SB4000 Support Thread

[Whoops]

Thanks unfortunate mate as those SB4000 boards were really good.

I guess Serpent Audio decide to quit the DIY bussiness and just start selling already built products.

Is that even any SSL bus comp pcbs being sold at the moment?

The GSSL PCB was really outdated as it needed a lot of addons, but even that one I don’t see for sale

 

[calaverasgrande]

PCBgrinder still has GSSL.
Have to say a lot of parts for the SB4000 are getting hard to source.
Same as with MNATS FET500.

 

[Whoops]

PCBgrinder still has GSSL.

I see, but it's a pretty outdated board the GSSL, it's around 18 years old, it was never updated. You need a separate Turbo Board, separate PSU extra filtering and a SideChain board. It's just messy to do it.
Later SSL bus comp projetcs like the SB4000 and Igor's Mixbuss had all the circuits built in the same board, it made completely sense

 

[tonycamp]

Hey SB4000 guys, check out this link.....
https://groupdiy.com/threads/cavendish.70128/post-1154856

 

[Shea Stedford]

Hello all, long time….
I’ve recently got my sb4000 back and had a rewire/solder of the Xlr connections and new THD resistor pots. For some reason the now when in bypass the unit is 6db quitter than the input signal. I’ve searched the thread but can’t really find an answer other than something to do with Xlr shorting to ground but I’m sure the Xlr connections are fine.
The unit sounds amazing but I can only use it engaged and have had to trim the unity gain pots up by 6db for a like for like in/out signal.
Am I missing something really simple here???
Attached a picture of the unit cos it looks noice

 

[thelivingroom]

Hello all, long time….
I’ve recently got my sb4000 back and had a rewire/solder of the Xlr connections and new THD resistor pots. For some reason the now when in bypass the unit is 6db quitter than the input signal. I’ve searched the thread but can’t really find an answer other than something to do with Xlr shorting to ground but I’m sure the Xlr connections are fine.
The unit sounds amazing but I can only use it engaged and have had to trim the unity gain pots up by 6db for a like for like in/out signal.
Am I missing something really simple here???
Attached a picture of the unit cos it looks noice

Since the bypass just routes the in to the out (if I remember correctly), I’d put it in bypass and check continuity between each pin of the corresponding I/O XLR’s first (In Pin 1 to Out Pin 1, then 2 to 2, etc.). Also check for continuity between pins on each connector itself, especially 3 and 1, to make sure they’re not swapped and 3 is accidentally going to ground. Sounds like you’re missing a leg.

 

[Shea Stedford]

Thanks for this mate really appreciate it!

 

[Shea Stedford]

So I just broke the HPF rotary switch when trying to change the knobs….gutted. Fully split open and the two little ball bearings came out, it’s like it exploded.
After looking at the original BOM I can’t seem to find the exact switch to buy to replace it.
Will this one be ok?
https://uk.farnell.com/lorlin/ck105...NJNgJZ1FotD5XzhBw3o6udZ2YURMQyiRoCaaEQAvD_BwE

Kinda baffled at all the various options…
Again apologies, I’m still new hahahah

 

[JMan]

That is indeed the correct part

 

[Shea Stedford]

That is indeed the correct part

Thanks for the swift reply!!!

 

[jmamma]

Longshot. Troubleshooting an SB4000 I never completed.

Having trouble getting any movement on the gain reduction meter. It's pinned left.

Audio path is okay. Makeup gain working, but no compression.

Voltages are correct.

Noticed U13 (the TL072) gets very hot. Even upon replacement. Makeup gain is functioning, however.

Some weird observations in the Right SC circuit. I see signal at TP12 and can calibrate VR7, but at voltage divider R79/R78, the signal disappears on VCA in (U9) when THAT2181 is present. Swapping L/R VCAs does not resolve, and problem is not present on Left SC.

In mono mode, I see a rectified signal in the Left SC circuit, but no idea what correct function should be.