Installing an auxiliary input into the main channel of my analog console.

[skippy]

<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman" size=3>Hi folks,</FONT></P>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman" size=3>I am thinking of installing an auxiliary input into the main channel of my Lowrey H25R2 and my Thomas Celebrity 871. It should be easy enough on the Thomas since the audio signal input into the main channel amp is just a plain old RCA connection. A RCA double adaptor should do the trick. If I was to connect a keyboard to the old analog beast to utilise its more realistic rhythms would it be better to use the line out connections or the phones connection. And there is the issue of stereo to mono. Is it safe to use stereo to mono adaptors?</FONT></P>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman" size=3>I know that the audio signal going into the organ amp is the result of a mix of different pre-amps. Could the extra signal cause damage to these pre-amps or generally interfere with the electronics of the organ?</FONT></P>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman" size=3>Your comments are most welcome and appreciated.</FONT></P>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman" size=3>Skippy</FONT></P>

[fredy2]

Re: Installing an auxiliary input into the main channel of my analog console.



DO NOT USE A WYE ADAPTER !!!!!! You would have the same effect as trying to parallel two gas generators... The driving electronics in the organ and your external device will fight each other, possibly doing damage, but certainly causing distortion.</P>


If you want to inject signal you need to use a mixer that ADDS the signals together. You might get away with a simple resistive mixer, although it would disturb the audio level coming from the organ portion a bit.</P>


ALSO be concerned that the extra audio level COULD overdrive the amp and speakers of the organ causing distortion.</P>


Design of a resistive mixer using as few as two resistors depends on the impedance and level at the point you are injecting the external signals. A simple one would consist of a series resistor fromeach source (organ and external) going to the input of the amp.</P>


Grounding is important to not introduce noise pickup.</P>

[skippy]

Re: Installing an auxiliary input into the main channel of my analog console.

<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia">Thank You Fred.</SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia">I will ponder, digest and experiment. Nothing to lose except a zero value old relic. And here aresome sillyquestions from an old carpenter.</SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia">1. Would the use of diodes prevent the two signals fighting each other?<O></O></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia">2. Do diodes have a resistance diminishing the signal? <O></O></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia">3. I have seen adaptors that combine separate stereo left and right into mono. Are they safe to use?</SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia">I am looking forward to your valuable advice.<O></O></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia"><O></O></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia">Have a musical day,</SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Georgia">Skippy<O></O></SPAN></P>

[kkeys]

Re: Installing an auxiliary input into the main channel of my analog console.

<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-bidi-font-family: 'Times New Roman'">Use resistors as they allow unidirectional current flow. Diodes are devices which allow current flow in only one direction so they would not be suitable. Resistance would likely be very low. They require a certain amount of voltage to conduct current. </SPAN></P>
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[skippy]

Re: Installing an auxiliary input into the main channel of my analog console.

[quote user="kkeys"]
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-bidi-font-family: 'Times New Roman'">Use resistors as they allow unidirectional current flow. Diodes are devices which allow current flow in only one direction so they would not be suitable. Resistance would likely be very low. They require a certain amount of voltage to conduct current. </SPAN></P>
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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><FONT face="Times New Roman">Thanks Keith,<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></FONT></FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-AU; mso-bidi-language: AR-SA">Just the answer I was looking for. I thought that the use of diodes and their one way current flow characteristics may protect the electronics of the organ from the auxiliary input signal. Obviously not suitable.</SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-AU; mso-bidi-language: AR-SA"></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-AU; mso-bidi-language: AR-SA">Cheers,</SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-AU; mso-bidi-language: AR-SA">Skippy</SPAN></P>
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[fredy2]

Re: Installing an auxiliary input into the main channel of my analog console.



One of the resistive stereo to mono mixers might work. One can't be sure because the organ impedances presented to it might result in vastly reduced signal levels. If the circuit diagrams are available, one can easily determine the best way to work the problem.</P>


Frankly, I would first try one of the stereo to mono devices and if it works, you are done. It is UNLIKELY that it could damage anything. Use one that is NOT intended to be used with headphones, as headphones are low impedance devices.</P>


There are many types of diodes. NONE are applicable here. Some are designed as one-way devices, some as voltage regulators, and some even as noise generators and oscillators.</P>