Is it the AI-1 interface question #1

hearingimpared · August 2006

I just purchased a pair of SDA/SRS 1.2 TLs. The interface cable that came with them doesn't show AI-1 interface on it anywhere even though the seller says it is just that.

It is a pin/blade configuration with a transformer (at least that's what it appears to be) that is marked, " SDA Non-Common Ground Amplifier Interface." It does not appear to be a home made cable like one described in Raife's SDA Compendium.

Is this the AI-1?

Thanks,
Joe

dorokusai · August 2006

Yes.

trubluluc · August 2006

What Mark said!
It states on the top of the box:
"Non common ground"

-Luc

DarqueKnight · August 2006

Joe,

If you are going to be using a common ground amp, you might want to compare the sound using the AI-1 cable with the sound using a fabricated SDA interconnect (only the pin carries a signal). Some people have said they heard no difference between the AI-1 and a regular SDA interconnect. Matt Polk said that the AI-1 slightly diminished soundstage width. Others have said that the AI-1 slightly diminished clarity and detail.

Congrats on the acquisition.:)

hearingimpared · August 2006

Thanks guys . . .

Some people have said they heard no difference between the AI-1 and a regular SDA interconnect. Matt Polk said that the AI-1 slightly diminished soundstage width. Others have said that the AI-1 slightly diminished clarity and detail.

Raife the above info is noted in your compendium. I read both the user manual and your compendium several times, I still have one question. 1). If I choose to use two amps bridged mono one for each channel low frequencies and use the AI-1, can I still use a good adcom or rotel to bi amp the high frequencies? 2.) If indeed the AI-1 diminishes any soundstage or details, if I connect the grounds on the bridged amps can I just use the regular interconnect?

Thanks,
Joe

DarqueKnight · August 2006

hearingimpared wrote:

1). If I choose to use two amps bridged mono one for each channel low frequencies and use the AI-1, can I still use a good adcom or rotel to bi amp the high frequencies?

Yes.

hearingimpared wrote:

2.) If indeed the AI-1 diminishes any soundstage or details, if I connect the grounds on the bridged amps can I just use the regular interconnect?

Yes. If the amp manufacturer says it is ok to connect the amp ground terminals together, you could then use the regular SDA interconnect. That is what I did when I used a pair of Adcom GFA-565 mono amps and also what I am currently doing with a pair of Parasound JC 1 mono amps.

hearingimpared · August 2006

Thanks, Raife!

F1nut · August 2006

You don't want that AI-1, so I'd be happy to take it off your hands.

hearingimpared · August 2006

You don't want that AI-1, so I'd be happy to take it off your hands.

I haven't tried the AI-1 yet and the combinations of amplifiers. But when I do and if I find that the AI-1 doesn't deliver the goods you can have it. That being said maybe we could trade the AI-1 for a regulare interconnect cable.

Thanks,
Joe

F1nut · August 2006

I'm up for a swap.

riglehart · August 2006

Jeeze. And I just spent a month messing around with transformers to build one.

FYI. On my homemade AI-1, you definately loose something when you stick a transformer on the cable. It's unavoidable. I have a non-common ground NAD 2200 and am seriously considering using something else just so I can go back to the straight cable. The AI-1 seems to be a "work around" that, in my opinion, should be avoided.

DarqueKnight · August 2006

riglehart wrote:

Jeeze. And I just spent a month messing around with transformers to build one.

I'm sure yours, with the heavy duty toroiday transformer, sounds worlds better than the stock AI-1.

riglehart wrote:

On my homemade AI-1, you definately loose something when you stick a transformer on the cable. It's unavoidable.

Matt Polk also said that you lose something (stage width) with the stock.

riglehart wrote:

The AI-1 seems to be a "work around" that, in my opinion, should be avoided.

My conclusion exactly. As always YMMV.

F1nut · August 2006

On my homemade AI-1, you definately loose something when you stick a transformer on the cable. It's unavoidable.

What do you feel is lost?

Matt Polk also said that you lose something (stage width) with the stock.

I haven't found a loss in stage width. In fact, if it was any wider it wouldn't be believeable.

riglehart · August 2006

The stancor transformer sounded bad all around. Volume on the SDA driver was 1/2 (or less) as much as with a straight cable. Plus it sounded really flat. Imagine putting a pillow up against the speaker.

The torroidal helped a lot. Volume on the SDA driver was probably 80-90% of a straight cable, plus it was good sound.

You can't really do a side by side test with the two cables (straight cable vs transformer) without 30 seconds of downtime during the swap. The difference isn't enough for me to really notice. My hearing memory isn't that good 30 seconds later. So, it is a pretty close contest. However, if I sit in front of the speakers in the sweet spot and have someone do the plug/unplug routine while something is playing, I don't notice as dramatic of a difference on the ai-1 as with a straight cable.

If I scrap my NAD, I'd be willing to "borrow" you my torroid AI-1 for a couple weeks if you really want to try it. Right now I need it, though.

F1nut · August 2006

Ok, thanks for that info. I'd love to try your torroid AI-1 if it becomes available. Of course, I'd pay shipping both ways.

dorokusai · August 2006

I've noticed no difference with the stock cable or an Avel(Toroid) based DIY....but maybe I'm just losing my hearing.

riglehart · August 2006

dorokusai wrote:

I've noticed no difference with the stock cable or an Avel(Toroid) based DIY....but maybe I'm just losing my hearing.

I notice a post from you where you gave the Avel model. I think you used a bigger (probably better) one.

Here's mine...

http://www.polkaudio.com/forums/showpost.php?p=477212&postcount=33

univera · August 2006

riglehart wrote:

Jeeze. And I just spent a month messing around with transformers to build one.

FYI. On my homemade AI-1, you definately loose something when you stick a transformer on the cable. It's unavoidable. I have a non-common ground NAD 2200 and am seriously considering using something else just so I can go back to the straight cable. The AI-1 seems to be a "work around" that, in my opinion, should be avoided.

Just curious if when referring to the 2200 as being non-common ground if you meant bridged mono or in stereo as well?

Also, is there any sonic disadvantage to connecting the grounds of two amps if one doesn't have the A-1 interface? Seems that if all things are equal, then connecting the grounds on two amps and not using the Interface eliminates any possible degredation of volume and or soundstage. I realize thanks to another member it wouldn't work on my speaks, but interested in learning just the same.

What exactly does connecting the grounds involve? Again, please keep in mind that I am not a technical or mechanical whiz:o

univera · August 2006

dorokusai wrote:

I've noticed no difference with the stock cable or an Avel(Toroid) based DIY....but maybe I'm just losing my hearing.

Rumor has it that placing the A-1 interface across 8, high quality, acrylic Signal Cable Risers POSSIBLY eliminates any reduction in soundstage caused by the A-1 and may eliminate the need for any ampification whatsoever:D

DarqueKnight · August 2006

univera wrote:

Also, is there any sonic disadvantage to connecting the grounds of two amps if one doesn't have the A-1 interface?

You should always ask the amp manufacturer if the grounds can be connected. If the grounds can be connected, use a heavy guage insulated wire equal to or greater than the guage of your speaker cable wire. I made common ground connecting cables out of 10 gauge wire and terminated them with bananas.

I have not run across a case of sonic degradation when connecting amp grounds, but it is possible depending on the design of the amp. Again, the manufacturer knows best.

univera · August 2006

Do the ground connects just connect to the body of the amp?

DarqueKnight · August 2006

Usually, you just connect the negative speaker terminals together. Sometimes, as in the case of the Adcom GFA-565 mono amps, the manufacturer will specify that a wire be connected the cases in addition to a wire connecting the negative speaker terminals. For my GFA-565's, I soldered a thin metal washer to the ends of my grounding cable and then attached it to the amp cases with one of the case screws.

Also, you should be aware that some amps have the ground connection at the postive speaker terminal rather than the negative terminal.

BOLIN6861 · August 2006

If You Still Have The Cable Would You Like To Sell It?

2-tall · September 2006

Does anyone know if a carver tfm 24 is common ground?What are the best components to make a standard interconnect cable?

dbnh · September 2006

riglehart wrote:

I have a non-common ground NAD 2200 and am seriously considering using something else just so I can go back to the straight cable. The AI-1 seems to be a "work around" that, in my opinion, should be avoided.

I used to use a NAD 2200PE with the SDA 1-Cs. I subsequently switched to Odyssey Audio Extreme Monoblocks. I had a very experienced DIYer from Head-Fi custom build me an AI-1, and I've used it with the NAD and my current Odyssey Extreme Mono amps. For my hearing, the Odyssey monos work synergistically with the rest of my set-up to make the Polks absolutely sing with the custom AI-1 in use. The NAD is, from my many years of listening, no where close to refinement and effortless power/reserves of the Odyssey amps; I wonder how much of what you're hearing is due to the limitations of your NAD, the rest of your gear, unremedied Polk driver plug/tab oxidation over the years, etc. [Of course, the NAD amp was no where near the cost of the Odyssey Extreme monos (not that the Odyssey gear is overly expensive - I find Odyssey's gear to be very reasonably priced.) On the other hand, the NAD2200PE gave me plenty of years of pleasant and absolutely reliable service, and is the current amp in my teenager's stereo system.]

Regarding possible soundstage diminishment when using the AI-1: I don't hear any downgrade with my gear/system. With the Odyssey amps in the system, the soundstage is noticeably wider and deeper than with the NAD in play. I reiterate that I don't have a stock AI-1, and have no opinion on what the stock component sounds like. FYI - I have no idea what transformer was used in the building of my AI-1.

YMMV. Happy listening!

Is it the AI-1 interface question #1

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