ina134 and drv134 - for ssl-comp??

[matthias]

how good and suitable is the ti solution for line input and output driver ics ??

is it possible to replace the g-ssl input/output stage with ina 134 and drv134??
so you could avoid some of the electrolytic caps in the signal path...

mat

 

[gyraf]

Possible, yes, but it won't give you much advantage anyway - the electrolytic contribution to "sound" is much less than the VCA's ditto.

And then you'd have to deal with minute amounts of DC on top of signal..

The Danfield version is made with SSM2141/42's IIRC..


Jakob E.

 

[DrFrankencopter]

I don't see how using a DRV and INA 134 will let you avoid electrolytics in the signal path....those devices want to be AC coupled just like the GSSL's 5534's.

If you really want to get rid of the electrolytics, you have 2 options:
1. Install a servo circuit....check the archives here, as I've posted one for the SSL
2. Increase the input impedance a little, and go for big polyprops out front (Solen makes some big ones that won't break the bank).

You don't want any DC (well, it can be at -120 dB) going into the VCA as it will get modulated by the gain reduction, and will appear as a 'thumping' sound.

The output is tougher, as it is low impedance....prolly can't get away with a polyprop there. Best bet is a servo again.

Though, like Jakob said, its not really worth making all these mods if you stick with the same VCA's....now, a 4 pack of 2181LA's with a low noise buffer IC, that could make a difference (and is what I have planned for my SSL whenever I get around to making it)!

Cheers,

Kris

 

[radiance]

[quote author="DrFrankencopter"]I
The output is tougher, as it is low impedance....prolly can't get away with a polyprop there. Best bet is a servo again.
[/quote]

Those "gssl servo files" where only for the input right?
Would love to see an output servo schematic for the gssl. I guess this requires two DOA's ....hm that would be 6 in total for 1 gssl. :?

 

[DrFrankencopter]

Been a while since I've been here...

Yeah, the servo files were only for the input....but, the same logic can be applied to the output. The only difference is that you need 2X as many (6 in total: no pain, no gain), in order to handle the balanced output. You'll be using an inverting configuration, for which the design notes that I wrote apply. The equations for that configuration are all there...I think.

The only gottcha is determining the input impedance, and it turns out that it's determined by the resistor feeding the VCA input (10k if my memory is correct).

Maybe someday soon I'll find the time to get working on this again!

Cheers

Kris