where to find Schematics for presonus tube pre

[migidee]

Does anyone know where I can get a schematic for the presonus tube pre?  Any help is appreciated, Thanks.

 

[mulletchuck]

you'll probably have to send it back to Presonus if it needs repair.  whole lot of Surface Mount stuff in those boxes, and the schematics aren't released cuz they're production units.

 

[migidee]

you'll probably have to send it back to Presonus if it needs repair.  whole lot of Surface Mount stuff in those boxes, and the schematics aren't released cuz they're production units.

Thanks for the reply!

Let me clarify, my unit is not broken.  The tubepre was actually a gift from my wife when we first met.  So the problem I have is, I never use it, and I don't dare sell it.  I was hoping someone might have a schematic so I could study the circuit and see if I can modify it to be a little more useful instead of a pretty blue paperweight I think I found a broken link to a schematic for it on this site once, and I was hoping someone might still have a copy of it.

 

[mulletchuck]

http://www.groupdiy.com/index.php?topic=44834.0 

it's in the Technical Documents section.

 

[zebra50]

http://www.groupdiy.com/index.php?topic=44834.0 

it's in the Technical Documents section.

Is it just me but... I can't see a tube in that schematic!

 

[mulletchuck]

i thought the EXACT same thing!!! 

 

[mad.ax]

There seems to be another board that holds the tube, and that must be soldered on the main board. On the left side of the schematic you can see edgeslots numbered E1 to E10.
They use the 48V as plate voltage. Signal comes from pin1 of U2A into the grid (E9) and goes out on E8. Given the small value of C13, I guess its a plate...
Heater is derivated from +15V through R22 (E7). There should be a resistor on the add-on board for the cathode, and maybe another one for the plate...
Looking at that board should also tells if they use only one side pr both side of the tube...

Axel

 

[frazzman]

These things are rubbish, the only thing you could do to improve it would be to take a hammer to it

 

[gemini86]

Where it says "edgeslot". That's the tube. Running on 48v... meh.

 

[migidee]

http://www.groupdiy.com/index.php?topic=44834.0 

it's in the Technical Documents section.

Perfect! thanks! ;D

 

[offramp]

These things are rubbish, the only thing you could do to improve it would be to take a hammer to it

Funny... I replaced the ****** Chinese tube with a NOS RCA - and then a Mullard - and got some surprisingly good work from it.

 

[offramp]

I would love to know what it was that Black Lion did to these things....

 

[frazzman]

These things are rubbish, the only thing you could do to improve it would be to take a hammer to it

Funny... I replaced the sh*tty Chinese tube with a NOS RCA - and then a Mullard - and got some surprisingly good work from it.

Weird... I think there are bigger problems with the design rather than the tube, that being that it is a starved plate design, but I guess if it sounds good then what's it matter