Free 1176 true-bypass/HPF/buffered meter/send-return boards! [ALL GONE]

[dmnieto]

It seems that my post on the thread was not seen so I will do a separate thread. Short story, I had built a relay board to add some functionality in the stereo linking, basing it on the design from Purple Audio. I was going to offer the Gerbers to the community, but Purple Audio vetoed it.

I still have 13 boards with the last prototype. I offer them for free, heck I will even pay postage for the guys in the US, it is just sad seeing them unused. I wont re-spin the design, share the gerbers or do additional runs. So this is it.

For the "lucky" people that get them, I will provide the BOM and some instructions about how to wire it properly (I should have added many more GND pads), also it has SMD parts... LOTS of them, but they work, and if you want the challenge... Some people may not need all the features. You need two for a stereo build.

The only thing I ask in return is that when you finish the design you post a picture of it.... so who is taking?

So finally I managed to finish my dual rev D stereo with the following modifications:

- True bypass with relays.
- Addition of the super-slow attack switch and the ratio 2 (it has ratios 4, 8, 12, 20, SLAM and 2).
- Buffered metering.
- Side-chain high-pass. (with relay switch)
- Side-chain send-return. (with relay switch)
- Link mode (with relay switch)

Oh boy this has been difficult... I had to design and re-spin boards, prototype, sort out routing and grounding schemas, drill more holes than I thought possible, and solder lots of small SMD parts,... But yeah! It works and sounds great!. The feeling of actually designing even a part of it by yourself is very rewarding when it finally works

With the mess of routing I made I am surprised there is no noise, or motor-boating, or oscillation ( even If I know the relays help)... I have to thank mnats, mike, dan and everybody in this thread for their help and for making something like this available to everybody.

Unfortunately Purple Audio vetoed the sharing of the schematics and the gerbers of the add-in board (as it is their right), but I still have 12 (unpopulated) boards around here if somebody else wants it (but I warn, this has been the most difficult build I have ever done... oh my god the smd parts). I can also describe how I added the 2:1 ratio to the rotatory version (having 5 ratios + slam) and the simple fix that is to add the super-slow mode.

So pictures here:



My wife is really digging the combination of super-slow attack, fast release, 2:1 ratio and hpf sidechain as a master bus compressor

 

[dmp]

Cool. Sent a PM

 

[rainton]

PM sent 

 

[dmnieto]

Updating:

okgb (2)
dmp (2)
critterkllr (2)
peskado (2)
rainton (2, let's see if I can get them to you for cheap, if not I send to your friend)
winetree shabtek(2)

 

[okgb]

maybe too much for my pal so , just a pair thanks.

 

[dmnieto]

So this is the layout of the board.

It has several issues (it was a prototype), the worst one is that there is only one GND pad (and there should be several...) Also, the second one was a stupid mistake, the relays are active high, instead of active low (d'oh). This mean you need to route the 24V to the switch SPST switch. While this is not critical, it prevents from using the TRS jack switch detection (it closes to GND when something is plugged in), which is REALLY handy for the SEND/RETURN or if you are adding stereo connection to a mono unit.

It is reasonably easy to solve though, by jumpering R139-R141 and adding pull-up resistors. Of course, you will need to use PNP transistors (sot23 and VCEO > 30V), and then the relays will close on GND closure.

 

[dmnieto]

maybe too much for my pal so , just a pair thanks.

Sure, it is not an easy one, but a wonderful practise of Zen, SMD skills and patience. Your PM is full, PM your address

 

[dmnieto]

So in terms or functionality:

- Power supply, it has the possibility of generating 24V. If you are using the DS1E or DS2E at 24V it is actually unnecessary. The relays will work fine with a 30V supply even if they are rated to 24V.

- The simplest functionality I recommend is the true-bypass, and If you want to get rid of any oscillation in the circuit the metered buffer.
RV101 will be used to ensure that you get unity gain.
For that route the X and Y wires to the board using shielded cable, and also the IN-/IN+ from the XLR IN to the board (with shielded cable as well) wire M+/M- to the XLR out.
Then use the "M" pad to the board and connect it to the "Y" in the meter, ground X.

- For the High-pass filter I recommend using http://sim.okawa-denshi.jp/en/OPseikiHikeisan.htm to determine the values for C117, C109 R112 and R116. Please take into account that when connecting it to the circuit, C117 is in series with a 1uF capacitor, so if you want the 0.22uF you actually need to put a 0.18u in C117. The current values give a 80Hz HPF.

- Send/Return sidechain are not normalled though, they are fully differential. The send channel is ALWAYS sending an electrically balanced copy of the signal after the compressor preamp, it does not have any of the mojo of the output transformer or the line-amp, but could be useful even in some conditions. I recommend using TRS connectors. On the return TRS make sure that you wire the TRS switch so it shorts to GND the selector when the jack is plugged.

- The stereo link relay can be wired as above for mono units as well, to prevent having to route another switch... For stereo units it is  nice not having to route the signals to the front panel

 

[dmnieto]

The boards in a party saying goodbye to my other prototypes! Two of them will go to Europe!

 

[shabtek]

I'd take a pair.

 

[dmnieto]

I'd take a pair.

Oh dang, I only have one left now...

 

[Winetree]

Go ahead and give my two to Shabtek.

 

[dmnieto]

If you are wondering where are your boards. I owe an apology.

I got sick (tooth infection) and didnt have the time to buy the envelopes to send the parts. I will go to the shop tomorrow.