Hi,
I need to replace transistors on some amplifiers. The transistors are the combo Motorola BD139-16 / BD140-16 and the Motorola BD441 / BD 442.
For now, I found the combo Toshiba TTA004B / TTC004B and/or the Toshiba TTA008B / TTC015B to replace those. Is it a good replacements choice or do you have other transistors to recommended.
Thanks
I need to replace transistors on some amplifiers. The transistors are the combo Motorola BD139-16 / BD140-16 and the Motorola BD441 / BD 442.
For now, I found the combo Toshiba TTA004B / TTC004B and/or the Toshiba TTA008B / TTC015B to replace those. Is it a good replacements choice or do you have other transistors to recommended.
Thanks
BD139/140 can be replaced by KSC3503 and KSA1381
BD441/442 can be replaced with MJE243/253
BD441/442 can be replaced with MJE243/253
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Hi,
Thanks for your answer, I will get a look at those transistor. If I understand you correctly, you consider those transistors to be a better replacement choice compared to the Toshiba ?
Thanks for your answer, I will get a look at those transistor. If I understand you correctly, you consider those transistors to be a better replacement choice compared to the Toshiba ?
NO. I would not replace those transistors. Any replacements should not be much better.
I should keep those you have.
There is not much gain by replacing.
For example BD139-16 and BD140-16 are very good.
16 means they have high gain.
What is your problem, in the sense that you need to replace them, or just want to try?
Too many fakes around, be careful.
I would not replace until essential.
And depending on your location, different series may be more easy to obtain, Japanese, American etc.
Too many fakes around, be careful.
I would not replace until essential.
And depending on your location, different series may be more easy to obtain, Japanese, American etc.
Hi,
Yes, I need to replace them, they are short-circuited. They're Motorola, and they're obsolete. So I wanted to take the opportunity to update them.
And since the Toshiba are encapsulated, no more Mica needed. I've already replaced the output transistors with Toshiba's 2SA1943 and 2SC5200, that's why I was looking at the TTA and TTC series.
Yes, I need to replace them, they are short-circuited. They're Motorola, and they're obsolete. So I wanted to take the opportunity to update them.
And since the Toshiba are encapsulated, no more Mica needed. I've already replaced the output transistors with Toshiba's 2SA1943 and 2SC5200, that's why I was looking at the TTA and TTC series.
BD139-16/140-16 are excellent bipolars for driving the 5200/1943's and still available.
I bought 100 of both a few months ago for good prices.
Foundries and suppliers are struggling with all kind of production/storage/transport hiccups.
Things will ease somewhat in (less then) half a year (lots of issues though!); I've halted a serious production line for that very reason.
I'm using the 5200/1943's also for driving... the 5200/1943's! Use silpad's instead of mica.
I bought 100 of both a few months ago for good prices.
Foundries and suppliers are struggling with all kind of production/storage/transport hiccups.
Things will ease somewhat in (less then) half a year (lots of issues though!); I've halted a serious production line for that very reason.
I'm using the 5200/1943's also for driving... the 5200/1943's! Use silpad's instead of mica.
BD441/442 are rated 36 Watts, which is unusual for that package. I have to wonder if you should consider a to-220 device to replace them like MJE15030.
Thanks Citizen124032 for the information. Unfortunately I'm unable to use the 2SA1493 and 2SC5200 as a pre-driver. Not enough place, too big.
Which brand do you use for the BD139-16/140-16 that you consider very good compare to the Motorola ?
I would like to use ceramic as isolator for the 2SA1943 / 2SC5200. It will be my first time of using ceramic, I hope that it will be good.
Steveu, I will take a look for the MJE15030, thanks for the info.
Which brand do you use for the BD139-16/140-16 that you consider very good compare to the Motorola ?
I would like to use ceramic as isolator for the 2SA1943 / 2SC5200. It will be my first time of using ceramic, I hope that it will be good.
Steveu, I will take a look for the MJE15030, thanks for the info.
The idea of using a compliant coating / gasket is to remove the air gap and obtain better heat transfer.
So please use mica with heat transfer compound, or silicon pads, even if the transistor has encapsulation, or the heat sink is ceramic.
A minute gap will cause local heating and early device failure.
Also, look up circuits for the 5200/1943 pair, see what transistors are used to drive them, that will guide you as to what device to choose.
So please use mica with heat transfer compound, or silicon pads, even if the transistor has encapsulation, or the heat sink is ceramic.
A minute gap will cause local heating and early device failure.
Also, look up circuits for the 5200/1943 pair, see what transistors are used to drive them, that will guide you as to what device to choose.
A simple but best transistors sound test: Simply insert e.g. in a power supply. As a diode. This way the "current" through the component, the sonically relevant character becomes audible.
So what does the original circuit look like? EF2, EF3? Power supply voltage? Whether the BDs, Toshiba’s or which MJEs are better is dependent on what they are actually doing.
Hi Dante,
A comparison between the TTC004B/TTA004B and 2SC3505E/2SCA1381E was recently carried out in the Wolverine build thread and shows that both pairs perform extremely well in that design. Bear in mind that the Wolverine amplifier is an EF3 design (Triple Emitter Follower Output Stage) where these devices are the pre-drivers. The link is below for your reference:
https://www.diyaudio.com/community/...he-wolverine-build-thread.385920/post-7212415
The 2SC3505/2SC1381 complementary pair have now now replaced by the KSC3505/KSA1381 however, they are only available in D and E beta grades respectively. Ideally, they should be matched reasonably closely for beta when used as a driver pair. The KSC3505/KSA1381 pair are only rated at a maximum collector current of 100mA making less suitable for drivers in a standard emitter follower output stage.
The TTC004B/TTA004B pair are have an VCEO rating of 160V and IC of 1.5A making them a good replacement for the BD139-16/DB140-16 devices. They also come in the same beta grades and are currently still readily available - ignoring the current semiconductor crisis. Cheers.
Paul
A comparison between the TTC004B/TTA004B and 2SC3505E/2SCA1381E was recently carried out in the Wolverine build thread and shows that both pairs perform extremely well in that design. Bear in mind that the Wolverine amplifier is an EF3 design (Triple Emitter Follower Output Stage) where these devices are the pre-drivers. The link is below for your reference:
https://www.diyaudio.com/community/...he-wolverine-build-thread.385920/post-7212415
The 2SC3505/2SC1381 complementary pair have now now replaced by the KSC3505/KSA1381 however, they are only available in D and E beta grades respectively. Ideally, they should be matched reasonably closely for beta when used as a driver pair. The KSC3505/KSA1381 pair are only rated at a maximum collector current of 100mA making less suitable for drivers in a standard emitter follower output stage.
The TTC004B/TTA004B pair are have an VCEO rating of 160V and IC of 1.5A making them a good replacement for the BD139-16/DB140-16 devices. They also come in the same beta grades and are currently still readily available - ignoring the current semiconductor crisis. Cheers.
Paul
Hi,
Thanks Linear22 for the information about the comparaison of the TTC004B/TTA004B and 2SC3505E/2SCA1381E, very interresting.
For wg_ski, it is for repair an old Electrocompaniet amplifier IIa (the successor of the legendairy 25w) back in the end of the 70' and the beginning of the 80'.
For NareshBrd, I saw somewhere that the TTC004B/TTA004B was use as pre-driver to drive the TTA1943/TTC5200 the newest version of the 2SA1943/2SC5200
For history, the original output 2SA1141/2SC2681 was replaced with the 2SA1943/2SC5200, recommended by Electrocompaniet as a direct replacement.
The original BC141-16/BC161-16 was replaced by the combo BD139-16/BD140-16 as Electro itself do that in their latest revision of the amp.
This amplifier suffer for a lot of heat problem, and now the pre-driver BD441/BD442 and BD139-16/BD140-16 need to be replaced.
I think that the TTC004B/TTA004B will be a very good replacement for the BD139-16/BD140-16 and really easy to find, but for the BD441/BD442 (pre-driver), I'm not sure if It could not be better to use the TTA008B/TTC015B as the maximum collector current is rated at 2A, compared to the BD441/BD442 rated at 4A but now obsolete and hard to find.
Thanks Linear22 for the information about the comparaison of the TTC004B/TTA004B and 2SC3505E/2SCA1381E, very interresting.
For wg_ski, it is for repair an old Electrocompaniet amplifier IIa (the successor of the legendairy 25w) back in the end of the 70' and the beginning of the 80'.
For NareshBrd, I saw somewhere that the TTC004B/TTA004B was use as pre-driver to drive the TTA1943/TTC5200 the newest version of the 2SA1943/2SC5200
For history, the original output 2SA1141/2SC2681 was replaced with the 2SA1943/2SC5200, recommended by Electrocompaniet as a direct replacement.
The original BC141-16/BC161-16 was replaced by the combo BD139-16/BD140-16 as Electro itself do that in their latest revision of the amp.
This amplifier suffer for a lot of heat problem, and now the pre-driver BD441/BD442 and BD139-16/BD140-16 need to be replaced.
I think that the TTC004B/TTA004B will be a very good replacement for the BD139-16/BD140-16 and really easy to find, but for the BD441/BD442 (pre-driver), I'm not sure if It could not be better to use the TTA008B/TTC015B as the maximum collector current is rated at 2A, compared to the BD441/BD442 rated at 4A but now obsolete and hard to find.
See why the heat problem occurs.
Many reasons, including high bias, and poor heat management.
Also, see what is easy to get in transistors, use a higher current substitute if possible.
Many reasons, including high bias, and poor heat management.
Also, see what is easy to get in transistors, use a higher current substitute if possible.
What I was more interested to know is if the BD44x were in a true pre-driver position (which runs cold) or as a VAS (which might run quite hot if only driving an EF2). If it’s a hot-running stage the completely insulated packages might NOT be a good idea. A 4 amp rating is not needed in either place - the heat dissipation is more the issue. And fT should always be decreasing (and Cob decreasing along with it) as you go from pre-driver (or VAS) to driver to output. Get that wrong and you can end up with stability problems that didn’t exist before you effed with it.
BD139/140 are not obsolete yet, I think. Motorola split off their semi division years ago, but OnSemi still have them as active so you should still be able to obtain these.
ST also manufactured these and last time I looked they also had them as available.
But the BD441/2 might be. ST used to manufacture those so have a look on their website.
Perhaps TIP41C/42C would work as replacements, if you can fit TO-220 into the space of the TO-126. They have similar fT, but higher speed devices may need additional modifications to stop oscillations.