SB4000 Support Thread

[ruckus328]

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?

Read modification info at beginning of thread, it lists which components on main board need to be modified (all sent to you with your quad boards).  Didn't have any 250R pots on hand so use the 5K's that I sent, turn them fully counterclockwise to start.  To trim for unity gain turn them clockwise SLOWLY, you'll only need to turn them clockwise a tiny bit fo unity gain.

Only JMP8 & JMP9 get jumpered on the main board.

You 'no output" issue has me stumped, even without the main board modifications you should still have some sort of signal.  Verify you have +15V on the V+ & -15V on the V- pins on the quad boards.  Verify there is ground connection on the quad boards (buzz pin 6 on one of the THAT2181's).  If all this checks out feed the compressor a signal,  verify the signal is present at "LD" & "RD" on the main board.  Note the voltage you read there.  Now check for signal present at "IN" on the VCA boards - you should see this same voltage as you saw at LD & RD.  If not, your problem is before the VCA's.  If signal is present, then check if there is signal present on the main board at "LW" and "RW".  Just to mention, don't bother checking for signal at "OUT" on the VCA boards, this is current out node held at virtual ground, you won't read any voltage there.

Report back, we'll go from there.

 

[DOMC Mastering]

replaced all parts as per mode on front page - did the checks that you suggested.  looked at sb4000 and said Ruckus is watching...sb4000 decided to start working again...dont ask me why or when or how (maybe after I reseated the boards)

WOOT!!!!


damn this thing is awesome

 

[atticmike]

uh that sounds awesome

any hunch on how much it'll be with the board along with the faceplate?

Mike

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.

 

[drjoe]

I'm a little confused about this chart.

I'm using THAT2181A for audio and THAT2180C for sidechain.

Since I have a mix of the two, which column do I follow?

Is the chart only regarding the audio section VCAs?

I wanted to post the chart in the discussion anyway since I had overlooked it this entire time and was trying to figure out which JMPS to jump based on this thread. I never realized the chart was hiding on the schematic.

I'm documenting my build on my wordpress blog here: http://www.joestulpin.wordpress.com.

 

[ruckus328]

Is the chart only regarding the audio section VCAs?

Yes, correct.

 

[drjoe]

Question about the 'lowest noise' mods on the front page..

I've made all the substitutes, but I accidentally got 220uF caps in my last order instead of 220pF as replacements (oops). I don't want to order 2 single caps from mouser and pay more in shipping than on the components.

Do these mods have to be done all together to benefit the unit positively?

Basically, if I've switched everything out expect those 2 caps, will I still be making an improvement? Should I do them all or nothing?

Thanks! This support thread has been very helpful. Much appreciated.

 

[tmuikku]

Yello! Just got my unit powered up and did quick calibration and test with my friend's computer/interface. Thanks ruckus, seems to be cool unit. I got some oscillation when cranking the gain knob but it could have been anything including direct monitoring through the interface Have to check it in more familiar environment and with scope some day.

 

[ruckus328]

I got some oscillation when cranking the gain knob but it could have been anything including direct monitoring through the interface Have to check it in more familiar environment and with scope some day.

Shouldn't be any osciallation whatsoever.  Ground issue perhaps?

 

[ruckus328]

Question about the 'lowest noise' mods on the front page..

I've made all the substitutes, but I accidentally got 220uF caps in my last order instead of 220pF as replacements (oops). I don't want to order 2 single caps from mouser and pay more in shipping than on the components.

Do these mods have to be done all together to benefit the unit positively?

Basically, if I've switched everything out expect those 2 caps, will I still be making an improvement? Should I do them all or nothing?

Thanks! This support thread has been very helpful. Much appreciated.

Those value changes all need to be done in conjunction, if you cange one you need to change the others to accomodate.  You can probably get away with leaving the feedback caps at 100pF, but to keep hf rolloff the same as stock, change to 220pF is required.  Chances are you won't hear any difference, but osciallation is possible if you don't change to 220pF.

"For lowest noise" - What I mean by this is:  There are a ton of different possible ways one could implement the quad boards, each way coming wth its own group of value changes.  The group of values I have indicated would yield the most optimal results, and lowest noise (which is really the whole point of the quad boards).

 

[atticmike]

do the distortion OP-AMPs have to be surface mounted or through hole?

 

[ruckus328]

do the distortion OP-AMPs have to be surface mounted or through hole?

You have to clarify, I have no idea what you mean by "distortion opamps"?  Everything on this board is thru-hole

 

[atticmike]

do the distortion OP-AMPs have to be surface mounted or through hole?

You have to clarify, I have no idea what you mean by "distortion opamps"?  Everything on this board is thru-hole

that is what I've been asking for, just whether everything is strictly thru-hole. Thanks

And about the resistors, what does the R-EU_0204/7 mean? 

 

[Harpo]

And about the resistors, what does the R-EU_0204/7 mean?

R=resistor, EU=european symbol, 0204=type/rating, /7=pin spacing
something like http://www.soselectronic.de/a_info/resource/a/A10_rezis_siete/MF0.pdf

 

[atticmike]

And about the resistors, what does the R-EU_0204/7 mean?

R=resistor, EU=european symbol, 0204=type/rating, /7=pin spacing
something like http://www.soselectronic.de/a_info/resource/a/A10_rezis_siete/MF0.pdf

thanks and what about the wattage these components can take ? 1/4, 1/2 ?

 

[wave]

Can this part:
http://www.mouser.com/ProductDetail/Kemet/R82EC1150DQ50J/?qs=sGAEpiMZZMvOcEq4GH1AArKxAGb%252bUDf3uByaJKOPzew%3d

Be used as a replacement for this::
http://www.mouser.com/ProductDetail/Kemet/MMK5152J100J01L4BULK/?qs=sGAEpiMZZMvOcEq4GH1AAlEnXbJRHweNSxOD3ArhXhM%3d

 

[wave]

The Quad VCA BOM download is not working for me. Could someone email it to me?
wave.audio(at)gmail(dot)com

 

[bieckmusic]

Strange, first time hearing an issue like this.  There is an error somewhere, but this has nothing to do wih the 47K resistor.  Could be alot of things, but my first suspect would be dodgy +/-12V control voltage.  Check and make sure you have proper +/-12V on the main board.  Check voltage on the pins of your threshold pot on the control board (you should have +12V on the CCW pin and -12V on the CW pin), to make sure you have propper +/-12V on the control board.  Buzz out your ribbon cable and make sure you have continuity to rule out a potential bad connection.

Also, run a mono signal just on the left channel and see if you still have this problem.  Then repeat for the right channel.  This will help narrow down if it is an issue in one of the channel's ratio/feedback networks or if it is happening after the summing point.

Hi ruckus328, if I can trouble you with a question or two   
First, Happy Hollidays!!! 

Secondly,
I have not fixed my SD4000 yet  (I originally posted my issue on this thread page 30), and can't figure out what's wrong.    It works at low thresholds but when a medium to strong transient comes along the compressor pegs wildly and the audio cuts out momentarily.  Non-compressed audio quality is awesome, and the unit works and compresses ok at <4dB of compression in the 2:1 mode.  The attack and release controls seem to be doing what they're supposed to...

Also, if I slow the attack mode down to 30ms (lowering the transient compression) it lessons the amount of the problem, but it still messed up and freaks out at high levels of compression...

To explain the problem, if a solo piano is playing through the unit it sounds good till it hits a hard chord then the unit slams un-proportionately hard and audio cuts out for a split second.

Question  ???  Does the threshold pot move the Compression Meter with the compressor in bypass mode?  Mine does, it seems strange to me...  Maybe that's a hint to where the problem is...

Also, the same error happens with the compressor in both mono or stereo internal sidechain mode.  The ext sidechain is not connected...

So I followed your advice and tried running a mono signal, through both the left and right inputs.  There is no difference, in both channels I get the same error??

Also, I checked voltages.  If you're looking at the unit the threshold knob's left wiper measures +11.85V and the right measures -12.11V.
I get similar voltages at the power supply.  I did install a variable resistor on the power supply vr19 because I couldn't get the voltage right with the supplied fixed resistor...

I also double checked all of the solder joints, because on my other projects that always seemed to fix any issues. 
I flip flopped the vcas around too, just for grins 
I checked each pin of the ribbon connector and it checks out ok, and I reversed the ribbon cable and everything went berzerk, so I think the ribbon's ok ??

If it was bad vca's wouldn't I notice a big difference between the left and right channel, they're pretty consistent.  It seems like there is a problem with the detector circuit??

Sorry for the long email, but if you have any ideas or testing points I'd greatly appreciate it!

bless, 

Greg

 

[jandoste]

Hey Guys,
I have finished the calibration and now I got a phase when I insert it on Pro Tools.
Do you you have an idea about that?
Thanks for any advice...
cheers

 

[sr1200]

is the delay compensation set properly in PT?

 

[jandoste]

is the delay compensation set properly in PT?

I don't think that because of delay compensation. I own 2 PT Hd pcie and I got
this phase just with sb4000 and I insert it on master fader.
Thanks