Parasound HCA-1200 schematic ?

[promitheus]

Hi,

I have a Parasound HCA-1200 amplifier that doesn´t turn on it stays in stand-by.
does anybody have a service manual or schematic for this amp?

Thanks in advance.

 

[promitheus]

Well this is one more try to get some help.
I have asked Parasound for help but not much yet.
If anybody can help please post.

 

[john curl]

Pro. I have a 1200mk2 schematic on adobe acrobat that I can send you, just email me at j_curl@earthlink.net, if this will help. If not, email Parasound at Tony@parasound.com. He just sent me a schematic this week the same way.

 

[promitheus]

Thanks for the tip.

I already sent you an email for your schematic.
If possible I would like to have it.
I also sent an email to the guy you told me at Parasound.

Thanks a lot.

 

[john curl]

The first thing that I would try to measure is output offset. If it is too much, then the protection relay will not close. This is also true of any input offset from your preamp.

 

[promitheus]

Thanks a lot for the schematics and suggestions.
I will see what´s wrong with it and post the results.

 

[rmhuizenga]

Tony seems to be pretty quick about the schematics. I just bought an HCA-3500 and he had schematics to me within a couple of hours. Heck of an amp for only $850 used. The parts alone would cost 3x that to buy!

One thing I'd be curious about Promitheus--Is the supply capacitance in the amp / on the schematic the same, and does it match up with Parasound's claims? I was a little surprised when I got the HCA-3500 to find only 66000uF per channel instead of the ~98000uF Parasound claims on the website and in the manual..

 

[promitheus]

well on the schematic i see only 60 000 uF. There are 4 caps of 15000uF.

 

[john curl]

You have to count ALL the caps, not just the big power caps. You have driver supply caps, etc, as well. That's marketing! Still a good buy. I couldn't buy the parts at that price.

 

[rmhuizenga]

Yup.. I added them all up and sure enough, it came within a few uF of the quoted figure. Nice marketing gimmick, and it clears up one of the difference between the JC-1 and the 3500 I'd wondered about before I bought the 3500. Using Parasound's quoted figures the claim for twice the capacitance Mr. Crump and yourself had mentioned was always confusing. Time to tack in my stack of el-cheapo Teapo caps.

Considering the high quality parts and great design, it's a steal. At $200 for the outputs, $300 for the trannies, $300 for the caps, having it all assembled into an amp with PCBs and other parts and a chassis for $800 was a deal.

POOGE time? 🙂

 

[lumanauw]

Mr. John Curl, I have 2 question about this schematic.
1. What is IC101 1/2 doing, giving lowpass to the output? Is it to detect any DC coming from the input?
2. The small power supply (D002), does the ground is the same as the main ground, or it is floating?

 

[promitheus]

the Ic at the output is a dc servo. It control the DC offset at the outputkeeping it at 0V

 

[john curl]

I'm a little confused as to what IC101 does, myself. It is part of the 'housekeeping circuitry' added by the manufacturer in Taiwan. It appears to sense any incoming DC from the source preamp, amplify it, and then send it to the protection network. I can't say how the grounding appears to be connected. Usually the driver ground is the same as the main power supply ground at some point.
Many people think that I directly work for Parasound, but this is not true. I am a consultant, who gives them the specific topology and some of the necessary parts to be used, BUT I don't design the amp entirely. Housekeeping, power supplies, remote control, little blinking lights ;-) are not what I do. Someone in Taiwan does this. I even refrain from repairing these units if I can avoid it, and send it back to Tony at Parasound.

 

[nelidovo8]

Parasound

Hi! I have a PARASOUND HCA-1200 and for some reason will not power up.
Can anybody email me a shematics for the amplifier or info where to get it.
Aleks.