Thanks Jeff interesting interpretation.
So is 3 digits date code.
48 is the last week of the year
The logo change most likely occurred at the time when Harris decided to sell its commercial and military semiconductor product lines, which happened in 1998.
The IRFP9240s I have display the newer italicized "H" and have manufacture date code: 9840.
Tea-Bag response about newer Harris version
GB Pass M2 Clone Boards with 120mm UMS spacing by Tea-Bag
Is OK
GB Pass M2 Clone Boards with 120mm UMS spacing by Tea-Bag
Is OK
My problem I was having a couple pages back is solved! Everything on the non-functioning channel, er, I should say non-correctly-functioning channel, checked out OK. I went ahead and removed the LM385s, removed all the solder with braid, cleaned pads, and very very carefully replaced them. Fired it up and it worked perfectly! I defiantly couldn't see it, but I guess I had a teeny weeny bridge on one of those devices. Now both channels warm up slowly and sit rock solid stable at 1.3A, plus or minus a small handful of milliamps. Now I just need to adjust a couple resistor values to sort out the offset, then I'm off to the races!
Thank you Mr. Pass for the design, Grimberg for the excellent PCBs, and everyone who contributed their time and expertise to this thread! I can't wait to have a listen!
Thank you Mr. Pass for the design, Grimberg for the excellent PCBs, and everyone who contributed their time and expertise to this thread! I can't wait to have a listen!
Same, I've ended up with negative offset on both channels right around -100mV. One channel I have pretty much sorted out by increasing R7. I went up to 56.2k which was far too much, rookie mistake I guess. I ended up paralleling it, with clip leads, with a 500k resistor which lands me at about 50.5k, essentially the same as your 49.9k. I was able to zero that channel, so I'll do the same with the other and I should be good to go!
Just to be clear, it is my understanding that the outputs Teabag has, (but I do have an inquiry to him) is that these are not Harris pairs, but a combination of Harris on one side, and Vishay on the other.
http://www.diyaudio.com/forums/grou...-120mm-ums-spacing-tea-bag-6.html#post5119124
Russellc
http://www.diyaudio.com/forums/grou...-120mm-ums-spacing-tea-bag-6.html#post5119124
Russellc
That's what I use too. It's only the IR/Vishay P-channel parts that have the linearity glitch.
Cheers,
Jeff.
Mine uses Vishay FETs in both positions, I suppose time will tell if I'm disappointed with that choice 
I went home over lunch, slung some solder, and fired up both channels to "burn in" while I ate. Back downstairs about 30 minutes later, everything was nice and toasty, and I was able to easily null the offset on both channels. Unfortunately I had to return to work, otherwise I would be listening right now! Seems like tonight will be the night I do some final checks and hook everything up. It's going to be a long 4 hours until I'm off work
Quick question, curiosity more than anything, is it normal for the offset to bounce around a little bit? Now, by bounce around I'm talking +/- 0.0005V or so, absolutely nothing I'm worried about. Like I said, curiosity.
Happy listening everyone!
I went home over lunch, slung some solder, and fired up both channels to "burn in" while I ate. Back downstairs about 30 minutes later, everything was nice and toasty, and I was able to easily null the offset on both channels. Unfortunately I had to return to work, otherwise I would be listening right now! Seems like tonight will be the night I do some final checks and hook everything up. It's going to be a long 4 hours until I'm off work
Quick question, curiosity more than anything, is it normal for the offset to bounce around a little bit? Now, by bounce around I'm talking +/- 0.0005V or so, absolutely nothing I'm worried about. Like I said, curiosity.
Happy listening everyone!