Holo Audio Serene Preamplifier

[justthemusic]

4 hours ago, happybob said:

And to add to what Fourlegs said about the DC4 LPS being more significant than the MScaler when added to Dave: if you enter the realm of PGGB upsampling (highly recommended) then there is no longer a need for an MScaler at all (except for streaming music - and even that could change relatively soon). PGGB goes way beyond (in a good way) what the MScaler can do, but for now it only works with downloaded files with offline upsampling. The combo of a Dave with a DC4 LPS and PGGB 16FS upsampled files is quite compelling - but who's to say this beats the Holo May? Would be a great direct comparison!

 

Though I was not aware of PGGB until learning of it here recently and doing some subsequent reading, am I wrong to assume that other DACs besides Chord Dave could benefit from it similarly? Is the Dave designed in such a way as to benefit more so from this offline upscaling process than other DACs? Holo May, among others, are mentioned in the literature on the PGGB website as well, so it may not necessarily be a check mark in the Dave column in a direct comparison.
 

If upscaling is going to be part of the signal chain, high end DACs do seem to benefit from offloading this processing to upstream hardware or software. The chip-based upscaler in Holo May was maybe more of an afterthought given the relative strength of its non-oversampling modes. I have not heard the Dave / DC4 / PGGB combo, and I don’t doubt the experienced ears here that it sounds terrific or that the PGGB filters could make the MScaler superfluous.

 

Getting back to the pre-amplifier topic, and specifically Serene, I do wish for simplicity’s sake and for shorter signal paths that more top level DACs had analog attenuators built in (or at least properly implemented non-destructive volume controls). The lack of such appears to be a technical hurdle of R2R DACs such as Holo May. One slightly less polished aspect of the May is that it ships with the same remote as the Serene preamplifier except for that the volume up / down buttons do not function.

 

 

[Fourlegs]

37 minutes ago, happybob said:

Very interesting! I've not yet tried HQP, but have compared MScaler to PGGB and PGGB is a lot better than the MScaler with my Chord Dave. I know Audiobacon did an HQP vs Chord MScaler and found he liked the MScaler better https://audiobacon.net/2021/03/17/hqplayer-better-than-a-5000-upscaler/. Lots of variables of course...

 

@goldenone it would be really great if at some point you can compare HQP to PGGB - perhaps with a Holo May and also ideally a Chord Dave with Sean Jacobs DC4 LPS.

I have been discussing with Sean and we will hopefully make your wish come true for @GoldenOne to be loaned a complete DC4 Dave (and an SRC.DX for good measure) . . . . . . 

[justthemusic]

1 hour ago, Fourlegs said:

I have been discussing with Sean and we will hopefully make your wish come true for @GoldenOne to be loaned a complete DC4 Dave (and an SRC.DX for good measure) . . . . . . 

Looking forward to @GoldenOne’s feedback if/when this comes to fruition!

[Zaphod Beeblebrox]

7 hours ago, justthemusic said:

Though I was not aware of PGGB until learning of it here recently and doing some subsequent reading, am I wrong to assume that other DACs besides Chord Dave could benefit from it similarly? Is the Dave designed in such a way as to benefit more so from this offline upscaling process than other DACs? Holo May, among others, are mentioned in the literature on the PGGB website as well, so it may not necessarily be a check mark in the Dave column in a direct comparison.
 

If upscaling is going to be part of the signal chain, high end DACs do seem to benefit from offloading this processing to upstream hardware or software. The chip-based upscaler in Holo May was maybe more of an afterthought given the relative strength of its non-oversampling modes. I have not heard the Dave / DC4 / PGGB combo, and I don’t doubt the experienced ears here that it sounds terrific or that the PGGB filters could make the MScaler superfluous.

ted_b had asked a similar question and I responded  here: 

 

[GoldenOne]

8 hours ago, Fourlegs said:

I have been discussing with Sean and we will hopefully make your wish come true for @GoldenOne to be loaned a complete DC4 Dave (and an SRC.DX for good measure) . . . . . . 

If this is possible that'd be absolutely awesome!
Would love to do a video on it.

Shoot me a DM And let me know what's needed to make it happen. Thank you!

[Fourlegs]

@GoldenOne Done.

[Buffdriver]

So does KTE May DAC have sufficient output (5V I believe) to skip Serene preamp and go direct to good power amp (say 30W/ch tube amp) if I don't require any other source material (i.e. phono). Sort of asking previous question on this thread, but answer didn't seem clear enough to me.  What spec should I be concerned with on the power amp to be sure.  I will be running very efficient speakers (97dB) that have active bass drivers (Spatial Audio X5).  

Thank you.

[GoldenOne]

3 minutes ago, Buffdriver said:

So does KTE May DAC have sufficient output (5V I believe) to skip Serene preamp and go direct to good power amp (say 30W/ch tube amp) if I don't require any other source material (i.e. phono). Sort of asking previous question on this thread, but answer didn't seem clear enough to me.  What spec should I be concerned with on the power amp to be sure.  I will be running very efficient speakers (97dB) that have active bass drivers (Spatial Audio X5).  

Thank you.

It'll depend on the gain of your amp. Almost certainly yes but then you have no vol control

[John Hughes]

I think it does.  I have both a VTV Purifi amp and an Orchard Audio Starkrimson.  Both seem to be driven very well by the May.  I do want to try a good preamplifier though.  I use Roon for volume control. 

[GoldenOne]

It's often better not to use dsp vol control as you end up sacrificing dynamic range. Whereas a preamp like the serene will have much higher effective dynamic range (I believe its 147dB for the may). Meaning with most dacs you can attenuate by 20dB+ before you actually start losing any dynamic range across the whole system. 

 

Whereas with dsp vol control you're losing it immediately. 

[John Hughes]

Have you seen this analysis of Room volume control?  BTW, I started the original thread on Roon's website :)  Looks to be better than we though.  I would like to try the Serene though. 

 

https://www.audio “science” review/forum/index.php?threads/the-final-truth-about-dsp-volume-control-in-roon.23552/

[GoldenOne]

I did a brief comparison of a few vol control options a while ago. 

 

Any dsp vol control will reduce dynamic range Inherently. 

 

 

Pay attention to 'dynamic range' row. 

 

Roon, hqp and adi-2 dsp all lose 15dB of dynamic range. Meanwhile goldpoint preamp or adi-2 ref level adjustment do not

 

 

[Quadman]

40 minutes ago, Buffdriver said:

What spec should I be concerned with on the power amp to be sure

Look at the amplifiers gain and sensitivity, mine are about 26db gain (anything above 25 db should be fine) and about .8 volts for sensitivity (.8 volts input equals full power output) and that should work fine with Holo May. I use HQplayer as my up sampling software AND volume control.  Although with some older recordings when I up sample to DSD, I am cutting it close and sometimes run out of volume.  DSD reduces output by 6 dB compared to PCM (1/2 less output voltage), plus in HQP I set max volume to -4 dB to avoid digital clipping.  Hence on older less loud recordings I can run out of volume.  For 95% of what I listen to it is fine and I have no issues.  That said I run single ended which outputs 1/2 the voltage of balanced output on the May, so if you run balanced you should be good, minding the 2 parameters I mention.

[Buffdriver]

Thank for all the useful feedback.  

[scintilla]

I found that the gain structure of my May to amp wasn’t enough with an agressive RC filter that I use to integrate a subwoofer with my full rangers. So I just ordered a Serene. I’m certain that will fix my issues and remain completely transparent. 

[Buffdriver]

After reading all the replies I am considering that also, or a good integrated amp.

Thank you 

[lpost]

Serene on the way to compliment May and compare to BHK preamp with a very nice set of Telefunken ECC802S.

 

Thanks for the heads up on the pricing increase. Just snuck in under the line.

[Hish]

I just received my Serene KTE and May DAC KTE. Absolute beauties! I do have one question though. I originally setup the Serene using the XLR 2 output (40 ohm impedance) feeding my Krell EVO 3250 amp (which powers my Monitor Audio PL 300 floorstanding speakers). With this setup, the speaker volume was really low compared to my previous preamp (Classe CP-800 with 300 ohm output impedance). I had to go to volume -25 on the Serene before hearing anything through the speakers. When I switched the Serene to XLR 1 output (3 ohm impedance), the volume increased significantly. I know the two XLR outputs have different impedance but the Krell amp input impedance is supposedly 100,000 ohm so there should not be this huge a difference (or should there?). 

 

Is there something I am missing? I would prefer to use XLR 2 output so I can keep the XLR 1 output for my headphones. 

 

Any comments/suggestions would be greatly appreciated! Thanks! 

[lpost]

On 7/16/2021 at 5:21 PM, GoldenOne said:

I did a brief comparison of a few vol control options a while ago. 

 

Any dsp vol control will reduce dynamic range Inherently. 

 

 

Pay attention to 'dynamic range' row. 

 

Roon, hqp and adi-2 dsp all lose 15dB of dynamic range. Meanwhile goldpoint preamp or adi-2 ref level adjustment do not

 

 

 

With any sort of DSP (convolution in my case) performed in HQPlayer some headroom is required to prevent intersample overs and Jussi recommends a minimum -3dB regardless. It seems there is no way to get around some the dynamic range reduction. Since CD 16-bit is only capable of ~96dB range is there any significance to 104dB vs. 120dB in practice?

 

Have you measured the Serene or has some one with comparable data to the table above?

[John Hughes]

This!  I use a speaker eq in Roon and have to cut the gain about 6db  in order to not overload the digital signal. So that is why I don't have a problem using Roon to do my volume control as well. And I personally love this choice over the other solution of a passive crossover in my speakers :)

[Hish]

@GoldenOne Hello sir! I’m hoping for your input on the following:

 

I just received my Serene KTE and May DAC KTE. Absolute beauties! I do have one question though. I originally setup the Serene using the XLR 2 output (40 ohm impedance) feeding my Krell EVO 3250 amp (which powers my Monitor Audio PL 300 floorstanding speakers). With this setup, the speaker volume was really low compared to my previous preamp (Classe CP-800 with 300 ohm output impedance). I had to go to volume -25 on the Serene before hearing anything through the speakers. When I switched the Serene to XLR 1 output (3 ohm impedance), the volume increased a bit but is still a lower than my old preamp. I know the two XLR outputs have different impedance but the Krell amp input impedance is supposedly 100,000 ohm so there should not be this huge a difference (or should there?). 

 

Is there something I am missing? Is the Serene output just lower (hence lower output volume). I would prefer to use XLR 2 output so I can keep the XLR 1 output for my headphones. 

 

Any comments/suggestions would be greatly appreciated! Thanks! 

[GoldenOne]

14 hours ago, Hish said:

@GoldenOne Hello sir! I’m hoping for your input on the following:

 

 

I just received my Serene KTE and May DAC KTE. Absolute beauties! I do have one question though. I originally setup the Serene using the XLR 2 output (40 ohm impedance) feeding my Krell EVO 3250 amp (which powers my Monitor Audio PL 300 floorstanding speakers). With this setup, the speaker volume was really low compared to my previous preamp (Classe CP-800 with 300 ohm output impedance). I had to go to volume -25 on the Serene before hearing anything through the speakers. When I switched the Serene to XLR 1 output (3 ohm impedance), the volume increased a bit but is still a lower than my old preamp. I know the two XLR outputs have different impedance but the Krell amp input impedance is supposedly 100,000 ohm so there should not be this huge a difference (or should there?). 

 

Is there something I am missing? Is the Serene output just lower (hence lower output volume). I would prefer to use XLR 2 output so I can keep the XLR 1 output for my headphones. 

 

Any comments/suggestions would be greatly appreciated! Thanks! 

There definitely shouldn't be any volume difference between XLR-1 and XLR-2

In regards to your old preamp, it'll depend on how much gain your old preamp had. The serene deliberately focuses on attenuation and low level performance, not gain, because with most dacs nowadays you don't need any additional amplification.

It can go up to +6dB gain though.

[Hish]

@GoldenOneThank you for the input!

 

 I guess then I may have a defective unit… I ran a little test where I set the Serene to -25dB and played the same song (source is a Bryson bdp-2 player) through xlr 1 and then xlr 2 output and measured output with an spl meter. Xlr 1 output had a peak of 67dB while xlr 2 was at 51dB! Maybe I need to burn in the xlr 2 output longer (the unit is brand new)?
 

I messaged Tim at Kitsunehifi and he mentioned some amps pair better with the lower impedance out of xlr 1. As you mentioned earlier though, I don’t expect this much of a difference between the outputs (simply because of the impedance difference). 
 

I assume you have not seen this volume difference between the two xlr outputs feeding your speakers? 
 

thanks!! 

[GoldenOne]

6 hours ago, Hish said:

@GoldenOneThank you for the input!

 

 I guess then I may have a defective unit… I ran a little test where I set the Serene to -25dB and played the same song (source is a Bryson bdp-2 player) through xlr 1 and then xlr 2 output and measured output with an spl meter. Xlr 1 output had a peak of 67dB while xlr 2 was at 51dB! Maybe I need to burn in the xlr 2 output longer (the unit is brand new)?
 

I messaged Tim at Kitsunehifi and he mentioned some amps pair better with the lower impedance out of xlr 1. As you mentioned earlier though, I don’t expect this much of a difference between the outputs (simply because of the impedance difference). 
 

I assume you have not seen this volume difference between the two xlr outputs feeding your speakers? 
 

thanks!! 

The outputs are all from the same amp. It's not separate output stages or anything. The only difference is that xlr-1 doesn't have the load resistors (put on most dacs/preamps outputs to offer protection in the event of a short). 

 

If there is a volume difference it'd be something to do with your amp, not the preamp. 

Do you have another amp you can test with? 

 

[Buffdriver]

If Hish did not change the XLR inputs to his amp (assuming they may only have one input pair) then the amp wouldn't know which XLR out he chose.  Would it be that sensitive to the load resistance at the preamp output?