements and Frequency response analysis might say otherwise.
Maybe changing the Capsule will bring more of a drastic change in sound?!?



M

 

[Emmathom]

If Warm audio followed faithfully the original Neumann Schematic, IF they did...
May I point out that, C-3, 5, 6, 8, 10 are not even in the audio signal path (correct me if wrong).
But C-1, C-2, C-4 on the other hand seem to be getting audio signal through.
Honestly the Styro caps they used and what looks like WIMA (red caps) are good caps.
Better build than what I would expect really. Over all, will changing Caps make a real difference?

I'm always suspicious of the "improving the sound" by only changing few Caps.
I have been down that route and never heard that big of a difference. As @Khron said : "only depends how strong your confirmation / expectation bias might be." If you really want to hear an "improvement" after desoldering-changing caps-resoldering-sweating, your brain will tell you: "Yes, there is a difference!" But measurements and Frequency response analysis might say otherwise.
Maybe changing the Capsule will bring more of a drastic change in sound?!?



M

Thanks for your answer... yes the styro. are ok but C4 is straight on the signal path and it's a (poor) tatalum that's why I intent to replace it by a 1uF Muse BP wich sounds better in any case (especially on signal path)
C3 is also decoupling the Fet source > can be change (I would by Elna Silmic II 4,7uF > much better)
But ! if you guys tell me it isn't worth it, I will let the mic as it is...

 

[Emmathom]

by the way and this is a bit off subject (forgive me please) I've ordered 2 U47flat to Soliloqueen and I'd like to know what is this big "RS" part I see on most mics ? see pict please...

 

[cyrano]

When I look at these pics, cleaning comes to my mind. It seems WA even used vintage production means. One of the WIMA caps definitely has some resin on it. Makes me think there will be resin elsewhere too.

Might just make more of a difference than changing caps...

 

[cyrano]

by the way and this is a bit off subject (forgive me please) I've ordered 2 U47flat to Soliloqueen and I'd like to know what is this big "RS" part I see on most mics ? see pict please...

I guess that's a giga-ohm resistor?

 

[Khron]

by the way and this is a bit off subject (forgive me please) I've ordered 2 U47flat to Soliloqueen and I'd like to know what is this big "RS" part I see on most mics ? see pict please...

I guess that's a giga-ohm resistor?

A reed-relay for connecting the rear diaphragm in/out of the circuit (for omni with, or cardioid without).

 

[Emmathom]

When I look at these pics, cleaning comes to my mind. It seems WA even used vintage production means. One of the WIMA caps definitely has some resin on it. Makes me think there will be resin elsewhere too.

Might just make more of a difference than changing caps...

You're right cyrano ! in fact I bought a pair with one out-of-order... I cleaned the two mics with isopropylique alcool and there it was ! they work well now...
there was solder impurities everywhere... (not serious job from WA !)

 

[Emmathom]

A reed-relay for connecting the rear diaphragm in/out of the circuit (for omni with, or cardioid without).

ok... ! thanks Khron (it's to avoid 60v or more through a normal switch ? or does it improve better connection ?)

 

[cyrano]

A reed-relay for connecting the rear diaphragm in/out of the circuit (for omni with, or cardioid without).

Ah, of course. Thanks for setting me straight!

 

[callgrlmusic]

WA has obvious QC problems from time to time but they use a lot of the real deal as far as component choice.

 

[Khron]

(not serious job from WA !)

Don't worry, they didn't assemble the boards (or even the complete mics) themselves, i don't think.

(it's to avoid 60v or more through a normal switch ? or does it improve better connection ?)

I guess the attempt was to not have a manual switch in that high-impedance area - it made the mechanical side of the electronics a bit more convenient. You'll have to ask whoever cooked up that circuit for details, i'm mostly just speculating...

 

[mrgrooves666]

As Khron mentioned, I don't think you'll make those mics better sounding than what they are now. If you want to make them close to 84, the capsule is what will be stopping you. The rest seems good parts already. And I believe those may already be using 3U capsules? Could you share a picture of the back of the capsule please?
Btw seems Warm has a a thing for making messy sights..

 

[Emmathom]

Ok I will soon post picts of the back of the capsule...
So as far as I understand, you guys advice me against changing any cap in this circuit (not even the tantalum in the signal path...) > I still think that this 1uF tantalum should be exchange for a Nichicon Muse BP but will follow you

 

[Admiral-dk]

I would be very careful with C4 - electrolytes are in some situations a VERY Bad Idea when you connet them to an Audio Transformer

Reason - Some Audio Transformers react to a DC Current and form a Filter.

Example ; tc-electronic used a Very high quality Transformer in their old 19" Parametric EQ (Land-Line Version), that had a Bandwith 5-200KHz. when feed with a 10µF Filmcapacitor in series with a 600 Ohm Driver + loaded with 600 Ohms on the secondary and a Filmcapacitor between it and the next stage. It only took a few mA. of DC current through any of the two coils and you had a 1KHz. Bandpass filter with 80dB/Octave ...!

So a Tantalum Capacitor usually has between 0.1-1% of the Leakage Current of a good quality Electrolyte Capacitor => Far better suited as C4 ...!!!!

And before I get loads of flak - a Film Capacitor would be the absolute best as C4 - but I don't see enough space inside your microphone for that ....

One thing that can totally ruin the idea of using a Tantalum in a similar circuit - is if it hasn't got at least 33% of it's rated DC voltage across it - as this WILL make it distort the Audio (or any other AC voltage) ....

Per