Sm Pro Audio PR8E?

[aortizjr]

[quote author="aortizjr"]Wow there is some great info in here.

Anyway I have the PR8, the mods have really opened it up. Its biggest weakness though is that the "Gain" control is not a gain control at all.. but an Output level.

Does the PR8E still have this issue? Or is the "Gain" control really a gain control.

Thanks![/quote]

Hearing these clips has re-sparked my interest and the need for some more pres.

Anyway from looking at the clips those pots are dual ganged. Which means they must be a gain of some kind I would think. Without a schematic it is still hard to tell what is going on with it for sure. But that would definitely be an improvement over the PR8.

 

[MBBCFP]

There are those of us still reading these threads.

I just received my second PR8E, this one fom B&H Video for $149 new, and should receive my shipment of LM4562NA chips from Avnet direct early next week. They sell them for $2.62.

I have a stock PR8E in my DAW rack that has recorded quite a number of excellent classical gigs. Having read these threads, I can only imagine the improvement the $45 of chips will make. I'll report back after installing them.


www.MikesMobileMics.com

 

[grw]

Hey all - another new guy showing up...

I have been considering picking up at least one EP84 for starting out a home studio, and would like to hear more on how the mods are going with this family of pres.  So, please, keep up this thread so I can come up with ideas as I start to play with it.

To take this a step further - it looks as if the EP84 has two 4580s in the input section (based on info from "the19thbear") whereas the pr8e comes stock with a single 4558 in the input section.  Based on the type of sound I want (and the information I have seen on this thread), it looks as if I would want to mod the 4580s with LM4562s.  However, I was a bit discouraged that there didn't seem to be a whole lot of difference (again, based on the reports of the19thbear) changing out the 4580s with 5532s.

Please advise if I missed something, as I am definitely not an EE (actually an ME with ears, a soldering iron, and a bunch of guys willing to let me record them for practice!)

Thanks!

 

[xefe]

I just ordered a PR8E from on-line store and i'm getting ready to mod it like crazy.

Does anybody have a schematic from a PR8E? Can you post it or send it to me?

Can you guys make a summary of the mods that work on the PR8E?
Right now i'm thinking about changing the input caps for something bigger like 100uf and changing the opamps to 5532's. Can i cut out "c13" and "c14" out without risk of putting the 5532 in oscillation?

thanks.

 

[xefe]

What would be the benefit by removing the three 680p caps like in the BLA mod? And what's up with the paralleled transistors(BLA)? Since the pr8e now has a real gain control shouldn't it have a bigger gain pot capacitor (original is 470uf)? will not the lm6172 oscillate with all ceramics removed?

 

[moley1390]

Hey, for anybody still reading this thread, I've done a trace and have posted a schematic (asked for many times in this thread), and I've started a new topic at http://www.groupdiy.com/index.php?topic=49009.0

Cheers,
Scott

 

[k.steeze]

For any of you guys who have modded the PR8E I have a question about chassis grounding.  When I received my used unit off ebay I noticed it has a grounding screw in the chassis but to my dismay it isn't connected to anything.  No wire to the power plug or anything.  The power plug does have a middle prong free, although the power supply is only a two prong supply so I don't know if that even matters?  Basically I'm trying to avoid being electrocuted and wondered if I should use a hook up wire from the middle prong to the grounding screw?

 

[RuudNL]

The middle contact is probably a break contact, to (for example) switch off battery power when an external power supply is connected.
(Of course battery power isn't used here, but it is a standard connector.)

 

[k.steeze]

Thanks RuudNL!  I did test the unit without receiving any electrical shocks, so I suppose all is well so long as the pcb or components don't touch the chassis .