SSL 4K channel dynamics. (And more in future). PCB's/kits: Available!

[xarolium]

Dear Igor,

I'm building two units of this 4KCC but i miss FB and TBD resistors value.
What's the values of this resistors?

Best regards,
xarolium

 

[xarolium]

With a little bit of research i found this thing:

FB is a ferrite bead , isn't it ?
For the TBD resistor:
My relay coil is 288ohm resistance so,
2*288= 566ohm.  24V on 566 is 43mA ,  then 1.25/43mA = 30ohm TBD resistance
Is it right too ?

Thank you for your help

 

[xarolium]

So the resistor value seems to be ok.
Now my problem is to calibrate it.
How do i calibrate VR1 and VR2 ?    :-[

 

[xarolium]

Please somebody can help me to clibrate the 4K dynamic  ? 

 

[Electrobumps]

This can be worked out using the schematics in the build documentation and the 4000 series calibration documentation I've just posted.  I'm a few days off working this out.

Please post how you get on.

 

[Spencerleehorton]

Hi All,

are these pcbs still available?

regards

Spence.

 

[Electrobumps]

Still available

PCB  - http://ramshacklerecording.com/
Metal work - http://www.frontpanels.de/

 

[Electrobumps]

For anyone building this check what is common on your relays.  Mine did not work with the board.  I had socketed my relays so was able to swap legs in the sockets for correct operation. 

 

[EmptyMusicBox1]

hello i have just buy PCB for 4KCC what i need to build it ?

exist a BOM or a Mouser cart ?

thanks for your help

For anyone building this check what is common on your relays.  Mine did not work with the board.  I had socketed my relays so was able to swap legs in the sockets for correct operation.

 

[Electrobumps]

hello i have just buy PCB for 4KCC what i need to build it ?

exist a BOM or a Mouser cart ?

A BOM is available in the download at ramshackle.  I would also look at all the pictures provided as it gives few build hints. 

I'm working on a setup procedure for the unit.  I think I am getting close to something that makes sense.  However I am unable to get unity gain.  I get 6db of gain with the circuit in and all pots at zero. 

Be really great to hear from people who have done a build from a ramshackle board if they have this same issue.  There was no mention of the relay issue in the DIYRE build guide. 

Be great if any new builders could help support this thread. 

 

[Meathands]

I just plugged in my 4KCC I built back in 2011. I can confirm that the relay bypass works fine and the unit is close (-1dB) to unity gain in bypass mode.

 

[Electrobumps]

I can confirm that after searching the relays used in Igors pictures the switching contacts the first pin is common.  My relays the middle pin is common.  Not that easiest to get hold of M4 12H or equivalent in the UK. 

Still trying to work out this 6db of gain when the is in and all controls are at zero.

 

[Electrobumps]

Still trying to work out this 6db of gain when the is in and all controls are at zero.

worked this out, the BOM quotes for IC100 to be either a THAT1246  or  INA134P     

I used the INA134P,  which gives unity gain.  The THAT1246 is -6db.  So if you want your unit to have unity gain make sure you use the THAT1246.

 

[Electrobumps]

Be good to get peoples feedback on how they have set up their compressors.  I was confused by the slightly cryptic nature of the notes provided on the schematic when comparing to the original service manual. 

Feed 1.55vrms measured at test point 4 into the unit.

VR1 - According to schematic, this Should be adjusted to 0vdc at TP1.  However I can only get this down to 78.mV when fully CCW. 

Is it relevant that the 200R Trim has been changed to 500R from the original schematic?  Do we need more resistance at R6/trim?  or do we ignore this note on the schematic?

I then went on to see if I could continue to setup with the service manual.  I set compressor and applied +14db as stated.  Switching the attack switch does create the 1.5db difference in level as stated. 

I was then able to adjust VR1 to get + -1db apart from at the start of GR when it was a little more.  I used my DAW (protools) in calibration mode and ramped the level up and down in and  adjusted the VR2 to be within + or - 1db regardless of the amount of gain reduction. 


VR2 - This I can be adjusted to read -5v at TP2 as noted on the schematic.  I believe this would normally be verified on the setup manual as setting 0dbm while measuring a 4db drop at the insert.  We do not have this insert so I will trust the notes on the schematic. 


VR3 - the manual set up was not so clear to me and we had no notes on schematic,  VR3 is a trim on the threshold.  I sent +4Vu from my DAW and set the threshold to +12 I then set then adjusted VR3 to trigger at this point.  I  hope in use this will give me enough of threshold range for gating loud and quite signals, although this may not be the intended setup for the gate, it will give me continuity across my 2 units.  Considering many multi tracks I receive tend to be on the hotter side.  I will see how I get on at this setting and may adjust depending on how I get on. 

Setting Sym - you will need a program that measures THD.  I tried this on my USB scope THD measurement, but it was not very accurate.  I run mac and will need to install a windows partition if I'm to do this completely accurately on dedicated free software.

General this sounds like an SSL on steroids.  When you are in light medium compression this acts and sounds like an SSL channel.  However on an SSL channel when you really over compress the sounds become a little dead and unexciting and looses character.  This unit seems to give character in extreme compression rather than killing the sound.  I like that.  Gate acts I would expect.

 

[jasonallenh]

Does anyone possess the DiyRE build guide for this? I'm trying to collect all the notes I can before I start. Also, does this thing ONLY run on 24V, or can it also run on 16V? I've seen it mentioned, but I haven't seen what changes have to be made to do this.

=jh=

 

[jasonallenh]

Nobody? Anybody?  :-\

 

[Gustav]

Nobody? Anybody?  :-\

Isn't this one of Igor's projects? Not sure why DIYRE would've made an assembly guide for it!?

Gustav

 

[Dreams]

There was a build guide at one point, I believe. Have you tried emailing them?

 

[ramshackles]

DIYRE did have an assembly guide up.
It has been taken down...which is a shame. Wayback machine has a snapshot of it from 2014:

http://web.archive.org/web/20140715154919/http://www.diyrecordingequipment.com/4149/i-j-research-4kcc-build-guide/

 

[jasonallenh]

DIYRE did have an assembly guide up.
It has been taken down...which is a shame. Wayback machine has a snapshot of it from 2014:

http://web.archive.org/web/20140715154919/http://www.diyrecordingequipment.com/4149/i-j-research-4kcc-build-guide/

JAMES you are a lifesaver. I'm going to PDF the crap out of all of this and document the process during my own build so the project can continue to thrive (at least until all the boards disappear!)