SB4000 Support Thread

[sheadstedford]

Hahaaa poor *******

 

[sr1200]

Im still at a loss on my second unit.  im beginning to think that perhaps i have a bad relay.  What pins can i jump on the compress in/out relays to test my theory.

 

[sr1200]

K, im ready to toss it out the window lol.  Any chance anyone wants to make a few bucks lookin at this thing for me?

 

[minor_glitch]

I think I'm just about ready to power up my unit and start testing/calibrating, but I want to make sure I've wired up the power supply properly.  Ideally, I want to avoid turning my home into a crater when I power it up!

I'm using the VPT36-690 transformer so the primaries are blue and gray, and violet and brown.  The secondaries are black and red, and orange and yellow.

For the primary I tied the blue and violet, attached them to the bottom pin of the power switch, then ran a wire from the center pin of the switch to the pin after the fuse on the iec inlet.  The gray and brown are tied together to the other pin of the iec (the ground pin obviously going to the star ground).
Would it make any difference if I had done it the opposite way with gry/brn to the switch instead of blu/vio?

For the secondary, I have the wires hooked up black, red, orange, yellow.  Black being closest to the bridge rectifier.  I'm fairly confident those are fine.

Now for the stupid question.  If I remember electronics class correctly from many years ago, even though the tranny is wired for 115V, it's perfectly fine to use with my home's 120V right? 

 

[Neil]

Finally started getting my build together from PTown's kit and have a question. I'm not sure if it should go here or in PTown's thread.

R169 is labelled 47k or jumper. At least one person I see has had to jumper it but I have an extra 47k resistor from PTown's kit so should I use it or should I jumper the location? I was set to use it until reading where someone had to remove it and put a jumper to fix a threshold problem.

Neil

 

[ruckus328]

Guys, will get to questions this evening, very busy at the moment.

Neil - Jumper.

 

[0dbfs]

I had already installed the 47k when that info came up and forgot to take it out... I gotta say that the threshold works fine for me without jumping it... Pretty much works as expected.. I don't normally use these into deep GR... 4db, maybe more if parallel but the 47k give me a nice range of resolution over which to tweak so that bumping it doesn't necessarily send it flying off the handle...

By all means, test it and see what works best... How about a 50k tweaker pot/rheostat so you can set it like you prefer without having to disassemble your unit.

Cheers,
jb

 

[Neil]

The 50k pot isn't a bad idea, but I don't really see needing to adjust it afterwards and it's easy enough to snip a jumper and solder in a resistor if I have to I guess.

Thanks guys!

 

[sonic02]

Got my boards and parts this week, cheers ruckus & ptownkid for shipping to oz. My first post and very first build, sure this newb will have a few q's to ask along the way, will post some pics as it progresses.
Stu

 

[ruckus328]

I think I'm just about ready to power up my unit and start testing/calibrating, but I want to make sure I've wired up the power supply properly.  Ideally, I want to avoid turning my home into a crater when I power it up!

I'm using the VPT36-690 transformer so the primaries are blue and gray, and violet and brown.  The secondaries are black and red, and orange and yellow.

For the primary I tied the blue and violet, attached them to the bottom pin of the power switch, then ran a wire from the center pin of the switch to the pin after the fuse on the iec inlet.  The gray and brown are tied together to the other pin of the iec (the ground pin obviously going to the star ground).
Would it make any difference if I had done it the opposite way with gry/brn to the switch instead of blu/vio?

For the secondary, I have the wires hooked up black, red, orange, yellow.  Black being closest to the bridge rectifier.  I'm fairly confident those are fine.

Now for the stupid question.  If I remember electronics class correctly from many years ago, even though the tranny is wired for 115V, it's perfectly fine to use with my home's 120V right?

Sounds about right.  You want to switch the line like you have it (in your case going to gry/brn on your toroid), not the neutral connection.  Yes, it would work just the same if you switched the neutral instead, however for safety purposes you always want to switch the line.  Otherwise there will be live mains voltage going to the toroid at all times, even when the unit is turned off.

One other thing, generally I connect the center pin to the toroid and the NC (normally open) pin to the IEC connector if you're using a SPDT power switch.  Reason being, if you connect the center pin to the IEC, then the other pin (the one not going to the toroid) has live mains voltage on it when the unit is turned off, which can be dangerous if you're poking your hands around in there.  Just something to note for future builds.  If you already have it wired up you can leave it as is, but I'd put some shrink tubing around the unused pin.

115/120 - same difference.

 

[ruckus328]

Im still at a loss on my second unit.  im beginning to think that perhaps i have a bad relay.  What pins can i jump on the compress in/out relays to test my theory.

You need to systematically narrow down where the problem is.  You haven't really given any info on what issues you're seeing now.  There's no way to jumper the relays with them installed, you would need to depopulate them completely to hardwire them into compression mode, but honestly a simple multimeter on continuity test will tell you if they're working or not.

Step 1 is verify the audio path is intact and passes audio -

-Remove ALL IC's except for The input 5534's (U3/U5) and output 5532's (U8/U4)
-Jumper pins 1 & 8 on both audio VCA's (U11/U17) (use a diode leg or buss wire, etc)
-Take the sidechain out of the equation completely.  Lift one end of R12,R13, & R33 (located near the external in connector).  This will severe the singal going to the sidechain, and will let you verify your audio path is working first.
-Now check if the unit passes audio
-If it does, install the Audio VCA's and check again that it passes audio

Report back, we'll go from there.

 

[dtrax]

I think I'm just about ready to power up my unit and start testing/calibrating, but I want to make sure I've wired up the power supply properly.  Ideally, I want to avoid turning my home into a crater when I power it up!

I'm using the VPT36-690 transformer so the primaries are blue and gray, and violet and brown.  The secondaries are black and red, and orange and yellow.

For the primary I tied the blue and violet, attached them to the bottom pin of the power switch, then ran a wire from the center pin of the switch to the pin after the fuse on the iec inlet.  The gray and brown are tied together to the other pin of the iec (the ground pin obviously going to the star ground).
Would it make any difference if I had done it the opposite way with gry/brn to the switch instead of blu/vio?

Ruckus already answered this, but I just wanted to add my 2 cents as someone who's relatively new to DIYing.

Wiring mains was the most intimidating thing for me, mainly because I have no formal training with electricity. I've bought a few books and read them cover to cover, and obviously the interwebs are invaluable for the 1000's of questions that pop into my head. While I probably only retained about 1% of the content thus far, I have a better understanding of the dangers and now have a much greater respect for electricity as a whole. I still make dumb mistakes all the time, but the fear part has gone away because I know what not to do. Simple things like never have the AC cord connected while you're working on the unit (unless you're testing voltages and such), and avoid using both hands in the chassis if power is in fact being applied to the circuit. That's because if you happen to accidentally touch the Live/Hot wire from the IEC inlet and the chassis, you're now part of the path of electricity. Not a good feeling.

Just the other day I was cleaning up some of the wiring of my SB4K, and the mains accidentally shorted to the chassis because I hadn't finished putting on shrink tubing over the exposed wires/connections on the switch. Needless to say, I popped the circuit breaker in my house, and scared the sh!t out of myself. I smoked about 5 cigs back to back. The compressor is fine, and that's all that matters! (kidding...)  8)

For this reason I've been using SPST switches for mains. It's only got 2 lugs, so mains go 1 lug, tranny primary to the other. No guess work. Here's the guy I use for all my builds lately:

http://www.mouser.com/Search/ProductDetail.aspx?qs=nCir7VBz9Cj1xbxtDtbojg%3d%3d

 

[minor_glitch]

Thanks so much for your help ruckus and dtrax!

I'll definitely swap the power switch wiring and attach the center pin to the toroid.  Can't wait to fire it up.  I'm just waiting for a replacement 2181a to arrive, then it's go time!

 

[sr1200]

So I finished replacing all the parts on the input/output section on unit 2 and im running!  YAY!!!!  couldnt say what was blown or what wasnt, but I only have one prob left.  Ive run out of room on the VU meter calibration.  Needs to go a bit lower, anything over a steady -9db is causing the meter to PIN to the top.  Suggestions (was thinking of changing the trim pot to something highter)

 

[ruckus328]

Ive run out of room on the VU meter calibration.  Needs to go a bit lower, anything over a steady -9db is causing the meter to PIN to the top.

If you're using a 1mA meter then something else is wrong (possibly resistor value somewhere).

 

[sr1200]

Sorry its not the VU-VU meter meter its the LED VU meter lol The Needle VU is as precise as Ive ever calibrated (across the 3 ratio settings its almost PERFECT)

 

[ruckus328]

Well, first question:

-9dbwhat? 

dbu?  dbfs?  dbvu?  dbv?

"db" could mean many different things.

 

[sr1200]

as far as i know, the output metering in PT is dbfs.

 

[ruckus328]

Had a feeling you'd say that.  The Vu Meter is just that - VU, sure it's an LED display, but this is still analog gear. 

0Vu = +4dbu =  1.23V RMS

Dbfs is a digital scale, and really has no reliable set relation or standard to the analog world.  It varies depending on converters/soundcard, my profire2626 outputs +4dbu/0Vu at about -11.3dbfs.

Generally, +4dbu will translate to anywhere from -18dbu to -10dbu depending on your setup, so giving a number in dbfs is pretty much useless and won't mean anything to anyone unless you can tell them what the dbu equivalent is.  This is why when refering to "db" it should always be converted to "dbu". 

Point being - you're meter is just fine, you're trying to configure it for the digital world (which it wasn't intended for, because there is no standard in the digital world).  If you really wanted to you could configure it to match your protools, but I wouldn't recommend it.  For one: if you add any other analog gear the VU meters on those are just going to read in Vu anyways.  Also, if you work with a reasonable amount of headroom (at say -8dbfs to -12dbfs) then you LED meter is going to not be of much use, as it'll constantly be down at the -10 light (where there is no resolution).

 

[sr1200]

Understood, and i can probably get the equivalents tonight, i think my apogee is in dbu on the analog side.  As it is right now though, when sending say, over heads to the unit, the input level is just fully on, if i turn down the output and switch it to output mode, then it's kinda ok (still pins a lot even at 0 gain and compressing fairly hard)  was just wondering if i put in a higher value trimmer in the bar meter section is i could tame it a bit more.