Using a Moreplay in series with a digital attenuator (DSP)

[Hypops]

Hi folks.

I've been wanting to add a tube preamp to my system for a while now, and I've landed on building a Moreplay kit. But I've got a couple questions I hope you all might help me with. While I'm no electrical engineer, I do have some prior kits under my belt.

My current source chain goes from a DIY streamer (pi2AES) to a DSP (miniDSP Flex) to a DAC (Denafrips Ares II) to a class-D integrated (Peachtree Nova150 in power amp mode). I plan to put the Moreplay between the DAC and the amp, obviously.

My questions:

1) I currently use the miniDSP for gain/volume attenuation. Would it make sense to eliminate the volume pot from my Moreplay build rather than futz with gain staging between the two devices? If so, can I just add a resistor in place of the Moreplay's volume pot? Or is it more complicated than that? Would I be better off just keeping the build as is and manually adjusting the gain to taste/need?

2) I've read through most of the Moreplay sub-forum and came across some discussion about using another attenuator in series with the Moreplay. There were recommendations made that went way over my head about modifying the Moreplay build to better accommodate the additional attenuation component. Would this apply in my case? Or should I just "set it and forget it"?

Thanks!

 

[ccmccull]

I also have ability to adjust the signal volume digitally before the moreplay and the moreplay volume. It's no big deal, and the moreplay volume is needed if you connect analog sources later on without a volume, like a turntable and phono preamp. I'd leave it in.

On the attenuation point, there are some power amps which provide a lot of gain, to the point that the moreplay volume is only useful at its lowest few degrees of rotation. I'd recommend building the moreplay as is and see how it integrates with your power amp. If you find the more volume too touchy, you can buy an inexpensive set of RCA attenuators at that point.

 

[hmbscott]

Given that you will have two means of volume control in your chain, there's should be no issue of too much gain. The Moreplay at full volume does add about 9dB to gain (if my memory is correct). If it had no volume control, that might make controlling volume tricky for your DSP, given that it will need to reduce it's output by 9dB to achieve your current system volume. So leaving the Moreplay's volume control is an advantage for you since you can dial it back a bit if that proves to be too hot.

 

[Mucker]

Until recently I've been using a Topping E70V outputting to a Moreplay and then into a SS power amplifier. Going it without a remote was no bother for me so decided to just set run the DAC full tilt boogie into the Moreplay. What I mean by that is the E70V can be run in two different modes, DAC mode or PRE mode. DAC mode sets the DAC to constantly output full voltage (2.5V) with no ability to adjust volume. PRE mode allows variable voltage to be outputted and therefore volume control.

When running in DAC mode, the volume knob on Moreplay would never go past the 9 o"clock postion or it would be too loud. I ended up padding the resistors which worked well to gain more range on the volume knob, but not by much. There was no penalty in audio quality.

Another route I tried was to set the DAC in PRE mode and set it to -12bB. Then adjust the Moreplay volume knob to my normal listening volume. If I wanted it louder, I could use the remote increase the level toward 0dB or if I wanted it quieter reduce it toward -24dB. That way I could use the remote. Again, no penalty in audio quality was perceived.

I have since removed the padding resistors from the Moreplay and just finished building a Stereomour II integrated amp to replace the solid state amp.

So now the plan is to just leave the DAC in DAC mode at 2.5V output either going directly into the Stereomour or do the same going into the Moreplay but turn the Steremour volume to maximum while using the Moreplay to control the overall volume.

One thing to be careful with is connecting a DAC directly to a power amp. There are reports of some DAC's losing their volume settings and outputting max into the power amp on startup. Obviously, that's a very unwanted scenario.

 

[Hypops]

Awesome. Thanks, all. Sounds like the Moreplay will be easier to integrate than I thought!

 

[2wo]

My experience with Digital volume controls is, They work best at the top of their range. You Can you use The Moreplay Volume control to keep you in the sweet spot...John