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Brent: Once you get below a certain point of capacitance, you really don't gain much other than that one can use a longer length of cable with less potential high frequency degradation. While i agree that capacitance should be kept reasonably low in an interconnect, i've used some cabling that is VERY high in capacitance without noticing any major problems. The reason for this is that most of my interconnects are reasonably short and i try to select gear that is reasonably stable.
On top of that, there is such a wide impedance mismatch between most sources to pre's and pre's to amp's ( due to improper industry standards ) that it doesn't make as much of a difference as one might think. After all, changing the nominal impedance of an interconnect by a few ohms to even several hundred ohms isn't that big of a deal. That's because the output impedance of a preamp might be 50 ohms and the input impedance of the amp is 10,000+ ohms. Compare that to where the output impedance of an SS amp is less than one ohm and a speaker is 4 - 8 ohms and you get a better idea of where i'm coming from.
Obviosly, one would want to use a cable that produced a nominal impedance that was somewhere between the input and output impedances of the equipment being connected together in order to achieve "reasonable" levels of performance. With the electronics, that gives you a very wide range from below a hundred up to thousands of ohms. With the amp / speaker interphase, you've got a much narrower selection. This is why i've stated that one should get the speaker cabling right first and then worry about interconnects.
While i'm NOT saying that interconnects don't matter ( they definitely do ), i don't think that they are as critical as speaker cable selection. That is, so long as common sense in setting up the system is applied. Those that haven't noticed differences in speaker cabling have probably compared designs that are equally poor i.e. share similar defects in signal transfer characteristics that they therefore share common sonic signatures.
Having said all of that, are you looking for RCA's or XLR's? Sean
Sean , just the man I was damn near praying would catch this thread ! Thanks . Oh and yes , i just got back from the show and am in simple awe . I had the time of my life and kept one eye on the badges to see if the elusive Sean could be spotted! I had my digital camera just in case as many feel you are not a real person , just a program that was created to help us out!!lol. Thanks for the help. I was asking because the manual makes a big deal of this issue actually stating that the wrong capacitance cable can be detrimental to the performance . I am looking for rca btw and was looking at re cabling the entire system once and for all. Purist Audio is on the top of the list at the moment . Sean the preamp I am speaking of is the Conrad Johnson Premier 17 LS 2. The output impedance is 'less than 850 ohms '. The input impedance of my Carys is 100k ohms. As always , I sincerely appreciate all the help you have and continue to give . Brent
Brent: You're in a situation that i don't normally deal with. After reviewing it, it has helped me to better understand a few things about mass produced tube based systems and why they sound as they do. I really have to think about this a bit and even then, i might not have much of an answer for you. One thing does come to mind though and it involves a DIY type project. Using such an approach, one can build a cable of whatever quality level that they chose to. I don't know if you are interested in such things, but if you are, let me know. Sean
Brainwater...'less than 850 ohms' is quite high even for a tube preamp, although I have seen 2000 ohms quoted. High output impedance makes you sensitive to cable capacitance (HF roll off) and noise pickup. When I was into tubes, 600 ohms was the common value for 12AU7 cathode followers. Solid state preamps run 50 ohms and sometimes less.
1. DIY as Sean suggests (unless you just want to get rid of some money). You can buy wire and connectors just as good as what the high priced labels use.
2. Keep them short (again as Sean suggests).
With your tube gear I do think that the interconnects can affect sonic quality. I myself have good but not exotic interconnects because my stuff is all SS, 50 ohms or less.
The spec's on the Bogdan cabling are very misleading due to their construction. The nominal impedance of this cable will vary wildly due to the unequal spacing between the conductors over the length of the cabling. This means that the signal will end up going through an "obstacle course" as the impedance, power transfer and phase related issues vary along the length of the cable. Sean
Arthur: When i make a comment, i'm simply sharing my thoughts and that's all that they should be taken as i.e. my personal opinion. Nothing more, nothing less.
Many of my comments are simply observations made on the technical aspects of the product and the performance that it is capable of delivering. This doesn't necessarily mean that the product that i'm commenting on won't get the job done, is piss poor in every aspect of design quality / construction / performance OR that the product doesn't have some good ideas / redeeming qualities that others might like & enjoy. This is true even if my comments come across as being somewhat negative about the product over-all.
The reason that i say this is that it is hard to make a product that does everything right and keep the price reasonable. By being aware of the specific flaws ( manufacturers call these "design decisions" ) of a product, one may be better able to assess whether it will fit their specific needs and desires. As such, i try to point out the obvious points of contention that i see so that others can be made aware of it too.
In wording things as i do, i probably come across as "harping" on the negative aspects of specific products. Given that i consider "proper design" and consistency of performance to be ordinary goals, i tend to think of these things as being a "standard feature" more than something to tout or rave about. As such, i don't offer as much praise for specific products or design attributes as i should. This is because solid engineering practices and a product that is "working right" is nothing out of the ordinary / worthy of praise to me. I reserve praise for products that are truly outstanding and set themselves above the crowd as an example in multiple different areas.
With that in mind, i've always said that one should buy & use what they like and will enjoy. After all, they are the ones that have to use and listen to their investments, so who better to try and satisfy? Sean
I mailed Mark your post and he could'nt find this thread so he asked me to post this response.
Hi Sean, your post is an epic. I've done a once through and only wish to
offer one correction, plus one suggestion. The correction I recommend you
make relates to the listing you gave near the end of your post. Re: cables
of differing nominal impedances dramatically influencing power available
from an audio amplifier. You know it doesn't work that way, but the listing
implies you can only get X watts through a cable of Y ohms Zo, given some
fixed amplifier output (Volts i guess). I can elaborate but I'm sure you
will agree without my spelling it out in detail.
The suggestion I have is to always have in the back of your mind, and that
of all readers here, the electrical wavelength of any audio signal of
interest, as the wavelength is of crucial importance in considering the
impact of impedance mismatches.
I'll go with a reminder that audio amps don't have output impedances
matching their anticipated loads or speaker cables, yet RF amps all do match
(try to anyway) the cables they feed.
As i've said before, I concur that low Zo audio speaker cable is a logical
marriage of RF and low frequency design, and support your cause in this
respect. Cheers Mark Koester (RF engineer)