[knut_the_viking]

I'm counting my pennies, and wanted to ask the honorable members of this circle if the RCA outputs from a Squeezebox can be used to drive a pair of D-100s, without a preamp in between?
Are there gain or impedance issues here?

Follow-up question is: If I get a preamp, how high should the SB output be set? Always to 100%? 50%? What would be optimal for the best sound quality?

[Charles Calkins]

Yes it will.
The SB3 volume control goes from 0 to 100. More than one person has a setup like this. Not necessarily with the D-100's but other amps.

 Me! I wouldn't do it. I'd be very afraid that something would go booboo and then I'd have burned amps and blown speakers. I've a tube preamp running my D-200's Much safer that way.


                                                         Cheers
                                                         Charlie

[richidoo]

I used it that way for a long time, with an integrated tube amp (not CIA). The stock Squeezebox has 220ohm output impedance thanks to an output buffer opamp. Many people yank that out ("mod") for improving the sound, but the output impedance suffers. CIA are the easiest of all amps to integrate into a system. Small, cool, 100k input impedance, very low output impedance, plenty of power, great price. Modded or stock SB will have no problem with it. The great design of the amp allows easy use of passive volume controls.

But the Squeezebox does have a little known reputation for deciding to make full scale white noise occasionally even when the digital volume is turned down. The digital volume control maybe turned down but the output stage is always at full gain, as you can hear when music is stopped and you put your ear next to the speaker. Turn it on and off while muted and you will hear the output stage turning on and off, especially with the display lit up. I have only hear the noise once in 2 years, but that was enough. Several others have been zapped with it, but not in a long time. Maybe they have eliminated the possibility on newer models.

If you put a passive attenuator in there you can set SB to 100 for maximum sound quality, and turn down the passive volume control  to your maximum volume level you will need. Then use the SB remote to adjust. You have eliminated the possibility of overloading speakers but still have plenty of volume available and also maximum resolution of the SB. If you turn down the SB below 60 or so you may be able to hear some of the grit caused by throwing away bits to lower the volume digitally, even before the stream makes it to the DAC. Safer and sounds better, but costs more than direct connect.

But the SB can easily drive the D100 by itself and it will sound good. You can protect your speakers from the .01% chance of white noise attack by inserting a CIA passive volume control, or other resistive attenuator available from other sources.

If you don't already have one, an upgrade power supply for the stock SB is an awesome upgrade. You will be glad you did. I am glad to see Dusty introduce his own excellent version, but I just use a homemade version with good results, probably not as refined as Dustys version. He has a great rep for PS design, which is why the CIA amps stand above DIY UcD amps.

Sorry for the rambling. I hope this helps a little!
Rich

[Tim S]

I have a transporter that goes directly to my D-100's. I have hear about the issues with the Squeezebox's digital volume control occasionally malfunctioning but I've had this setup for quite a while with no problem. I think it might have been a bug with an early version of the software.

In my initial setup, BTW, I had a Sonic Frontiers Line 1 tube preamp in between them. I decided after some comparisons that it wasn't really worth the heat and took it out of the path.

Tim

[knut_the_viking]

<snip>
But the Squeezebox does have a little known reputation for deciding to make full scale white noise occasionally even when the digital volume is turned down. The digital volume control maybe turned down but the output stage is always at full gain, as you can hear when music is stopped and you put your ear next to the speaker. Turn it on and off while muted and you will hear the output stage turning on and off, especially with the display lit up. I have only hear the noise once in 2 years, but that was enough. Several others have been zapped with it, but not in a long time. Maybe they have eliminated the possibility on newer models.
<snip>

Never heard of that, but something to keep in mind, for sure

<snip>
...SB to 100 for maximum sound quality...
If you turn down the SB below 60 or so you may be able to hear some of the grit caused by throwing away bits to lower the volume digitally, even before the stream makes it to the DAC. Safer and sounds better, but costs more than direct connect.

Great! Thanks! Exactly what I was fishing for!

<snip>
If you don't already have one, an upgrade power supply for the stock SB is an awesome upgrade. You will be glad you did. I am glad to see Dusty introduce his own excellent version, but I just use a homemade version with good results, probably not as refined as Dustys version. He has a great rep for PS design, which is why the CIA amps stand above DIY UcD amps.

I don't yet, but I definitely will when I get the rest of my system (work in progress, y'see...)
I've posted my disbelief about the PS when I unpacked the SB (on Xmas morning) on here somewhere.

Sorry for the rambling. I hope this helps a little!
Rich

Sure did! Much appreciated!!

[JLM]

I have the old VMB-1 monoblocks and have run them with and without a VPC-3 using a modded SB and an Oppo universal player (both those sources have their own remote controlled volume controls).  No problems.  Very satisfied with the sound in any combination.

Check the input sensitivity of the D-100 amps.  The VMB-1 input sensitivity is only 0.6 volts (to reach full output), so you'll only be using 30% of the volume control range of a 2.0 volt output device.  In fact I almost need more lower volume range from the Oppo when running without the VPC-3.  (Based on your room, speaker efficiency, etc. YMMV.)

Some recommend running the SB/Oppo (or any digital volume control) at full output.  In that case you'd only have 30% of a passive volume control available.  This is what I've found with the VPC-3 (the amps are at full output with the volume control at 10:00).  Trying a pre-amp with gain would only make matters worse.

As mentioned above, the CIA amps are properly designed to eliminate impedance matching concerns, so pre-amp impedance buffering isn't needed.

[mcgsxr]

I don't have the amps listed, but have always run the SB3 (Bolder modded in my case) direct to my Magnavox amp.  I often run it at 100, and have 0 preamp attenuation (this is a s/w capability with the Slimserver s/w) but then again my amp is really only pushing 2-5wpc into my mid 90's efficient Visaton speakers.

So, from a sound quality perspective, I find it extremely satisfying - as in no changes in over 2 years satisfying!