Hi all,
I have two tonearms on my turntable; I used to swap cables but now I'm tired. I want to add a switch to my pre-amplifier which controls the two phono inputs: One directly from a MM cartridge, the other from the tube head-amplifier (pre-pre-amplifier).
What do you people suggest for this plan? Too much signal degradation? Which switches are suitable for this process? I can either use a quality Seiden/Elma rotary switch or a toggle switch. Which one gives the best quality?
Any input will greatly appreciated.
Regards,
Firat.
I have two tonearms on my turntable; I used to swap cables but now I'm tired. I want to add a switch to my pre-amplifier which controls the two phono inputs: One directly from a MM cartridge, the other from the tube head-amplifier (pre-pre-amplifier).
What do you people suggest for this plan? Too much signal degradation? Which switches are suitable for this process? I can either use a quality Seiden/Elma rotary switch or a toggle switch. Which one gives the best quality?
Any input will greatly appreciated.
Regards,
Firat.
If I was doing this,
I would not use switches. I would use audio grade relays and switch them from the rotary switch using pure regulated DC. To reduce the possibility of pick up from the relay coils. The type of relay is Very important (BT type silver nickel contacts) or better. Don't use a change over type for the two signals use two relays one for each input. Make sure the input is not left floating use a grounding resistor for each input (left right). put a diode across the relay coils in reverse (blocking) to catch the EMF from the coils. The relays could be mounted in a screening can (box) to eliminate pick up.
NB if you are switching between a pre-pre and direct what about the RIAA Eq?
I might even mute the signal output during switch over.
Regards
M. Gregg
I would not use switches. I would use audio grade relays and switch them from the rotary switch using pure regulated DC. To reduce the possibility of pick up from the relay coils. The type of relay is Very important (BT type silver nickel contacts) or better. Don't use a change over type for the two signals use two relays one for each input. Make sure the input is not left floating use a grounding resistor for each input (left right). put a diode across the relay coils in reverse (blocking) to catch the EMF from the coils. The relays could be mounted in a screening can (box) to eliminate pick up.
NB if you are switching between a pre-pre and direct what about the RIAA Eq?
I might even mute the signal output during switch over.
Regards
M. Gregg
Last edited:
Something like that:
Input Source Selector DIY Kit 4 to 1 Way 4 Channel Selection Stereo | eBay
Audio Input Selector Relay Board with 12V Regulator | eBay
One of the signals is MM; the other is MC with a head amplifier (which is amplified to MM level). So basically two MM inputs. I'll switch them at closest point to RCA inputs, output of the switch is connected to RIAA.
Regards
Input Source Selector DIY Kit 4 to 1 Way 4 Channel Selection Stereo | eBay
Audio Input Selector Relay Board with 12V Regulator | eBay
One of the signals is MM; the other is MC with a head amplifier (which is amplified to MM level). So basically two MM inputs. I'll switch them at closest point to RCA inputs, output of the switch is connected to RIAA.
Regards
Remove the terminal blocks and use solder pins made from good quality copper or silver plated copper wire. So you have soldered joints to the phono sockets. Make sure you keep the earth side of the sockets isolated from the box so they go straight from input to output and ground the box to the preamp or power Gnd. You don't want the box ground linked to signal Gnd.
NB make sure the power to the relay coils is smooth.
Regards
M. Gregg
Last edited:
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