[sayh]

Hello,

Recently I ordered a Master 1 preamp to try in my system.  I own a Ref 7 DAC with version 3 of the DSP-1, so I also ordered a version 5 of the DSP-1 to toss in when shipping the preamp.  Are there any directions on-line for swapping out the DSP-1 units?  It looks like a number of people have done it, but if there are any helpful tips I should be aware of I would appreciate knowing them.

Thank you,
Alan

Just take note the correct position to unplug v3/ plug in v5, and the settings of the dip switches and jumpers between the 2 to be same.

If you are sure what you are doing, you may set it the way you want.
http://www.audio-gd.com/Pro/dac/DSP1/DSP1ENspecs.htm

 

[kschiu]

em... a new "Master 7".  I wonder what the difference is.

 

[RedBull]

Same analog section, but can accept higher rate digital input, especially USB

 

[kschiu]

Looks like there is no more jumpers for DSP1 ...
 

 

[RedBull]

Maybe Kingwa cannot find Audiophile grade jumper, he completely remove it

 

[Kingwa]

Still have the jumpers setting for different options.
http://www.audio-gd.com/Master/Master-7/M7EN_Use.htm

 

[lmswjm]

When running the 7.1 in NOS mode, is it recommended to leave the PLL setting, Digital Filter Stopband Attenuation, and Data Dithering functions at their default settings?

 

[Kingwa]

In NOS model, the digital filter will stop running so there is no attenuation  for setting .

 

[ccschua]

does the USB comes with galvanic isolation, meaning if using cheap usb cable and computer, the ground is isolated.

 

[doobooloo]

The Master 7 couldn't join the party, but here goes!
 

 
From left to right...
 
Phoenix, new version (click buttons and 3 feet)
Phoenix, old version (rotary dials and 4 feet)
On top of the Phoenixes: NFB-1WM
 
Modified Reference 1 with DSP v5 at the bottom
Reference 7 with DSP v5 in the middle
Neko Audio D100 v2 on top
 
DI-DSP with PSU on front
Squeezebox Touch with Enhanced Digital Out (files are all FLAC)
Kramer VS-4X passive quad XLR input selector
Silver box in cable bunch: Mini-circuits ZSC-4-1-75 BNC splitter
 
Reference 7.1 with DSP v5 at the bottom
NFB-1ES on top
 
Master 5 on the far right

---

 
 
Since this is just a comparative testing rig where I attempt to discern the differences in sonic signatures among DACs and amps, and given my lack of trust in my own auditory memory, I put the ability to quick-toggle sources first and foremost for easy comparison. Given that this adds a few extra pieces in the signal chain (BNC splitter on the digital side, XLR input selector on the analog side) I decided not to fool myself into thinking that expensive high quality cables would make a difference in this exercise. Well, financial reasons played a part too, but I'd like to think it was for a more noble reason.
 
Also, my initial plans were to use an ACSS based connection on the analog side, but I got too lazy to solder 4 pairs of mini-XLR jacks on the cables so I stuck with traditional balanced out. Then I thought, this might be more interesting as this uses more of the DAC's analog output circuitry and hence perhaps is more telling of the differences in the DACs. Perhaps another justification, but whatever.
 
Anyway... some impressions to come shortly! But keep in mind... my impressions will be very subjective, personal, and done under subpar conditions.

 

[FauDrei]

 
...and I thought I was A-GD fanboy...

 

[doobooloo]

Shoot, I wrote a lengthy initial impressions message and I accidentally went into Chrome developer/debug mode and the whole thing disappeared... 

 
So, here's a much shorter version. Compared the NFB-1ES with the three Ref series DACs through the Master 5 driving HD-800 headphones.
 
1. Ref 7.1 sounds full, lifelike, with the widest soundstage and great bass texture. Compared to other DACs, this makes me feel like I'm actually at the performance, whereas the others lack the depth and consequently sound like recordings.
2. NFB-1ES and Ref 7 share a similar tone, sounds nasal and compressed in comparison to the Ref 7.1.
3. Surprisingly the old Ref 1 is closer to the Ref 7.1 in tone and therefore things sound more real and natural, but the Ref 7.1 surpasses the Ref 1 in soundstage, bass depth, and overall fullness of sound.
4. NFB-1ES's bass is especially poor compared to the PCM1704 DACs. Quantity wise it is lacking; more importantly, however, it sounds monotonic and uninvolving. There's something odd about the decay, I think, that makes it sound unnatural. On the Ref 7.1, deep contrabass notes or bass drum of orchestras sound very real and lifelike, but on the NFB-1ES, they sound muffled and distant. Then I thought, perhaps on electronic/synthetic music, the NFB-1ES may fare better. Turns out, even with electronic music, the PCM1704 series still outdo the NFB-1ES in terms of impact and smoothness of bass notes.
5. Not much stood out in terms of difference in treble. Not sure if this is because of cheap cabling. The midrange tone and timbre were very apparent, though as mentioned above.
6. Perhaps I thought the "fullness" of sound and the stronger bass response of the Ref 7.1 was from a higher volume output. So, I tried comparing with the Ref 7.1 volume lowered by a notch compared to everything else. However, this did not change my impression of superiority of the Ref 7.1 in tone/timbre, soundstage, and bass depth and texture.
7. So far, I would rank the DACs in the following order: Ref 7.1 > Ref 1 > Ref 7 > NFB-1ES.
 
Sorry, I wish my earlier impressions post survived the web browser disaster...

 

[Kingwa]

For the digital source SPDIF output can't use the BNC split , the standard design of the coaxial output must assume connect to 75 ohm input impedance DAC , if connect to two DACs through the split, the load become 37.5 ohm which is put the source output level lower a bit and maybe can't proper transfer the digital signal.

 

[doobooloo]

Kingwa - I believe the BNC splitter used is a proper 75ohm splitter, check out the datasheet here:
 
http://www.minicircuits.com/pdfs/ZSC-4-1-75+.pdf
 
What do you think? I don't hear an obvious degradation in sound due to the 75ohm splitter in place...

 

[doobooloo]

Also I should note - the differences are quite subtle and even the negatives are only on a relative basis and exaggerated to get the point across. They're all excellent DACs that produce superb sound... none of them produce "bad" sound.