I've found some rather expensive 40410's and 40409's on ebay and I was wondering if someone knows of a NPN and PNP to replace these older RCA transistors.
Transistors
2N3440 and 2N5415/6 add finned heat sinks
The MJE devices will generally not fit the skinny holes in the PCB and they are much taller once inserted
2N3440 and 2N5415/6 add finned heat sinks
The MJE devices will generally not fit the skinny holes in the PCB and they are much taller once inserted
The RCA 4049 & 40410 are TO-39 with welded heat sink. 90V, 3W. I used the full family (40406-40411) in the 150 family @ Acoustic Control Corp.
They are drivers, I would use a plastic TO220 with a heat sink as a replacement and it may need some miller cap to be added.
They are drivers, I would use a plastic TO220 with a heat sink as a replacement and it may need some miller cap to be added.
ebay is full of counterfeits.
TO220 & TO126 parts will be BCE instead of EBC. I tried twisting the legs around, broke some transistors over time & peeled the lands off my PC15 as a result.
Surplussales.com has some TO5 transistors which are EBC. You'll have to add the heat sink yourself. Arvid etc still sell TO5 heatsinks.
50 v Vceo parts won't be much use in a ST150 but 70 v might.
I just bought some 2n2270 60 v npn, 2n4036 PNP moto, & 40406 PNP , which is a RCA number without the heat sink. He sells out of auctions, and doesn't guarantee his parts, but the last load of LED's, they worked.
In fully guarenteed parts, newark usually has one pnp and one npn TO18 part which with heat sink is reputed to go up to 10 W. TO18 is EBC. Heat sinks would have to be bought separately.
TO220 & TO126 parts will be BCE instead of EBC. I tried twisting the legs around, broke some transistors over time & peeled the lands off my PC15 as a result.
Surplussales.com has some TO5 transistors which are EBC. You'll have to add the heat sink yourself. Arvid etc still sell TO5 heatsinks.
50 v Vceo parts won't be much use in a ST150 but 70 v might.
I just bought some 2n2270 60 v npn, 2n4036 PNP moto, & 40406 PNP , which is a RCA number without the heat sink. He sells out of auctions, and doesn't guarantee his parts, but the last load of LED's, they worked.
In fully guarenteed parts, newark usually has one pnp and one npn TO18 part which with heat sink is reputed to go up to 10 W. TO18 is EBC. Heat sinks would have to be bought separately.
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Insufficient data.
WHERE will you use them? (Brand and model)
Supply voltages?
What are they driving?
Is schematic available?
Do you have a PCB picture? , to have an idea of available space.
The more/better data the better the answers become.
Where will I use them? I plan to try to make a updated version of the South West Tech Tigersarious 250 watt mono block amp using updated transistors and outputs on a new PC board that will support the different footprint of the newer transistors. I am somewhat confident that a newer board a better laid out board will yeald an amplifier that doesn't blow itself up due to faulty construction and workmanship. The two Mono block amps I had worked very well and sounded quite good.
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I had actually used the 3440 and 5415 as replacements for the blown RCA transistors on the Tigersarious driver boards along with heatsinks. The amps were still working when I gave them to a neighbors son prior to moving. I was thinking there was possibly something a little more robust. That and the fact they are getting hard to find also.
MJE340/350 are a close cousin to 2N3440/5415. Easy to find a way to heat sink, too. To-39’s are a pain in the ***. 340/350 are often used as replacements for unobtainium originals for predriver or VAS duty in many vintage 200-250 watt per channel amps. Also still a reasonable choice for new construction.
Thanks, now we´re talking.
If you were repairing one or building it using original artwork (or leftover original PCBs) I would have recommended TO127 transistors, because skinny legs woukd fit original holes and light weight, while TO220 are both too large and way too heavy.
Up to +/- 40-42V (old Acoustic, Ampeg, etc. musical instrument amps) I used BD139/140 , now for +/-70V, yes, MJE340/350 stand the voltage well, problem is that in practice they are weak current suppliers, not really suitable as direct power transistor drivers, it was usual to add an extra current gain stage, as in driving one power transistor which in due time was used to drive an extra pair.
Since you can´t do that, you WILL need more robust drivers.
COOL. Then go straight to TO220 drivers, such as MJE15030/31
MJE340/350 will be marginal as drivers, they are suitable in all other positions.
The original 40409 and 40410 are also weak current suppliers. MJE’s or 3440’s are no weaker. The problem is that the originals are underrated in that application, period. Use MJE1503x for drivers if your amp has two stages of current gain, one of the other types for predrivers if you have have three. MJE1503x is less suitable for VAS duty due too its high capacitance. Don’t use them for Q4 andQ8.
I think I may have found another substitute for these. NTE128 and NTE129 seem to be replacement parts.
I'm having a similar situation with an Acoustic bass amplifier:
Can I adjust the bias and substitute this driver transistor?
I'm having a similar situation with an Acoustic bass amplifier:
Can I adjust the bias and substitute this driver transistor?
Just be careful to leave lots of room around the 10W power resistors that do the voltage dividing for the drivers -- R33, 34, 35, and R36. They start throwing off a total of 24W as soon as the rails go up. And there are several others that'll get pretty toasty as well.
Not to throw a wet blanket on your project idea, but I'll be really surprised if the reliability of this design can be substantially improved with board layout. Just about every part between the outputs and the input long-tails are being ridden pretty hard.
It is a tasteful, aesthetically pleasing design, I'll admit -- full complementary-symmetry. The early Bryston 4B is very similar in concept (though not device p/n), and they're notably hard to pop, at least by my experience.
Maybe instead of looking for close replacements to the 40409/40410, find out what Bryston used for the VAS and drivers. I bet they'd hold up better.
Cheers
Not to throw a wet blanket on your project idea, but I'll be really surprised if the reliability of this design can be substantially improved with board layout. Just about every part between the outputs and the input long-tails are being ridden pretty hard.
It is a tasteful, aesthetically pleasing design, I'll admit -- full complementary-symmetry. The early Bryston 4B is very similar in concept (though not device p/n), and they're notably hard to pop, at least by my experience.
Maybe instead of looking for close replacements to the 40409/40410, find out what Bryston used for the VAS and drivers. I bet they'd hold up better.
Cheers
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I was just searching 40409 and stumbled across this. I've never had a 40409 or a 40410 go bad but I wanted to buy some spares just in case - I bought and built 15 Tigersaurus' back in high school in the 70's and I still have most of them. I have a curve tracer some some good transistors so I can trace them but I'm not sure how to go about finding what device would be the best replacement for them.
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40409/40410 morphed into 2n5320/5322 a couple of years later. TO5 versions have gone the way of the dodo bird but ST was producing some TO39 versions a few years ago. I've one surviving pair RCA originals in a ST120, and with the heat sinks dyna put on them they will drive mj15003 to 70 w/ch for 5 seconds.
If you don't have to have EBC pinout, can lay out new boards, mje15028/29 aren't as capacitive as MJE15032/33. I've used the previous as drivers on the mate to the dynakit PC14 board, and they sound just as good. TIP31c/32c in the same driver position sounded like logs. No highs. I used GE D44R4 as VAS on that board, and despite all the dire warnings about TO220 packaged transistors, that ax6 board reproduces top octave Steinway piano, cymbals, or tinkly bells without fuzz hash or vibrato.
Beware NTE Central Semi NewJersey semi substitutes. If you look at the datasheet, they left off all the specs but Vce & Vsat. In particular, the 50 mhz Ft of the 40409/40410 made them stellar parts for hifi drivers of single OTs & VAS. 20 mhz D44R4 and 30 mhz mje15028/29 seem to be adequate to pianos & cymbals. TIP31c/32c with 6 mhz Ft seem to be fine only for guitar amps or men that are already deaf (the majority) over 4000 hz.
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I used to separate the heat sink from the TO-5/39 by hitting the bottom with a punch. Then you can solder the heat sink onto a new (metal) transistor.
But today I would probably use a MJE243 /MJE253 as replacements, and modify the PCB as required, and add a small heat sink. There are lots of other good driver transistors too. Take your pick. You just have to fix the pin-out. I should mention that those old amps usually need a bit of updating like cross-coupling or reduced base resistors on the OPs, etc. I'd simulate the circuit and determine what changes were essential, practical etc. There was a post about updating tiger amps in DIYA. Many old amps just need the whole module replaced with something newer. There are plenty of Chinese modules on the internet.
But today I would probably use a MJE243 /MJE253 as replacements, and modify the PCB as required, and add a small heat sink. There are lots of other good driver transistors too. Take your pick. You just have to fix the pin-out. I should mention that those old amps usually need a bit of updating like cross-coupling or reduced base resistors on the OPs, etc. I'd simulate the circuit and determine what changes were essential, practical etc. There was a post about updating tiger amps in DIYA. Many old amps just need the whole module replaced with something newer. There are plenty of Chinese modules on the internet.
Mouser shows 469 of 2N5321 NPN) in a TO-39 package for $3,26 each, $29,40 for 10, if that helps. The Vceo is listed at only 50V, though.
DigiKey stocks more than 250 each of 2N5320 and 2N5322, $3,09 and $3,26 respectively, also TO-39, and 75V Vceo.
Likely either would need some creativity to apply a heatsink.
A modern alternate might be less trouble.
Cheers
edit: The punch technique to separate the heatsink may deform the baseplate enough to compromise the die attachment.
DigiKey stocks more than 250 each of 2N5320 and 2N5322, $3,09 and $3,26 respectively, also TO-39, and 75V Vceo.
Likely either would need some creativity to apply a heatsink.
A modern alternate might be less trouble.
Cheers
edit: The punch technique to separate the heatsink may deform the baseplate enough to compromise the die attachment.
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