Simple DiodeBridge Compressor

[richiyobs]

Thanks for clarifying....
I read an interesting interview about Gyraf s G24... As I understand this device has a unique way to drive 2 cascade/series sidechian...
By the way... A great device i d like to have one...
Cheers

 

[Heikki]

maybe adding something like this in front of your threshold...

View attachment 89099

When the detector is cap coupled won't there be have some charging effects going on with C1 & C2. What happens if steady sine wave is fed to the sidechain? Am I talking nonsense? I'll have to fire up the simulator when I get home because I don't have the mental capacity to think about it.

 

[Script]

And I was about to use it like that on your vari

Do you mean diode resistance having effect on time constant and/or filter ?

 

[Heikki]

And I was about to use it like that on your vari

Do you mean diode resistance having effect on time constant and/or filter ?

My worry is that if the sidechain is fed constant signal the CV won't be constant. There will be a peak first but steady signal won't sustain it. I'll check it out with spice when I get home from work.

 

[richiyobs]

Me too updated according to this mod... I only checked on spice if the slopes by the caps were symmetric... And yes with the values shown 37Hz same slope before bjt buffer and before vthr diodes....
Hope it helps...
Varying caps after the bjt buffer, also varies the slope but only in this stage if I remember...
Not so experienced to evaluate

 

[abbey road d enfer]

Thanks for clarifying....
I read an interesting interview about Gyraf s G24... As I understand this device has a unique way to drive 2 cascade/series sidechian...

What is the source of this "document"? I see two major interrogations there.

• Rotating phase by a specific amount across the audio bandwidth is not a minor feat in the analog domain. How do they do it?
• Rotating Left by -90° and Right by +90° makes correlated signals cancelling in the positive sum (the "M" component). It could make the "S" component viable, but not more than using simple basic substraction.

The side-chain does not really care about phase of the signals it processes.

 

[richiyobs]

They do using the mono listen compatibility c. Room feature of old console
Full article... Translate from German...
https://www.amazona.de/interview-jakob-erland-zum-gyratec-xxiv-cadmium-compressor/As said... for me is very interesting the concept of this device

 

[abbey road d enfer]

They do using the mono listen compatibility c. Room feature of old console
Full article... Translate from German...

With all respect due to gyraf, I'm not convinced by the +/- 90° thing.

 

[Heikki]

I'll check it out with spice when I get home from work.

On green is the sidechain output with trasformer input and the blue line is where the transformer is replaced with the circuit from post #65.

 

[Script]

The PRR vari has an opamp between cap and diode. There bias goes thru that opamp. So would a buffer make any difference or does this mean the PRR has the same issue ?

 

[Heikki]

The PRR vari has an opamp between cap and diode. There bias goes thru that opamp. So would a buffer make any difference or does this mean the PRR has the same issue ?

Can you post the PRR vari mu schematic?

 

[richiyobs]

On green is the sidechain output with trasformer input and the blue line is where the transformer is replaced with the circuit from post #65.

Thanks for comparison and infos

 

[abbey road d enfer]

The PRR vari has an opamp between cap and diode. There bias goes thru that opamp. So would a buffer make any difference or does this mean the PRR has the same issue ?

The proposed transistor circuit has an output Z of 33k, when an opamp has near-zero. It's bound to make a difference.

 

[richiyobs]

looked for PRR schematic, but only missing links
so curious

 

[richiyobs]

https://groupdiy.com/threads/prr-varimu-bluebird-mod-help.34554/post-423240is this one?

 

[Script]

Can you post the PRR vari mu schematic?

Full of scribbles. But I drew one

 

[richiyobs]

https://groupdiy.com/threads/prr-varimu-bluebird-mod-help.34554/post-425648whith hpf

 

[Heikki]

Full of scribbles. But I drew one

PRR sidechain won't have the same issue. It's only an issue if the detector is cap coupled.

 

[richiyobs]

good to know... i ll check for what i can
thanks

 

[Heikki]

I posted what I think is better solution for replacing the transformer here. The signal does need to be large enough for the transistors to start conducting. If used with the schematic on this threads post #1 I would bias the transistors or add an amplifier stage.