SB4000 Support Thread

[ruckus328]

Hey Mike, what's that pad or insulator you've got under your transformer? The big square looking thing.

It's DMD 100, a little gross overkill for the job (insulates to 20,000V) but we use it here on our HV equipment so always have some at hand.  That's a 50VA transformer (which won't fit in the parmetal 1U enclosure with the provided foam pads/mounting brackets) so just used the DMD underneath instead.

 

[bieckmusic]

Hi everyone 

I'm super excited to be at the final stage of building and had a few quick questions.  I've read through the entire forum and  haven't found the answers (i might have missed them) so I just wanted to check so I don't blow something up.  Reading the schematic answered all of my jumpering/resistor questions.

Is there any documentation explaining how to wire the x-former. (I have the stock Ptownkidd kit with the transformer from the BOM)

Here's what I was going to do - (this might be totally wrong)
For the primary - Connect blue/violet to bottom pin on the switch.  Connect top pin on switch to Live pin on IEC.  Connect the grey and brown to the Neutral on Iec. 
Secondary - I was going to copy the color coding in the picture in the build manual.  It Blk Red Org Yellow, I think it makes sense with the data sheet I got from triad. 

Also, the common terminal on the toggle switchs is the center terminal?  right, just checking before I solder everything.

Lastly then I'm ready to power up.  On the Meter I got from Ptownkidd there are two sets of terminals.  Am I correct in assuming the larger terminals are for the meter and the small silver terminals are for the LED?  It's the al19 style meter from the Ptownkidd website.

thank you all so much!!!!  apologize for any redundancy.  I'm loving this project, the most fun I've had so far  8)

bless,
Greg

 

[minor_glitch]

bieckmusic - sounds to me like you have the wiring right, although I think you want to connect the bottom and middle pins of the power switch, not the bottom and top.

As for the meter, I'm sure someone will correct me if I'm wrong but the big tabs are wired to the anode and cathode spots on the main board and the small ones are the + and - spots.  Anode is the big tab above the +, Cathode above the -.

 

[bieckmusic]

Thanks minor_glitch, appreciate the help!

Interesting, my power switch only has 2 pins.  There's a plastic tab where a third pin would be but it looks like the metal has been pulled out.  I wonder if this means the switch is broken, is it a big deal?
best, greg

 

[minor_glitch]

Thanks minor_glitch, appreciate the help!

Interesting, my power switch only has 2 pins.  There's a plastic tab where a third pin would be but it looks like the metal has been pulled out.  I wonder if this means the switch is broken, is it a big deal?
best, greg

*facepalm* you're right. just checked my unit.  the switch that comes with ptownkid's kit has two pins.  sorry about that!

 

[bieckmusic]

cool, thanks, I tested the switch and it works fine.  Can't wait to join the mix-buss compressor club!!  My wife was making fun of me because when I first plugged in my first diy (1176 rev a) project I had a fire extinguisher in one hand 

best, greg

 

[etheory]

Hi all,

here's another update on the road to powering up....

http://www.evolutionarytheory.com/2011/07/sb4000-bus-compressor-%E2%80%93-build-%E2%80%93-day-3/

enjoy,

Luke

 

[ruckus328]

Hi all,

here's another update on the road to powering up....

http://www.evolutionarytheory.com/2011/07/sb4000-bus-compressor-%E2%80%93-build-%E2%80%93-day-3/

enjoy,

Luke

Rinse out the bass inside 

 

[ruckus328]

Thanks minor_glitch, appreciate the help!

Interesting, my power switch only has 2 pins.  There's a plastic tab where a third pin would be but it looks like the metal has been pulled out.  I wonder if this means the switch is broken, is it a big deal?
best, greg

2 Pins just means it's a single throw switch, which is all you need here.

 

[ruckus328]

bieckmusic - sounds to me like you have the wiring right, although I think you want to connect the bottom and middle pins of the power switch, not the bottom and top.

As for the meter, I'm sure someone will correct me if I'm wrong but the big tabs are wired to the anode and cathode spots on the main board and the small ones are the + and - spots.  Anode is the big tab above the +, Cathode above the -.

Big tabs are for the meter itself,

tiny tabs are for the LED, + to anode (A), - to Cathode (K)

 

[minor_glitch]

Oh, good thing I haven't powered it up yet.  I think I have my meter wired backwards.  So the small tabs go to A and K on the main board and the big tabs go to + and -?

 

[tfletchii]

Looks like a hand full of us have had some confusion about the ribbon cable. I found a nice pdf on assembling one so I've posted it. Hope it helps someone else out

 

[tfletchii]

I'm not getting any response from the controls on the control panel. I'm guessing this means something is messed up with the ribbon cable but I'm pretty confident I have it assembled correctly.  I tested continuity of the ribbon cable by checking the ends of the cable while installed and everything looks good. All the wires are pierced nicely and I don't have it upside down/flipflopped.

the unit passes audio fine. If I move the gain knob the led meter reacts when checking output but there isn't any change in the output signal through my speakers. The led meter doesn't respond when I'm measuring the input. All the other control panel pcb knobs (threshold, ratio...) are not functioning. 

I've jumped the Threshold resistor and I got no change.

I checked the ext in / in switch and notice no change. I'm going to just remove it when I get a chance to see if for some reason that fixes things. I don't have the left/right send/return wired in yet (J3) but i didn't think it was necessary inorder for things to work.

I only have Jump's 1 & 4 populated in the VCA section and I'm using the Ptown Kit

I'm also not getting any reading on the analog meter.

My test points T 1-7, 8&10 all look good.

Any ideas. I feel like it is going to be something simple

 

[minor_glitch]

It's ALLLLLIIIIIIIVE!!!!

No explosions, no craters, no smoke, no flesh wounds!  The calibration even went smoothly.  Almost...

For some reason I couldn't match the voltage at TP11 and TP12 when calibrating T1. 
T2 calibrated perfectly, but for T1 I got a voltage of 1.443VAC from TP11, but the max I could get on TP12 was 1.208.  That was with VR5 cranked to its limit.  It's by no means a huge deal, but still.

Man, the sense of accomplishment you get from having something like this go smoothly is great.  Thanks so much for your help everyone!

I'll post links to my last batch of photos sometime next week.

*Oh, and after calibrating I got my THD down around 0.022 with that RMAA software.  Sounds good to me, just wondering if everyone else is somewhere around that range.

 

[bmaughan]

Hi, I was wondering if any one could give me advice or tell if there is any audible sonic differences between using the 2181's and the 2180's for the audio vca's. I oviously want it so sound as good as possible but if the 2180's sound just as good and simply remove another calibration step, I'd rather go with those.

 

[etheory]

I have what I personally think is a rather strange issue and I was wondering if someone could give me some advice on it.

Today I was basically intending to finish off my kit, which I almost managed to do, except I stopped short because of the following problem.

I am in Australia so my power transformer windings are being used in serial.  In order to wire them up "nicely", I came up with the idea of wiring the Active from the mains ( after it passes through the fuse ) to the Blue wire of the transformer ( primary winding 1 ), then the Gray and Violet to a main on/off switch ( which would effectively be the centre tap of the transformer, joining winding 1 to winding 2, or the part that the spec sheet says to bridge for 230/240V ), putting the two windings in a serial configuration, then the Brown of the transformer of winding 2, goes to Neutral of the IEC socket.

Now I am pretty good with electronics as I've been dealing with it for some time now, and I assumed that breaking a circuit ( i.e. the bridge between the primary windings 1 and 2 ) would be perfectly OK, as, well, it breaks the electrical circuit, but, well, that's where it gets weird.

I am super anal about checking everything more than once, so after wiring up the IEC, the fuse and toroidal and the main on/off switch, I turned it on to test the AC voltages at the secondaries of the transformer and that's where things got a bit weird.

At power on everything was fine, and the secondaries gave totally respectable voltages ( about 20V each secondary winding ), but when the main switch was off, I still got 3V on the secondary windings!!!!

Why the heck would that and could that be?  Does a transformer actually have a resistance between it's two primary windings akin to a bridge from one to the other?

I mean, I could easily fix this by rewiring it to switch the active connection into the unit and just hard bridge the 1 and 2 primary windings, but I would just like to understand why this happens?

I've attached a picture of how I've wired it up to help understand the situation.
The switch as per the diagram still shows 3V on the secondaries, which has me baffled....

If it matters, in the test, the transformer was not under load on the secondaries ( except for a multimeter ) and did not get hot.

 

[Wembley]

This is an exceedingly basic question but the Ptown kit seems to have 2 11-pin SIP sockets for the 20-pin bargraph.  I can clip one off each SIP but I just wanted to confirm this is the way to go, or whether this is an indication of an error elsewhere (checked BOM/schem several times but you never know).  Also desoldering SIPs is kind of a pain and substitutions can throw me for a loop when I am building something new.  Thanks.

 

[minor_glitch]

This is an exceedingly basic question but the Ptown kit seems to have 2 11-pin SIP sockets for the 20-pin bargraph.  I can clip one off each SIP but I just wanted to confirm this is the way to go, or whether this is an indication of an error elsewhere (checked BOM/schem several times but you never know).  Also desoldering SIPs is kind of a pain and substitutions can throw me for a loop when I am building something new.  Thanks.

Yeah that's fine.  You can just clip the extra pins.  Worked for me.

 

[Neil]

I have the same kit and had to clip mine too, Wembley.

 

[ruckus328]

If I move the gain knob the led meter reacts when checking output but there isn't any change in the output signal through my speakers.

Unless you have magic resistors/IC's, this isn't possible.  LED meter sniffs the output signal.  If the LED meter goes up then the output signal is going up.  Check your soundcard routing, I suspect this could possibly be the issue.  Don't use your speakers as your calibration device, measure the voltages at the unit with a meter, that will tell you what's really going on.

As far as other issues, buzz your ribbon cable out with a meter.  Also make sure "external in" is not engaged, or just temporarily disconnect the wires for it to verify.  If you still have no luck I explained basic troubleshooting procedure a couple pages back.