Using the original schematic , the BD139/BD140 paired with 2SA1302/2SC3281
seems the best combination.
Dont forget the 100pf that is connected from base to collector of the PNP driver, though..
seems the best combination.
Dont forget the 100pf that is connected from base to collector of the PNP driver, though..
I guess you know these were discontinued around 2000. On-Semi has cloned them quite successfully in about 8 versions and packages like TO247, TOP-3 etc. as the MJL3281/1302 series that retains the last three digits 281 and 302 to denote the same basic devices.
If you are trying to source NOS Toshiba product, you will be a prime target of fakes, so maybe it's better to get used to what is practically identical, and widely available? 🙂
If you "buy" them from ONsemi then you are guaranteed to get genuine product.
The "buy" cost is postage and packing of the samples. But you are limited to 5 off each.
The "buy" cost is postage and packing of the samples. But you are limited to 5 off each.
Hi Andrew, I did a search on their website but they are not being produced anymore. MJL3281/1302 are the replacements. Jacco/Sakis have lots but they are for collection, so not selling =(
I think that is what Andrew is acknowledging here and adding that there is security and benefits in dealing directly with On-Semi or its licensed agencies, such as a samples programme for qualifying individuals and corporations. Think about it....enough said?
And your only supposed to order samples once to evaluate if it is what your looking for, if it is, you go ahead and buy the required/wanted quantity either from On Semi or a distributor like digikey, mouser or farnell to name a few.
woke up with a strange idea ...
next days i am willing to use a set up of classic P3A version ( as described in the post ) use 829-830 drivers use 2SA1169 2sc2773 sanken pairs ( kinda beefy ) got two pairs very original sanken and go with 50 volt rails while respect the amplifier and only use it strictly for 8 ohms load and casual listening ...
need to check if my LTP is happy with such a voltage
need to see if this will provide more headroom an/or anyother diference
i will do and let you know
next days i am willing to use a set up of classic P3A version ( as described in the post ) use 829-830 drivers use 2SA1169 2sc2773 sanken pairs ( kinda beefy ) got two pairs very original sanken and go with 50 volt rails while respect the amplifier and only use it strictly for 8 ohms load and casual listening ...
need to check if my LTP is happy with such a voltage
need to see if this will provide more headroom an/or anyother diference
i will do and let you know
Sakis, since you did already so much shange, I'd go for 2SC2240 for LTP, without any doubt.
bye
effebi
bye
effebi
could be ... but i already i have about 100 ltp pairs closelly matched ...so getting new ones and match that closly is a boring job to do ...
( ha ha ha also my employes will know that i work on an new toy and will start teasing on me ) !!!!!
( ha ha ha also my employes will know that i work on an new toy and will start teasing on me ) !!!!!
we are discussing the idea between friends and one ringed a bell from me that this was the classic japanese topology IE only two transistors in rails of 50-60 volts some times but always together with VI limiters
so one may benefit from the higher rail voltage skip the VI limmiter and be carefull with the amp ...
lets see ...we have to wait a bit since politics in my country as we speak is more or less a tomatosoup but also i am waiting for my newst sassi
so one may benefit from the higher rail voltage skip the VI limmiter and be carefull with the amp ...
lets see ...we have to wait a bit since politics in my country as we speak is more or less a tomatosoup but also i am waiting for my newst sassi
oki doki .... Bc 546 is 65volt transistor lets see how hot might be at 50+50 volt rails
kind regards sakis
kind regards sakis
I believe the problem can be that you are not guaranteed that Vce in the LTP will be limited to the single rail voltage (i.e. it could be more than 50v), especially with large signal transients.
I see it very risky. There are a lot of better transistors than the (good) BC546 for such voltages. I hate the burnt silicon smell.....
BTW can you measure Vce (static) on the LTPs and on the CCS with a standard 42 V rails P3A?
ok ..one version is sitting on my bench and rails are 38.5+38.5.... in this situation Vce (static) is 39.5 volts CCS is 37 ...
marginal i think .... will see
marginal i think .... will see
there is an old saying in my country when someone trying to "milk a mosquito "
last night ( very night ) i thought about opening a dual mono P3A that exist in the shop almost 3years now the duty is to operate 10-15 hours a day providing casul background music for the shop.
Idea was first to take a look of any obvious faults after so many hours of operation ...task completed with no obvious problems and then was to repalce the all pavjkadge of drivers since this one was made with 139-140 combo ...
BD 829- 830 as drivers MJE15033 as VAS and all went fine
obviously there was diference slight as usual better high tighter and punchy bass while midle remains the same clean .... some marginal improvment was also a better kick generally
Still .... i think that we are talking of "a litle bit here and a litle bit there" ... so now the mosquito is milked ....
last night ( very night ) i thought about opening a dual mono P3A that exist in the shop almost 3years now the duty is to operate 10-15 hours a day providing casul background music for the shop.
Idea was first to take a look of any obvious faults after so many hours of operation ...task completed with no obvious problems and then was to repalce the all pavjkadge of drivers since this one was made with 139-140 combo ...
BD 829- 830 as drivers MJE15033 as VAS and all went fine
obviously there was diference slight as usual better high tighter and punchy bass while midle remains the same clean .... some marginal improvment was also a better kick generally
Still .... i think that we are talking of "a litle bit here and a litle bit there" ... so now the mosquito is milked ....
Sakis, any chance you can test different output transistors?
So far I can say that the Onsemi MJL21193/94's are warmer sounding than the Fairchild 2SC5200.
So far I can say that the Onsemi MJL21193/94's are warmer sounding than the Fairchild 2SC5200.
I will verify that stress test that i ve made in the fiarchild transistors prove to be extremely relaible ( next to many ) but on the other hand sound kinda muffled in high frequencies next to the 3281 1302 combo ...
None of the amps i ve made ( that will include other stuff like the lynx the DX quasi the hameleon and so on included 21193/4 so actually i have zero expirience with them )
None of the amps i ve made ( that will include other stuff like the lynx the DX quasi the hameleon and so on included 21193/4 so actually i have zero expirience with them )
not very often i have the ability to test two identical amplifiers with minor changes so i am able to make A-B tests ...
Produced two identical amplifiers to be used in a friends dinner driving 4 speakers each 4 1/2" 2way monitors for background music in the dinner
one amplifier featured Toshiba 2SA1943- 2sc 5200 and the other amplifier used the sanken 3263 1294 ...
The sanken i know since are originall Yamaha replacement parts that are really original and best of quality ...
The Toshibas i cannot tell eventhough i performed many stress tests on them i think that these are fakes but of a better quality ....
Bottom line is that the sanken play b far better .... dont no wh but seems that the toshibas are kinda muffled in the high frequencies ...
Idle and pcb is the same drivers and vas is BD139-140 family
Kind regards sakis
Produced two identical amplifiers to be used in a friends dinner driving 4 speakers each 4 1/2" 2way monitors for background music in the dinner
one amplifier featured Toshiba 2SA1943- 2sc 5200 and the other amplifier used the sanken 3263 1294 ...
The sanken i know since are originall Yamaha replacement parts that are really original and best of quality ...
The Toshibas i cannot tell eventhough i performed many stress tests on them i think that these are fakes but of a better quality ....
Bottom line is that the sanken play b far better .... dont no wh but seems that the toshibas are kinda muffled in the high frequencies ...
Idle and pcb is the same drivers and vas is BD139-140 family
Kind regards sakis