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25th February 2010
| #211 |
| Gear nut Join Date: Dec 2008
Posts: 103
| Hi All, The past tuesday i brought the mixer to a technician. Maybe he founds the origin of the ground loop. It is not that easy to build audio gear and make it work  ...At least all circuits receive current properly and resistors and capacitors run cold. Another issue is the LCR switch, which works good at center or left position on some channels but not at right position. (and viceversa). I think it is due to the resistors. Although 1% tolerance, i think slight mismatches can degrade performance, and this is true (i think) also for the summing network. Maybe a balanced panpot is an alternative, i have enough space in the box. Also i want to paint it in that SSL white slightly grey color....  JAY X |
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25th February 2010
| #212 |
| Lives for gear Join Date: Sep 2004 Location: UK
Posts: 4,567
| Hi The tolerance of 1 percent resistors will not cause that much grief, you have wired something incorrectly. Matt S |
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25th February 2010
| #213 |
| Gear nut Join Date: Dec 2008
Posts: 103
| Hi Matt, I feel better now.  I will re-check these circuits.JAY X |
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5th June 2010
| #214 |
| Gear nut  Join Date: Mar 2010
Posts: 97
| Douglas Self Delasoul: So far Douglas Self's Small Signal Analysis has been the best audio electronics book I've been able to find. I also have his Power Amplifier Handbook but I'm finding Small Signal to be a better read. Probably because I'm more interested in recording gear than amplifiers. Amazon.com: Small Signal Audio Design (9780240521770): Douglas Self: Books
__________________ And I always thought negative feedback was a bad thing. |
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15th September 2010
| #215 |
| Lives for gear Join Date: Jul 2002
Posts: 742
| If I'm understanding this correctly, because the opamps is inverting the input, the transformer is needed to correct the phase. The positive side would go the the negative of the primary of the transformer and vica versa. Is this correct? Also, for a 4 channel summer would I up the input resisters to 44K? |
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15th September 2010
| #216 |
| Lives for gear Join Date: Sep 2004 Location: UK
Posts: 4,567
| Hi The transformer is a convenient way to correct the phase although if you build te thing 'balanced' you could just swap the wires over. No for any number of channels the input resistors stay the same value as do the feedback resistors unless you want the thing to lose gain. Matt S |
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