For the record, the Parasound JC-2 is the best effort in designing a preamp that I can make and not build it myself.
The CTC Blowtorch is still my reference. It is different from the Parasound JC-2 in several ways. One, it does not use loop feedback. Two, it uses even better switches, pots, wire, circuit board material, etc. Third, the signal thru-path is very short in the CTC, compared to the JC-2. Still, my associate, Carl Thompsen, sold his CTC Blowtorch and uses a Parasound JC-2, mostly because it has remote control that he finds very useful, since he uses a wheelchair. There is a subtle difference sonically between the two preamps, in any case.
The CTC Blowtorch is still my reference. It is different from the Parasound JC-2 in several ways. One, it does not use loop feedback. Two, it uses even better switches, pots, wire, circuit board material, etc. Third, the signal thru-path is very short in the CTC, compared to the JC-2. Still, my associate, Carl Thompsen, sold his CTC Blowtorch and uses a Parasound JC-2, mostly because it has remote control that he finds very useful, since he uses a wheelchair. There is a subtle difference sonically between the two preamps, in any case.
As I remember the cable is only for the relays (there are a lot). With a lot of relays using a ribbon cable is a reasonable way to ensure all the connections are made correctly. Using something like a flex PCB would be neat but the scale makes those a little impractical. The PCB's are large by current standards. The connectors are all soldered directly to the PCB's so no subsequent connectors or cables. All the control and communications stuff is below the stainless panel well shielded from the active circuits. The basic form is used in both the preamp and the phono stage.
I have seen similar including screw terminal strips and molex .156 tin connectors on other, even more expensive products in this category. John's focus on minimal and very high quality connections has not been taken up across this market.
Unfortunately really good modern design and packaging ends up too small and hard to sell.
I think the 32,000 $ preamp with ribbon cable was the Dagostino preamp. Dan created a nice looking preamp with pretty cool operation and features with good specs. People buying it don't care about ribbon cables. I use ribbon cables in the Pass preamps for control signals etc like Demian says they are a nice way to build and ensure proper connection and I always double up the pins.
For that matter, I have not seen any evidence that you couldn't use them
to carry signal.
😎
Sure you can, as long as they have been threaded only by virgins younger than 20, on the east side of the Andes, from 5 to 6 AM on a sunny morning in May.😀
That's guaranteed to give them a hint of mystery. 😀 You can't prove that, but hey, that's how you hear it. 😛
Let's give it a break, dvv! '-)
We use what counts WHERE it counts. Fancy wire for relay circuits seems silly, at least to me.
We use what counts WHERE it counts. Fancy wire for relay circuits seems silly, at least to me.
No its not, been involved in many cases of EMC pollution from ribbon cable based interfaces, especially where they are used to connect a display to a PCB....
I have said for some signals they are OK, but not for todays high rise time switching digital, there are better solutions
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Of course it is, John. For audio signals, I understand and agree. I choose pure silver, but since they are not all the same, my choice is specific, it applies to pure silver braided wire from Neotech.
I'd use a shoe string to let a relay have his 12V if I could. Or a LED to have its signal.
Maybe what I should have said is there are many implementations of interfaces using ribbon cable that are an EMC nightmare, generally due to the lack of good returns for the signals being carries, happy now😛
Enumeration of good practices for emc control of digital cable in this application would be enlightening for many of us. 🙂
Hi,
Agreed in general where you need reliable high speed data transmission.
In which case you use braided flat cable with extra ground wires inbetween the signal carrying ones. (See high speed SCSI cable for example)
Anyhow, it is a little simplistic to just point at a flat cable and saying it is a cause of trouble without even knowing what is being used for, no?
Cheers, 😉
Agreed in general where you need reliable high speed data transmission.
In which case you use braided flat cable with extra ground wires inbetween the signal carrying ones. (See high speed SCSI cable for example)
Anyhow, it is a little simplistic to just point at a flat cable and saying it is a cause of trouble without even knowing what is being used for, no?
Cheers, 😉
I have explained myself, no need to labour the point, I was just passing on a view about bad experiences regarding EMC and ribbon cable problems I have seen. Your normal service can now resume discussing the benefits and differences in sound between silver and copper conductors....😉
As for good practices , Henry Ott, better source of info than me and a look at the new types of connectors and cables for digital signal transmission, Samtec have some good ones, my own preference is for double sided flexis, with one side providing a contiguous return plane.
As for good practices , Henry Ott, better source of info than me and a look at the new types of connectors and cables for digital signal transmission, Samtec have some good ones, my own preference is for double sided flexis, with one side providing a contiguous return plane.
Yes, sometimes a ribbon cable will only use ONE of the wires for a ground. Good HF practice would be every alternate wire for grounds.
Hey, is it feasible to make a current sense resistor out of a trace on a PCB? How much variance is there in the copper thickness, IE how much accuracy could you expect from that?
Not a good idea, if you have a plated through board the outside copper is also plated, the amount of this plating is not controlled to the level required for a sense resistor. For the amount of money saved this would only be done on the cheapest of cheep assemblies or where you can get away with a very high +/-% change. Then you have to control heating effects, both due to current and proximity heating from other devices.
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