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  • chaddavidkelly

Our handmade U47 and U48 are back for a limited time!

They say that absence makes the heart grow fonder, and it's definitely true that I've gotten a lot of inquiries since taking down my U47 and U48 from inventory on the Signal Art webstore. I finally have set aside a few minutes to explain what was going on, and to let people know that the SAE 47 and 48 are back, at least for the moment.


We've actually been shipping them again for about 30 days but just didn't have time to fully update all the literature. This will be fixed finally this evening. There have been a few changes to the build which required editing of the language, and I wanted to make sure that was done right.


So, the biggest change, first and foremost, is that we are now building the handmade mics with OPR Capsules, which are fully handmade in Australia. The brass is milled, the backplates are skinned, tuned, tested, and shipped from Australia. These capsules are actually much more historically accurate replicas of the original German part, made (like the original K47) from a single brass backplate, double sided, tuned the same way, etc. If you are after the sound of the original mic, I don't think you can get much closer. I can also assure you, these capsules are as fine, and as expensive as the Heiserman K47 which we had used for several years prior. We did not take this component change lightly. This is why we shut down sales of the mic for several months. We evaluated a number of quality capsules, and OPR were the clear winner for what we are going for (vintage, big sound, historical accuracy). What we definitely refused to do was to cheapen the brand by going with a more economical capsule (although a new baseline edition mic may be in the cards next year). We had to find a solution that lived up to the rather high bar set by Heiserman. We think our mic is now as good or better than ever, and believe you will agree.











The OPR K47 capsule has a lot going for it. One thing that impressed me quite a lot was a very strong side-to-side consistency and capsule-to-capsule consistency as well. No capsule ever seemed to have a more dominant side, and every capsule seemed to sound the same. None have ever come off as more dark, bright, or sibilant. I feel like they have some really strong QC protocols in place there, and it gives me confidence to feel that each mic I build will be consistent for the years to come.


Just in case anyone needs to ask what happened with the Heiserman capsules; its nothing other than just everyone being over-booked with running their own operations. They've had a good deal of success and will probably only get much more busy in the coming years as they release new products. They just didn't have time to do everything they'd probably like, and have had to suspend OEM capsule sales to focus on their own production. I totally understand this, as we are in the same boat here! There are a lot of things I have to turn down for the exact same reasons; just not enough hours in the day and no technology yet that will allow me to clone myself. We're all still friends, and still have an ongoing business relationship regarding engineering/development and other things. OPR currently do have the bandwidth to be able to help us, and so we're grateful for the opportunity to work with them.


People have asked me what the sonic differences are between the OPR K47 and the Heiserman K47. There are some differences, but they are not huge. The OPR seems a bit more open and neutral across most of the frequency range; but both the very low and the upper frequency limit seem to be more extended in reach. I picked up some very low frequency sounds with these capsules (the vibration of machinery like the AC, refrigerator, semi truck going down the road, etc.) that are so close to subsonic that they aren't usually picked up by the mics... and now they are. I can see how this would add weight by capturing, say, the low 'air' from a kick drum, etc. And because the top end reach seems to go out just a touch further, the capsule also sounds a touch more crisp and loud at the same time; but (critically) not actually more bright. The Heiserman, on the other hand, is probably a little more deliberately voiced, focusing on the most relevant musical range of the spectrum and ever slightly pushing a bit more into the midrange and low mids. And I love both capsules. I don't think I would pick a favorite. Bear in mind that the differences I describe probably constitute about a 1% difference in sound that many people wouldn't pick up on.


What else is new?!


We have dabbled in this before with a few different prototypes, and gone back and forth with a very high quality and robust Triad part; but now I can officially say that we ship all of our handmade U47 and U48 models with a custom wound toroid made specifically for us by Avel Lindberg Group. This toroid is robust, hefty, and equipped with a Goss band for no audible hum or buzz. The transformer is dead quiet, does not vibrate or produce resonance or noise of any kind. It's the first toroid I've ever worked with that I simply don't even have to 'tune' (turning it while monitoring for hum/buzz, locking down at the quietest position... a common practice with toroidal power supplies). This part provides four times the available current that the mic circuit would ever require, and its potting and thick rubber platform provide exceptional acoustic dampening. It's everything I wanted in a PSU transformer, and they all do ship with them now.



What else is new?


Now we get into the nitpicky. I did stop including the handmade IEC power cable that I built from Gotham AC power cord and Wattgate connectors. The process was just so incredibly time consuming to make the boutique cable to my standards, and it was also a bit more bulky than I honestly prefer. I did not like how it had to be packed outside of the main foam enclosure because it did not fit, and some customers actually forgot to find it there amidst the packaging material between the inner and outer box. So now I use a very high quality and rugged hospital grade IEC cable on domestic mic shipments, which fits in with the other cables in the proper compartment of the foam shipping tray. This cable is very reliable (hence hospital grade) and actually seems to have a more firm grip on both connector ends (to the wall, and to the device) than most handcrafted cables. Ordinarily, I do like to spare no expense and go to any length to make a better product; but in this one situation I really did have to face the fact that I just had no free time to be a boutique cable shop on top of all my other duties; and on top of that, the Wattgate/Gotham handmade cable was more of an inconvenience to the way that I want to pack and ship my product than it was of any particular benefit.


We are on board revision 4.1 now. Forever making tiny incremental updates to the design; but in this case its really only of benefit to me, the builder, and not worth going into those specific changes.


We are still using the NOS Western Electric 408a pentode valve, while supplies on them last, and we are still using the AMI BV8R output transformer. We did dabble with a few other transformer options; but the AMI is just the clear winner still.


That's all for now, now I have a webstore to update!


Best,

Chad



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