Feeling proud of myself for actually making progress. I got my ground bus bar (3" x 12" x 0.125") drilled out for the main cap connections and mounted the power transformers. I bought brackets to mount them vertically but since they fit (barely) laying flat that's the way to go.
I'd hoped to finish this amp today, but life has interfered, and I am waiting on a few parts. Resistors for the CRC, fuse holders for each transformer, and some hardware scheduled for delivery next Wednesday.
I can see that I am going to have to do the cap screw heat sink mounting mod - Otherwise I'll never get the front panel attached or be able to adjust the amps.
Nothing particularly special about the board setup, I used the store BOM other than using Fairchild IRFP240s and BC546C I had on hand. I bought the jfets a long time ago from ampslab and was pleasantly surprised to find at least 4 pairs with idss around 10 mA matched within .03 mA out of 20 pieces. I was also able to make 4 perfectly matched sets for my F5T.
There's not a lot of room to spare. Transformers are Antek 4220s. Smoothing caps are 68,000 µF/50V. Chassis mount 25W 0R1 resistors will mount on the ground bus. I realize that's an "old school" power supply. Rectifiers and AC connections will be on the front panel.
Progress will be even slower for a month or two, as the surgeon says I can't lift more than 10 pounds after much needed back surgery. I may have to turn my daughter into my amp mechanic so I can listen to it during my recovery.
I'd hoped to finish this amp today, but life has interfered, and I am waiting on a few parts. Resistors for the CRC, fuse holders for each transformer, and some hardware scheduled for delivery next Wednesday.
I can see that I am going to have to do the cap screw heat sink mounting mod - Otherwise I'll never get the front panel attached or be able to adjust the amps.
Nothing particularly special about the board setup, I used the store BOM other than using Fairchild IRFP240s and BC546C I had on hand. I bought the jfets a long time ago from ampslab and was pleasantly surprised to find at least 4 pairs with idss around 10 mA matched within .03 mA out of 20 pieces. I was also able to make 4 perfectly matched sets for my F5T.
There's not a lot of room to spare. Transformers are Antek 4220s. Smoothing caps are 68,000 µF/50V. Chassis mount 25W 0R1 resistors will mount on the ground bus. I realize that's an "old school" power supply. Rectifiers and AC connections will be on the front panel.
Progress will be even slower for a month or two, as the surgeon says I can't lift more than 10 pounds after much needed back surgery. I may have to turn my daughter into my amp mechanic so I can listen to it during my recovery.
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Thanks, guys.
ZM, I've put it off as long as I can stand. Actually I can't stand much, so it's time. I've managed to work the "No brain, no pain" theory to my advantage. Problem is I can't be on my feet for more than about 15 minutes or my legs go to sleep and I fall down. My personal doc/good friend is an avoid surgery if at all possible guy but has been pushing me to get it done for a couple years. Same guy did wonders for my neck, so I'm expecting good results.
I should be back making dodo posts in a week or so...
ZM, I've put it off as long as I can stand. Actually I can't stand much, so it's time. I've managed to work the "No brain, no pain" theory to my advantage.
Problem is I can't be on my feet for more than about 15 minutes or my legs go to sleep and I fall down. My personal doc/good friend is an avoid surgery if at all possible guy but has been pushing me to get it done for a couple years. Same guy did wonders for my neck, so I'm expecting good results.I should be back making dodo posts in a week or so...
As it turned out I wasn't to be free long. I expected a bit more pain on days 3-5, but when my legs stopped working I went back. There were a few days of terrorizing the nurses once my legs stated working again. They had silly rules like don't get out of bed without help. Returning from the bathroom I was invited to sit in the recliner, which I noted they had just added an alarm to tell them if I got up. "I'll stay in bed since you alarmed the chair." "There's an alarm on the bed, too." "You realize that this means war! I'll sit in the chair." In 15 minutes I had disabled the alarm in the chair, got up and disabled the alarm on the bed. They were more than happy to clean me and the bed up if I couldn't hold it for the time between hitting the call button and them arriving, and somehow not understanding that at 55 years of age I am not interested in messing myself if it can be avoided.
Now I appear to be home for good. The repeat hospitalization means I won't get to spend as much time teaching my daughter the finer points of crimping and soldering, but my son made a surprise appearance. Spending time with the kids is a better thing to do, anyway.
Bones, that's always the hardest part for me. I have a hard time controlling myself while I feel good and don't notice that I have reached my limit until it is well past. Hoping to do better this time.
Will post progress photos as it happens.
Now I appear to be home for good. The repeat hospitalization means I won't get to spend as much time teaching my daughter the finer points of crimping and soldering, but my son made a surprise appearance. Spending time with the kids is a better thing to do, anyway.
Bones, that's always the hardest part for me. I have a hard time controlling myself while I feel good and don't notice that I have reached my limit until it is well past. Hoping to do better this time.
Will post progress photos as it happens.
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