"Crush-n-Blend"

[dandeurloo]

Hey guys this looks like a sweet project.  Are you guys getting anything figured out for this to be a kit project?  A stereo unit would be great for drums buss stuff.

 

[iangomes]

OK, made some 'modifications' to the original schematic with correct pinouts, here it is!

http://www.dagoosemusic.nl/temp/crushnblendV2.gif

So whatever became of this design? I started it ages ago, and just recently finished it (trying to clear out old projects) to find tonnes of noise and distortion on the signals... Then I came back to this thread and the design seemed to have died.. I knew I should have checked this thread before finishing it...  :-[

 

[iangomes]

totally got it working today (no more crazy distortion). Still needs a few modifications though.

 

[RedNoise]

Hi Iangomes , do you know where the distortion came from?

 

[iangomes]

what I have done which has solved the issue is connected pins 5 and 6 of the 2141 (I also meant to connect pin 1 to ground but looking again, it seems I totally forgot. Going to try that out now). This completes the feedback loop in the amplifier.
I then also added .1 uf ceramics on the V+ and V- to ground on the 2142 (I read in a book that without them, the unit is very prone to high amounts of distortion).
http://img24.imageshack.us/img24/7127/crushnblendv3.gif

 

[shuchoco]

if someone made a PCB or kit for this, i would buy a dozen.

would love to have a crush-n-blend box for each of my comps as i don't have a console to do proper parallel compression.   

 

[iangomes]

I'd do it but it's not my design.

I'm also doing a very fun little mod to the design which uses a 11 step switch instead of a pot. I'm setting it up so that as you turn the switch (10% per position), the gain of the circuit doesn't change. I found that my current version (with the pot) made the output gain increase or decrease depending on the amount of crush or blend. I wanted the gain to be linear. i'll post some results when i get the money for a few relays (need a paycheck!!!). Needless to say, having a standalone version is pretty awesome.

 

[crisotop]

that sounds awesome - total recall crush'n'blend, I'd be in for a board as well!

 

[helterbelter]

if someone made a PCB or kit for this, i would buy a dozen.

would love to have a crush-n-blend box for each of my comps as i don't have a console to do proper parallel compression.    

Livingnote has "Internal crush 'n blend boards". They're smaller, and without the de-balancing and balancing opamps.  I've used one for my GSSL, works great. He hasn't posted in a while (busy man !), but he probably has got a few cnb's in stock.

Check here :
http://www.groupdiy.com/index.php?topic=31246.0

If you really need to build them in a seperate box including the (de-)balancingchips, you could ask Ricothetroll of he will fab a few boards of Keith's design.

 

[livingnote]

Hooooa. Done. Got rev4 finished and etched, gonna prototype it tomorrow.

 

[rrs]

Great been lookingt forward to testing this thing out.

 

[guy_4]

Hello,
Nice project...
I am in for several boards ! 
Best,
Guy

 

[regularjohn]

I'd do it but it's not my design.

I'm also doing a very fun little mod to the design which uses a 11 step switch instead of a pot. I'm setting it up so that as you turn the switch (10% per position), the gain of the circuit doesn't change. I found that my current version (with the pot) made the output gain increase or decrease depending on the amount of crush or blend. I wanted the gain to be linear. i'll post some results when i get the money for a few relays (need a paycheck!!!). Needless to say, having a standalone version is pretty awesome.

Are you sure the increase/decrease in gain wasn't because the compressed level is lower due to the gain reduction applied?  I've found if you match the output level of the compressed signal with the uncompressed signal there's no change in gain between the two.

 

[iangomes]

I'd do it but it's not my design.

I'm also doing a very fun little mod to the design which uses a 11 step switch instead of a pot. I'm setting it up so that as you turn the switch (10% per position), the gain of the circuit doesn't change. I found that my current version (with the pot) made the output gain increase or decrease depending on the amount of crush or blend. I wanted the gain to be linear. i'll post some results when i get the money for a few relays (need a paycheck!!!). Needless to say, having a standalone version is pretty awesome.

Are you sure the increase/decrease in gain wasn't because the compressed level is lower due to the gain reduction applied?  I've found if you match the output level of the compressed signal with the uncompressed signal there's no change in gain between the two.

yup, as far as i found with running tones through it, i had an increase in overall gain at fifty percent compared to 0 or 100 percent

 

[livingnote]

Phew. Rev4 is done.

Got it on the surgery table right now, gave it some relays to take it completely
out of the circuit and fiddled with bias compensation to keep noise down as far
as possible...but you don't know till you know, right?

That with the 11 step switch sounds great. It's the nature of the beast, I adjusted
the divider values as well as I could to get it as linear as possible, but you'll always
be doing the bell curve with the pot of course. How funny is that, now there's a
mod for the mod, haha...might just take it on board (oh no rev5 . Me I just tend
to have one paw on CnB and one on makeup when I mix and go by ear.

I'll get some pictures for ya as soon as I get the camera in here.

 

[regularjohn]

That sounds great, Lukas!  I can't wait to see the new version!

 

[Sammas]

Hey guys,

I've been goofing around with some bits and pieces in my parts drawer and came up with the following... Bare in mind, I'm not apt in circuit design but it does work on the breadboard. It is using an SSM2141 essentially to interface with a balanced input, then NE5534's as buffers for the mix circuit.

Does anyone has any words of wisdom on the schem? There is a dB or two increase as the "mix" reaches 50%, but otherwise it seems ok.

 

[abbey road d enfer]

As I see it, unity gain is not ensured. Assuming you selected a 5k pot, the attenuation in the fully CCW position is 3.6dB (that includes 6dB gain in the 2142).
Volume variation is not what it should be. At the moment, and again assuming VR1 is 5k, the variation between CCW and mid-position is only about 2dB. Depending on the application, volume drop at mid-position should be between 3 and 6 dB. For reverb, since the dry and wet signals are largely uncorrelated, drop should be 3 dB. For "parallel compression" it should be 6 dB, since wet and dry are almost 100% correlated. With the chosen pot arrangement, it is impossible to achieve 6dB. Any attempt to approach this value leads to increased basic attenuation, and noise problems. I reckon you could get satisfactory operation by reducing the pot value to 2.2k (or increasing resistors R7, 8, 9 and 10) and adjusting R11 for correct unity gain.
The only solution to make the law right without the degradation in performance is to use dual pots (quad for stereo operation). or VCA's...

 

[JAY X]

Hi all,

¿Does anyone experienced image shift problems with this kind of panpot arrangement?. I mean, the more i turn the panpot to the right position, the stereo image  shifts to the right, althought the panpot here is not intended to do that in this particular application. Maybe a dual (quad for stereo) potentiometer would overcome this problem.

I used 10k dual  linear pot with 5k/15k summing resistors instead of 2k2/4k7.

Thank you for your help,

JAY X

 

[EmptyMusicBox1]

Hi EveryBody

where i can find a PCB and BOM for a Crush'n Blend option for a SB4000 ?