Soliloqueen's k87(k67) and k47 capsules

[Purplenoise]

google drive, dropbox etc...

Hmmm…could I send it to you to upload?

 

[soliloqueen]

Hmmm…could I send it to you to upload?

sure, over what? email?

 

[Purplenoise]

sure, over what? email?

Awesome, yeah pm me your email and I’ll send it to you.

 

[soliloqueen]

 

[mrgrooves666]

Sounds sweet thanks, building a DEF-47 with this capsule seems very appealing to me, hopefully for next year,

 

[kingkorg]

That sounds like everything i'd ever want form a guitar/mic combo!

 

[soapfoot]

Interesting result with the flat K47 in the ancient Royer-mod MXL2001!

This was built over a decade ago using the Jensen direct box transformer, a Mullard 5840, a Solen 1µF and a cheap panasonic MKT .1µF. It makes use of Royer's cheap voltage-tripler power supply. Absolutely nothing fancy or optimized at all... just a cheap old DIY project that's effectively been obsoleted by the modern tube mic kits.

The result with the flat K47 is decidedly "not bad!" I forgot to record it with the stock capsule (and it's been forever since I used it), so I'm honestly not really sure how far we've come. But I'm quite confident it's a fair bit nicer.

I made three test recordings: one of an acoustic guitar (a 1940s Gibson SJ), one of a ride cymbal on-axis (but mic'd a bit too close, probably), and one of the same cymbal with the same level of preamp gain, but off-axis (as though mic'ing a floor tom).

The off-axis cymbal test is something I find to really punish poor microphones and poor capsules in particular. The better microphones and capsules will be attenuated by quite a bit, and while the timbre will usually be different it should be free from really harsh or unpleasant peaky resonances.

I'll post the clips below.

Now for my editorial:

On to acoustic guitar: pretty damned impressive in this cheap mic circuit, as you'll hear. After my initial evaluation, I pulled the attached recording into a session recorded on the same guitar and signal chain but with a much better mic (a U47 with a Telefunken EF800, an AMI BV08 and Thiersch blue-line M7).

Side-by-side, it held its own impressively well even with all the other factors working against it (if interested, I can post an imperfect comparison). Compared to the EF800/M7 U47 copy it may have lacked just a bit of extra "something," but it'd be silly to blame the capsule.

The flat-K47-equipped Royer/MXL was maybe slightly less-interesting to me in the low end? But this is also subjective, I can't swear mic positioning was identical, and the impact of the the cheap-as-chips power supply and literal direct box transformer are surely not "zero."

On the cymbal, as I said I mic'd a bit too close. The cymbal (an old K) is fairly trashy, and this is well-represented. Still, the result was nice enough.

Off-axis is what I was most interested in, and I'm happy to report that it's pretty much as I expected it to be--low end quite a bit attenuated; leakage fairly bright but not overly harsh and no obvious weird, peaky-resonances. This leakage may not be a major asset, but it'd also be fairly-unlikely to be a major problem.

One quick test won't tell me much, but first impressions are that I think this is quite well-done! In a better mic this could be an exciting capsule. I'm almost curious to try it in the above EF800-equipped U47, but I'm not really inclined to dismantle a working microphone just for a capsule test. Maybe if things get slow over the winter...

If nothing else, the flat K47 made the Royer-modded MXLs into something I might be curious to try on a source now and then instead of just sitting in a drawer forever... and that's all I was hoping for!

Acoustic guitar:

View attachment acoustic gtr.wav

Cymbal on-axis:

View attachment cymbal on axis.wav

Cymbal off-axis "bleed"

View attachment cymbal off axis.wav

 

[Kori Rose]

Awesome! As for shipping time, 99% of the time I do same day shipping. Usually it's packed up and in the outbox to be picked up within 20 minutes of getting an order.

Good day do you sell K67 type capsules? If so how or where can I buy one? Thanks.

 

[soliloqueen]

Good day do you sell K67 type capsules? If so how or where can I buy one? Thanks.

the k67/k87 is currently running slightly late, seems it'll be mid january now. a lot of businesses buy stuff for the beginning of the year, so the machinists etc are a bit backed up. sorry all!

 

[Kori Rose]

the k67/k87 is currently running slightly late, seems it'll be mid january now. a lot of businesses buy stuff for the beginning of the year, so the machinists etc are a bit backed up. sorry all!

Thanks. Could you please let us know when they are in stock? That’ll be great!

 

[soapfoot]

A bit of an apples-and-oranges test between:

• U47 with Thiersch Blue Line, Telefunken EF800, AMI BV08
• MXL Royer Mod with SQ Flat K47, Mullard 5840, Jensen DB/E

While I set up the test to be as equitable as possible--mics positioned head-to-head into identical channels (Seventh Circle N72s), gain matched and then normalized after recording to 99.5% (in an attempt to get equal loudness)--this is clearly not at all a fair fight for the capsules. The modded MXL is much more cost-conscious in every respect. Still, after the capsule swap I think it acquits itself remarkably well.

I hear some pretty interesting differences, but it's almost pointless to enumerate those. Too much is different between these two projects--circuit, tube, transformer, headbasket acoustics--to confidently attribute anything to the capsule design (much less the capsule quality).

What does stand out, for me, is that the modded MXL with flat K47 very much sounds like a microphone I'd use. It didn't sound like that with the stock MXL capsule.

Both mics sound good enough to allow me to hear the music before hearing the microphone (if that makes sense), which I think is the most important thing.
View attachment U47-THIERSCH BLUE.wav
View attachment MXL ROYER-FLAT K47.wav

 

[soapfoot]

(by the way, if it's not clear--the U47-with-Thiersch is first; the Flat K47-equipped MXL/Royer is second).

Aside from the loudness normalization performed in the box, there is no processing of any kind applied to either channel--this is mic into preamp into converter.

 

[rock soderstrom]

A bit of an apples-and-oranges test between:

• U47 with Thiersch Blue Line, Telefunken EF800, AMI BV08
• MXL Royer Mod with SQ Flat K47, Mullard 5840, Jensen DB/E

While I set up the test to be as equitable as possible--mics positioned head-to-head into identical channels (Seventh Circle N72s), gain matched and then normalized after recording to 99.5% (in an attempt to get equal loudness)--this is clearly not at all a fair fight for the capsules. The modded MXL is much more cost-conscious in every respect. Still, after the capsule swap I think it acquits itself remarkably well.

I hear some pretty interesting differences, but it's almost pointless to enumerate those. Too much is different between these two projects--circuit, tube, transformer, headbasket acoustics--to confidently attribute anything to the capsule design (much less the capsule quality).

What does stand out, for me, is that the modded MXL with flat K47 very much sounds like a microphone I'd use. It didn't sound like that with the stock MXL capsule.

Both mics sound good enough to allow me to hear the music before hearing the microphone (if that makes sense), which I think is the most important thing.

Thanks for the sound samples! In this application I find the Thiersch/EF800/AMI BV08 combo slightly better, despite the reduced treble.

The Royer with SQ capsule sounds a bit unclean and boomy in the lower range. Of course, this may also have something to do with the microphone position. Edit: after listening to it several times in concentration, I would not name the differences that way now. The mics sound clearly different but both have their qualities that I like very much.

What PSU are you using for the Royer? Original with tripler?

Thanks again for the sound examples, that makes the whole discussion much more understandable for me even if these always only represent one concrete situation.

 

[soapfoot]

Original with tripler, yes. I probably built them around 2007-2008, when I had even less of a clue what I'm doing than I do now.

I also prefer the low end of the U47 setup... not sure I'd call the modded MXL more "boomy," but something about it is less-great.

Where I really hear a difference in character is in the midrange (maybe what I'm hearing as a more-restrained midrange you're hearing as an emphasized low-end). The midrange reminds me just a little bit of a 414 B-ULS... that almost hollowed-out feeling (though not in a bad way, here). Compare 0:45-0:50 of the two recordings to hear what I'm talking about.

But there's no way to really parse out which sonic distinction is a result of which variable. I figure headbasket acoustics will be a predominant factor, as will the direct box transformer compared to a really nice BV08 reproduction.

The capsule surely matters, too, but until someone does a similar test with all variables controlled, I'm afraid this won't tell us much in conclusive fashion. The signs do seem to point to Flat K47 being quite good, though.

 

[rock soderstrom]

Both mics sound good enough to allow me to hear the music before hearing the microphone (if that makes sense), which I think is the most important thing.

+1

 

[rock soderstrom]

I also prefer the low end of the U47 setup... not sure I'd call the modded MXL more "boomy," but something about it is less-great. Where I really hear a difference in character is in the midrange.

Same here, I corrected my statement after listening several times on my best headphone setup, but I see it like you. The Royer does something in the lower mid-range which I do not like so much. The differences are not gigantic but audible.

But there's no way to really parse out which sonic distinction is a result of which variable. I figure headbasket acoustics will be a predominant factor, as will the direct box transformer compared to a really nice BV08 reproduction.

The capsule surely matters, too, but until someone does a similar test with all variables controlled, I'm afraid this won't tell us much in conclusive fashion. The signs do seem to point to Flat K47 being quite good, though.

+1

 

[soapfoot]

I'd really be interested to hear the "historically-inspired" K47 (with presence lift) when it comes out. It would be interesting to hear the difference in midrange character between the two in the same microphone.

 

[rock soderstrom]

I'd really be interested to hear the "historically-inspired" K47 (with presence lift) when it comes out. It would be interesting to hear the difference in midrange character between the two in the same microphone.

Me too. I would also be very interested in a direct comparison of the SQ capsule in the Royer against the original MXL capsule! Of course, only if you have too much free time ;-)

On the subject Royer power supply: I've been looking into voltage multiplier circuits lately and I think the Royer PSU is set up a bit too thin. Of course it works, but maybe you could make it sag a little less with larger capacitors and separate regulated heating, making the low end a little more stable.

Just as an idea...

https://groupdiy.com/threads/my-first-voltage-multiplier-psu-😎-for-tube-mics.82104/post-1062116

 

[C12VR]

Is it just me or does the flat capsule sound very quick? It has an almost clinical sound to it.

 

[kingkorg]

Is it just me or does the flat capsule sound very quick? It has an almost clinical sound to it.

You can't really come to that conclusion with this test simply because there are way too many variables between the two mics. You would have to test two different capsules in identical circuits under exactly same conditions. Royer mod circuit is pretty much most transparent circuit you could make with a tube.