Agreed. I just bought transistors that work with the ums, so I got most of it taken care of. I still need to tap holes for the other 3 transistors. Does anyone have a link to buy threaded inserts or a part number? All the ones that come up when I search look a lot different than the ones that came from modshop.
Thanks! I had to go find that. Never heard of White Town before. Interesting ...
Not sure what you mean the holes are drilled and tapped, only reason you would use an insert is for thread repair, but hopefully that does not happen. You need a 2.5mm Drill Bit, bit stop and a 3x0.5mm Spiral Flute Bottoming tap for the holes.
Yes, it stay between 41 and 45 at idle. I notice it takes a while for the voltage to come up from a cold start, Over 5 minutes.
Only 5 minutes?
For me it takes about an half hour and more to get there from the cold start of 9-10mv to 44mv.
Αt this point I would like to add that from the members there are not many references to the behavior of the amplifier as far as quiescent current is concerned.
Also, I'm using Toshiba's 2SC5200/A1943 from Mouser that I just purchased for this. I did notice during initial setup, I noticed the heatsink in the middle of the chassis warmed up much faster than the other. So further inspection I noticed that 3 of the outputs would get up to 116 deg's pretty quick while the others sit around 80 to 90 deg's
I remember from way back yesteryear to check the voltage across each large emitter resistors to find the one that has a higher voltage than the others, this shows that that particular transitor is a current hog and will heat up faster than the others.
Have not done this yet, I'm waiting to get a batch of TTC5200/TTA1943 from Mouser to replace the 2SC/A's. Then I'll see.
I remember from way back yesteryear to check the voltage across each large emitter resistors to find the one that has a higher voltage than the others, this shows that that particular transitor is a current hog and will heat up faster than the others.
Have not done this yet, I'm waiting to get a batch of TTC5200/TTA1943 from Mouser to replace the 2SC/A's. Then I'll see.
I always measure mV at each emitter at first powerup, just to be sure that the output transistors is somewhat within the safezone without to big mismatch in-between those. Especially if the heatsinks is on the small side I found this important.
Might be overdoing things, but it makes me sleep well🙂
Might be overdoing things, but it makes me sleep well🙂
Μe i dont measure the emitters voltages because i will lost my sleep.......hahahahaha.😊😊😊😊😊😊😊😊 I don't have other transistors Toshiba 2SC5359 and 2SA1987
I ordered 50ps from the same batch of Onsemi MJL1302/3281 a while back for another project. I was quite surprised how well the VBE measured between the devices for quad pairs. Haven't tested Hfe though, and the project was paused when I spotted this thread and saw the measurements of the Wolverine 🙂
Thanks for spotting that. I have update that in the Build Guide. The first Q9 should be Q10.
As far as putting D3 and D12 before Q7 and Q8.
As D3 and D12 only need soldering from the bottom I keep D3 and D12 after the installation of Q7 and Q8 as this will allow you to place some solder on the top pads for Q7 and Q8.
I'm surely not using Youboob to determine this. Just experience with both type amps.
There are modern equivalents . They are getting rarer. Class D steals the show in output power and efficiency.
Hi Guys,
I have updated the Build Guide, Current revision is now 38.
Revisions are noted at the end of the document.
I have updated the Build Guide, Current revision is now 38.
Revisions are noted at the end of the document.
With DIYA Italian case + the power supply (1KVA toroid) 500+ $ easily.
If you are poor/cheap (me). I have 2 cases like the "dissipante" 5U X 300mm for 80$ (broken EBAY amps). They came with 2 working 400W SMPS !!
ANTEK in NJ had overstock 500VA 45V trafo's for 45 + 15$. Mouser order is 150+$. Mouser caps are pricey 12 X $6.30 (6800/80V). I'm going to clear out all my E-waste hardware in both these amps.
I might get away with 2 amps for <300$. Shop around.
There are so many sources , it would be subjective to try to estimate. Non-US will also have crazy import fees for US based sourcing !!
OS
