[AnalogEuphoria]

Please don't ask...

 

[rkt31]

So the high end M scaler that I am currently working on is in a Choral (Dave) chassis. I don't know where this idea of 4M taps came from, as it's not that.
Remember, that the algorithm is way more important than the number of taps too...



So the dynamic range number is SINAD referenced to 1% THD full output, and A weighted. So that's 125dB (Mojo2) and 127 dB (TT2).
I don't do SINAD for higher levels, but I do do it at 2.5v - for Mojo 2 its 118 dB A wt. TT2 is 126 dB, A wt ref to full OP voltage.

126db sinad of tt2 at 2.5v should be one of the highest around.

 

[flyte3333]

I was thinking of the reputedly "top of the line" speaker amplifiers. Vitus Audio, Pilium, Boulder

These are 'top of the line'?

No mention of Benchmark AHB2 or Purifi (next gen of Hypex) ?

 

[ecwl]

These are 'top of the line'?

No mention of Benchmark AHB2 or Purifi (next gen of Hypex) ?

I debated whether to include Benchmark AHB2 but I haven’t had enough time to audition thoroughly. I probably should. It too uses a highly regulated switching power supply I believe.
I still haven’t heard a Purifi amp yet because of the pandemic. But definitely with Hypex amps, I find there is a loss of transient accuracy, even with nCore. Theoretically, as Rob Watts has previously pointed out, class D amps are not switching at high enough frequencies to prevent loss of transient accuracy so I suspect Purifi would be the same. But I would like to hear them first before I make an informed decision. Part of the challenge is that it’s easier to find Hypex or Purifi amp in various products but it’s hard to find a Chord Hugo2/DAVE paired with a Hypex or Purifi amp so I can hear whether I’m getting loss of transient accuracy. It took me years before I was able to test DAVE with an nCore amp and be impressed by everything except for transient accuracy.

 

[rkt31]

I use tt2 directly into ahb2 both in low gain.

 

[Another Audiophile]

@Rob Watts are the charging instructions for poly+Mojo2 the same as Poly+OG mojo? I have been using a 2.1A charger to charge the unit instead of charging the mojo and poly separately. Is that the case with the new mojo?

 

[Rob Watts]

Haha... To get @Rob Watts into a totally different topic, I was thinking more about DC servo that's in Hugo 2 and now Mojo 2.
I was thinking of the reputedly "top of the line" speaker amplifiers. Vitus Audio, Pilium, Boulder all have DC servo but have more conventional power supplies. Whereas Chord or Soulution amplifiers don't have DC servo but uses switching power supplies that are heavily regulated. Obviously, many amplifiers have conventional power supplies and no DC servo.
Presumably most high-end amplifiers have excellent power supply regulation. But I was wondering about @Rob Watts how important it is in speaker amplifiers to incorporate an extremely high regulation of DC, either with DC servo or other methods.

When I used to design analogue power amps (I started as an analogue designer) I never used analogue DC servos - as you are not actually eliminating the SQ of the capacitor, as the integrating cap has audio signal voltages across it. With my digital DC servo, the output from the analogue integrator is fed into the FPGA ADC, and that digital DC error signal is very aggressively filtered to remove audio components, so that only a DC trim is added internally.

When this system was developed for Dave, with the final version, I could switch off the digital DC servo, and there was no change in sound quality at all.

DC regulation of itself isn't important, so long as the DC offset is suitably low; but what is important is how you go about achieving this - and that's where it gets extremely difficult if you want completely transparent operation with negligible DC offset.

@Rob Watts are the charging instructions for poly+Mojo2 the same as Poly+OG mojo? I have been using a 2.1A charger to charge the unit instead of charging the mojo and poly separately. Is that the case with the new mojo?

I don't know for sure, Poly is not my project. My guess is that it should be the same, but you could email Chord support. Or simply run it and see what happens.

 

[kennyb123]

PGGB is giving me 250 million taps but I am preferring mscaler these days.

I had to chuckle at this. Like you, my preferred method of scaling has evolved though I think we are going in opposite direction. Haha. You were preferring HQPlayer when I had an M-Scaler, if I remember correctly. I eventually gained the ability to use HQPlayer but gave up M-Scaler to get there. It was a wonderful component and if I was more flush with cash and shelf space I would have hung onto it. My hope is that there will eventually be an M-Scaler 2 but with an isolated USB output that passes on no RF.

 

[GryphonGuy]

I had to chuckle at this. Like you, my preferred method of scaling has evolved though I think we are going in opposite direction. Haha. You were preferring HQPlayer when I had an M-Scaler, if I remember correctly. I eventually gained the ability to use HQPlayer but gave up M-Scaler to get there. It was a wonderful component and if I was more flush with cash and shelf space I would have hung onto it. My hope is that there will eventually be an M-Scaler 2 but with an isolated USB output that passes on no RF.

It sounds like your wish of M-Scaler 2 is happening. M-scaler is reportedly coming out at some point in a Choral case (aka DAVE shape) and may even be the much awaited DAVINA ADC/DAC since it needed an MScaler to work its magic. I'm guessing later this year for Christmas if supply chains allow.

Regards
GG

 

[rkt31]

@Rob Watts , Hugo 1 and mojo did not have hf cut filter. It was first introduced in Dave then in Hugo 2 and tt2 and now mojo 2 has by default hf filter always set on. I wanted to ask, the regular filter cuts the frequencies beyond half of sampling frequencies then how hf cut filter is different and what was the idea behind implementing it ?

 

[Progisus]

I had to chuckle at this. Like you, my preferred method of scaling has evolved though I think we are going in opposite direction. Haha. You were preferring HQPlayer when I had an M-Scaler, if I remember correctly. I eventually gained the ability to use HQPlayer but gave up M-Scaler to get there. It was a wonderful component and if I was more flush with cash and shelf space I would have hung onto it. My hope is that there will eventually be an M-Scaler 2 but with an isolated USB output that passes on no RF.

I still think hqplayer is an equal solution to mscaler. Way back when I had my first mscaler and was comparing to hqplayer, I mentioned the issues with software vs hardware. Software had the intermittent handshake issues and hardware really required the rfi mitigation either with cables, optical isolation or battery supplies. I wasn’t able to pursue those at the time so sold the mscaler and picked up the Antipodes server with embedded hqplayer. Since then I realized the simplicity of the hardware solution and was able to get the Wave cables so mscaler entered my system again. PGGB is a fantastic way to push the boundaries on multi million tap filters but unfortunately is not real time for roon. I was just preferring not switching things to PGGB for my local library. My next project is to put my components in a proper stand. This will leave space for my PGGB rig.

MSCALER: Antipodes(roonbridge)-usb-srcdx-bnc in on mscaler-dual bnc out to TT2
PGGB: Antipodes(roon/hqplayer embedded)-direct ethernet-pi4(audiolinux/naa)-usb out to TT2
This only requires switching the TT2 from bnc to usb in with the remote for A/B comparing as both can run simultaneously on the Antipodes.

 

[Rob Watts]

@Rob Watts , Hugo 1 and mojo did not have hf cut filter. It was first introduced in Dave then in Hugo 2 and tt2 and now mojo 2 has by default hf filter always set on. I wanted to ask, the regular filter cuts the frequencies beyond half of sampling frequencies then how hf cut filter is different and what was the idea behind implementing it ?

So the primary reason is the HF filter is there to help with 96/192 kHz and above recordings, as they have a lot of noise and distortion built into the recording - eliminating this improves sound quality noticeably with 192k recordings. But it also has a smaller benefit for 44.1k recordings too.

In previous implementations, I could not do an aggressive HF filter without it affecting 20kHz, and not giving a ruler flat frequency response. Some may object to that, and the engineer in me agrees (the music lover in me of course doesn't). But with Mojo 2's UHD DSP it does allow good HF filtering, and ruler flat frequency response (20Hz to 20KHz). Upon listening to the HF filter in Mojo 2, it simply sounded much better in all circumstances with it on, so I left it on all the time.

 

[rkt31]

So the primary reason is the HF filter is there to help with 96/192 kHz and above recordings, as they have a lot of noise and distortion built into the recording - eliminating this improves sound quality noticeably with 192k recordings. But it also has a smaller benefit for 44.1k recordings too.

In previous implementations, I could not do an aggressive HF filter without it affecting 20kHz, and not giving a ruler flat frequency response. Some may object to that, and the engineer in me agrees (the music lover in me of course doesn't). But with Mojo 2's UHD DSP it does allow good HF filtering, and ruler flat frequency response (20Hz to 20KHz). Upon listening to the HF filter in Mojo 2, it simply sounded much better in all circumstances with it on, so I left it on all the time.

@Rob Watts , thanks for the reply. Curious about hf noise in 192khz recordings. What could be the reason ? Is it due to poor src used for downsampling from dxd to 192khz or is due to excessive processing with 192khz ?

 

[alxw0w]

@Rob Watts
Rob I have a question regarding HF filter on Dave.

As I remember correctly you mentioned it somewhere that when using M Scaler the HF filter could be left always OFF as there is filtering already done in the MScaler. (I might be wrong)
But lately I've changed my headphones, and started doing evaluations with different settings (hf filter, crossfeed, phase etc...).
And I realized that with HF filter ON music sounds smoother (on 44.1khz).
The difference is not big (with previous headphones I couldn't spot it) but still sound especially in vocals is smoother a bit more easy going.
Vocals loose a bit of grittiness and roughens on the edges.

Is that even possible ? Or I made this in my mind ?

 

[rkt31]

@Rob Watts
Rob I have a question regarding HF filter on Dave.

As I remember correctly you mentioned it somewhere that when using M Scaler the HF filter could be left always OFF as there is filtering already done in the MScaler. (I might be wrong)
But lately I've changed my headphones, and started doing evaluations with different settings (hf filter, crossfeed, phase etc...).
And I realized that with HF filter ON music sounds smoother (on 44.1khz).
The difference is not big (with previous headphones I couldn't spot it) but still sound especially in vocals is smoother a bit more easy going.
Vocals loose a bit of grittiness and roughens on the edges.

Is that even possible ? Or I made this in my mind ?

As per my memory, rob told to use hf filter in on position with m scaler, even if source is cd quality.