A non active preamp stage means the preamp stage is passive and just controls volume, there is no gain just attenuation. I have not personally heard the CA-150 so can't comment there.
What is a non-active pre-amp stage?? Are their advantages to this design??
I am considering an Conrad Johnson CA-150 integrated amp which offers a "non active pre-amp stage"
Need and explanation of this design. What are its pros and cons?? Does it provide better sound quality or performance, than an "active pre-amp stage" ?
Any comments about the C.J, CA-150 integrated amp sound quality??
Thank you,
S.J.
13 responses Add your response
Not heard it but removing the first stage input amplifier does a number of things. It takes out an extra stage of electronics with the idea that simpler is purer. Less crap in the path. You might want to check the input impedence matches the source. Depending on the design it may reduce the "drive" of the amplifier compared to one with an active stage. It is a balancing act between the two. |
@sunnyjim - I do not have the CJ, but I have a Naim 5i (Mk II) which also has a passive front end. Just as another poster pointed out - no active components, just a resistor ladder for volume attenuation and input selector buttons. When I heard the amp, I was quite taken by the clarity, dynamic performance and expansive image and then over time came to love the very neutral nature of the amp. I cannot comment on the CJ, but I suspect it would offer similar characteristics. Checkout if it has a resistor ladder for volume attenuation, because they tend to provide better focus to the image (i.e. in my case) As with any component, the tone may be altered significantly by the cables you choose. I found the NAIM 5i to be very responsive to cable changes. Unfortunately, I developed my own DIY cables, so I am unable to make any brand/model specific recommendations, but cables that have performed well with my amp include products from KLE Innovations. I also like the look of the cable geometry of Nordost cables. I have heard a couple of their early power cables and they made a noticeable improvements in dynamics, clarity and image. See if the store will let you demo the amp with your system. Hope that helps a little - Steve |
@sunnyjim - Yogiboy might be right about the phono stage, but I have no problems with my Simaudio Moon phono stage which has an adjustable gain jumper in it. Passive "pre-amps" only attenuate the signal. Sometimes they have an intermediate "booster amp stage" between the inputs and the actual power amp section in order to provide the same overall abilities as amps with an active pre-amp. If all of your components output the standard "line level" output voltage then everything should work fine. The CA 150 does have a remote (as stated in the manual), so yes - you can do everything from your armchair. Hope that helps - Steve |
From the look of the product page on their site this is an integrated amp by another name without input buffering before the attenuator... which is a pretty normal integrated amp design. Personally I prefer to buffer the input to the attenuator (which makes it active), this allows the use of lower value resistors (800Ω instead of 10,000Ω) in the attenuator which means lower (johnson) noise levels. I'm afraid I've not heard the amp in question so can't comment on that but it might be worth auditioning passive vs active if you can get a dealer to set that up for you. |
sunnyjim jond You heard of Nelson Pass no doubt (Pass Labs, Threshold ect ect) This is what he said about passive volume controls, and yes he does make/ designs active preamps after all he is a business man.
Cheers George |
Just to be clear, an active preamp doesn't have to add gain, there is benefit to be had in using the active component/s to present a high impedance to the source and low impedance to the load. DIYers are in a better place to decide which way to go as they are more likely to properly understand the impact of their choices and the electrical characteristics of the equipment connected. A passive device needs to be selected carefully because too low an input impedance may overload the source equipment... okay so lets choose a high resistance pot / attenuator. But in the absence of any active components the output impedance of the preamp is the one presented by the pot / attenuator. The output impedance of any preamp in conjunction with cable capacitance creates a low pass filter - with well matched equipment this will be at a higher frequency than we care about in the audio world. However with a passive preamp this may start to creep in to the top end of the audio range. There are other advantages to active preamps that I could go into but I feel I may have been too technical already. One architecture isn't necessarily better than the other, but if you don't fully understand the characteristics of your components then you're probably safest going active. |
I just re-read the original post and realised I'd forgotten we were talking about an integrated amp (not a passive preamp). You will be able to trust the engineers have taken into account the impedance internally (and so can disregard most of what I just said), the unit has 10k input impedance so that should be fine for most, if not all sources. I still think that sometimes it's worth using active components to overcome the limitations of passive ones e.g. if you want minimum noise levels 10k pot has minimum noise of -115dBV, a 500Ω attenuator has minimum noise of 127dBV but will require some active buffering. Apologies if I've added more confusion, I should have re-read the original post properly before responding. |
I still think that sometimes it’s worth using active components to overcome the limitations of passive onesIf there are no impedance issues "limitation" as you say, then a passive will sound better, more transparent, better dynamics, and less coloration/distortions. (see Nelsons quote) And aren’t we searching for the Holly Grail? Why compromise plus the expense with an active, why not strive to get the passive right? Or better still going direct if it allows it. Cheers George |
I don't think it's as simple as passive is always better... the rest of the amplifier is active, just no buffers or gain on the input. There always needs to be a reason for the extra components though. It's fairly easy to produce a very low distortion amplifier with either architecture. As I described, active components can help to minimise the noise floor which for me is important (I'm not talking about hiss or interference) as I like that pitch black background you get from an super low noise amplifier. I guess we're all looking for our own Holy Grail, but the chances are we won't all agree on what that is. Personally I go for the solution that delivers the most accurate representation of the input signal (just bigger). Apologies to the OP for going so far off topic... it would have been much more useful if I'd actually heard the amplifier and could just say it's great! |