SB4000 Support Thread

[trichomatic]

Is there anything wrong with using this chassis:
http://www.redco.com/shopexd.asp?id=1974

..assuming I can punch holes for the xlrs on the back?

 

[tmuikku]

Yello!

What are the pretrim values for VR3 and VR4? minor_glitch has already asked this but I didn't find answer from the thread nor the documents. I'm using THAT VCAs, not DBX202. Half way seems to be the way to go judging by the schematics (0v)

 

[TijuanaKez]

Is there a list of what the test points should read somewhere?

 

[ruckus328]

Yello!

What are the pretrim values for VR3 and VR4? minor_glitch has already asked this but I didn't find answer from the thread nor the documents. I'm using THAT VCAs, not DBX202. Half way seems to be the way to go judging by the schematics (0v)

There isn't a pretrim value, just center them is fine, they get fine tuned in-circuit.

 

[ruckus328]

Is there a list of what the test points should read somewhere?

No, not posssible with most, the reading will be totally dependant on the signal level you're feeding the compressor.

 

[ruckus328]

Is there anything wrong with using this chassis:
http://www.redco.com/shopexd.asp?id=1974

..assuming I can punch holes for the xlrs on the back?

Probably but without any dimensional info can't guarantee anything.  You need to make sure the internal height of whatever case you pick is tall enough for whatever power transformer you pick, only you can answer those questions.  Why not use a parmetal case which is guanteed to work?

 

[TijuanaKez]

Hmmm, I'm getting correct voltages from the power supply but when I hook up the main board, r182 & r183 start to  burn up. (I've seen a small whiff of smoke before cutting the power but they still read 10ohms). Any ideas where to start looking? Haven't hooked up the control board or any front panel stuff except the power LED which lights up when power is on.

 

[buildafriend]

Is there anything wrong with using this chassis:
http://www.redco.com/shopexd.asp?id=1974

..assuming I can punch holes for the xlrs on the back?

Probably but without any dimensional info can't guarantee anything.  You need to make sure the internal height of whatever case you pick is tall enough for whatever power transformer you pick, only you can answer those questions.  Why not use a parmetal case which is guanteed to work?

Par-Metal worked great for me

 

[ruckus328]

Hmmm, I'm getting correct voltages from the power supply but when I hook up the main board, r182 & r183 start to  burn up.

Then you know the problem is on the main board, somewhere on the 12V rails.

(I've seen a small whiff of smoke before cutting the power but they still read 10ohms).

They should be replaced, if they smoked then eventually they'll fail completely.

Any ideas where to start looking?

Somewhere in the sidechain section (bottom right area of board).  Look on schematic in sidechain section for all components running off of +/-12V.  Look for backwards IC's (in particular the sidechain VCA's), and/or bad solder joints/shorts, wrong resistor values in this area.  Somewhere there is a mistake.

 

[TijuanaKez]

Somewhere in the sidechain section (bottom right area of board).  Look on schematic in sidechain section for all components running off of +/-12V.  Look for backwards IC's (in particular the sidechain VCA's), and/or bad solder joints/shorts, wrong resistor values in this area.  Somewhere there is a mistake.

Sure enough U16 was backwards (I think, there is a dot on one side and a key hole on the other side, I align the dot with the dot right?). I flipped U16 but r182 & r183 are still burning up. I tried just connecting the 12V on J15 and that seems to be ok. Then I connected only the 15V rail but although r182 & r183 were ok, U20 and U21 started to get very hot very quickly so I cut the power.

 

[sr1200]

I did something similar and blew the IC's...  You may have to replace the IC's you put in backwards along with some others.  See if you can check the chip to see if its open.

 

[ruckus328]

Somewhere in the sidechain section (bottom right area of board).  Look on schematic in sidechain section for all components running off of +/-12V.  Look for backwards IC's (in particular the sidechain VCA's), and/or bad solder joints/shorts, wrong resistor values in this area.  Somewhere there is a mistake.

Sure enough U16 was backwards (I think, there is a dot on one side and a key hole on the other side, I align the dot with the dot right?). I flipped U16 but r182 & r183 are still burning up. I tried just connecting the 12V on J15 and that seems to be ok. Then I connected only the 15V rail but although r182 & r183 were ok, U20 and U21 started to get very hot very quickly so I cut the power.

No, dot on the board just indicates where pin 1 is.  On a TL074, the U shaped indent indicates the pin 1 side, sometimes there will be a dot as well from the mold, sometimes this dot represents pin 1, sometimes it does not, it will vary from part to part and manufacturer.  Whenever you see a U indent though, this will always represent Pin 1.  When you're not sure of these kind of things, always consult the datasheet or ask.  So you've now installed U16 backwards, assuming U15 is probably backwards as well.  Do not turn the unit back on until you are 100% positive all IC's are installed correctly, otherwise you'll just keep blowing parts, possibly damaging other parts in the process, will send yourself on an endless wild goose chase.  Any IC's that were installed backwards, recommend that they be replaced, very high probability they are blown, or damaged and now unstable, or will die a quick death.

 

[TijuanaKez]

No, dot on the board just indicates where pin 1 is.  On a TL074, the U shaped indent indicates the pin 1 side, sometimes there will be a dot as well from the mold, sometimes this dot represents pin 1, sometimes it does not, it will vary from part to part and manufacturer.  Whenever you see a U indent though, this will always represent Pin 1.  When you're not sure of these kind of things, always consult the datasheet or ask.  So you've now installed U16 backwards, assuming U15 is probably backwards as well.  Do not turn the unit back on until you are 100% positive all IC's are installed correctly, otherwise you'll just keep blowing parts, possibly damaging other parts in the process, will send yourself on an endless wild goose chase.  Any IC's that were installed backwards, recommend that they be replaced, very high probability they are blown, or damaged and now unstable, or will die a quick death.

Well don't I feel like an idiot. Well luckily enough, I actually ordered the TL074's twice so I have some spare. What about all the other 8 pin ICs? Somewhere along the line I fell under the assumption that the dot always represented pin 1. Checking the data sheets is obviously the sensible option, especially in hindsight, but I might suggest this would be a handy piece of info to be included in your build manual.

 

[TijuanaKez]

12V rails are all good now but something's up on the 15V rail. I'm getting 15V from the PS when the 15V is not connected to the main board, but when I connect it, **** starts getting hot and +15 only measure +3.

 

[atticmike]

guessing this topic is more popular so I'll repost it :


does it require any particular in / output transformer such as the 1176?

looks like it purely consists of mouser parts.

is there also a mouser cart list for the parts ?

 

[minor_glitch]

No transformers required.
BOM on page 1 lists Mouser part #'s.

 

[ruckus328]

12V rails are all good now but something's up on the 15V rail. I'm getting 15V from the PS when the 15V is not connected to the main board, but when I connect it, sh*t starts getting hot and +15 only measure +3.

Same answer as before.  You have a solder short(s) or backwards IC(s).  Really advise to turn it off, take the board out, and do a thorough inspection.  Every time you power it on with these faults present you'll risk damage.  Let us know what you find and we'll go from there.

 

[ruckus328]

guessing this topic is more popular so I'll repost it :


does it require any particular in / output transformer such as the 1176?

looks like it purely consists of mouser parts.

is there also a mouser cart list for the parts ?

Most parts can be had from any of the major distributors (mouser, digikey, farnell, etc).  I just listed mouser part numbers as a reference since that's where I do most of my shopping.  That BOM is over a year old, so chances are likely there will be some parts out of stock, but you'll have the info necessary to cross reference.

If you want to wait, I'll have PCB component kits available end of next month.

 

[TijuanaKez]

Quote from: TijuanaKez on November 24, 2011, 07:26:32 pm
12V rails are all good now but something's up on the 15V rail. I'm getting 15V from the PS when the 15V is not connected to the main board, but when I connect it, sh*t starts getting hot and +15 only measure +3.

Same answer as before.  You have a solder short(s) or backwards IC(s).  Really advise to turn it off, take the board out, and do a thorough inspection.  Every time you power it on with these faults present you'll risk damage.  Let us know what you find and we'll go from there.

halle-frickin-lujah she's alive! The 3rd TL074 was dead, it was in the right way but must have blown. I replaced it with a fresh one and the 15V rail came good. Passes audio and compresses.

Now on to calibration, I'm not %100 clear on the instructions...

Firstly, just to be sure, I would be setting my apogee's XLR inputs to +4 and not -10 for this correct?

With the unit in bypass, export a 1Khz test tone into the unit and back into your DAW. Note the L/R levels. Engage the compressor, and adjust VR1 (Right Channel) and VR2 (Left Channel) until you get the same levels as were seen when in bypass.

I'm assuming the test tone should be 0dbfs 0.775VAC? Where do I set the front panel controls for calibration? Won't the output level's depend on where the threshold and gain knobs are set when the compressor is engaged?

4) Meter/Ratios:
Export a 1Khz test tone through the unit and back into the DAW. Adjust your volume levels so your DAW meter reads somewhere around -10dbfs. Now adjust the threshold knob on the compressor until there is 10db of compression (DAW should read -20dbfs). Adjust VR17 until the meter on the compressor shows 10db of compression.

'Adjust your volume levels' ... Am I adjusting the level of the 1khz test tone here or the gain on the compressor or does it not matter?

 

[DOMC Mastering]

I just installed my quad boards and get no output - just silence.  I did the jumpers at the back./... should all jumpers at the back of the board be done?