Srs1.2 Tl Problem

[Leftplumma]

Hello,
I recently purchased a used set of srs1.2tl speakers, as well as other equipment from a friend.
I also aquired a pair of Hafler xl600 power amps with the package.
These amps were sent to George kay audio for the tube hybrid upgrade.
Upon seting up the gear, I found the sound to be very harsh, and somewhat lacking bass.
I then found that if I ran the left side out of phase, things got a bit better.
Upon further inspection I realized that when I turn on the left amplifier, as soon as the warmup circuit engages, all of the drivers rush forward and stay there, (or backward depending on the phase) and there is little or no movement of the drivers during music playback.
I am assuming that this would be a problem with the left channel amp and not the speaker???
Has anyone ever encountered this.
Any help would be much appreciated.
Thank you

[F1nut]

Welcome to the forum.

Let's check a few things. Are you using the AI-1 interconnect cable since you are running mono blocks? If so, try swapping the left and right amps to see if the problem follows. Are all your connections between the amps and pre amp in the right location?

[trubluluc]

Are you using the interconnect cable?
If so, try disconnecting it.
Second I would try a different power source, as in a receiver just to make sure the speakers are working properly.
Then move to trying to figure out what's happening with the amps.

-Luc

[BobMcG]

...there is no AI-1 in place?

Story: Years ago a family member was running a similar pair of Hafflers (not hybrids) in mono with a pair of 2Bs without the use of an AI-1. He was told (I think by Haffler) he could make a common ground system by connecting the two amps together and how to do it. It didn't show up for a while but eventually problems developed. It seemed as though something was going wrong with the speakers but it was the amps that were getting ruined. A ckeck from Hafler confirmed one amp's outputs were in deep crap and the other was developing problems too. Well long to short, the amps were fixed (for free at that) and talks with Hafller and Polk decided it was an AI-1 or nothing and so an AI-1 it was and was the end of all problems. (They were still available from Polk then.)

[F1nut]

And then there is this copied from Polk's site.

"One way to check is to turn on the system but play no music. Take off the speaker grilles and observe the woofer(s). If they are moving or are pushed out or pushed in rather than at rest in the neutral position, then your amp is putting out a DC voltage and that is a BAD thing."

[dorokusai]

I don't think you could get any more specific than that....good eye F1....even tho' they are old.

[Leftplumma]

OK,
First of all, thank all of you who responded in such a timely manner to my questions.
In answer to yours, I am running an interconnect cable that has an Isolation transformer on it.
is this the cable that you have all mentioned???
I think that there was a problem before, and then the cable was used thereafter.
Also, does the presense of dc voltage mean I should tie my sailboat to this amp in the spring, or can it be repaired?????
Also does anyone know of a good place to have the work done??
Thank you all again for your help.

[F1nut]

Yes, that is the cable mentioned, so that's not the problem. Looks like it's the amp. Why not contact George Kay Audio since they are the ones that worked on it, must have a warranty of some sort.

[BobMcG]

I think that there was a problem before, and then the cable was used thereafter.

Were the amps ever inspected for damage by a competent repair center "after" the problem was discovered and "before" the proper cable was put into play? What I mean is, is it possible it was already too late for the amps and nobody realized it?

In the problem example I offered above, even thought the amps had sustained some damage by not having the AI-1 in place (one more than the other) they still ran but you could tell something wasn't right and was only getting worse. They were unhooked and sent back to be inspected before they could harm the speakers. Hafler said they were on the way to possibly doing just that. The damage didn't occur as a quickly fried amp or as an obvious problem right off the bat that couldn't be overlooked.
Just currious.

[Tour2ma]

Did you try, as trubluluc suggested, disconnecting the AI-1?

Don't know if it is possble for isolation transformers to go bad, but since in general tranformers can short out...

If it's OK with the SDA interconnect unplugged, check the AI-1 with a VOM to be sure there's no continuity...

[Leftplumma]

Hello again, and thank you for all of your help.
Just a quick update.
After reading your last replies, I hooked the SDA"S up to an old sansui BA-5000 amp that I had laying around and "POOF"
The speakers seem to be acting normally now (except for the two blown drivers on the left) and actually sound pretty good.
I think that I will abandon the haflers right now, and stick to this known good amp.
I think that I will replace most or all of the drivers considering their age, and history of abuse.
I am also thinking of the tweeter upgrade, and also upgrading the crossovers too, (per. Darqnite specs).
I do not think that George Kay is still in buisness, but I am looking into other alternatives for the Haflers.
Thank you all again for your help, and if you ever need any Plumbing or heating advise please feel free to contact me at mechenrg@metrocast.net.
Jeff

[Tour2ma]

Looks like F1 and BobG nailed it...

Thanks for the update and good luck...