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'Movin' On Up...

Just a brief status update on some things that will change with the site and our offerings, and a really cool technology update to our Ultimate Edition mods that has been a long time in the making.

First, its no secret that developing products for United and running the company are taking more and more of my time. To that end, we're discontinuing some of the less popular mods and some of the ones that we honestly did more as a public service than anything else. For instance, almost no one sends in the MXL or PreSonus mic, so those are going to go. Likewise, mods like the SM57 mod and Warm 87mk1 mod are mods that we don't really make anything on and take a lot of our time (the transformer for the SM57 mod costs like $100, so we really make little to nothing on it, its just an upgrade we highly believe in)... So those things are going to go for the time being, just to enable me to start catching up on things. Likewise, I'm eliminating the standard upgrade for the WA-47 and WA-251 and just focusing on the newer Ultimate upgrades for them, which are far more thorough. Repetition helps with efficiency, and I've just kind of reached the point that the ultimate upgrades don't take too terribly much longer than the standard one, and I just feel like at this point, its not worth getting it on my bench and setting aside a day of my time unless I can take the mic all the way to its absolute fullest potential. Of course, existing orders in the system will be handled as such, but as of around 6/1 these changes will take effect.

The WA-47 has been available as an ultimate upgrade for some time, and will continue as so but with one improvement I'll get to later. With the WA-251, in addition to all that was already done, we will now be replacing 100% of all internal components aside from some metal film resistors (those are fine) with the best possible name brand tantalum, polystyrene, etc. capacitors, as well as replacing all internal wiring with Belden's silver-teflon wire. This, of course, in addition to all that was already done, along with one more new technology update, same as mentioned above on the WA-47. These additional tweaks, along with increases in shipping costs, will mean prices for these mods is going up slightly.

Finally addressing an elephant in the room... and extending tube life/compatibility.

One of the things I've been somewhat aware of for years with these 2 mods, in particular, is that the mics have a tendency to go through tubes more often one would like. I know that many end users are aware of it too, and at least some at the company were as well (I've been told by a couple folks that they send out a number of tubes, which shouldn't be normal). This was, in part, one of the reasons why I discontinued the use of NOS tubes in my mods; though I didn't get into that particular detail of it at the time. I just couldn't afford to sacrifice super-expensive tubes, and many NOS tubes are just less tolerant in their old age to certain operating conditions than some new production tubes. My move to only new production TAD Germany 12AY7 and 5751 Highgrade tubes was the workaround solution for years; because they not only sound great and are super clean, but also just more resilient in this circuit. I never had time until now to really try to dig deep into this issue and try to resolve it; but the time has finally come and its been resolved. Time for a deeper dive...

So, the PSU for the WA-251 and WA-47 are essentially the same; an Asian design with a two rail power supply. The power supplies are designed to be mass-manufacturable and maintenance-free. No calibration needed, either at the point of manufacture or by the end user. There is a certain wisdom to this, and I think there is a 'right way' to do that. So, often in this type of design you might see a voltage regulator for the tube heater rail, and you might typically see an adjustable regulator like the LM-317T. But, this means that someone has to do the adjusting (to 6.3v in the case of these), and then later if you change the tube out, or after many years of use, you might need to adjust it again. A fixed regulator solves this problem and puts out a constant voltage regardless of current draw or changes in operating conditions, etc. The caveat is that there is no +6.3v fixed regulator (the optimal heater voltage for most small signal tubes), and so a 6v regulator will be used. At the output of this circuit, the fixed part used would have an output of about 5.9v due to loss, so a diode is used between the regulator's ground pin and circuit ground, which causes the regulator to have a voltage output of +6.6v, though this does come at a cost. Now we are slightly over-heating instead of under-heating; but at least now we are now just within a 5% +/- tolerance specified by most tube makers.

This design is not the end of the world, and as I've said, early on I realized something like this was going on and moved to use a new production tube that was very tolerant of those conditions. But I feared putting NOS tubes in these mics, and saw many expensive JAN 12AY7 and 5751's die during burn-in. The time has finally come to fix it. At the end of the day, I want our customers to feel confident that the tube in their mic will last the absolute longest time that it possibly can (esp with the rising cost of tubes today) and to have no (or less) fear of trying NOS tubes in the mics. To that end, we worked with a US manufacturer to create a custom made FULLY DISCRETE voltage regulator which outputs exactly +6.3v. It will put out precisely 6.3v come hell or high water, no matter how many times you change the tubes or where you move to; and not only that, it means that the power supply is now 100% fully discrete (no IC's, on either rail!). Not only that, but the voltage output of the discrete regulator is an order of magnitude cleaner than even the best package IC's, which themselves, are still cleaner than direct heating via a transformer. The tubes will have never had it so good, and should now last longer than ever. This additional upgrade represents a big investment for a small shop like ours; but its something we wanted to do for a long time. Ultimately, it costs us slightly less to do this upgrade than it costs to replace a tube with another new tube of our choice... plus it makes the mic even better, so this was just a no brainer.

There's slightly more to the PSU re-work than what I am choosing to mention above; but like MacGuyver, I want to leave out a few bits of detail so nobody else tries this at home. LOL I'm not really in the business of helping another manufacturer to make their products better. This is really just for the benefit of those sending in the mic to us for upgrade work.

We're in the process of getting the first batch of the new discrete regulators manufactured now, and are very excited about it. They will be automatically put in to all orders after 6/1 and the WA-251 and WA-47 upgrades will all be the ultimate upgrade and will have those incorporated. Before anyone asks, this is not applicable to the Sterling tube mic upgrades, as those have an adjustable regulator for H+ voltages and we already re-calibrate those by hand when we get them in.

Later this year we will hopefully bring back the handmade 47's as well as have some exciting new things to show you in Signal Art land. Stay tuned.

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Hi, This last year I got the Ultimate Mod for a WA-47 I sent you. Would it be a good idea to return the PSU to get this mod added?

Jun 11, 2022
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Hi, if it is still going strong then it is probably OK and tolerant of the higher heater voltage. The JAN GE tubes were definitely not, and that played into why I had to quit using them. Some were and some were not. This is also why the factory moved to a different tube; they just did not understand why it was happening, likely. It took me a long time to make time to figure it out; but I finally did and now the 2 (soon to be 3) Warm tube mic mods have ultimate upgrades which make them tube-burnout-proof!

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