Alpha-Core Goertz speaker cables

I have use Goetz AG-1 center stage for about 10 years now with a variety of equipment. It temporarally gets replaced but somehow I always wind up going back to it. A friend of mine loves his Goetz Micro-Pearl interconnects. I highly recommend the Goetz stuff
Alan

I can tell you they are sweet sounding cables with terrific tone and an open quality (on the one system I am familiar with) though a bit lean.

I did not need the supplied zoebel networks with my Plinius amp and Maggie 1.6 speakers you may need them

My favorite 'economy' cable.

though several years since I owned them and cables like Morrow are out there which are also very good.

YMMV of course

A lot of people have reported excellent results with them, but I'd be cautious, as Elizabeth suggested. Their ultra-low inductance is achieved at the expense of ultra-high capacitance, and if a Zobel network is not used that can cause some amplifiers to oscillate, and possibly fry. Although since you are using monoblock amps the relatively short cable lengths will reduce that possibility, since the total capacitance of the cable is proportional to length.

The extent to which the ultra-low inductance will make a difference (as opposed to being overkill) depends on the impedance of the speakers at high frequencies. The lower that impedance, the greater the likelihood of there being a difference (which is not to say that the difference will necessarily be for the better, subjectively). But as with most dynamic speakers (as opposed to electrostatics, for instance), I suspect that the impedance of your speakers rises considerably, rather than falls, at upper treble and ultrasonic frequencies.

The combination of ultra-low inductance and ultra-high capacitance also results in the cable having ultra-low Characteristic Impedance, about which the Goertz website says as follows:

The characteristic impedance of the Goertz MI cables in the order of 2 to 4 ohms closely matches the impedance of loudspeakers. Almost all other speaker cables have characteristic impedance ranging from 50 to 200 ohms, a mismatch which causes distortion due to signal reflections. Impedance matching primarily improves the clarity of the highs and upper mid-range, but many users have also experienced improvements in the lower mid-range. The cause seems to be that signal reflections caused by impedance mismatch enter the feedback loop of many amplifiers and disturb their ability to reproduce faithfully even lower frequency signals.

IMO that makes no sense, at least in the context of a dynamic speaker. The reflection effects that it refers to will only occur at RF frequencies, and possibly to a small degree at ultrasonic frequencies. At those frequencies the impedance of a dynamic speaker will be much higher than the 4 or 8 ohm impedance it may have at audible frequencies, and at those frequencies the impedance of the speaker therefore will not come close to being a good match to the characteristic impedance of the cable. Very conceivably it could even be a worse match than would exist between the speaker impedance at those frequencies and the characteristic impedance of a cable having ordinary parameters.

Regards,
-- Al

The MI-2 is a nice cable at a great price. I have a set I still use on occasion in my system. As mentioned, the Zobel network may be required in order to prevent the amp from oscillating. I purchased mine with the Zobel network built in but you can get the Zobel network separately as well. Look up some posts by Audiogon member Sean (he dropped off here quite a while back) and you will find some interesting discussions on this speaker cable.

A p.s. to my previous post. In addition to capacitance being proportional to length, as I had mentioned, inductance is also proportional to length (as is resistance, for that matter). The relatively short length that you require will reduce whatever difference having low inductance per unit length might make.

Regards,
-- Al

Thanks to all. Al, I was hoping you would reply, so thanks to you as well. I understand better now and think it is an interesting approach but it may be "an answer in search of a question".

FWIW, I have used both the MI 2's and MI 3's with Alpha-Core's external RC networks (zobel's) and have found them to be the best sounding speaker cables I've ever used. I do suggest you do a search here on Audiogon, there was quite a bit of posting done on them, some of the most interesting by Sean. Better yet, give them a try,
Alpha-Core has a generous free trial policy, don't forget to ask for the RC networks.

I've been using the MI3 speaker cables for many years with out any amp problems, but I recently purchased new speakers with a tri-wire connectons on back. I have the opportunity to purchase another set of (used) MI3 cables, but I wonder if doubling the amount of these cables will cause my amp problems. Anyone out there had experience with this? I've had my cables since 1997 so I don't know what I did with the networks or if I ever had them.

Gkp, without knowing any of the details of your system and setup, particularly what amplifier you are using and how long the cables are, I'd have to say that without a Zobel it would be a significant concern.

The MI3, along with the AG3, have the highest capacitance of any of the Goertz cables, at 1500 pf/foot. From the perspective of the amplifier, using a biwire pair will double that.

Factors that would increase the likelihood of a problem are long cable length, the amplifier being solid state, the amplifier having wide bandwidth, and the amplifier using relatively large amounts of feedback.

Regards,
-- Al

Thanks for your insight, Al. At this point I will probably pass on the extra set of cables and just get better jumpers. But if the system matters that much, here you are: Tube amp--AudioPrism Debut Mk1. It is very flexible in that the output can be set to 2,4,6, or 8 ohms, and the feedback has settings for each of those outputs. Right now I'm using the 4 ohm output setting and the '6' feedback setting. Only problem is that the bottom panel must be removed to make any changes. I think it has 16 screws!

My speakers are the Spendor SP 9/1. They have a 5.6 minimum impedance, and are rated at 91dB sensitivity. The MI3 cables are 8 feet long.

So, good or bad match for the bi-wire option?

Thanks again.

Gkp, if it were a solid state amp, with 8 feet of cable being required, I would definitely recommend against using a pair of biwired MI3's (without a Zobel, at least). I couldn't find detailed specs on the Debut Mk1 (particularly bandwidth and how much feedback position 6 corresponds to), but FWIW my instinct is that since it is tube-based you would probably be ok, but nevertheless the risk isn't worth it.

I suspect that the chances of oscillation and/or damage occurring would be small, but even so putting 24,000 pf of capacitance across each of the amplifier outputs doesn't figure to be helpful sonically.

At this point I will probably pass on the extra set of cables and just get better jumpers.

Sounds like a plan!

Regards,
-- Al

You might want to read a review of the AG 2s I did back in 2005 for ultraaudio, a webzine.

I owned, simultaneously, the Alpha Core and the Valhalla (both interconnect and speaker cables) and found them nearly (not completely) indistinguishable.

Interestingly enough, back around 1998 or maybe a bit later, TAS also had a review of the Divinity line, and found them superior to the Nordost. Roman Zacjew wrote the review. HP later commented on them, and was surprised to hear that they were nearly indistinguishable - but later on, he used a turntable and found the differences more pronounced.

I should point out the Nordost of that time was the SPMs. And, just to see if I could remember which issue it was (and I could), it was issue 113.
Aside from that, I also had for review, the copper wire, which I found to be quite, quite good. As I was using Nola Elite speakers, which needed bi-wiring, this came in handy.