Vivaldi External Clock Setting for Mutec Ref10

[Jack]

Hi,

I’m experimenting with adding a Mutec Ref10 SE120 as the clock reference for the Vivaldi Clock. The Mutec spec lists square wave output at 75ohm but when I configure the Vivaldi Clock reference setting to TTL it has no lock to the Mutec. Changing it to AC then it locks with no issue.

Tested two 75ohm clock cables (a Van Damme and an Audioquest) with the same result. Wonder if anyone has similar experiences or know if TTL or AC is the correct setting for the Mutec?

Thank you!

[meltemi (Martin)]

Mutec specifies its outputs as square wave @ 2Vpp.
TTL would require a higher voltage level (up to 5V).
So AC is likely to be the correct setting.

[Jack]

Ah I see. Thanks Martin for the insight.

[Ermos (Erno)]

@Jack

TTL or AC

Add 10mhz clock : sin wave or square wave?

It’s on Page 13 of the Vivaldi Clock Manual; [dCS Clock Manual PP13] The “TTL” (Transistor-Transistor-Logic) is in reference to Square wave reference clock input signal, while the “AC” is in reference to a Sine wave reference clock input signal. An impedance mismatch of a 50Ohms clock output to the 75Ohms dCS reference clock input is liable to work unpredictably, especially given the relatively high frequency of 10MHz, I expect there’ll be lots of reflections in the signal.

[meltemi (Martin)]

@Add 10mhz clock : sin wave or square wave?

An impedance mismatch of a 50Ohms clock output to the 75Ohms dCS reference clock input is liable to work unpredictably

On Mutec Ref10 SE120 only use the 75Ω outputs (outputs 3 to 8)! Outputs 1 & 2 are 50Ω outputs.

[Jack]

Yes, I’m using the 75ohm output for the Vivaldi clock so the impedance is matched. The reason why TLL doesn’t work is likely due to the voltage level difference as Martin pointed out.