My health and the Sun Storm.

It has been a very difficult past few weeks for me due to a personal injury.  Bulging discs in my back and neck.  I had to take about 10 days off of work.  If you're not aware, LBA is my full time job.  Just before this incident started I got very far ahead on my workload.  Now I'm right in line and just getting back to work.  I'm not 100% healed and worried about not meeting deadlines.   The 23Fe+ batch that has been pre-order is scheduled for January 8th.  I still believe this deadline is realistic since I had the project mostly complete before my injury.  I have multiple custom jobs on the bench, with more incoming.  Those are the things I'm most worried about meeting deadlines with.  I'm going to do my best.  One in particular has been pushed back and will probably be  pushed back further.  That one is a custom stereo optical tube compressor for a very cool French customer.  I want to develop this thing to the max and make it my greatest product ever.  It is the next product in the Storm Series... the Sun Storm.  I want this to be my greatest creation.  The Trinity tube channel strip almost was that, but it ended up never becoming a product due to multiple factors.  This I think will surpass it in complexity and awesomeness.  The Sun Storm is what I really want to talk about because I have been putting a ridiculous amount of time and effort into it since starting in October. 

When I'm not injured, I'm working 5-6 days per week and no less than 48 hours.  Since October 2024, 4 of those days per week are devoted to the development of the Sun Storm.  My daily personal journal confirms that for me.  You probably want to know what the Sun Storm is and what inspired it.  It's not based on anything.  The whole purpose is to create a unique compressor design that is highly flexible and offers a tube tone with components that are currently manufactured today.  A vari-mu compressor is a cool thing, but nobody makes variable-mu vacuum tubes anymore... at least within realistic prices.  I heard some company is offering a very specific vari-mu tube in new-production form for an absolutely obscene price.  That's a no-go.  I love my extremely modified (LBA) Altec 438-C variable-mu tube compressor, although it's way too colorful for most situations.  I also love my home-brew ultra-Hi-Fi variation on the Teletronix LA-2A vacuum tube optical compressor, but it is extremely limited in use due to it's fixed attack and release controls.   I absolutely love my 1176 compressor, but I don't want to make a clone.  Clones are not cool in my book.  To be honest, the 1176 is not ideal for every situation, nor is any compressor.  That's why we have options! 

This whole "build a unique studio compressor" thing began with a lot of people asking me if I would bring my Op-2 Compressor pedal back.  I'm not interested in doing pedals because I see that market as over saturated.  Too much competition is why I got out.  Many who know a little bit about electronics start making pedals because it can be easy.  That ease floods the market.  However, I recognize that particular pedal is a step above the norm and people really want that revision B version of the Op-2.  I pondered over it for more than a couple years.  My next move has been to make a professional studio version with more features and a much higher quality of sound (and with no limitations or design restrictions).  After getting as far along as I am with the R&D I can say that is an understatement.  The current prototype stage of the Sun Storm absolutely blows away the Op-2.

I started a new thing for me, which is keeping a daily journal in the development of the Sun Storm compressor.  It may seem like an obvious thing to do for some, and regretfully I should have done this for every product before.  It has made it easier and faster to develop by having an easy way at looking back at previous design ideas.  Every day I write down on paper with time and date stamps each development good or bad and I draw schematics of ideas and successes.  This has helped me to speed things up.  Also I have developed over many years some building block circuit boards which also help to speed things up.  Getting older sucks in the sense of injuries and healing time, but it's not so bad when I think about how much smarter I'm getting.  I'm excited about this compressor.  I think it's cool and If you keep reading I'll share why.

The Sun Storm is a hybrid device.  It has a 100% vacuum tube signal path.  That is, your audio will only flow through my LBA transformers (input and output), 2 vacuum tubes, and some resistors and very high-quality film capacitors.  There are currently 2 tubes in the design.  One is a 12DW7 and the other a 12AX7.  The 12DW7 is a nifty tube in that 1/2 of it is a 12AU7 and the other 1/2 is a 12AX7.  Did you know the 12AX7 (and many other tubes) are actually 2 separate triodes in the same glass envelope?  You probably would if you work with vacuum tubes.    In the Sun Storm, the first tube stage is a 12DW7 and the first triode is a 12AU7, which is used as a phase splitter.  1/2 the signal goes to the audio path, the other half goes to the control voltage, which I'll refer to henceforth as the CV.  The audio signal from the 12AU7 stage travels to the next vacuum tube (not the next triode in the envelope), which is a 12AX7.  This second vacuum tube is arranged in a circuit designed to drive a custom wound LBA output transformer... the FS21.  The second stage of the first tube is a 12AX7, but this triode is part of the CV.  It uses the compression knob on the front panel as a volume control for the input of this triode.  This triode is necessary to boost the signal voltage enough to be somewhat usable.  It's still not fully usable, so a second stage is required to boost it more.  The second stage is transistor based.  It is to be noted we are talking about the control voltage for the compressor here, not the direct audio path.   This second stage of the CV is essential to providing enough power to effectively operate the proceeding controls...  The attack and release functions.  The attack and release controls have their own independent transistors to control what I call a "timing capacitor".  I'm literally making this stuff all up in real life.  It may have been done before for some different application that I'm unaware of, but for a compressor I think it's probably unique.  The CV post attack and release goes to an LED light source that is reacted upon by high-speed photo resistors.  The photo resistors are there to manipulate the VU meter and the output volume.  This is a feed-forward design.  There are trimmer controls to calibrate the meter and I have found it to be fairly accurate... especially comparing to compressors like the 1176.   

The compressor speeds have not yet been accurately measured, but I can say initial in-studio testing implies it's very flexible.  The attack time seems to vary from super fast (maybe a ms or 2 to rather slow... like a second or two, with the release being similar).  It seems like the fastest release is slightly longer than the fastest attack.  It's practically impossible to measure with ears, so I'll need to do some proper lab testing in the future. 

The compressor is capable of boosting the signal over unity under max compression a substantial amount at this current state in time.  Max compression seems to be well over -20dB.  The THD according to circuit simulations should be super low.  In real life it sounds very transparent.  Testing of THD has not been done yet.  The headroom is obviously high with a noise floor that is not perceivable.  Noise measurements will come later as well. 

The only issue I currently face with this design is the compression ratio.  It seems to be extremely high.  I have 3 separate ideas for how to remedy this.  Further testing is necessary.  This is a work in progress, but I expect this will be resolved next week.