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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: lordbelial on April 09, 2007, 03:41:21 PM

Title: Reactive Sound Boost box HaCK?
Post by: lordbelial on April 09, 2007, 03:41:21 PM
Hi,

I've opened my reactive sund boost box to see which OA were installed into.

There are two (2) LM 833 N OpAmps installed in there.

I could try to trace the whole circuit some day and to take notes on the reference of every component. Don't really know if the performance of this pre could be improved by replacing OAmps or Caps (which are electrolytic)

Any suggestion?
Title: Re: Reactive Sound Boost box HaCK?
Post by: Javier Cinakowski on April 09, 2007, 03:50:37 PM
Quote
The LM833 is a dual general purpose operational amplifier designed with particular emphasis on performance in audio systems.

This dual amplifier IC utilizes new circuit and processing techniques to deliver low noise, high speed and wide bandwidth without increasing external components or decreasing stability. The LM833 is internally compensated for all closed loop gains and is therefore optimized for all preamp and high level stages in PCM and HiFi systems.

The LM833 is pin-for-pin compatible with industry standard dual operational amplifiers.
Title: Re: Reactive Sound Boost box HaCK?
Post by: corsair on June 03, 2007, 09:46:29 AM
Hi,

I've opened my reactive sund boost box to see which OA were installed into.

There are two (2) LM 833 N OpAmps installed in there.

I could try to trace the whole circuit some day and to take notes on the reference of every component. Don't really know if the performance of this pre could be improved by replacing OAmps or Caps (which are electrolytic)

Any suggestion?

Do U plan to unsolder the 2 opamps and put 2 DIP sockets in its place?
I can think of some opamps like the AD8620 or OPA627 to try..
Title: Re: Reactive Sound Boost box HaCK?
Post by: Church-Audio on June 05, 2007, 09:55:49 PM
Hi,

I've opened my reactive sund boost box to see which OA were installed into.

There are two (2) LM 833 N OpAmps installed in there.

I could try to trace the whole circuit some day and to take notes on the reference of every component. Don't really know if the performance of this pre could be improved by replacing OAmps or Caps (which are electrolytic)

Any suggestion?

The lm833 is a hog for current.. I would try using the OPA2227PA chip I would also change all the caps in the signal chain to film caps.. After that I would change the cb cable on the output to a "shielded" cable... Then you might have a pretty good preamp for some reason all of these boxes I have looked at have unshielded 3 conductor cable on the output? Very strange I guess they feel that because its an output it does not need to be shielded, and that would be true if you were always using a lot of gain because your signal would be much louder then the inducted signal. But I feel that its always better to use shielded cable when ever your dealing with audio. Last but not least I would put in a few 2pf caps in the feedback loop to reduce RF.
Chris