I recall those in Threshold production after they were introduced. Earlier were 2n5876 and 78.
You can also use the On Semi MJ15022G/023G parts as well. I know of three Stasis 2 rebuilds done with these transistors successfully. No problems using the ones you suggest as well. For these TO3 devices these days, it all comes down to availability and price.
That's what I used but then I like the TO3 cans and their heat dissapating ability. And to me they look cool. 🙂
Some where back in this thread I posted gerber for 3 different output board for TO3 devices, small number, medium, and 20 devices per board. And the DXF files for the mounting plates for heat sinking, like the original Master's design. 🙂
Some where back in this thread I posted gerber for 3 different output board for TO3 devices, small number, medium, and 20 devices per board. And the DXF files for the mounting plates for heat sinking, like the original Master's design. 🙂
Yes I remember those and I had some of the 20 device boards made. Been sitting on these for about a year. I thought I saw those mounting plates now that you say that. I have about 200 pieces of both 024/025 also from same lot codes. BUT, would be alot easier to use 247s. None of the mounting plates I'm assuming. Don't know about building nowdays since can't get the chassis anymore.
I didn't think the 5U was available still?? I noticed alot of the other lines were not available.
Absolutely still available. Just need to order direct from @Gianluca
https://modushop.biz/site/index.php?route=product/product&path=242&product_id=784
https://modushop.biz/site/index.php?route=product/product&path=242&product_id=784
Yeh, the @johnhenryharris TO3 boards need the 5U chassis height. Have that pcb/mounting plate built with TO3's - just need to get a 5U chassis.
I just used some heatsinks from Heatsinkusa.com and made top and bottom and rear plates of 1/8" aluminum plate, and front panels from 1/2" aluminum plate. You don't need a factory chassis, just DIY. 🙂
My first bash at measuring outputs for best matched set.... Using 2SC4468
The test circuit is arranged per Nelson Pass's Mosfet matching article with a 100 ohm 5W load on collector, 2.2k on base which is then shorted to the collector. I am using a lab supply set at 50mA constant current across the `load-collector-emitter'.
Measuring Vbe directly on the pins I get
0.902 V
0.886
0.909
0.912
0.834
0.915
0.905
Before I do all the rest, do these numbers seem reasonable?
cheers
The test circuit is arranged per Nelson Pass's Mosfet matching article with a 100 ohm 5W load on collector, 2.2k on base which is then shorted to the collector. I am using a lab supply set at 50mA constant current across the `load-collector-emitter'.
Measuring Vbe directly on the pins I get
0.902 V
0.886
0.909
0.912
0.834
0.915
0.905
Before I do all the rest, do these numbers seem reasonable?
cheers
just one of the places where you can read about matching bipolar transistors
https://sound-au.com/transistor-matching.htm
https://sound-au.com/transistor-matching.htm
Thanks ZM, I am familiar.
I picked one and measured at 10mA and got a Vbe of 0.64. On the same transistor at 170mA Vbe appears to rise to 1.25V although I didn't wait for it to warm up. So I suspect the numbers are good, but I was hoping for confirmation that these numbers are in the ballpark by the omnipresent and sage counsel offered by this forum....
I picked one and measured at 10mA and got a Vbe of 0.64. On the same transistor at 170mA Vbe appears to rise to 1.25V although I didn't wait for it to warm up. So I suspect the numbers are good, but I was hoping for confirmation that these numbers are in the ballpark by the omnipresent and sage counsel offered by this forum....
I looked at matching the TO3 cans but they were all from the same lot so I just built the boards and after bias and temperature settled I measured the DC offset at the output and had 9 mv, which is one reason for matching, the other is so all the transistors are working the same, none loffing or working too hard. So just my opinion that matching on the outputs from the same lot of Bipolars wasn't worth the effort. But if you have the time then it is just nice to know. Your number are close enough to each other to say they are matching, for me.
I understand that ideally the parallel devices in the output stage should be matched.
What about the driver transistors N1 and P1?
I assume there is much less imperative to match these to the 6 (or 8) output devices that they drive(?)
As an aside the measuring/matching process got a lot more clear when I dumped the new meter (aka under-damped random number generator), and reverted back to the faithful old Fluke 75
What about the driver transistors N1 and P1?
I assume there is much less imperative to match these to the 6 (or 8) output devices that they drive(?)
As an aside the measuring/matching process got a lot more clear when I dumped the new meter (aka under-damped random number generator), and reverted back to the faithful old Fluke 75
If you use the TO3 version output board there was some mounting plates that had to be built also correct? Anybody know where those prints were, are??
What about N1 and P1 (drivers?) against the actual parallel output stage devices N2-N6, and P2-P6?