Hafler IRIS Preamp Schema or info ?

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I have an old Hafler preamp IRIS. I can´t find any info on this preamp. I need a schematic or service manual to some repairs and modifications. I would also need maybe some info on an IC called LM8500 which I think is not working correctly.

If anybody has some help or some links to share I would be very happy to accept them.

Thanks in advance.

I've also been looking for the IRIS schematics with no success. The manual posted on the Hafler website is missing the schematic pages.

The IC you are looking for is not an LM8500, it is a CLM8500/2 made by Clairex. It is a dual center tapped LDR.

You can find this info on the James C. Strickland patent about the "Cyberoptic Audio Level Control System" used in the IRIS preamp. US Pat. No. 4,905,291. The patent provides a schematic diagram that should closely match the "real thing".

This is the best I've been able to find out so far.

Be prepared to spend some time on that circuit as it is overly complex (but brilliant as well!).

I hope this helps...

I was fortunate to be the Canadian service technician for Hafler
products, at the time the Iris pre-amp was being manufactured.
The circuitry is indeed brilliant, standard for Jim Strickland, who of
course, also designed the Acoustat products.
There is another opto that can be used in place of the CLM8500/2,
being the Vactec VTL5C4/2.
I found these only needed replacing if there was a symptom of
poor, or no control of the volume.
A common cure for obscure faults was cleaning the circuit board
around this control circuitry absolutely clean, clean, clean! This
was due to the high impedances involved, and the flux used,
affected the operation. I hope this helps.
the patent that jim strickland filed for the cyber optic volume control may help also. i'll see if i can find it.
alas, i've never seen the schematic for the actual preamp either.


ok, i found the patent number: US4905291
title is "cyber optic audio level control"
good luck!

hafler iris

Greetings from Port Elizabeth,South Africa

I was fortunate to stumble upon this thread and would be most grateful if folk on the forum could shed some light on the following Hafler Iris pre-amp issues:

1. I have the Iris linked to two Hafler P700 amps. The Iris appears to have a slight problem at the lower end of the volume range i.e. when the volume is quite low(back-round music level) it cuts out the lower tones and only produces the "tweeter" section on the speakers. Is there any solution for this problem (I did try and clean as per the recommendations on this thread but to no avail)? Alternatively is there a schematic to enable me to take it in for repair (which could be problematic in this part of the world as there are many hack artists who would do more harm than good)?

2. Did the Iris come with the remote control card fitted as standard and if so could one possibly use a learner type remote to activate this. If not is there any where in the world one could purchase the remote control functionality ?

My apologies for what may appear to be uniformed questions but that is exactly what I am and to boot do not have the original manual for the Iris (did download one from the Hafler site though)
Hafler Iris volume

Hi Cracklin
It appears the fault is not the preamp, but that the
volume contol to the "tweeter" amp is set just a bit
higher than the one driving the bass. Re-adjust
slightly and all should be ok.
The Iris did come as remote contolled but due to the
unique nature of the volume contol ( a manual pot on
the remote) you won't be able to use a learning
The person you bought the preamp from should
still have the remote....he hasn't delivered all you
paid for.
I know that this is an old thread to dig up, but I wanted to add some info for anyone that pulls this thread up while searching for Hafler Iris schematics. Just go to the Hafler.com website and call their tech support number, you'll actually be calling Rockford's tech support. It took me less than 5 minutes to get a copy of the schematics via email. I wish I had thought of calling before spending all that time searching the internet for them.
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