congo5 Posted February 4, 2017 Report Share Posted February 4, 2017 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 Quote Link to comment Share on other sites More sharing options...
fat joey Posted February 5, 2017 Report Share Posted February 5, 2017 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) Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted February 5, 2017 Report Share Posted February 5, 2017 lower the values of the 1300 ohm resistors Quote Link to comment Share on other sites More sharing options...
fat joey Posted February 6, 2017 Report Share Posted February 6, 2017 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? Quote Link to comment Share on other sites More sharing options...
cspirou Posted February 10, 2017 Report Share Posted February 10, 2017 To power 2 ubal/bal boards and 4 diamond buffer, is one GRLV enough? Quote Link to comment Share on other sites More sharing options...
congo5 Posted February 10, 2017 Report Share Posted February 10, 2017 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 1 Quote Link to comment Share on other sites More sharing options...
congo5 Posted February 12, 2017 Report Share Posted February 12, 2017 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 7 Quote Link to comment Share on other sites More sharing options...
JoaMat Posted February 12, 2017 Report Share Posted February 12, 2017 The beauty of making your own boards. Really nice. Quote Link to comment Share on other sites More sharing options...
cspirou Posted February 15, 2017 Report Share Posted February 15, 2017 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? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted February 15, 2017 Report Share Posted February 15, 2017 (edited) 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, 2017 by kevin gilmore 1 Quote Link to comment Share on other sites More sharing options...
cspirou Posted February 18, 2017 Report Share Posted February 18, 2017 (edited) Thanks! Very much appreciated. I don't see it posted. Does it take awhile? Edited February 18, 2017 by cspirou dobl post Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted February 18, 2017 Report Share Posted February 18, 2017 (edited) Its there now, I put it in the wrong place Edited February 18, 2017 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
sbelyo Posted February 19, 2017 Author Report Share Posted February 19, 2017 Can you configure it for more than one output? Quote Link to comment Share on other sites More sharing options...
cspirou Posted February 20, 2017 Report Share Posted February 20, 2017 (edited) The output is just a straight connection, no switches. I would just add another pair on the panel in parallel. Edited February 20, 2017 by cspirou Quote Link to comment Share on other sites More sharing options...
jose Posted February 20, 2017 Report Share Posted February 20, 2017 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? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted February 20, 2017 Report Share Posted February 20, 2017 2x is just fine for this Quote Link to comment Share on other sites More sharing options...
jose Posted February 20, 2017 Report Share Posted February 20, 2017 Thanks Dr. Gilmore Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted February 21, 2017 Report Share Posted February 21, 2017 found an error with the input board, fixed and updated Quote Link to comment Share on other sites More sharing options...
sbelyo Posted February 21, 2017 Author Report Share Posted February 21, 2017 Can you take a look and make sure I have all the right gerber files for these boards Thanks Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted February 22, 2017 Report Share Posted February 22, 2017 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 Quote Link to comment Share on other sites More sharing options...
congo5 Posted February 23, 2017 Report Share Posted February 23, 2017 (edited) 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, 2017 by congo5 change schematic Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted February 23, 2017 Report Share Posted February 23, 2017 That schematic does not match the current board Quote Link to comment Share on other sites More sharing options...
congo5 Posted February 23, 2017 Report Share Posted February 23, 2017 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. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted February 23, 2017 Report Share Posted February 23, 2017 the board is the dual servo one, I thought I published the final schematic, will have to look Quote Link to comment Share on other sites More sharing options...
congo5 Posted February 23, 2017 Report Share Posted February 23, 2017 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. Quote Link to comment Share on other sites More sharing options...
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