bullittstang 13 Posted August 12 Posted August 12 Hey everyone - glad to be a part of the community. Looking forward to reading through some of the posts and getting more knowledge of amplifiers and circuits. Build and repair amplifiers (notice I didn't day design) for almost 6 years now, which started with designing and building speakers about 15 years ago. 7
bullittstang 13 Posted August 12 Author Posted August 12 (edited) Reason for the join, is this forum was mentioned to me from DIYAudio.com, where I posted for some help on a Carver A-220 and setting the bias. A friend found a working, decent condition A-220 at an Estate sale and asked me to look it over before he hooked it up to any speakers. It all checks out, all original (it appears), except for a 14-gauge plug, although it's still only 2-prong. I checked the repository and there is a Specs Sheet and Owner's Manual, but no schematic or Service Manual for this model amplifier. Like I said, it works (listening to it as I write this post) and sounds great. I only want to check what the Bias procedure is, because when I check the voltage over the emitter resistors I get 0-1mV and the heatsinks are barely above room temperature after 2 hours of playing music. I would expect there to be 10-20 degree rise over ambient after that long. So mainly want to see if this design requires special bias procedure, and what the voltage measurement at what points is correct for factory spec. Thanks and appreciate any help or comments. Edited August 12 by bullittstang 4
Community Admin AndrewJohn 11,503 Posted August 12 Community Admin Posted August 12 Welcome, @bullittstang. The A series amps came in the timeline late in Carver Corp's life. A little less rigor on the service manuals and schematics production - so we haven't found a copy for the library, yet. If you find one out there, we'd value adding it to the library. Another tech here (I'm not one) might have the answer to your question from their experience. Glad you like the amp! It's easy to fall in love with these Carver components! Again, welcome! 1 1
Brian K. Totten 499 Posted Tuesday at 11:31 PM Posted Tuesday at 11:31 PM Welcome, from San Antonio! Without a service manual, you may still be able to look at the amplifier section, identify the output stages and any variable resistors nearby. Typically, in most amp circuits I have seen, the process is to measure output transistor emitter current as a voltage drop across the very low value, and usually a 5-watt emitter resistors. Look around, see what you may find. I the amp is running cool, no distortion in the output signal. there may no need to adjust anything. 2
Receiver2000 5,089 Posted Wednesday at 02:20 AM Posted Wednesday at 02:20 AM (edited) Welcome ' great to have you with us!!!! Edited Wednesday at 02:21 AM by Receiver2000
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