Hello All,
I have a tube 3 12 ax7 phono RIAA with a cathode follower final stage, followed by Goldpoint 23 kohms resistor volume control (Holco resistors) and selector switch.
It is driving my Belles MB200 power amplifiers which have a 100 kohms input impedance .
Interconnect is the Nordost Red Dawn 1,5 m.
Is it a good impedance match?
I am considering potentially changing the volume control with transformer volume control (SAC Thailand STA 522 or Music First).
Any recommendation are highly appreciated.
Thank you
I have a tube 3 12 ax7 phono RIAA with a cathode follower final stage, followed by Goldpoint 23 kohms resistor volume control (Holco resistors) and selector switch.
It is driving my Belles MB200 power amplifiers which have a 100 kohms input impedance .
Interconnect is the Nordost Red Dawn 1,5 m.
Is it a good impedance match?
I am considering potentially changing the volume control with transformer volume control (SAC Thailand STA 522 or Music First).
Any recommendation are highly appreciated.
Thank you
Depends on the tube, but generally quite high unless a high power device. Certainly a 12AX7 is a low current tube and can't compete with solid-state buffers unless in a feedback loop. Buffering takes the load from the tube and may improve its linearity. With a buffer you can use lower pot values if you want too, passive controls are always rather a compromize. Not many amplifiers give data on their distortion sensitivity to source impedance - the datasheet will show the values for when driven from a low impedance source.
And I answered that. Then you asked me ‘shall I change it?’ I don’t know what you’re going to do, or why you’re asking me.
Everyday again I am surprised that questions are being asked with a description of a circuit instead of a schematic. Really, that sign language has been invented to enable clear communication.
If the attenuator has a high output impedance like that the logarithmic transfer characteristic is changed. I would say not a big deal, you adjust the volume to what you need. The attenuator still attenuates between 0 and 100%.
The impedances are a bit high to my liking for transferring a signal over cables. But hey, if you have the correct input and output impedances you might run the risk of not hearing cable effects. And that is against audiophile policy.
If the attenuator has a high output impedance like that the logarithmic transfer characteristic is changed. I would say not a big deal, you adjust the volume to what you need. The attenuator still attenuates between 0 and 100%.
The impedances are a bit high to my liking for transferring a signal over cables. But hey, if you have the correct input and output impedances you might run the risk of not hearing cable effects. And that is against audiophile policy.