I dont understand passive preamps for turntable setups.

[ceefaxer]

So I was looking to upgrade my ancient rubbish setup to an NVA system a friend gifted me. However I really don't understand the benefit of a passive pre amp.

So at the moment my chain is:
TT----cambridge phono preamp-----cambridge amp

If I change to the system a friend has gifted I think it would become:
TT------cambridge Phono preamp----NVA P20 passive pre amp - NVA a20

What I don't understand is what is the P20 doing in this set up? It seems like its just passing on the signal from the phono preamp. But I don't have a clue about this kind of thing.

Are passive preamps more for when you don't need a pre amp, like through some DACs etc.

 

[Leemix]

A pre-amp is basically a source selector and volume control.
(And as you mention it can also have a DAC and other features)


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[killdozzer]

So I was looking to upgrade my ancient rubbish setup to an NVA system a friend gifted me. However I really don't understand the benefit of a passive pre amp.

So at the moment my chain is:
TT----cambridge phono preamp-----cambridge amp

If I change to the system a friend has gifted I think it would become:
TT------cambridge Phono preamp----NVA P20 passive pre amp - NVA a20

What I don't understand is what is the P20 doing in this set up? It seems like its just passing on the signal from the phono preamp. But I don't have a clue about this kind of thing.

Are passive preamps more for when you don't need a pre amp, like through some DACs etc.

Just take time and make sure everything is as you want. I checked the NVA P20 online and it seems it doesn't have the phono-in. You didn't write which TT you have. Some (rarely) have a phono amp built in. If yours doesn't you might benefit from the phono pre amp.

I'm not saying you certainly will, but you might. You might need your Cambridge phono preamp to shape the signal before sending it further down the chain.

Leemix said it right as far as pre amps go, but phono pre amp boosts the TT signal, so to speak.

Connecting your TT (in case it doesn't have the amp built in) directly to any other input won't yield good results.

The input for TT has different resistance and voltage. You might have to go TT - phono pre-amp - pre amp - amp

In this case ^ You can go to aux(iliary), so: TT > phono pre-amp > aux of the pre amp > amp

 

[PENG]

Are passive preamps more for when you don't need a pre amp, like through some DACs etc.

As Leemix said...

Other than that, in you case if you only have the TT and a Cambridge Audio phono preamp then adding the P20 is not going to help and may even add noise to the signal chain.

 

[killdozzer]

As Leemix said...

Other than that, in you case if you only have the TT and a Cambridge Audio phono preamp then adding the P20 is not going to help and may even add noise to the signal chain.

Yes, you can also stick to the combination you have.

 

[highfigh]

A pre-amp is basically a source selector and volume control.
(And as you mention it can also have a DAC and other features)


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You left out the part where it amplifies the signal. If it doesn't do that, it's only a switch with a volume control and the output from a phono cartridge isn't usually high enough to pass through a volume control without being degraded because the response is highly dependent on the load it's connected to.

 

[Leemix]

You left out the part where it amplifies the signal. If it doesn't do that, it's only a switch with a volume control and the output from a phono cartridge isn't usually high enough to pass through a volume control without being degraded because the response is highly dependent on the load it's connected to.

Hes not asking about the phono pre-amp i think, just the passive pre amp after the phono pre-amp.
The phono pre-amp does do other things than a “normal” pre-amp as it amplifies the weak signal from the cartridge like you say and also applies an EQ curve to undo the curve they use so the music grooves wont be too disk space hungry.


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[slipperybidness]

I'm making an assumption that a PHONO passive pre-amp is used to add the needed RIAA equalization only. I did not look up the info and specs on these components in particular.

 

[highfigh]

Hes not asking about the phono pre-amp i think, just the passive pre amp after the phono pre-amp.
The phono pre-amp does do other things than a “normal” pre-amp as it amplifies the weak signal from the cartridge like you say and also applies an EQ curve to undo the curve they use so the music grooves wont be too disk space hungry.


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The EQ curve has nothing to do with disc space, it's to allow the recording to be played with a more modern cartridge because strong bass causes the needle to mistrack.

RIAA compensation-

RIAA equalization - Wikipedia

en.wikipedia.org

 

[Leemix]

The EQ curve has nothing to do with disc space, it's to allow the recording to be played with a more modern cartridge because strong bass causes the needle to mistrack.

RIAA compensation-

RIAA equalization - Wikipedia

en.wikipedia.org

Didnt read much on the wiki but i have heard and read many times that without the EQ the play time on a record would be too short for what they wanted. (As well as better tracking)
Edit: It was at the very beginning in the wiki that its also for longer play time.


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[highfigh]

Didnt read much on the wiki but i have heard and read many times that without the EQ the play time on a record would be too short for what they wanted. (As well as better tracking)
Edit: It was at the very beginning in the wiki that its also for longer play time.


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But the longer play time was long before digital audio recording was a thing- less bass means the groove on a vinyl recording will be narrower and several other EQ schemes existed before RIAa was accepted.

 

[ceefaxer]

Hes not asking about the phono pre-amp i think, just the passive pre amp after the phono pre-amp.
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Yeah I'm just wondering about passive pre amps really. I know what the phono preamp I have is doing. Its just my mate whos gifted me the stuff was saying you'll need a phono pre amp for the setup. Considering I have nothing else in this chain (DAC etc) to switch to and from, it seems any passive preamp would be superfluous to my needs and I can just use the my current kit (Project TT , Cambridge phono pre amp) and swap out the amp to the a20 power amp

My friend had a DAC for bluetoothing his tv audio and Bluetooth from tidal etc and then his TT. So it makes sense for the passive preamp just being a selector and volume.

Is there any situation where you could ever use a passive preamp with a turntable that didn't have a phono pre amp built in?

 

[highfigh]

Yeah I'm just wondering about passive pre amps really. I know what the phono preamp I have is doing. Its just my mate whos gifted me the stuff was saying you'll need a phono pre amp for the setup. Considering I have nothing else in this chain (DAC etc) to switch to and from, it seems any passive preamp would be superfluous to my needs and I can just use the my current kit (Project TT , Cambridge phono pre amp) and swap out the amp to the a20 power amp

My friend had a DAC for bluetoothing his tv audio and Bluetooth from tidal etc and then his TT. So it makes sense for the passive preamp just being a selector and volume.

Is there any situation where you could ever use a passive preamp with a turntable that didn't have a phono pre amp built in?

Passive preamps can't add gain to the signal and the best example of a signal that needs gain in order to be useful is from a turntable with any cartridge that isn't called 'ceramic' because those generally don't need as much boost. You have the Cambridge phono preamp but the A20 can't drive speakers since it's a preamp, not a power amp. I didn't see anything about the A20 on their website, so it may be an older model.

 

[slipperybidness]

Yeah I'm just wondering about passive pre amps really. I know what the phono preamp I have is doing. Its just my mate whos gifted me the stuff was saying you'll need a phono pre amp for the setup. Considering I have nothing else in this chain (DAC etc) to switch to and from, it seems any passive preamp would be superfluous to my needs and I can just use the my current kit (Project TT , Cambridge phono pre amp) and swap out the amp to the a20 power amp

My friend had a DAC for bluetoothing his tv audio and Bluetooth from tidal etc and then his TT. So it makes sense for the passive preamp just being a selector and volume.

Is there any situation where you could ever use a passive preamp with a turntable that didn't have a phono pre amp built in?

@TLS Guy can set us all straight on this topic.

 

[ceefaxer]

but the A20 can't drive speakers since it's a preamp, not a power amp.

the p20 is a passive pre amp, I'm pretty sure the a20 is a power amp though. Could be wrong like...

 

[killdozzer]

Passive preamps can't add gain to the signal and the best example of a signal that needs gain in order to be useful is from a turntable with any cartridge that isn't called 'ceramic' because those generally don't need as much boost. You have the Cambridge phono preamp but the A20 can't drive speakers since it's a preamp, not a power amp. I didn't see anything about the A20 on their website, so it may be an older model.

No the A20 is the amp. The question is whether he can do without the pre amp, going phono pre-amp directly to power amp?

 

[killdozzer]

I really think I saw it coming in my first post.

@ceefaxer if you really don't plan on using any other source, then you probably can do without the P20.

 

[highfigh]

No the A20 is the amp. The question is whether he can do without the pre amp, going phono pre-amp directly to power amp?

The website doesn't show the A20, so it's hard to say what can be done.

If the Cambridge amp has a volume control, it should work because it has a volume control but he didn't show the model, so that doesn't let us know if that has a pre-out.

 

[ceefaxer]

No the A20 is the amp. The question is whether he can do without the pre amp, going phono pre-amp directly to power amp?

And more generally. If you only have a turntable with no preamp built in. Is there ever a situation where a passive preamp can be used to the benefit of the final audio.

I think this seems like a decent summary
The simplest passive pre-amp is an input selector and a volume control. If you use only one source, that is capable of driving your power amp properly, and it has a volume control you probably don’t need a pre-amp.

If you have multiple sources either with or without a volume control or you use a single source which does not have a volume control, but they/it can drive your power amp properly, you need a pre-amp. You can almost certainly use a passive pre-amp.

If you use multiple sources, with or without volume controls, and one or more of them can’t drive your amplifier properly, you need an active pre-amp. A phono stage is an active pre-amp or possibly an active pre-pre-amp.

 

[ceefaxer]

its a 551p mm phone pre amp and it doesn't have a volume control

my current amp does have a volume control, but the a20 doesn't I don't think....so ahhhh...maybe I do need the p20