Trinnov Amethyst - can it be used with a tube preamp?

[Heavy G]

I’m currently using a Trinnov Amethyst as my Roon streamer/DAC with room correction. I wanted to integrate a tube preamp in my system and was wondering if the volume control could be bypassed or if the only work around was to set the volume at 0db. My old Aesthetix Pandora had a feature where it could be set to a static output level, bypassing the volume control and be used only as a DAC within the system.

 

[NekoAudio]

There's no issue with setting the Trinnov Amethyst volume to whatever you want (it doesn't need to be 0dBFS) and then feeding the analog outputs into a separate preamp. I'm not aware of a way to "turn off" volume control. Since it is going through the Trinnov Optimizer and any other processing you have enabled anyway, I don't think there would be any particular benefit to forcing it to be 0dBFS versus some other volume level other than for convenience. In fact, if your preamp doesn't want "higher than standard" input voltage, then using something like -12dB might be better so there is headroom for any boosts from the DSP.

I think the closest you might be able to do is to configure a specific source to start with a specific volume setting (Settings > Sources), and to also specify a max volume setting (Settings > Power-on Default).

 

[7ryder]

Basically, what you really need is a tube buffer, then you'd be able to use the Amethyst's volume control. That said, many of these don't have great specs (like the cheap ones on eBay). Modwright is coming out with one shortly named the Analog Bridge. Check out this thread (skip to the last page for current info). Quick Product Poll! Tube Buffer with Volume Control?

Chris

 

[Heavy G]

There's no issue with setting the Trinnov Amethyst volume to whatever you want (it doesn't need to be 0dBFS) and then feeding the analog outputs into a separate preamp. I'm not aware of a way to "turn off" volume control. Since it is going through the Trinnov Optimizer and any other processing you have enabled anyway, I don't think there would be any particular benefit to forcing it to be 0dBFS versus some other volume level other than for convenience. In fact, if your preamp doesn't want "higher than standard" input voltage, then using something like -12dB might be better so there is headroom for any boosts from the DSP.

I think the closest you might be able to do is to configure a specific source to start with a specific volume setting (Settings > Sources), and to also specify a max volume setting (Settings > Power-on Default).

The only “Source” I use is Roon, so none of the inputs are active. I’m trying to figure out what volume setting would provide the same output voltage as a streamer without a volume control at this point. I know I can disable volume control in the Roon software (which apparently sounds better) and just use the volume on my preamp. The Amethyst is in a cabinet, so once I figure out the best volume setting on it I’ll never have to touch it.

 

[NekoAudio]

The only “Source” I use is Roon, so none of the inputs are active. I’m trying to figure out what volume setting would provide the same output voltage as a streamer without a volume control at this point. I know I can disable volume control in the Roon software (which apparently sounds better) and just use the volume on my preamp. The Amethyst is in a cabinet, so once I figure out the best volume setting on it I’ll never have to touch it.

The Amethyst setting that would provide the same output voltage as a streamer without volume control is 0dBFS but also with all of the Amethyst DSP settings at ±0dB or turned off (no room correction). Even then, different streamers output different voltages anyway.

My suggestion is to set the Amethyst at -12dB and leave it there for the Roon source. This should give you the necessary headroom for the Amethyst DSP (room correction) assuming other settings are the default. The resulting output voltage will probably be on average a little lower than what you would have gotten from a streamer without volume control, meaning you will probably need to turn up the volume knob a little bit on the downstream preamp, but that's better than if you have DSP turned on with the Amethyst volume too close to 0dBFS resulting in a distorted analog output signal.

 

[Heavy G]

Thanks, I’ll start at -12 and see how it goes. The preamp I’m considering is the Zesto Leto Ultra II. It has the option to adjust the input gain 3db, 6db and 9db. Zesto also says the preamp sounds best with the volume control between 10 o’clock and 2 o’clock. So with the Amethyst at -12db I should be able to get everything dialed in.

In terms of the Amethyst target curve, I’m thinking of starting flat (neutral) and trying different preamp tubes in the 12DW7 slot before making target curve adjustments to avoid digital clipping (although my current target curve adjustments all sit within a 1 db range).