You are in sin bin for 30 minutes (massive sentimental disruptive behaviour)
Have this picture of this technical achievement printed on a wall covering poster and sit by your beloved wife to enjoy the music you like played through other means. Have mercy and don't wear this polished beauty.
George
Have this picture of this technical achievement printed on a wall covering poster and sit by your beloved wife to enjoy the music you like played through other means. Have mercy and don't wear this polished beauty.
George
I installed two of those preamps in a University production suite and they work fine, no complaints other than normal marginal behavior when they encounter groove debris. I really like the fact that they allow you to change AC line polarity, although in an institution the wiring is usually to spec, but if L & N are reversed as it is in many locations, the switch would be a life saver.
John, do you know anything about these? They are not part of any JC signature series, but I cannot help but wonder if Parasound can't resist lifting designs you do for them for their non-JC equipment...?
Cheers!
Howie
OK, this is a first: A cartridge whose magnetic structure is made entirely from "highly graded samples of high-nickel meteoritic iron."
Sensitive Sound | | Solypsa
I'll take one for the team and say the obvious: it sounds out of this world!!
...runs and hides...
Howie
Sensitive Sound | | Solypsa
I'll take one for the team and say the obvious: it sounds out of this world!!
...runs and hides...
Howie
Hi Howie, I really don't have anything to do with the other Parasound products, other than what I am given credit for. I have found, over the years, that the other designers in Taiwan will often IGNORE my inputs in the phono area to not be accused of copying me. I usually don't even have a schematic of the other products, unless I ask specifically ask for them.
Phono circuit design has progressed to mostly 2 gain block designs, the schematics being on data sheets for low noise IC's. The only significant difference between these schematics and my own is DETAIL in the parts selection, and routing of the circuit paths. It does make a difference.
Now when it comes to even lower noise, of course, parts improved greatly over the last 50 years, so even the same JC-1 circuit can easily be quieter, maybe 6-10 dB quieter, depending on slight resistor changes and certainly bipolar transistor changes that have been available for the last 30 years.
Personally, I changed over to complementary jfet input as it is more linear than my JC-1 stage, but it takes more jfets to be as quiet as the same number of bipolars and complementary jfets became much more difficult to buy, so only the most expensive phono stages can afford to even get down to 0.4nV/rt Hz with these devices.
An exotic variation done today is paralleling low noise (1nV) op amps to make very low noise input stages. For example, 10 op amps could get you close to 0.3nV, but there are other potential tradeoffs in sonic quality doing it this way. Still it is a viable option, and cheaper too!
Phono circuit design has progressed to mostly 2 gain block designs, the schematics being on data sheets for low noise IC's. The only significant difference between these schematics and my own is DETAIL in the parts selection, and routing of the circuit paths. It does make a difference.
Now when it comes to even lower noise, of course, parts improved greatly over the last 50 years, so even the same JC-1 circuit can easily be quieter, maybe 6-10 dB quieter, depending on slight resistor changes and certainly bipolar transistor changes that have been available for the last 30 years.
Personally, I changed over to complementary jfet input as it is more linear than my JC-1 stage, but it takes more jfets to be as quiet as the same number of bipolars and complementary jfets became much more difficult to buy, so only the most expensive phono stages can afford to even get down to 0.4nV/rt Hz with these devices.
An exotic variation done today is paralleling low noise (1nV) op amps to make very low noise input stages. For example, 10 op amps could get you close to 0.3nV, but there are other potential tradeoffs in sonic quality doing it this way. Still it is a viable option, and cheaper too!
For people who already own a hublot with moon dust embedded in the face!
Given the whole planet is made from the corpses of dead stars I personally fail to get excited by that. But there is some good russian iron from the 50s that my Russian friend uses for cores. I like the romance of an air core MC. Dare I say Hans does too.
0.3nV/rt hz is possible with a Vendetta input circuit as well. It is just a matter of lowering bias resistor values. However, paralleling the lowest noise jfets can add too much nonlinear input capacitance, especially with complementary jfet inputs which offer even lower open loop distortion from single ended inputs. For measuring purposes, single ended jfet might be a better solution by using global negative feedback to linearize the input stage further. I prefer a no-loop feedback input gain block to minimize potential problems due to the fact that the phono input sees a very large bandwidth of input, some far above the audio range.
Nothing like a bit of bonkers Ben Duncan to get the discussion started
Spectral X-Contamination: Problems in Op-Amp Chips | Stereophile.com
Spectral X-Contamination: Problems in Op-Amp Chips | Stereophile.com
H&H 3rd Edition page 506 for a 70 PV/rt Hz ribbon mic pre With 32 Zetex 951’s in parallel. Power consumption is c. 100mA.
A single needed version is also presented but you need a 150 000uF input coupling cap - even they concede it’s ugly, but I suppose in the pursuit of low noise, crazy things are done.
I have build the non-differential version and I can say it works
as advertized.
< DSC_0485 | source of the idea | Gerhard Hoffmann | Flickr >
and the pictures to the left. LTspice is slightly optimistic with 40 pV, but the
amplifier HAS 70 pV/rt Hz.
There is also a SMD version for use in a chopper amplifier at a higher frequency
where the capacitors can be tolerated.
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