[dsch04]

Hi,

I've got a couple of Art DI/Os (one modded slightly, one stock) and both a SB1 and SB2 (both stock).

I originally found that I greatly preferred the Art DI/O over the SB1 analogue out but with the SB2 it's much closer. In fact, I've not had change to do any extensive comparisons yet.

Anyone else got both these units and care to offer any observations?

R.

[Wayne1]

I will do a quick comparison of the modded unit against my Mensa Plus DI/O later today.

Going by what I heard yesterday at Mike's, the modded SB2 analog outs will be sounding a LOT better than the DAC.

I believe that removing many mechanical connections, solder joints, and a LOT of components from the signal path will improve almost any system.

I have never like the sound of system using a passive preamp. I love the sound of the SB2 direct into an amp using the SB2s internal volume control

[chadh]

Wayne,

from your comments about the listening session, you were most impressed when using the digital volume control on the SB2, which was then fed directly to the amp.  When you're comparing the MENSA DI/O to the SB2, perhaps you could keep in mind those of us who have multiple sources and so will need to use a pre-amp.  

Is any perceived superiority of the SB2 analogue outs over the MENSA DI/O maintained when there's a pre-amp in the mix?

Despite your ambivalence to passive pre-amps, do you imagine that a passive would be a good option here, or would you still opt for a (tubed) active if you needed to use a pre-amp?

If you were using a pre-amp, is there any reason to imagine that the pre-amp volume control would be better or worse than the SB2 digital volume control?

I'm wondering whether a passive source switching device (with no volume control) would be a reasonable option if one were to use the SB2?

Chad

[Wayne1]

The best sound we heard was with the SB2 direct to the amps.

Putting anything else in the signal path WILL degrade the sound.

If you have multiple sources, you will either have to have separate systems or accept that the SB2 will not sound as good as it can.

I believe there are some preamps that have a HT bypass that switches out most of the circuitry. This would be the next best thing.

I cannot comment about what preamp would work best in your system. You would have to try out the various types and determine what YOU like.

I will hazard a wild guess that the SB2 will sound better through it's analog outs then the DI/O. There is a lot less in the signal path to mess up the sound. The preamp will have an effect on this depending on how much IT contributes to the sound of the system. It is possible that a preamp can mask the differences between the modded SB2 and an outboard DAC.

It is possible to construct a switch that would allow the SB2 to be inserted after the preamp and before the power amps. It is also possible that throwing the switch could cause noise the the amp and speakers would not like.

[JohnnyLightOn]

I think it's great that we have another experienced modder upping the capabilities of the Squeezebox 2.  

However, if you continue to call it SQ2 rather than SB2 you will drive everyone crazy!          It's hard enough to remember all the letters and numbers in this hobby (DEQX, AV123, VMPS, etc).  Please call the SB2 by the abbreviation that everyone else is already using.  

[Wayne1]

I edited my last post to call it the SB2

Sorry, earliy senility.

I have finished doing a quick comparison of my Mensa  DI/O with Bybee'd PS to the modded SB2. I can only use my headphone amp for this as my router is not anywhere near any of my other audio gear.

The Mensa DI/O sounded good from the digital output but not as good as the analog outs of the modded SB2. The modded SB2 had more dynamics, cleaner and smoother high end, deeper bass and more depth to the sound. I could hear a lot more of the shadings of the instruments.

Overall a VERY impressive difference.

At this point I can say that as good as a lot of DACs are out there, the analog outs of the modded SB2 may be a bit better. The truly cool thing is this mod will let folks sell off their DACs, power supplies and extra cables to have some spare money to spend on music.

[dsch04]

I will do a quick comparison of the modded unit against my Mensa Plus DI/O later today.

Going by what I heard yesterday at Mike's, the modded SB2 analog outs will be sounding a LOT better than the DAC.

I believe that removing many mechanical connections, solder joints, and a LOT of components from the signal path will improve almost any system.

I completely agree. You wouldn't believe the difference that removing the tone controls from the signal path made on my Rotel RA820A. There is a switch which supposedly bypasses the tone (On/Off/Mono) but removing this from the circuit entirely changed the sound of my system immensely.

I started with an RA820A and a pair of B&W DM610s - not particularly high-end. I felt that the sound was constricted some how and suspected the amplifier so I did a few mods (replaced op amps with Analogue Devices AD???, replaced some caps, bypassed others with low-value caps, etc.) and added an additional output to drive a power amp to power the LF. I now run a bi-amped rig with the modded RA820A as the preamp/HF amp and a Rotel RB850 driving the LF.

Before the mods, I couldn't hear the difference between the analogue output of my SB1 and the output of various DAcs driven from the SB1 digital output (Art DI/O, Arcam Delta, Perpetual Technologies P-3A).

After the mods, I am really happy with the sound I have achieved, and for not much outlay. In fact, I was considering buying some MA20s and took my Art DI/O and pair of Rotel Amps to audition them. The guy selling the MA20s had a Musical Fidelity Nu-Vista M3 which is apparently the poodles plums and retailed at close on $5000 and I can honestly say my Rotels were just as good!

I have never like the sound of system using a passive preamp. I love the sound of the SB2 direct into an amp using the SB2s internal volume control

Hmm. I wonder what it is that turns you off? Aren't passive pres supposed to be pretty neutral sounding? I wonder if this is an impedance issue?

Talking of which, when I added a pair of pre-out sockets to my RA820 I simply took the feeds from the pre-amp out on the main PCB at input to the internal power amp (basically, the output of the preamp op amp). Is this the right/best way to do this, or would I be better adding a buffer stage, or connecting through a resistor, or something?

Cheers,

R.

[Wayne1]

In my opinion, a lot of passive preamps have problems with impedance matching. They may sound good at a certain level but change the level and the sound changes. When I heard an early version of the Bent transformer passive, I felt it was too sterile.

I liked the bloom and fullness of a good tube preamp. Yes, it changes the sound, but I liked the changes. After taking Mike's preamp and cables out of the signal path and running the modded SB2 with a pair of Nitro interconnects straight into his amps, there was just more MUSIC there.

In order to match with a great variety of gear, a buffer stage would be better in your system. But you will be forcing the signal through more connections.

After listening to the system, I have become a convert to the simpler is better school. It is not possible for all systems. If you can set up a simple two channel only with a computer for source through the SB2, I feel you will be rewarded with some of the best sound you have ever heard.

[dsch04]

In order to match with a great variety of gear, a buffer stage would be better in your system. But you will be forcing the signal through more connections.

Yeah, I know. That's one of the reasons I went with the simple direct connection (well, I've also got a pot in there so I can balance HF vs. LF)

After listening to the system, I have become a convert to the simpler is better school. It is not possible for all systems. If you can set up a simple two channel only with a computer for source through the SB2, I feel you will be rewarded with some of the best sound you have ever heard.

Oh, I'm definitely with you on the "less is more" philosophy, but my system sounds much better bi-amped so I need to have some sort of split in the signal to drive two amps. I suppose I could just build a simple passive splitter box and drive a pair of power amps from the SB2 with no pre-amp - now that could be interesting, although I wouldn't be able to balance HF vs. LF but if the power amps are matched that shouldn't matter, in theory at least. I suppose I could always do something like this:

Code: [Select]


o----+------o output 1
     |
     |
     Z
     Z
     Z------o output 2
     Z
     Z
     |
     |
o----+------o ground


where ZZZZZ is a pot.

Or perhaps something like this would be better:

Code: [Select]


o----+------o output 1
     |
     |
     Z
     Z
     Z------o output 2
     Z
     Z
     |
     |
     Z
     Z
     Z
     Z
     Z
     |
o----+------o ground


i.e. include a fixed resistor to make the level adjustment range smaller

Thoughts?

R.

[macdaddy]

does the modded sb2 do 24/96..?

[Wayne1]

Stock or modded, the DAC in the SB2 is not oversampling.

It changes the word length to 24 bit but all sampling is done at 44.1 or 48 khz.

[macdaddy]

Stock or modded, the DAC in the SB2 is not oversampling.

It changes the word length to 24 bit but all sampling is done at 44.1 or 48 khz.

so what would it do with 24/96 WAV files..?

thanks for the response.

[Wayne1]

so what would it do with 24/96 WAV files..?

thanks for the response.

It would not be able to convert them.

All you would hear is white noise.

This is a feature that they are looking to add as a firmware fix.