Upgrading E/G Channel Dynamics from dbx 2150 to That 2180/2181

[marcmozart]

Can anybody post the steps to upgrade the VCA? I assume there is some small changes involved, few resistor values etc.

I just want to try this on a few channels. The 2150/2151 is great and crunchy. Wonderful for dirty drum parallel-chains etc. - I want to hear how the cleaner 2180/2181 changes the characteristics of the channel dynamics. For example on Lead Vocals.

Mouser.com Link:
http://mouser.com/Search/ProductDetail.aspx?R=2181AL08-Uvirtualkey61220000virtualkey887-2181AL08-U

[waltzingbear]

design note 137 Substituting THAT 218x VCAs for 215x VCAs in Existing Designs (68k) 

http://www.thatcorp.com/Design_Notes.shtml


Alan

[sintech]

Marc, got a 2004 sticked Factory spare here, it's has a That 2181 VCA

This could be used for comparison.

[marcmozart]

Marc, got a 2004 sticked Factory spare here, it's has a That 2181 VCA

This could be used for comparison.

Awesome Andy! Can you make a high-res photo? Will definitely try modding a few. BTW, my centre cards are also using the 2181AL.

[PMcC]

Hi Marc,

I did this change over from 2151 to 2181 years ago on my 4KE. I'd love to hear your views on any differences you perceived. I actually went a bit further by installing a servo circuit to eliminate the dynamics section output electrolytic. The input capacitor I kept as it is a much lower value component so it can be a posh dielectric type.

Regards

Pat

[marcmozart]

Thanks Pat,
what are the differences you're hearing? I haven't done any yet.

Hi Marc,

I did this change over from 2151 to 2181 years ago on my 4KE. I'd love to hear your views on any differences you perceived. I actually went a bit further by installing a servo circuit to eliminate the dynamics section output electrolytic. The input capacitor I kept as it is a much lower value component so it can be a posh dielectric type.

Regards

Pat

[PMcC]

Hi Marc,

Noticeably lower noise.

More transparent at modest -3dB to -6dB reduction levels.

And importantly no difference in that renowned room mic crush sound that seems very illusive with other non SSL compression.

Regards

Pat

[marcmozart]

exactly what I would love to hear - thank you!

Hi Marc,

Noticeably lower noise.

More transparent at modest -3dB to -6dB reduction levels.

And importantly no difference in that renowned room mic crush sound that seems very illusive with other non SSL compression.

Regards

Pat