Stereo 1176 support - Mnats/Hairball

[velo-hobo]

Interesting, now that you mention it I recall seeing that some other DIY versions used a 6-position switch but I hadn't considered it for use with Dan's cases.

The 2:1 option seems cool.  I searched through your posts here and couldn't find details on how you executed that - is there somewhere you explained it or would you mind giving away the particulars here?  I assume it's relatively simple in terms of picking appropriate resistor values for the associated switch position, yes?

Forgive me if this falls into general 1176 discussion rather than stereo-specific.  I'm sure I'll be spending some significant time in this thread!

 

[thunk]

Hello all.

I'm an intermediate builder at best.  I've built some SCA stuff, and rewired guitars and such, but nothing more complicated than that.

I'm a slow, careful and methodical builder, and a competent solderer, and I'm confident I could build a Hairball Complete FET Compressor Kit.

But what I *really* want to build is the Stereo FET Compressor.  It's just that it's a little bewildering.

Here are some potential issues I see:

[list type=decimal]

[*] There's no step-by-step guide like there is for the mono build.  I can follow directions, and I can improvise when I know what I'm doing.  But I don't know what I'm doing.

[*] Case layout seems to be entirely up to the builder, which scares me a little.

[*] I'm having difficulty finding mnats's power supply PCB.  Hairball's site refers you to mnats's site and vice versa.  I've read that you can just build each main PCB's power supply and run them off the same transformer, but that that unnecessarily increases component count.

[*] It seems even the advanced builders in this thread have encountered some serious issues, so I'm quite sure I will too.  But where they have the know-how to work around the problems, I might not.  Although I'm sure this forum will be a huge help.

[*] I can't find a Mouser cart for the Stereo FET "on board components, switches, pots, XLR and IEC".  I could probably piece it together from the mono FET carts/BOMs -- I've just never done that before.

[/list]

But despite all that I still want to jump in and build the Stereo unit.  Partly because I mostly want to print stereo buses through it.  And partly because the challenge is appealing.

So what would you good people advise?  Am I getting in way over my head?

(On a side note, I would *happily* pay for a complete Stereo FET Kit with an official assembly guide, and I'm sure many others would too.  Maybe Hairball would consider offering this in the future?)

 

[velo-hobo]

Hey thunk - my $.02:

Build two of the mono Hairball units, get them each working well, then do the stereo link.  It will cost more (about $200-300) and take up two more rack spaces, but it gets around the aspects of the stereo build that are giving you anxiety.  Doing those will help give you the confidence and experience to take on something more complicated and challenging like the 2-1176.

FWIW, if you really do want to go ahead with a 2-1176 buid, Dan lists some suggested part numbers on the Collective Cases page for his stereo 1176 enclosure, most specifically the XLR jacks, along with a couple other things.  For the rest, I started with a Mouser cart for the Hairball mono version, doubled it, then removed the unnecessary power supply parts.  It takes some careful reading and understanding of the schematic and PCB to make sure you are editing the BOM correctly.  Additionally, some of the Mouser items in those carts are currently on backorder, so you have to search Mouser or elsewhere for substitutes.  For example, I had to get NOS 2N3053 transistors from an eBay seller because Mouser and a few other sources wouldn't have them back in stock for months.

Then you also need to find the parts for the mnats dual PSU, knobs, toggle and rotary switches, pilot lamp parts, and other assorted bits.  Some of those things I was able to choose based on my previous experience with electronics, others I found by combing through the copious amount of forum posts here and elsewhere regarding the stereo build.

I would totally share my Mouser carts for the stereo Rev A and Rev D (I'm building both right now) but I haven't proven to myself that they are complete and without fault, so I am not confident offering them to others at this point.

Best of luck to you!  I'm sure I too will be posting some questions about my builds here soon enough.

 

[thunk]

Thanks velo-hobo -- that's incredibly helpful!  I will probably do as you suggest and start with two mono units.

And your info on parts for the 2-1176 is crucial.  That's the sort of consolidated info I've found difficult to locate.

There is a bit of an information gap between step-by-step all-parts-included kits and the big wide world of DIY-from-scratch.  Those of us looking to make the jump can find it difficult to find a foothold.  That, or it's all out there, and I'm just impatient, and need to keep digging and absorbing knowledge

Please do keep posting as you make progress.  I'm sure it will come in handy to others like myself.

Edit:  And I'd love to see your 2-1176 A/D Mouser carts whenever you're comfortable with them.  Even if they're not perfect now, with a disclaimer they could be a great starting point for others.

 

[tonycamp]

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

Hi Dmnieto, seriously killer build man! i would love to hear about the 2:1 and super slow attack?

Thanx
T

 

[velo-hobo]

Regarding super-slow attack time, quoting dmnieto from post#139:

1. I am adding the super-slow attack mode by using the SPDT switch in the attack pot to either have a 0.022uF (max 0.8ms time) or a 0.22uF (~8ms attack time)

Since the collectivecases stereo rotary switch version places the GR-off mode on the meter switch, the switching capability of the attack pot as supplied in Hairball BOM/Mouser cart is superfluous.  Using the switch on the attack pot to enable super-slow mode is a pretty brilliant idea, since the switch is located at the slow end of the dial and the cap (C27) which I believe affects attack time is right there on the pot.

Correct me if I'm wrong, but my interpretation of this approach is that the super-slow mode attack time is tunable by altering the capacitance of C27.  Does larger value=slower time? (furthermore, seems like it doesn't necessarily have to be .22uF for ~8ms, could be smaller for shorter time?  Does it work that way?)

Still not sure how the 2:1 ratio is implemented, but I haven't really spent any time thinking about it - I suspect it's a matter of picking the proper resistor values associated with the switch position?  Thus it may be possible to extrapolate those from the known R values for the other ratios.

At this point I have the cases assembled, PSU boards stuffed and tested and am headed towards stuffing the main PCBs.  Going to worry about the rotary switches after that.  Though it's always good to think ahead when one is considering implementing mods!

 

[velo-hobo]

Also, just dug this thread up:  http://groupdiy.com/index.php?topic=47196.0

Wherein implementing a 2:1 ratio is discussed, but in the context of replacing the 4:1-8:1-12:1-20:1 ratio set with 2:1-4:1-8:1-20:1, specifically in the Rev D circuit.

I'm interested in adding 2:1 to the typical set of ratios, in both Rev A and Rev D, which I think means different resistor values for each version.

Mostly because I had to buy a 6-position switch due to mouser being out of stock of the 5 position switches at the time I placed my order, but hey, 2:1 sounds pretty dang useful, especially with slower attack times.  5-position switches should be back in stock early August, in case this doesn't look like it will pan out...

 

[BenHer]

Hi everyone,
I'm building a 2 channel unit in Dan's case with Hairball/mnats parts and only 20:1 ratio works. The other ratios pass audio but its quieter with no compression. I'm getting 0.147 V at pad 22 @ 10db reduction 20:1, and 0 volts at any other ratio. I'm using a rotary switches wired for "slam mode". Both channels are doing the same exact thing. I've checked the switch wiring about 10 times. It looks right when compared to the mnats pics. Any help would be much appreciated.
Thanks
-Ben

 

[dmnieto]

Also, just dug this thread up:  http://groupdiy.com/index.php?topic=47196.0

Wherein implementing a 2:1 ratio is discussed, but in the context of replacing the 4:1-8:1-12:1-20:1 ratio set with 2:1-4:1-8:1-20:1, specifically in the Rev D circuit.

I'm interested in adding 2:1 to the typical set of ratios, in both Rev A and Rev D, which I think means different resistor values for each version.

Mostly because I had to buy a 6-position switch due to mouser being out of stock of the 5 position switches at the time I placed my order, but hey, 2:1 sounds pretty dang useful, especially with slower attack times.  5-position switches should be back in stock early August, in case this doesn't look like it will pan out...

I did keep the 1:2 myself...

You just need to split the resistors on the 4:1 ration on each of the series and wire the intermediate position to the additional switch position=> substitute the 150 for a 68then 82 ohm and the 47k in 20K then 27K

 

[dmnieto]

Using the switch on the attack pot to enable super-slow mode is a pretty brilliant idea, since the switch is located at the slow end of the dial and the cap (C27) which I believe affects attack time is right there on the pot.

Correct me if I'm wrong, but my interpretation of this approach is that the super-slow mode attack time is tunable by altering the capacitance of C27.  Does larger value=slower time? (furthermore, seems like it doesn't necessarily have to be .22uF for ~8ms, could be smaller for shorter time?  Does it work that way?)

thanks and yes . The time constant is R*C... higher C => higher attack time. It works quite linear... I have even use 2.2 and 22uF for 80 and 800ms... but at those levels... I dont think it qualifies as a 1176 anymore...

2.2uF is quite cool though... 80ms is a sweet value for me

Still not sure how the 2:1 ratio is implemented, but I haven't really spent any time thinking about it - I suspect it's a matter of picking the proper resistor values associated with the switch position?  Thus it may be possible to extrapolate those from the known R values for the other ratios.

At this point I have the cases assembled, PSU boards stuffed and tested and am headed towards stuffing the main PCBs.  Going to worry about the rotary switches after that.  Though it's always good to think ahead when one is considering implementing mods!

 

[ferrochrome]

dmnieto, I have a question since you figured out the external sidechain part on your relay board.
I built this stereo rev D a long time ago. Great unit, but I'd like to add external sidechain input. How would you go ahead and implement that into the stereo linked rev D?

 

[Spencerleehorton]

Hi all,

I have just put together a stereo 1176 with the link pcbs from hairball but getting some strange results.byave wired up per instructions but link switch cuts all audio.
Left channel doesn't seem to pass audio, output control doesn't work but input does as I can hear a faint bit of signal.
Right hand channel passes audio but doesn't seem to compress.
I'm thinking of pulling out the link pcbs again and rewiring just to check each channel does work correctly as it did before the install of the link pcbs.
The one weird thing which is quite cool is when I turn up the input and output on th right hand channel which works the LEDs dim!! Looks very retro!
Obviously need to sort this out as well as this shouldn't be happening.

Regards

Spence.

 

[Spencerleehorton]

Hi,

Right I'm a little confused now, I've taken out the hairball link pcbs and put everything back to how it should be wired with a balancing board as balanced output.
I have led on vu meter wired with 100r resistor on 30v power side and when I give input signal and turn up input and output the led dims as I increase.
Have checked voltage and voltage drops from 30v to 15v as input and output increased? Is this the vu meters drawing power?
This only happens on GR, nothing seems to happen when on VU, no compression I mean.
Attack and release seem to be working correctly, along with meter switch.
Any ideas what I'm missing here?

Regards

Spence.

 

[Spencerleehorton]

Hi,

Ok progress, right hand channel now compressing and no flashing lights anymore!!!
Seems the only thing I changed was the lead coming from the pcb balanced output into the balancing board input, reverse it?
I did have the output pot and the the output pot to the pcb round the wrong way so I've changed that as well
Gonna look at left channel now, get them both working then put in the link pcbs again.

Regards

Spence.

 

[Spencerleehorton]

Hi,

Got it back working both channels now, setting up both channels then I'm gonna attempt to put the link again!!!

Regards

Spence.

 

[Spencerleehorton]

hi,

in GR meter works fine but when in VU nothing happens to the meter? its all compressing but not quite the same on both channels, as channel one does sound much better and has better gain structure.
any clue to why meter dont work in VU mode?

regards

Spence.

 

[Stagefright13]

The link PCB is not so essential. Get you 1176's working properly first! Then link them. personally I linked pin 7 as cheat on my link switch. I use them on lots of stuff including drum overheads. Got snare and high hat on one side. And ride and Floor Tom on other. Like that will actually need A tight link.... LOL! Mnats compressors rock.
http://stagefrightrecords.com/21176.jpg

 

[Stagefright13]

Thanks! if ya build it right it rules! TY Mnats. Sorry image is all juncked up...

 

[Spencerleehorton]

Hi,

Stage fright I can see from your build you have the all button on your switches, is this possible using a lorlin switch? I know how to wire it up with a DPDT switch, just wondered if there was a Lorlin mod.
Still need some answers on why meter doesn't respond in vu mode?

Regards

Spence.

 

[Stagefright13]

Mako gives everything you can ask for on his site.Try this: http://mnats.net/1176_slam_mode_rotary.html
I did use A lorin switch for this tho.
Been A while. Been workhorse for years! TY Mnats!

John