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Parasound HCA-1200 in mono mode

purple1

purple1

Well-Known Member
I picked up another Parasound HCA-1200 from the big auction site. It should come in a few days. I already have one HCA-1200 and it is hooked to a set of IMF RSPM Mk. IV. I want to put the 2 HCA-1200s in mono mode and drive one of the IMFs from each. Do you think this is over kill? Will I hurt my IMFs?

The HCA-1200s are rated 600 watts in mono mode. I already plan on adding another circuit cause I can blow the breaker now if turned up. What say you, am I nuts?
 
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Whether or not the speakers get damaged is a matter of how you run the system, not the amplifier's power output.

There must be a lot of other fairly high load stuff on the circuit that's blowing, in addition to the existing amp?
 
whoaru99 said:
Whether or not the speakers get damaged is a matter of how you run the system, not the amplifier's power output.

There must be a lot of other fairly high load stuff on the circuit that's blowing, in addition to the existing amp?
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I like it loud sometimes when no one else is home or on movie nights.

Oh yes, this is only part of a 7.1 setup. Other amps include an Acurus 200x3 and a Kenwood power amp rated 150 watts/channel that the model number escapes me right now. Plus 4 powered subs.
 
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Considering I run high power in a couple systems, including HT, it would be hypocritical of me to suggest it's too much/unnecessary for you.

However, as I eluded to earlier, the amps are not responsible for any damage that could result.

With this level of clean power, particularly if the speakers are high-passed, one must be cognizant of the possibility for thermal damage to the speakers. This can happen without traditional symptom(s) of too much power. It is up to you to recognize/learn the limits.
 
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It's here! Now the fun can begin....

But first I have to install another circuit to power this rig. :naughty:
 
I approve of your idea to run two HCAs in bridged mono mode. They are excellent value amps, IMHO, bang for the buck.

You can over-power speakers with a clean signal. In my experience (with ADS speakers), you'll hear a very noticeable 'speaker strain' condition that tells you to turn down down the volume. I was able to turn it down without damage to the speaker.

The strain sound is hard to describe; it's like an electrostatic CRT 'scree' noise, and a feeling that the cabinet is going pop apart at the seams.

I can't even hazard a guess regarding heat damage to the drivers, or how soon that would take place.

Let us how you like the Parasounds in mono.
 
I have completed installing a new 20 amp circuit and I also upgraded the other 15 amp circuit to a 20 amp. All I had to do was change the wire to #12 for the upgrade and replace the breaker. I put both amps in bridged mono mode. I also replaced the center channel speaker with 2 larger pinnacle speakers. Wow! What a difference. The IMFs are now so much clearer. Replacing the center also made a huge difference.

Now it seems I may have a problem with my first Parasound HCA-1200. It is now taking about 2 minutes to go from standby to ready. I'm getting no sound from that amp until the green ready light comes on. It is not switching like you would think either. It is slowly turning on the green ready light and at the same time the red standby is slowly going out.

The other amp is not doing this. It comes on in standby and within about 2-3 seconds standby goes out and the green ready light come on. It may be time for service on the one amp. Any ideas what could be happing here?
 
That would be the 'protection mode'. You'll need to set the dc offset, and bias. Not sure exactly how to do on the HCAs. You'll need a DMM. Find the test points, and adjust the VR pots with a little screw driver. Look at the stickies in the DIY forum.
 
BigElCat said:
That would be the 'protection mode'. You'll need to set the dc offset, and bias. Not sure exactly how to do on the HCAs. You'll need a DMM. Find the test points, and adjust the VR pots with a little screw driver. Look at the stickies in the DIY forum.
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I'll look for a schematic as soon as I get a chance. I hope it is that simple and doesn't need a major repair. I have the tools and the skill, but just don't have the time. :eek:
 
Capacitor quality was high enough in the '90s, I think you'll be okay. The pots are just probably set, and need to be worked.
 
BigElCat said:
Capacitor quality was high enough in the '90s, I think you'll be okay. The pots are just probably set, and need to be worked.
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I'm sure you are correct. But it would be nice to have a service manual or at least a schematic to know what is what before diving in. A quick search on Google didn't turn up any thing for the HCA-1200. I found both service manuals and schematics for the HCA-1200ii but that is a totally different animal.
Can any one help with the HCA-1200?
 
I called and spoke to Tony at Parasound. He ask that I e-mail him so I did. He said he would try to find a service manual and\or a schematic. I'll let you know if he replies.
 
Wow. Less than 15 min. and I have the schematic in hand. Tony has come though. Now that is an awesome company. He also said "Bias should be 10mV across one of the emitter resistors after amp has warmed for at least ½ hour".

Now I just got to get the amp out of the cabinet and on the bench.
 
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