Chip Amps and Pre Amps

[bcmbob]

For us nubees - Can someone comment on the comparative advantages or disadvantages of using a passive attenuator as opposed to a separate unit such as a Carver C-1 or the preamp outs on something like a Denon receiver?

[Redshift187]

Many people (including myself) believe in the less is more philosophy. The idea being that every component in the signal path has an effect on the sound. The effect can be good for some equipment and some listeners, but that is up to your ears and your setup.

On the good side, using a retail pre-amp/pre-outs has the benefits that you are unlikely to have impedance matching issues, you probably gain useful functionality like remote volume control and possibly (if it's important), surround decoding.

[bcmbob]

Thanks Redshift. What do you prefer as the source in a CD signal path? I have seen both DIY turntables and DIY AD converters on some of the threads. Can you describe your system all the way from CD to speakers?

Regards, Bob M.

[bcmbob]

BTW - I have 4 PCB for MyRef-C and 1 Beian-G dual mono kit. I will probabally end up with two systems - one for stereo only and a seperate 7.1 HT setup.

[Redshift187]

I don't have a pre-amp/receiver to try, so I can't compare. I'm just using a passive attenuator (simple potentiometer).

[Speedskater]

You may not need either a pre-amp or a passive attenuator. A portable player with a built-in volume control (like an iPod) can be plugged directly into your amp. Pre-amps are more robust and give you more choices than a P.A. A passive attenuator may limit your choices of interconnect cables and of what units can be connected to what amplifiers.

[Redshift187]

A portable player operated from a single battery can often only output up to 1.07V RMS, and that may not be high enough for a typical amp depending on your listening habits and the amplifier configuration.

[Speedskater]

True. Any source with a built-in volume control could be used with-out a pre-amp. But if that source's output level is not high enough, then an active pre-amp will be needed. As passive attenuators can only make the signal smaller.

[AndrewT]

That is the most important question that must be answered before looking at details and options.

Do you need extra gain between your source and your receiver?
Will attenuation and no extra gain be sufficient for all my sources?

If you do not need extra gain then do not provide it.
Use a unity gain active buffer plus attenuator or attenuator alone.

[Gopher]

A lot of people report that the LM3875/3886 type gainclone sounds better with an input buffer following the volume control.

If it's a real observation, it probably has more to do with the source component not having enough oomph to drive a passive setup than a problem with the LM3875/3886 themselves.