Hi guys.
After a request on another thread
Have had a listen to both, the Mojo and the BTR5 as pre's.
Chain was Tidal exclusive mode on Surface Pro 7 > USB to Mojo/BTR5 > 3.5 to RCA cable > Audio GD R28 > XLR out to the Quad Era-1.
Mojo on Line out (3V)
BTR5 on H-gain at Volume level 60/60
First of all, what a pleasure to listen to both.
Volume on the R28 is set to my preferred listening levels in both cases.
Level matched by ear.
Mojo -> R28: Volume level at 65 out of 99, which is about 7.5% power output of the R28.
BTR5 -> R28: Volume level 75 out of 99, which is about 16.5% power output of the R28.
My guess is that the BTR5 puts out around 1.4V to 1.5V to the RCA-input of the R28.
Verdict is, that it works pretty well in both configuration.
Make sure that your amplifier has enough headroom when feed with the BTR5.
The thing is that the amp has to amplify ^^ the missing output power of the BTR5 in comparison to the Mojo, which throw 3V to the amp. (Industrial standard is 2V)
When the Mojo is set to 2V manually, the difference wouldn't be that much, i think.
I've to say that from level 55 to 60 (coupled with the R28) on the BTR5 it's a hugh jump in volume, but w/o any deterioration in sound quality.
Have a great day and keep listening to good music.
Chris
P.s.
As a pre-amp, the BTR5 stays quite cool instead of heating up when a headphone is connected.