idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #40 on: November 15, 2010, 02:24:00 PM »
How did you mount the PCBs, the output transformer bolts through the case as well?

I used 1/4" nylon standoffs with nylon screws, which is the only way I mount things these days.  The nylon stuff works very well and is strong as well. 

Yes, the output transformer bolts to a nylon standoff that is attached to the case, so it's pretty solid.

I used a 1/2" standoff to mount the switch daughter board to the main board.  Since it will still move/twist a bit when pushing the buttons due to there only being one attachment point, so I put a dab of hot glue along the edge where the daughter board meets the mother board.  That makes it solid and is easily removed if I need to do some repairs under the switch board.

Cheers,
--
Don




Re: Mitsos API 312 / 990 Build Thread
« Reply #41 on: November 15, 2010, 02:24:29 PM »
Originally, I thought I had a lot of hum/noise, but then in yet another "duh" moment I realized that I was running the output of this unit into the input of my other API 312, which means gain-o-matic! 
did the needle break the overshoot stop off of the mojo meter? ;)

this is getting me in the mood to rack mine (finally), looks great!  just have to sort out how i'm going to deal with the pesky vert mounting brackets on the shields of the altrans  :(
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!

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #42 on: November 15, 2010, 02:41:44 PM »
this is getting me in the mood to rack mine (finally), looks great!  just have to sort out how i'm going to deal with the pesky vert mounting brackets on the shields of the altrans  :(

I just removed them so I could mount the output transformers on the boards.  I wanted to use a 1U case and this seemed to be the best way to keep a low profile so I could do that.

Cheers,
--
Don

Re: Mitsos API 312 / 990 Build Thread
« Reply #43 on: November 15, 2010, 02:57:24 PM »
I just removed them so I could mount the output transformers on the boards.  I wanted to use a 1U case and this seemed to be the best way to keep a low profile so I could do that.

i'm considering hacking the brackets, if the shields have been mu-treated then that will probably impart less overall trauma to the remaining shield than bending would.  might give altran a call to see whether or not they're just your standard fare steel jobs.
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!

Re: Mitsos API 312 / 990 Build Thread
« Reply #44 on: November 15, 2010, 04:23:58 PM »
Good Job Don! Nice to see one complete! :)  good job on the case too!  hey, how powerful is the laser you use? I'm looking for someone around here to do some panels but some of them don't have much experience with this kind of thing but if they can tell me the laser's power I guess I'll know what it is capable of? Was your panel anodized then etched?

re: toroid shielding... a strip of GOSS around the toroid should be sufficient (rotate the toroid first to find the lowest interference, then install shield).

re: output trafos:  The output trafos came with channel frames because there were some people who wanted them that way and it is easier to take them off than to install them after the fact, because they have to be varnished after installation to avoid mechanical vibrations.  You can take them off, they are not for shielding, they are for mounting.  If you mount the trafos horizontally to the PCB, make sure you mount them to the case. 

hope that helps! 

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #45 on: November 15, 2010, 04:39:42 PM »
Good Job Don! Nice to see one complete! :)  good job on the case too!  hey, how powerful is the laser you use? I'm looking for someone around here to do some panels but some of them don't have much experience with this kind of thing but if they can tell me the laser's power I guess I'll know what it is capable of? Was your panel anodized then etched?

My laser is 40 watts, but it tests out at 45 since it's been recharged.  We bought it used and the company that made it, Universal, went through it before we took possession.  It's got a large bed and a pass-through door so we can put larger things in when needed.  We looked at Epilog and Universal machines before we bought one.  When this one became available we went with it and have been very happy with it.

We used a small one for a year or so (someone loaned it to us) and it was a 30-watt model.  It, too, didn't have any problems burning through the anodized coating.  

I always burn the panels after they are anodized.  The laser doesn't really etch the surface all that much, but it does burn the coating off and instead of seeing the bare aluminum underneath the lettering turns a nice off-white color.  The cool thing is that you can take a painted or bare metal panel, put some of that transparent blue tape on it (the stuff they use to protect shiny metal surfaces), and then burn your design through the tape.  You then give the panel a coat of paint and peel off the "stencil."  It looks very much like a silk-screened panel.  I've done that on a few projects but now usually just use an anodized panel.  It's a bit faster and less time consuming.

Cheers,
--
Don
« Last Edit: December 04, 2010, 11:05:56 AM by idylldon »

Re: Mitsos API 312 / 990 Build Thread
« Reply #46 on: November 15, 2010, 09:33:22 PM »
hey thanks for the tips. I've always wondered about the tape trick.  In your experience does the laser just go through the tape or does it mark the paint as well? Is there a name for this tape that you know?

Re: Mitsos API 312 / 990 Build Thread
« Reply #47 on: November 15, 2010, 09:47:20 PM »
Mitsos and/or Don- would you mind shooting me the front panel layout as well? Just talked Dan Deurloo's ear off about cases (poor guy) and I should get my end sorted out. Thanks!
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!

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #48 on: November 15, 2010, 10:25:27 PM »
hey thanks for the tips. I've always wondered about the tape trick.  In your experience does the laser just go through the tape or does it mark the paint as well?

The laser will burn through the tape and paint down to the bare metal.  It slightly etches the metal, which makes the paint used for stenciling stick real good.  It depends on the settings, though, and I imagine with enough tinkering around you could just burn through the tape without going all the way down to the metal.

Quote
Is there a name for this tape that you know?

It's this stuff:  http://www.ikonicsimaging.com/laser_tape.php

It can't be PVC because it will ruin the optics on the laser.  This stuff works very well, but it's pricey. 

Cheers,
--
Don

« Last Edit: November 16, 2010, 12:48:47 AM by idylldon »

Re: Mitsos API 312 / 990 Build Thread
« Reply #49 on: November 16, 2010, 08:26:21 AM »
Hey Grant, check your email.  All cases are a bit different so I sent you some basic mechanicals that you can use along with some basic measurements of the case.

hth!


Re: Mitsos API 312 / 990 Build Thread
« Reply #50 on: November 17, 2010, 08:28:02 PM »
Does anyone have a mouser number for a DI jack that works well for this?

Also function does R11 have, the BOM says it's not necessary, why is that? Should I just jump it.

Also I'm assuming that R2 is the unlabeled little line nearby R1, correct?

I can't seem to find the info now, but what all transformers can this board handle besides the Altrans and the ClassicAPI transformers?

Last thing, the jumpers; would you mind walking me through these. How do I configure JP2? The (- In Bias) and (Out Servo In) Jumpers how do we use those.

Thanks.
« Last Edit: November 18, 2010, 12:02:35 AM by benlindell »

idylldon

Re: Mitsos API 312 / 990 Build Thread
« Reply #51 on: November 18, 2010, 03:06:07 AM »
I just talked to my laser guy and he said that you can just use regular blue masking tape.  The kind that's easily removable.  It sure is a hell of a lot cheaper than the other stuff so I think I'll give it a try on my next panel.

Cheers,
--
Don

Re: Mitsos API 312 / 990 Build Thread
« Reply #52 on: November 18, 2010, 08:15:06 AM »
Does anyone have a mouser number for a DI jack that works well for this?

Also function does R11 have, the BOM says it's not necessary, why is that? Should I just jump it.
As far as DI, since it's off-boarded, any switching jack should work fine.

R11 is a 1K series R found on some API schemos but not on others. In general you may choose to use it (or not to). For me it helped to have it when using the input bias.

Quote
Also I'm assuming that R2 is the unlabeled little line nearby R1, correct?
R2 lost its R and its 2!  Yes it is near R1, right in front of R7 and R4 in fact.
Quote

I can't seem to find the info now, but what all transformers can this board handle besides the Altrans and the ClassicAPI transformers?
INPUT: Altran C-3402-2, Cinemag 75101APC, EA2622, (Various Cinemags and Jensens will fit this footprint), OEP A262A3C, Lundahl 1538 (footprint is there but has not been tested). There are many more that use the Altran/Cinemag/EA footprint, there are also some like the CMMI-8PCA for example, that have only one primary but should work fine (you won't be able to switch input impedances of course).

OUTPUT: Any 5/8"EI or 625EI output trafo (Altran C-3865, Cinemag CMOQ-2x, EA2503, or similar). Quadfilar for 2520, Bifilar and nickel for 990.
Quote
Last thing, the jumpers; would you mind walking me through these. How do I configure JP2? The (- In Bias) and (Out Servo In) Jumpers how do we use those.
JP2 lets you choose to have your primaries in series or parallel, for input trafos made with dual primaries. This will change the voltage gain of the input transformer as well as the impedance seen by the microphone.  Check the trafo datasheet or post it here if you are unsure. To give one example, say you were using the Cinemag 75101APC.  The datasheet shows that it can do 150 or 600 Ohm impedance input. For 150, you'd want the primaries in parallel (connect pins 1+2 and 3+4 of the trafo), which would give you a higher voltage gain (1:10). For 600 Ohm, you'd put them in series by connecting pins 2 and 3.

Input Bias, DC Servo are options that allow to not use caps "in the signal path." In general you can permanently link the Ibias jumper to the positive rail. The Servo jumper is there so you can disconnect servo from the circuit while adjusting the bias trimmer.  An adjustment procedure is described in John Hardy's M1 and 990 papers, both available for download on his website and highly recommended reading.

hope that helps!

 



Re: Mitsos API 312 / 990 Build Thread
« Reply #54 on: November 20, 2010, 07:47:49 AM »
Mouser is a bit unclear (says there're only 2 contacts, but the datasheet shows the switching contact so it should work.  Connect the switching contact (brake terminal in datasheet) to the trace coming from the transformer and the tip (transfer terminal in the datasheet) to the pad that goes to the opamp.  The ground pin should normally go to the case, but I have at times run it to the pcb ground instead.

hth!

Re: Mitsos API 312 / 990 Build Thread
« Reply #55 on: November 29, 2010, 09:21:18 PM »
Is TAW the best place to get the 22k omeg pots for this? What is the part number?

shabtek

Re: Mitsos API 312 / 990 Build Thread
« Reply #56 on: November 29, 2010, 10:15:40 PM »
@benlindell:
colin @ audiomaintenance
or
jeff @ classicapi
gots the pots if you are doing a 312 style (20-22k rev log pot)
"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

seavote

Re: Mitsos API 312 / 990 Build Thread
« Reply #57 on: November 29, 2010, 10:36:21 PM »
ben, im curious which type build your planning.  312 or 990 w/or wo/ servo.  this will determine what components are used and what you need to jumper.
Everyday is a gift. Thats why it's called the present

Re: Mitsos API 312 / 990 Build Thread
« Reply #58 on: November 30, 2010, 12:40:34 AM »
I'm doing 12 312s and 4 990s with the servo. I'll do the stepped switch for the 990 s well.

Did I read somewhere the bourns pots didn't fit correctly?

tmuikku

Re: Mitsos API 312 / 990 Build Thread
« Reply #59 on: November 30, 2010, 02:16:56 AM »
Yep, bourns doesn't fit good. Pins are ok, but the support pins didn't fit into pcb holes. Also the shaft is too short (compared to switches), wouldn't reach the frontpanel. Burns is great, just mount of it board ;)


 

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