V1.21 Changes (8/3/2020):
Digging around on the SPDIF code this past week I found a memory alignment issue occurs with the Magic function. Basically the two functions are offset by 25% in memory and the end result is that 25% of the Magic corrections don't get directed to the SPDIF port. With the update, SPDIF users will get improved Magic performance. So this is a highly recommended upgrade for all SPDIF users currently using V1.20 or earlier. Regular analog Puffin users who have already updated to V1.20 needn't bother with this update.
V1.20 Changes (5/26/2020):
Puffin User Manual
Magic: Removes a lot of crud from your vinyl. But doesn't whack it over the head with processing either. The goal is a simple control that is On or Off. I've tried to make it very gentle and non-digital sounding, and actually used an analog-like technique. This is intended to be used all the time and makes your best LPs sound better. Like they're extra clean. Scratched up records will receive some help, but don't demo Magic using them - use the good stuff.
Grade: Use this to grade your records - either to sort out dupes or find which records may need to be upgraded. Turn Grade on after the music fades in and turn off just as the music fades out. This cuts out all the noise in the beginning and runout grooves which affect the grade. Uses the American Grading System: A+, A, A-, ... D-, F. So you grade each side. Note that Grade is unaffected by Magic (i.e. grades it without the Magic corrections).
DeRumble is a true rumble filter using the Macaulay Method of summing the low bass to eliminate out-of-phase vertical rumble from the turntable.
RoomEQ compensates for the room's main resonance that ends up muddying the bass. Just roll with 300Hz or use a free octave RTA on your phone and the Puffin's fx:PinkNoise to find where it is located in your listening space. The RTA apps usually have peak search on as default, so couldn't be easier. I staggered OFFs between the different frequencies (200Hz to 400Hz) so that you could switch back and forth (before and after).
Clip detection: this is an asterisk that shows up at Volume and Gain. Definitely adjust Gain down if clipping as you are over-driving the input. Occasional clips at the DAC (Volume) are less of an issue as they are software handled.
TF fixes: Wow - I really screwed up the harmonic functions in the previous release. I had a semi-bad bug in the harmonic code with versions 1.04 and earlier, but the fix in V1.11 I caused the 2H code to be much more aggressive and the 3H code to not work properly at all. Should be good now.
The code is unified now, so this will work with either a regular Puffin or a SPDIF modded Puffin.
My general thoughts: Magic is fantastic but reminds me of anti-lock brakes. You turn it on and forget about it. It's only when you turn it off that you cringe and turn it back on. Grading, on the other hand, is an active feature - even a game of sorts - that you interact with. I really, really, love grading my records. When it tells me that my copy of Led Zep III is an F (and I kind of assumed it was), it gives me permission to get a new copy. And you can use it to test your cleaning methods, too.
How to Update the Puffin's Firmware
Using the supplied allen key and USB cable, the Puffin can be updated via an internal micro USB header with either a Windows or macOS system.Note that updating your firmware will erase old settings saved in the Puffin's memory, so write down any current settings that may help you set up after flashing the new firmware.
Note: Skip step 2 for recurring firmware updates (i.e. you only do this step once).
macOS (10.11 & higher) Method:
Note: Skip steps 4 through 7 for recurring firmware updates (i.e. you only do these steps once).
Initial release. SP
Added flash saves at Set?>OFF, Set?>LOAD, Set?>SAVE, and main menu Gain change. Moved phase polarity to pre-DSP so we can get 2H cancellation. SP
Fixed Load setting bug where 200 ohms setting could be overwritten to 47k. SP
Screen refresh timer was active during standby sleep. Would cause faint flicker on LCD if Puffin turned off with main menu set to Set? or Signal Levels. SP
Added immunity to static electricity discharge that could put unit into Standby state. SP
-Added adjustable RIAA eq function
-Added adaptive Bass Boost
-Added Pink Noise for Room EQ
-Added Null to Phase controls
-DSP code re-written for speed in assembly SP
Fixed Tube 2H function. Right channel had bug which could add extra non-2nd harmonic distortion. SP
Saved FPU registers to stack during DSP interrupt that could have caused "no sound from Puffin" when adjusting menu.
Adjusted Tube 2H and Tape 3H constants for much less distortion. SP
-Added Magic pop and click minimizer
-Added Grade which is a record grading function
-Added new clip alerts with asterisk * at
Volume (output/DAC clip) & Gain (input/ADC clip)
-Changed TF to fx: think Effects or f(x)
-Lowered 2H Tube distortion (7%THD at full signal)
-Fixed 3H Tape distortion (3.5%THD at full signal)
-Removed 2H&3H from fx
-Added Out function & merged with SPDIF branch
but Out:SPDIF is disabled on non-modded Puffins
-Fixed FPU memory stack bug
-General bug fixes and tweaks
-Added many new Lo filters SP
Bug fix for digital output SPDIF (analog users unaffected). Memory alignment issue dropped 25% of Magic corrections. SP