idylldon

Mitsos API 312 / 990 Build Thread
« on: October 10, 2010, 01:09:34 PM »
Since the API thread has gotten really convoluted with all the talk about various board incarnations and circuits, I thought it might be beneficial to have a thread devoted to this build.  I'll start with a couple of questions:

Quote
C12 -- Optional shunt cap as found on the 536 module.

What's the advantage/disadvantage to using it?

Quote
C8, C19 -- As in original 312 circuit, not usually necessary. May be necessary with EA2622

Necessary with Altrans 3402-2?

Quote
CZ -- Zobel cap, input tranfo dependent.

Has anyone determined the value for the Altran 3402-2?

I'm well on the way to putting together a 4-channel version of this project, and will post some pics when I finish.  Hopefully, that will be in a week or so since I'm up to my neck at work right now.

The bill of materials and other supporting documents:

http://www.groupdiy.com/index.php?topic=246.msg491104#msg491104

Cheers,
--
Don


« Last Edit: November 02, 2010, 11:27:39 AM by idylldon »


Re: Mitsos API 312 / 990 Build Thread
« Reply #1 on: October 10, 2010, 03:07:50 PM »
Beat me to it... I will post the project-related links here over the next few days.

C12 - I stuck that in to give me an option to have the 27pF shunt cap, mostly in case I wanted a more "original-like" console pre.  That said, I tried it a couple of times with cinemag/Altran but didn't hear much difference.  Maybe this is more useful when using the 2622 with it's LoadR and zobel network.

C18 and C19 are for RF. I tried them with a Cinemag 75101, not yet with the altran, but I consider them optional.

I tried some zobel values with the 3402-2 but decided against using any.  This was two years ago, but I can test again when I get home in a couple of weeks. If you'd like to try, you can very easily build a little test jig with a pot or two and a socket for swapping caps. There is an email posted somewhere here from someone at Jensen, describing the procedure.

EDIT: to post the project files here:

Here is some supporting info/docs for the group buy 312/990 boards which have just started arriving in people's hands:

Schematic
BOM for 312 with 1646 output
BOM for 312 with trafo output
BOM for 990
Component Placement

The component overlay and schematic need to be downloaded as I could not get the googledocs online viewer to open them. If anyone knows how to fix that, please let me know.

Thanks!
« Last Edit: April 17, 2014, 02:12:41 PM by mitsos »

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #2 on: October 10, 2010, 04:20:23 PM »
Thanks for the response!  I didn't mean to steal your thunder, but since the group transformer buy has been completed I thought some people might be starting the build so I thought I'd start a thread.

Cheers,
--
Don
« Last Edit: October 10, 2010, 04:23:20 PM by idylldon »

volker

Re: Mitsos API 312 / 990 Build Thread
« Reply #3 on: October 10, 2010, 04:32:16 PM »
Regarding Zobel some findings here.

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #4 on: October 10, 2010, 11:29:27 PM »
Regarding Zobel some findings here.

Thanks, Volker!  I think I'll try Kevin's values for R10 and CZ.

Cheers,
--
Don

Re: Mitsos API 312 / 990 Build Thread
« Reply #5 on: October 11, 2010, 12:59:02 AM »
Regarding the PSU for this build...

I have a Chandler TG2 & it's PSU can power another unit.
Just wondering if I could power 2 or 4 of these API units??

Thanks
Sean

Here's the PSU info Wade (Chandler) provided me...

You can use the second plug for something. Here it is
pin1- ground/0v
pin2 - 48 volt
pin3 - +28
pin4 - -28

You have about 200ma available so about any 2 channel unit should be fine.

shabtek

Re: Mitsos API 312 / 990 Build Thread
« Reply #6 on: October 11, 2010, 01:08:24 AM »
+/- 28 needs to be bumped down for most DOAs
may be enough juice for 4 depending on :opamp draw, what is burned getting the rails to where they need to be, assumption that 200ma are available for the  +/- rails
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

Re: Mitsos API 312 / 990 Build Thread
« Reply #7 on: October 11, 2010, 01:43:41 AM »
while you could probably get 4 2520s to run on 200mA per rail (into high impedance loads), I wouldn't recommend it. Maybe you can get 2 channels to run OK, but you'll have to watch the switch LED consumption. Maybe you can use it to test the circuits, but like shabtek said you'll still need another set of regulators to get the voltage down to about +/-16 or 18V.

You'll be better off building another supply.

Re: Mitsos API 312 / 990 Build Thread
« Reply #8 on: October 11, 2010, 10:16:48 PM »
Ok thanks
That's what I'll do.

Cheers
Sean

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #9 on: October 12, 2010, 07:56:33 PM »
What power supply does everyone plan on using?  I've got a Fivefish here that will give me the +.- and 48-volt rails, but I've been debating on the best way to power the LEDs. 

Cheers,
--
Don


tmuikku

Re: Mitsos API 312 / 990 Build Thread
« Reply #10 on: October 13, 2010, 01:16:02 AM »
What power supply does everyone plan on using?  I've got a Fivefish here that will give me the +.- and 48-volt rails, but I've been debating on the best way to power the LEDs. 

Cheers,
--
Don


APP psu, works fine, great price too ;) I'm runnin leds directly from positive rail. I've got only four channels running now, don't know how the psu behaves when I get all 8 channels running. I'm using 24V rails, 10k resistors for leds gives mellow glow.
http://www.groupdiy.com/index.php?topic=33576.0

Re: Mitsos API 312 / 990 Build Thread
« Reply #11 on: October 13, 2010, 11:12:58 AM »
I've been etching my own 4 rail PSU. I believe the files are out there somewhere, but probably not the latest revision.  If people are interested, I can put the newer etch files on the gmail account. I am pretty sure a couple of people (besides me) have used these.  It is a very basic bipolar with a pump charge for +48V and an extra positive regulator feeding off the rectifier.  I haven't yet had time to get boards professionally made, so I can't offer any to sell, but you guys are welcome to the files.

Besides that, a while back MikeFatom introduced a 4 rail PSU and kits in the WM. Maybe he's still selling them? And you could also get a 5-rail from JLM.  

You could also run another positive regulator off the rectifier of your fivefish PSU.

Finally, as tmuikku says, you also run them off your positive rail.

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #12 on: October 13, 2010, 12:22:19 PM »
Thanks for the replies, guys.  I was considering all of the options you've mentioned, but I hadn't seen the APP board yet.  I'll probably just tap off the positive rail since it's the easiest, though I do have a smaller regulator board already made up with a 12-volt regulator so I could just add that after the regulator.

Mitsos, I'd be interested in your newer etch files if you'd like to share them.

Cheers,
--
Don
 

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #13 on: October 30, 2010, 12:27:34 PM »
Anybody finish one of these yet?  I'm plugging through mine but life/work have gotten in the way the past couple of weeks.  I hope to have it completed this weekend.

Cheers,
--
Don

baadc0de

Re: Mitsos API 312 / 990 Build Thread
« Reply #14 on: October 30, 2010, 01:08:30 PM »
I'm waiting for app to get my PSU over.. and for an order from rutubes.com, so that I can collate what's missing and order around.. Should be done in three weeks or there about..

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #15 on: October 30, 2010, 02:21:58 PM »
When connecting the switch daughter board to the main board, where does the "g" (ground) connection go?  Is it there to provide a shield ground when using shielded wire and only connected on one end?

Cheers,
--
Don

mac

Re: Mitsos API 312 / 990 Build Thread
« Reply #16 on: October 30, 2010, 06:20:54 PM »
Hey Mitsos,
Is your PSU 317 337 based? I would like a copy of the etch files if possible, I am considering my PSU self etch options before I move forward onto the main boards....

Mac
Barclaycon: The client said 'That sounds great, what are you using on it?'
The engineer's reply was: '30 years of experience'.

Re: Mitsos API 312 / 990 Build Thread
« Reply #17 on: October 30, 2010, 07:45:52 PM »
Anybody finish one of these yet? 
Me! :)  Actually my 312s are working 100%, but my 990/M1's are in a state of...umm... underpower-ment. Just as I got them working I had to use (read: scavenge) the toroid and I hooked up another (slightly underpowered) one I had lying around which made phantom not play nice with the preamps at 24V so I had to lower the supply voltage (or not use condensers) until a new power toroid arrives.  :(

When connecting the switch daughter board to the main board, where does the "g" (ground) connection go?  Is it there to provide a shield ground when using shielded wire and only connected on one end?
That's exactly it. May or may not be necessary to shield the wire, but better safe than sorry. The trick is to use a piece of quad mic cable and ground the shield. I use canare cuz I have a bunch of it, the only tricky thing with that is that there are 2 whites and 2 blues so you have to keep track of which is which. The mogami neglex quad console cable would be better in that respect because each wire is a different color and thus easier to track.


Hey Mitsos,
Is your PSU 317 337 based? I would like a copy of the etch files if possible.

I made two different layouts(same basic layout, one with variable regs, one with fixed... only tested the variable so far). The plan was to get some fabbed and maybe offer them to those of you who need 4 rail PSUs but I'm not 100% done with it yet.  Anyway, I'll email the etch files/schematic to you, does your email start with "aw"?  If you guys want I can email them to lucas and you guys can get them etched from him. 

Also, mikefatom is selling a 4-rail PSU. The design looks good, a bit like what I had in mind for a 2 sided board. Looks a bit like JLMs, but I like how the wires go out to the left (if you mount it on the right of the case, makes the wiring neater).  The PCB is fairly priced, but you may be able to source the parts for less than the kits. I've never used one so can't endorse it or anything, but it is out there and it should work well for a few channels if planned/built well.

I really need to get cracking on some docs and help you guys out. Some of what I think should be noted while building is in the BOM notes. I've also sent a lot of info to the few people who have emailed me with questions. Tomorrow I'm going to sift through those and the schematic to write out a simple PDF so you guys have something to read through while building, and again, if you're stuck post here and/or PM me.

hope that helps!

volker

Re: Mitsos API 312 / 990 Build Thread
« Reply #18 on: November 03, 2010, 03:49:11 PM »
Mitsos, what is the hole diameter for the DOA sockets / which exact part did you use ?


Thanks!

Volker

Re: Mitsos API 312 / 990 Build Thread
« Reply #19 on: November 03, 2010, 04:01:22 PM »
There's nothing like the right tool for the job.
And -usually- that's what I end up using...
..nothing like the right tool for the job!


 

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