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Remove resistence to A75 for unbalanced use? - Click HERE for Original Thread
Danyele82
To A75 amplifier for unbalanced use I can remove R28 , R5.
R29 and R2 can be romoved?
Danyele82
look here the circuit A75
Alain Dupont
Danyele82,

>> To A75 amplifier for unbalanced use I can remove R28 , R5.
Yes, you can...

>> R29 and R2 can be romoved?
Well, I don't think so.

For the cost of 4 resistors, 2 XLR's and 2 switches, it's a shame to
remove the Balanced inputs of the A75.!! Who knows, you'll probably
build a balanced preamp sooner or later...

PS: Now with my CCS-X-Bosoz preamp I use my A75 balanced, and I prefer this type of connections, the balanced mode has great advantages...
And using Belden 89207 twinaxial cable, its not so costly to have balanced cables..

Alain.
Danyele82
For unbalanced use the gain is determinated by (R81 + R3//R27)/(R2//R29)?
If it's right the input resistence (R4) can be eliminated (or it's necessary for the low-pass with C1)?.
The quality of C7 and C5,C6 are important to the final result?
Alain Dupont
Danyele82,

>> If it's right the input resistence (R4) can be eliminated (or it's necessary >> for the low-pass with C1)?.
>> The quality of C7 and C5,C6 are important to the final result?

Keep R4, it wont interfere in the 75 K Ohms unbalanced impedance,
but globaly there must be symetry between positive and negative input's.

Norman Thagard and Nelson Pass tells: the only requirement being that corresponding values on the positive and negative input networks be matched.

For the quality of C3,4,7 4.7uF, 16V, electrolytic
C5,6 220uF, 16V, electrolytic

I have used Panasonics, quite standard types...

Regards.

Alain.

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