Totally my fault, not the circuit!

I was running SOT-23 devices like they were TO220

will adjust for sane values (75mw) and test soon

 

On 2017/1/28 at 10:33 PM, kevin gilmore said:

unbalanced to unbalanced, gain of 1

unbalanced to balanced, gain of 2

 

is it possible to make BAL-BAL into zero gain? Just like SE-SE, it's unity gain (When BAL-BAL is 0db gain, SE-SE is -6db gain, is this correct)

lower the values of the 1300 ohm resistors

 

which has best common mode rejection, the older one http://gilmore.chem.northwestern.edu/boards/balancedinput4mba.zip

the newer through hole one, or the newer SMD one?

To power 2 ubal/bal boards and 4 diamond buffer, is one GRLV enough?

37 minutes ago, cspirou said:

To power 2 ubal/bal boards and 4 diamond buffer, is one GRLV enough?

 checked my through hole one, (full size) its just under 200ma total with two inputs and four buffers

one GRLV is enough for several of these

Messing with this tonight.

Its playing into balanced ortho's. the gain is stock at 2 and its just enough, not real loud but sounds just great!

yes this is meant for Pre duty, this is one way I test them.

that 12va transformer is too small, but was just sitting here. 20-25va would be better.

GRLV is set for +-18V heat sinks are 35C,  with 4V of regulation

the buffer's are setup for 18v & that way I can use the cheaper servo's

room is 20C, buffer output transistors are 40-46C, transformer 42C

 

The beauty of making your own boards. Really nice.

For source switching I found this:

http://gilmore.chem.northwestern.edu/baseboardbal3.jpg

But I don't see any files for it. Have you made any progress on it?

Way old will have to look at it. If it has the 4pdt relays, those are obsolete

board file posted, everyting is the dpdt relays.  So you stack 2 for stereo, and use rca to xlr adapters for the unbalanced inputs otherwise it gets stupid complicated

Edited February 16, 20179 yr by kevin gilmore

Thanks! Very much appreciated.

I don't see it posted. Does it take awhile?

 

Edited February 18, 20179 yr by cspirou
dobl post

Its there now, I put it in the wrong place

 

Edited February 18, 20179 yr by kevin gilmore

Can you configure it for more than one output?

The output is just a straight connection, no switches. I would just add another pair on the panel in parallel.

Edited February 20, 20179 yr by cspirou

On ‎03‎/‎02‎/‎2017 at 4:03 PM, sbelyo said:

If I wanted to make a preamp with these boards can I omit the attenuator and wire it like this?

For example:

 

I would like to do something similar... I want send SE signals (cd and radio) to my KG electrostatics amps vía balanced.

Can I use the 2x gain for balanced signal or I need change it for 1X?

 

2x is just fine for this

Thanks Dr. Gilmore

found an error with the input board, fixed and updated

Can you take a look and make sure I have all the right gerber files for these boards

Thanks

those have not been updated in a while, so many versions, sorenb probably knows more about which is which than i do at this point

 Kevin's SMD layout, adapted a bit for my methods

                                                                                                               Servo's work

 

 

                                                         and a  plug in buffer with 1W MPSW transistors (for Turbo)

It seems that I like buffers............

Edited February 23, 20179 yr by congo5
change schematic

That schematic does not match the current board

 

Well its the one I have......

the CCS LED/10k resistors go to ground instead of each other

and Servo eats DC at the output

That's all I noticed.

 

the board is the dual servo one, I thought I published the final schematic, will have to look

I used the first one I found and  it was close enough to trace out the board and label it.

Do not see a link here for Diffinput3.pdf

I do  have a draft copy with sim graphs on it.