Hi, I came across a china made Hood 1969 amp full assembled kit - but it seems to use BUX41 for the output transistors - looks like a high speed high current. switching transistor meant for military / industrial but not sure if good as an amplifier transistor - Datasheet attached.
https://www.alldatasheet.com/datasheet-pdf/pdf/22120/STMICROELECTRONICS/BUX41.html
It seems these kits started out with used motorola 2N3773 transistors harvested from other boards, then moved to 2N3055/2N9255 (maybe counterfeit) and now BUX41's
https://www.aliexpress.us/item/2251832538128541.html
Any suggestions? Also how hard would it be to swap out the BUX41's for a different output transistor if I wanted to go that route? (Adjusting current etc - assuming the boards have necessary pots)
Thanks
ES
https://www.alldatasheet.com/datasheet-pdf/pdf/22120/STMICROELECTRONICS/BUX41.html
It seems these kits started out with used motorola 2N3773 transistors harvested from other boards, then moved to 2N3055/2N9255 (maybe counterfeit) and now BUX41's
https://www.aliexpress.us/item/2251832538128541.html
Any suggestions? Also how hard would it be to swap out the BUX41's for a different output transistor if I wanted to go that route? (Adjusting current etc - assuming the boards have necessary pots)
Thanks
ES
That type is about as good as an amplifier as a 2N3055. Gain at 4A is about the same, and power handing to 30V is the same. As a switch one can go to higher voltages than with the 3055 and it is a little faster. Those old lowish voltage class A amps don’t give a hoot about output transistor speed so that’s a wash. The 3773 would be better, as would MJ15003. But only real ones, of course. Prices have gone through the roof, and kit makers may be struggling to find real ones that fit their cost budgets.
That BUX41 (along with all ST TO-3’s) is long discontinued. Either they are fake, or they may have found a surplus batch somewhere. Not the prime choice, but suitable here if real. And if purchased for pennies on the dollar, hit the cost targets. The logic of how this could happen is at least clear to me.
That BUX41 (along with all ST TO-3’s) is long discontinued. Either they are fake, or they may have found a surplus batch somewhere. Not the prime choice, but suitable here if real. And if purchased for pennies on the dollar, hit the cost targets. The logic of how this could happen is at least clear to me.
Ah ok - I thought the 2N3773G is still available on Mouser ( not the 2N3773 )
Did not know the BUX41 is also obsolete - these seem to say made in Malaysia
How to tell if they are fake or not ?
Did not know the BUX41 is also obsolete - these seem to say made in Malaysia
How to tell if they are fake or not ?
I was going to suggest NTE might have suitable 'generic TO3's', but just found out they're gone.
Quote from: WA2SQQ on September 04, 2024, 02:03:25 PM
So NTE ELECTRONICS was a subsidiary of the ELECTRONICS BARN in Bloomfield NJ. Back about 25 years ago they were a great surplus place. The barn closed and NTE survived. Sad to see them go, but their semiconductor replacements were never inexpensive. They were the modern day version of RCAs “SK” and Motorola’ s HEP substitution line.
New Tone electronics (NTE) was started as a garage operation some time in the late 70's. Some time in the early 80's NTE moved to (depending on what door you walked through) 42/44/46/48 Farrand St. Bloomfield, NJ. At 48 Farrand St. they set up a walk-in retail store with lots of electronic (mainly computer related) stuff along with a retail counter where you could buy your semiconductor stuff domestic, Japanese, NTE, and later ECG.
I can't remember when Electronic Barn activity shut down and all sales going forward were done on line.
They also created another company called Solid State Inc. which besides semiconductors sold a variety of stuff.
This was posted on NTE's LinkedIn page last week:
"For more than 40 years, NTE Electronics Inc thrived with quality products, off-the-shelf delivery, and remarkable growth, earning respect across the industry while maintaining profitability under strong leadership. It is with great sadness that we announce the closure of NTE Electronics Inc. Following the sale of the company in late 2022, the new ownership's negligence and mismanagement in the past two years has resulted in financial difficulties, forcing the company to cease operations.
We are deeply grateful to our dedicated employees, loyal customers, suppliers, representatives, and partners who have supported NTE Electronics Inc. for over four decades. It has been a privilege to serve you, and we sincerely apologize for any complications and disappointment we may have caused during these challenging times.
Thank you for your trust and continued support."
I wonder if they are going to have dumpster walk-throughs anytime soon
| « Reply #4 on: September 04, 2024, 07:47:13 PM » |
Quote from: WA2SQQ on September 04, 2024, 02:03:25 PM
So NTE ELECTRONICS was a subsidiary of the ELECTRONICS BARN in Bloomfield NJ. Back about 25 years ago they were a great surplus place. The barn closed and NTE survived. Sad to see them go, but their semiconductor replacements were never inexpensive. They were the modern day version of RCAs “SK” and Motorola’ s HEP substitution line.
New Tone electronics (NTE) was started as a garage operation some time in the late 70's. Some time in the early 80's NTE moved to (depending on what door you walked through) 42/44/46/48 Farrand St. Bloomfield, NJ. At 48 Farrand St. they set up a walk-in retail store with lots of electronic (mainly computer related) stuff along with a retail counter where you could buy your semiconductor stuff domestic, Japanese, NTE, and later ECG.
I can't remember when Electronic Barn activity shut down and all sales going forward were done on line.
They also created another company called Solid State Inc. which besides semiconductors sold a variety of stuff.
This was posted on NTE's LinkedIn page last week:
"For more than 40 years, NTE Electronics Inc thrived with quality products, off-the-shelf delivery, and remarkable growth, earning respect across the industry while maintaining profitability under strong leadership. It is with great sadness that we announce the closure of NTE Electronics Inc. Following the sale of the company in late 2022, the new ownership's negligence and mismanagement in the past two years has resulted in financial difficulties, forcing the company to cease operations.
We are deeply grateful to our dedicated employees, loyal customers, suppliers, representatives, and partners who have supported NTE Electronics Inc. for over four decades. It has been a privilege to serve you, and we sincerely apologize for any complications and disappointment we may have caused during these challenging times.
Thank you for your trust and continued support."
I wonder if they are going to have dumpster walk-throughs anytime soon
Most fake TO-3’s will come apart easily. Take a pair of pliers and gently try to twist the top hat off. Real ones won’t come off without a fight, fakes will pop off easily. Base-emitter capacitance will run about 4-5000 pf, base collector about 500. If it’s much lower it’s fake.
ST discontinued all TO-3’s years ago. The last hold out was the 2N3055. There is probably still a BUW41 in TO-247. ON still makes BUV21 (and 22) but all the other ones are gone. And those have the thick pins, so might not fit a PCB and definitely not the socket. Malaysia-made TO-3’s would be ST. The 41 has better DC SOA than the 21, too. Surplus ST stock is conceivable, but their 2N3055 is often faked and lots of people have been burned by them. Test, test, test. It’s the only way to be sure.
Any OnSemi part with a G suffix just means lead-free. Same thing, but surface platings and die attach materials have all changed.
2N3773G and MJ15003G readily available at Mouser for 6 to 7 dollars
MJ15003 being suggested choice
MJ15003 being suggested choice
If the X41’s turn out to be real, I’d just leave them in there. Rugged enough for the application. If not real, just go straight to the 15003 and don’t look back. The 15003 is really just an improved 2N5631, which is a 2N3773 optimized for higher beta at high current. Gives up some of the ruggedness at Vce>50 but not needed if your supply rails are under that. The 15003 really is the right tool for the job.