Doug Schroeder Method, Double ic

I test and make cables daily. It is what I do. Yes, I test all manner of gauge, dialectic, twist, materials etc.., No, not just once or one combo.

It may be possible to find an outlier to my comment and in audio one must always leave the door of possibility open. I also know we all hear differently. My comment is based on my experiences, in general, with ICs. I did not take the time to post all my gauge testing in my post above.

Yes, the previous posts are in agreement with your comment about additional conductors being a good thing. This is a point of agreement. This is especially true when done in the DS arrangement.  However, if using only one positive and one negative individually insulated wire there is a point when the thicker gauge is no longer a benifit.  It actually becomes a sonic negative. I gave one example. 

Shotgun speaker cables has been around since the 1970’s. That’s not what the SM is about. If one wants to double up speaker cables, then have at it. Enjoy the SQ benefits!

Very interesting experiment you have going on here Doug. Read through most but not all of this thread as well as the original article posted on Dagogo. Bob Smith's response also made much sense although to have a complete understanding of all he had to say would require another reading or two at least for me.

I'm sure some EE on this website will correct me if I'm wrong but wouldn't it be easier, much easier in fact to create your own interconnects using two twisted pairs of high quality wire using a cross connected method. By that I mean each pair would have a positive and negative and both positives and both negatives are soldered to respective terminals on the RCA plugs. Shielding if needed could be added as well. To my way of thinking this is a far simpler way of accomplishing what you're doing with a litany of accessories. The exact same method could also be used on XLR plugs as well but with the addition of a third wire be it shielding or otherwise. 

It is worth noting some cable companies prefer to use twisted pair wire vs coaxial for line level interconnects. Ray Kimber I believe is a big proponent of this implementation. 

In the past I have built cables like this myself, both RCA and XLR using nothing more than dissected CAT 5 cabling. Granted probably not the best copper available but it made for an inexpensive easy to assemble test and experiment. 

Now all that out of the way, what I don't understand and surely someone will school me on this is why you think doubling the capacitance on an already low capacitance set of interconnects will create harmful oscillation between pre-amp and amp. I know this is true for wide bandwidth amplifiers where high capacitance speaker cable is used to drive the speakers. Goertz flat wire as well as excessive multiple braided wires come to mind, but only on amps that have high bandwidth. There are numerous cable companies manufacturing interconnects both RCA and XLR with much higher capacitance than we are discussing using any of these experiments and to the best of my knowledge without any harm. I do understand your sense of caution but not entirely sure what translates to the amp/speaker combination also translates to pre-amp to amp or line source to pre-amp. Hopefully this make sense.

routlaw, thanks for your well thought out reply. You seem to be advocating a DIY version of Schroeder Method, which certainly can be done. I was shooting for proof of concept when I used splitters and Y-cables. Also, it’s much less work to assemble them in a moment versus building them with no proof of concept. Ideally the splitters/Y-cables would be optional for variety and potential mixing of cables.

A good reason why a person would pursue the assembled version is that if cables were to be mixed, it would be a lot of hassle to build it and then find out that particular combination was not as perfect as another. Assembling them makes it far easier to compare.

Manufacturers are now making double ICs per Schroeder Method, and they are meeting with acclaim by users.

When I first proposed the idea to cable manufacturers and other designers one of the caveats was concern about use with class D amps in particular. I was simply covering my ass, so to speak, by putting the caveat out there. The concern may be dispensed with eventually, but I was not going to stick my neck out and say, "Hey, everyone! Try this!" and then potentially have someone report a bad outcome. I’m trying to be sensible while exploratory.

BTW, several other designers have said that there should be no problem. There has not been perfect consistency in feedback by the manufacturers and designers who considered it theoretically, so imo caution is not a bad thing. But, I do not know of an instance where there has been a bad outcome, i.e. incompatibility.  :)

Hi Doug,

Well the DIY approach is certainly one option but you have obviously proven other ways too. Using the approach I previously described the only real difference (that I can think of) from an engineering and scientific stand point is the two sets of conductors share the same shield, assuming a shield is even implemented. If not, then less capacitance anyway. The two sets of conductors also are considerably closer to one another and that geometry "might" have some effect either for better or worse.

However one great advantage of twisted pair wires especially when using the cross connection scheme is the effect of common mode noise rejection which could eliminate the need for any other shielding to start with, not to mention that twisted pair wire to some degree provides some shielding as a side affect.

Allow me to digress for a moment. I am not an EE, but have just enough knowledge to get into trouble from time to time with this hobby. IOW's my hypothesis could be all wrong, but am inclined to think it is correct.

You mentioned the difficulty in acquiring XLR connectors to implement this but the DIY approach using twisted pair wiring cross connected would nip this in the bud quickly. I was able to find however what looked like some fairly high quality male to female as well as female to male XLR splitters made by Hosa. They seem to be available at a number of different online venues.

Hope this helps.