What's the purpose of a preamp?

Since most -if not all- sources (e.g. DAC, CD player, phono stage) have an output voltage, that's capable of driving a power amp, then what's the purpose of an active preamp?

Doesn't a passive attenuator seem like a simpler, less intrusive and 'cleaner' solution of controlling volume, instead of an active preamp?

In my particular case, I have a Croft Micro 25RSLS (line stage only preamp), a pair of Croft Series7R monoblocks and Harbeth speakers. Should I consider replacing my preamp with a passive attenuator, such as the Goldpoint SA4M?

Thanks,
Panos

As well as providing some gain (not always necessary as you have pointed out), an active pre will usually provide better drive conditions to the power amp and an easier load to the source components.
I have specifically avoided using the word matching as that isn't accurate. As source components give only a voltage output, not a power output, the best loading is a reasonably high impedance, for my mind 50 kohms or above.

For the output a low impedance is better to drive whatever capacitance is presented by the interconnects and/or power amp.
An active pre can be considered as an impedance changing device, high on input and low on output.

A passive pre is always limited in how high and how low the impedance transform is.

My idea is to use just a passive attenuator, the least intrusive device in the signal path. Apologies for my lack of technical knowledge, but isn’t the passive attenuator different from a passive preamp?

Quote:

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Originally Posted by pankon

My idea is to use just a passive attenuator, the least intrusive device in the signal path. Apologies for my lack of technical knowledge, but isn’t the passive attenuator different from a passive preamp?

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A passive pre-amp is an attenuator.:)

Gary

Quote:

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Originally Posted by pankon

Since most -if not all- sources (e.g. DAC, CD player, phono stage) have an output voltage, that's capable of driving a power amp, then what's the purpose of an active preamp?

Doesn't a passive attenuator seem like a simpler, less intrusive and 'cleaner' solution of controlling volume, instead of an active preamp?

In my particular case, I have a Croft Micro 25RSLS (line stage only preamp), a pair of Croft Series7R monoblocks and Harbeth speakers. Should I consider replacing my preamp with a passive attenuator, such as the Goldpoint SA4M?

Thanks,
Panos

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I'd avoid the Goldpoint, it's expensive and not that good.

As my power amp has a volume control, I manage with just this. Changing interconnects from phono amp to cd player is a bit of a faff though. Would having a pre amp be a good thing sonically, or would it just be more 'stuff' in the audio chain?

No point adding more gear if you don't need to as long as you're happy using your system that way.

If there's room in the power amp case, you could even investigate fitting a remote control pot.

This is an old chestnut. Firebottle has explained the electronic purpose admirably which shows the limitations of the more usual passive attenuators, the fact remains that many audio buffs never the less like the presentation an active pre gives. The reasons for this are divisive and inconclusive and deeply system dependent.

I can only suggest you try and hear for yourself. If ever system synergy played a part it is in how this component interfaces with the rest of your system.

Me? I'm on the fence. Currently my pre is lying idle, but with many of my other amps in the system it goes straight back in!

Sent from my BLA-L09 using Tapatalk

Martin,
Someone suggested the Goldpoint as a very good dual mono passive attenuator. Obviously you do not agree, which is fine. Can you, or anybody else, recommend any better dual mono alternatives, that do not create any artifacts on the sound?
Thanks

What’s your budget?