Topic: Optimal way to connect computer > ADI-2 Pro Fs > Tube amp.

Thank you for reading and providing me with some advice.

I purchased an ADI-2 Pro Fs and a tube amp for my 300ohm headphones (ZMF Verite closed back). The audio source is my computer. Currently have the computer plugged into the USB on the ADI-2, set the ADI-2 to auto mode (USB active), and then using dual TS to RCA cables to send audio from the 1/2 TS output to the tube amp RCA input.

This set up is currently working without any issues. However, I'm not sure what other settings I should be using or if this is the most optimal connection path. Before purchasing the ADI-2, I thought it would be best to use "Pass thru" mode, but no audio is sent out of the TS 1/2 connection in this mode (no audio at my tube amp). I do not need the TRS jacks in the front for any other headphones.

AD/DA Source is auto.
Ref Level for output 1/2 is Lo-Power
Auto Ref Level is ON
Width = 1.00
M/S-Proc is OFF
Crossfeed is OFF
DA Filter is SD Sharp
De-Emphasis is Auto

Course Clock is INT

Re: Optimal way to connect computer > ADI-2 Pro Fs > Tube amp.

But why use that tube headphone amp at all? Your ADI has a perfect headphone amp, and adding anything will only degrade the sound quality.

RME ADI-2 DAC fs, Quad 606-2 power amp, Quad 2805 speakers, B&W PV1d sub with Antimode 8033 Cinema

3 (edited by cmadi 2020-11-18 00:48:23)

Re: Optimal way to connect computer > ADI-2 Pro Fs > Tube amp.

Tube amps have a unique sound that I enjoy. This is also an endgame exceptional tube amp (much higher cost than the ADI-2 Pro FS BE).

Re: Optimal way to connect computer > ADI-2 Pro Fs > Tube amp.

I am not sure about anything specific for tube amps, however, if you set the RME unit to 'Basic mode Auto' or 'DAC' then the rear TRS outputs will send audio to your tube amp (you may need TRS/RCA push-in adaptors) using RCA analogue cable.

You will have to decide which volume control (tube amp or RME) that you wish to use, there are other threads which discuss the pros/cons of each.

I have personally done as I'm suggesting here using a class A (not tube) headphone amp that I also have, and it works fine. I am still not sure however, whether the result is any better than using the RME headphone amp directly, in my case it sounds the same.

RPi4 | RME ADI-2 Pro FS R BE | Senn HD600 | Tisbury Mini Pre | Teddy Pardo i80d | Naim SBL

5 (edited by KaiS 2020-11-20 17:42:01)

Re: Optimal way to connect computer > ADI-2 Pro Fs > Tube amp.

As almost all tube amps have a passive volume control immediately at the input, they do not work input level dependent.

This means, it doesn't matter if you use ADI-2's volume control or the one built in the tube amp - the "tube effect" result is the same, as both volume controls are located at virtually the same position in the signal chain.

To maximize ADI-2's dynamic range (S/N ratio) it's best to have its volume control set to 0 dB.

So:
• Set tube amp's volume control at middle position or some above.
• Switch Off ADI-2's "Auto Reference Level".
• Set ADI-2's volume control to 0 dB.
• Select the reference level that fits best to your loudness demands.
• Use the tube amp's volume dial to control the final loudness.

• Once you start to use any of ADI-2's DSP functions like e.g. the EQ, compensate possible level boosts with ADI-2's volume control until the Level Meter does not show overs.