It can be. You have to decide what *you* think it is.
Some passive preamps cost thousands. Some active preamps cost little. So it's not expensive preamp vs passive.
The only people pulling wool are those pulling wool over their own eyes.
But I am speaking from direct experience. I was looking for a preamp and I discovered that there are very few cheap ones available. They start at say £500, and many of them start at £1000 upwards. On the other hand a passive preamp can be nothing more than a pot which costs pennies. So in my view the issue of the cost between active and passive preamps is significant.
My experience is that it cost a certain amount to put a box on the market. There's a substantial overhead in accomplishing that and quite honestly what's in the box may not affect the costs much, unless you have a leaning towards boutique components. Prices are set by what the market will bear, not by what's in the box. Sometimes things will sell well at a high price and not so well at a low price. Who's the target market? Now you have to sell the thing so you need a gimmick or selling point of some sort. If you tell people something about output impedance or low feedback or silver wire or whatever, when they like what they hear they'll think that's the reason. IMHO, people, even experienced listeners and designers, absolutely stink at connecting design choices with sonic qualities. Equipment does sound different, at least sometimes, but the reasons are usually straightforward and rarely what people think they are. If no one pulls the wool over our eyes for us, we're very good at doing it all by ourselves.
CH
CH
What? You've never used a subjective term? You don't have subjective evaluations of your gear? You don't ever say something sounds "good"?
Geez, indeed. 🙄
Some passive preamplifiers have transformer attenuators and cost thousands, but an active can be easily made from a cheap headphone amplifier. Just add RCA connectors instead of the jack output socket.
Such as…
Graham Slee model Novo Headphone Amplifier, about £225
A.N.T. Audio model Amber 3T (from DiyAudio member X-pro) starts at £199
Or e-bay at £195…
http://cgi.ebay.co.uk/Monitor-II-Reference-Series-Headphone-Amplifier-/130396539068?cmd=ViewItem&pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item1e5c3d48bc
If you decide to go with just a potentiometer consider something along the lines of the TDK units (available from Hi-Fi Collective), as they track better (left / right) at low volume compared to the very cheap pots.
Most headphone amps are designed to be used with a certain range of impedances usually 32 to 600ohms or something whereas the amp input could be 50kohm. What effect will this have? Can somebody tell me?
Hi,
a simple Pot is imho not the best way to go. I´m not too surprised to read something about subjectively lower dynamics with those compared to an active buffer. If You use a design with low and constant output impedance, dynamics will be outstanding on a large scale and even more so on a small scale. At least every listener stated that with our purist Pre (funny coincidence with the thread title ;-)), which features just such circuitry. With such a design You soon learn that a lot of active stages simple sound rough and grainy, which may lead to the impression of greater dynamics. But simply listening to a voice will put things right. It still always astonishes me how quick listeners evaluate the differences between the passive Pre and an active one and that without exception until now everybody favoured passive.
jauu
Calvin
a simple Pot is imho not the best way to go. I´m not too surprised to read something about subjectively lower dynamics with those compared to an active buffer. If You use a design with low and constant output impedance, dynamics will be outstanding on a large scale and even more so on a small scale. At least every listener stated that with our purist Pre (funny coincidence with the thread title ;-)), which features just such circuitry. With such a design You soon learn that a lot of active stages simple sound rough and grainy, which may lead to the impression of greater dynamics. But simply listening to a voice will put things right. It still always astonishes me how quick listeners evaluate the differences between the passive Pre and an active one and that without exception until now everybody favoured passive.
jauu
Calvin
I'm slightly confused that you say a passive pot isnt the way to go and then at the end you say passive preamps are favored. What is the point you're making?
Some replies are reminding you that what is between the passive volume pot and the power amplifier is important to the resulting sound.
I will reinforce that with two typical examples towards opposite ends of the range normally found.
Power Amp 1: Rin=100k, Rfilter=3k3, Cfilter=100pF, DCblock=470nF
If presented with a near zero (<200r) source impedance, the F-1dB response extremes will be ~6Hz to 230kHz
Power Amp 2: Rin=22k, Rfilter=220r, Cfilter=1nF + 47pF across RCA input socket, DCblock=10uF
F-1dB with 200r source impedance ~1.5Hz to 200kHz.
Now feed either of these power amps with 10k passive pot and 100k passive pot. The sound from all four combinations will be quite different.
Now add some longer interconnects using higher capacitance between hot and screen. Again the sound will change.
The Power amp and the Passive Pot and the Interconnect must be designed as a system, simply because the source impedance presented by the passive pot is not near zero ohms.
I will reinforce that with two typical examples towards opposite ends of the range normally found.
Power Amp 1: Rin=100k, Rfilter=3k3, Cfilter=100pF, DCblock=470nF
If presented with a near zero (<200r) source impedance, the F-1dB response extremes will be ~6Hz to 230kHz
Power Amp 2: Rin=22k, Rfilter=220r, Cfilter=1nF + 47pF across RCA input socket, DCblock=10uF
F-1dB with 200r source impedance ~1.5Hz to 200kHz.
Now feed either of these power amps with 10k passive pot and 100k passive pot. The sound from all four combinations will be quite different.
Now add some longer interconnects using higher capacitance between hot and screen. Again the sound will change.
The Power amp and the Passive Pot and the Interconnect must be designed as a system, simply because the source impedance presented by the passive pot is not near zero ohms.
Hi,
@JensB
Yes it´s a commercial product. If You want to know more about it please feel free to PM me.
jauu
Calvin
@JensB
Yes it´s a commercial product. If You want to know more about it please feel free to PM me.
jauu
Calvin
....the all thing reminds me someone that posted pictures of his silver something made interconnects ...that will be both plugs and cables if i remeber correct ... without any absolutely shielding just a couple fo very expensive silver solid wires to go from source to amp ...
said to my shelf ... nice .... also possible to operate ...at the moon or any other place that EMI or other factors will not effect signal by all means since there is no shield on anything ....
as about the passive of course imp. matching and choise of cables will make a diference in such a simple system
as about active ... i could go for something with minimal in design but use best available parts
regards sakis
said to my shelf ... nice .... also possible to operate ...at the moon or any other place that EMI or other factors will not effect signal by all means since there is no shield on anything ....
as about the passive of course imp. matching and choise of cables will make a diference in such a simple system
as about active ... i could go for something with minimal in design but use best available parts
regards sakis
Thank you for your kind offer. However my (selfish) desire was to learn from the circuit. However as it is commercial I understand that the circuit must remain without public release.
Good luck with it. 🙂
From my experience, there's a big difference in sonics using a stepped attenuator instead of a carbon pot.
I built my diy passive using a Goldpoint/Elma 20K mini-v stepped attenuator. I only have a CDP single source setup, so I don't need for an active preamp with lots of switching options.
People mention short cables, but my interconnects are 1 meter with no ill effects at all. My amp's input impedance is 47K, and modded cdp outputs 1.75V.
I've considered building the Pass B1 buffer, but I'm hesitant since I don't know what sonic advantage that would give me. It's simple enough to build, and I'd welcome any comments about adding it to my system. 🙂
I built my diy passive using a Goldpoint/Elma 20K mini-v stepped attenuator. I only have a CDP single source setup, so I don't need for an active preamp with lots of switching options.
People mention short cables, but my interconnects are 1 meter with no ill effects at all. My amp's input impedance is 47K, and modded cdp outputs 1.75V.
I've considered building the Pass B1 buffer, but I'm hesitant since I don't know what sonic advantage that would give me. It's simple enough to build, and I'd welcome any comments about adding it to my system. 🙂
IMO, 1 meter of low cap cable isn't a problem with a passive. Ditto on stepped attenuators. I have to wonder what contribution pots make. Certainly they're never in balance to the degree of a stepped attenuator. I think I've heard differences between other types of pot and it would be interesting to track down why. I'm no resistor connoisseur, but pots can be made with some pretty crummy materials compared to metal film resistors.
My Alien DAC has quite a low output (no op amp, its straight from the DAC chip to the RCA). When I was using a studio power amp (which has an op amp buffer on the input) it was fine with a passive "preamp" (stepped attenuator and input switch) kit I got from EBAY.
When I went to a simpler Class D amp module with no op amp buffer the Alien DAC output was really having difficulty driving the amp at reasonable levels compared to my other inputs via the passive.
So I made an active pre-amp kit (ESP p88) and it is great, for this low output source it has really helped the sound.
When I went to a simpler Class D amp module with no op amp buffer the Alien DAC output was really having difficulty driving the amp at reasonable levels compared to my other inputs via the passive.
So I made an active pre-amp kit (ESP p88) and it is great, for this low output source it has really helped the sound.
Conrad, I recently got to hear a well made shunt passive that uses 2K Caddock MK132's on the signal, it also uses a 10K PEC stereo log pot. I have to say that I was surprised how well it performed, and the balance seemed good to me. The PEC is made in Canada and seems to be of good quality.
Honestly, when I put my Goldpoint/Elma stepped attenuator back into the system the sound got a little more analytical, but I can't say it's any more musical. 😀
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