Great River MP-2 , info, schematics & discussions

[okgb]

Again , because of the onboard regulation of the preamps
the psu can be relatively simple or straightforward , but

I may be in for a Canadian jlm grp buy

And let's make Dan proud eh ?

 

[Ptownkid]

By the time these ship, I will have a universal adjustable psu available.

 

[Ptownkid]

It is time

http://www.groupdiy.com/index.php?topic=263279#263279

 

[okgb]

Saga ?

 

[AudioJunkie]

One last question that I don't recall being finalized on the discussion thread.

Were these going to be PCB switches and going the SMD resistor switch board? As per Greg's? Or the solder lug with resistors right on the switch? I have an Elma 24-position (but 2 deck) that I was going to use on another project, but gave up the idea because the solder lugs were so tiny that I couldn't figure out how to mount all the resistors without massive excess of leads and making the switch end up being double the diameter or depth. And that was using 1/8th watt resistors.

Daniel

 

[Ptownkid]

No, they are the solder lug ones.

Can you post a pic? I've heard from many people that they had no problem doing it.

 

[Bluzzi]

Anyone doing the group buy in the US?

I meanif no one does it may Ptownkid may still be able to get them. Its not about saving money all the time its about convenience for us lazy guys.

jim

 

[Bluzzi]

Also Ptownkid, your PS would include the Power Xfr right?

jim

 

[Ptownkid]

no, I can't handle stocking power xfmrs right now.

But, maybe some of us canadians can go in on some avel lindburgs...

 

[Bluzzi]

OK, so what's the spec on the transformer than? Same as before?

jim

 

[Ptownkid]

Greg mentioned it in this thread somewhere

 

[okgb]

Yeah it's back there somewhere , i think 30va 22-0-22 is fine
again the onboard regulators take care of allot so you could
just feed it the raw dc . may need more current for a quad ver.

Imagine all the mp-2 babies months later , just like a blackout

regards Greg

 

[Bluzzi]

OK, wasn't sure.

jim

 

[Bluzzi]

Anyone ordered the input transformers yet?

I am thinking Cinemag but there is also Jensen and Lundhal as well. Cinemag being cheapest and a good reputation is it worth going for any of the others?

I'll be going transformerless output for now with thought on adding later (money is getting tight).

Also what about some sort of peak led indicator? I have tons of VUs here. Anyone going to incorporate some sort of level indicator into the preamp? I guess a buffer is required right?

jim

 

[okgb]

There is a separate output for metering , it likely needs a driver
the power supply board had the l.e.d. drivers on the MPs

Time to see if anyone in the U.S. will step up for a Cinemag grpbuy ???

Anyone ?

 

[Bluzzi]

Greg do you know if the meter output is buffered? I imagine if its seperate it is. Then will it drive a proper VU meter? I have a few of those sitting doing nothing!

jim

 

[okgb]

take a look at the schematic , i don't think so but i can't rememeber
if it is just a separate pin or does come from a different place

regards Greg

 

[Bluzzi]

On the schematic I only see J7 as an output. It has 4 pins but pin 2 & 4 are connected and pin 1 & 3 are connected with R36 & R37. I'm not an techy for electronics but seems like a single unbalanced output.

I can't locate a second output on the schematic.

jim

 

[Bluzzi]

Looking at the schematic once again I am reminded that there is a lot of voltage regulation going on in this board. But I am not knowledgeable enough to deduce if there is any rectification or filtering going on. Doesn't seem so but I can't be sure.

Greg, do you know if I just need a transformer? It would seem that a seperate full blown power supply would be redundant in some areas. No? Or am I way off?

i'm just trying to ascertain if we need a complete PS or just a transformer, bridge rectifyer and caps for filtering (ok so that is almost a complete ps, but no regulation though).

jim

 

[okgb]

Well , quite believably , i've misplaced [ fileshuffled ] the documents ,
anyone want to resend them to me ?


Hey Bluzzi , i'm trying to keep the clutter off the tread so always email
me and once i get enough info i'll add a post .



I know there is a pin on the power connector [ because the led drivers are on the psu pcb ] for that purpose to feed them, look there , But i don't rememeber if it is just tapped off of the output for convenience or if there is some isolation , Perhaps another Dan question

Right because of the onboard regulation the psu can be filtered , rectified
dc as if it were just before the regulator , which in fact is the case
[ just that they are split apart & individual ]

Hope that helps , regards Greg