Prepare one screw in each heatsink to be your provisory ground
Solder one wire to each screw...or attach it tight, and run those wires to your central ground... star ground.. or the name you prefer.
Of course you will be able to ground your heatsinks if you are using insulators to your transistors...because not using them...each heatsink will be opposite in voltage.... one will have the positive supply and other the negative supply...Booooom!
regards,
Carlos
Solder one wire to each screw...or attach it tight, and run those wires to your central ground... star ground.. or the name you prefer.
Of course you will be able to ground your heatsinks if you are using insulators to your transistors...because not using them...each heatsink will be opposite in voltage.... one will have the positive supply and other the negative supply...Booooom!
regards,
Carlos
DAMNNNNNNNNN!!!!!!!!!!!!
I just thought it was ok, after takeing out the 47uf cap next to the 220 one.. it stopped crackleing, and I eventualy after an hour or so, hooked up some music... well it played nicely and then thud... blew both fuses... speaker is still ok though.
I was wondering... can I use those output transistors from Bora's amp in the DX?
I can get geniuine ones of that, if at an extravagant price...
I just thought it was ok, after takeing out the 47uf cap next to the 220 one.. it stopped crackleing, and I eventualy after an hour or so, hooked up some music... well it played nicely and then thud... blew both fuses... speaker is still ok though.
I was wondering... can I use those output transistors from Bora's amp in the DX?
I can get geniuine ones of that, if at an extravagant price...
The unit i have made was using the Dx amplifier output
Not exactly the same as Bora design.
I think the transistors you are using are enougth.
But of course, if those problems you had are not enougth and you want more problems....... than... serve yourself.
Those drivers are crazy to oscilate...they are terrible!
regards,
Carlos
Not exactly the same as Bora design.
I think the transistors you are using are enougth.
But of course, if those problems you had are not enougth and you want more problems....... than... serve yourself.
Those drivers are crazy to oscilate...they are terrible!
regards,
Carlos
Perhaps Carlos meant the drivers used in Bora's schematic, mje 15030/15031.
I've tried them as drivers in the DX, causing it to oscillate
well below clipping-level.
2sc3281/2sa1302 probably works fine for outputs, i haven't tried them.
2sc3421 works fine in the VAS, they can withstand higher voltages than bd139
Best regards,
Klaas
I've tried them as drivers in the DX, causing it to oscillate
well below clipping-level.
2sc3281/2sa1302 probably works fine for outputs, i haven't tried them.
2sc3421 works fine in the VAS, they can withstand higher voltages than bd139
Best regards,
Klaas
I was asking about swapping the output pair.... I thought those other ones would oscillate... but I ordered some genuine Toshibas now, will just have to wait till it gets here... will get a few extra pairs of the fakes, just to make sure it is not something else, before I stick the nice ones in there...
Yes.... i was talking about MJEs.... those ones are terrible
I have used for some monthes till i decide to not use them anymore...say.... those MJE15030 and 15031
The plastic ones, from Toshiba, the ones i have suggested to the high power unit,... are better, they have not too much gain....they are units not addicted to oscilations...even beeing able to work in very high frequencies.
BD139 is worst than TIP41 related oscilations....more addicted to...but better in audio, as it is able to work into higher frequencies... TIP41 and TIP42 selection was to avoid risk of oscilation...to make the amplifier more safe, more reliable...but off course have losses in sonics because of that...but less risk to receive complains back too.
Graham had many 2SC5200 fakes.... he discover that using a capacitor from base to colector made his units work fine...he used into his 200 Watts amplifier.... of course if underpowered fakes were your case.... it will burn to tell you they are fake.
Some fakes are only the units considered "junk" into the factory.... political and technical decisions were made:
For instance.... Dc gain lower than 80, than junk!
Those non accepted could be "deviated" from the trash box destiny .... and than entering the market with lower price...some of them can be original Toshibas that did not have passed into the quality control rules only...do not meaning exactly they are entirelly bad transistors..... TIP35 can be an option to replacement, at least to 8 ohms uses.... but also there are many fakes of TIP35... also 15004 and so on!
There are moments that i use the original parts the schematic indicates....more because the designer saying that his schematic was not followed exactly...reason why sounded not so good...in those moments i install the original to check and confirm...as i already know they do not make differences, if original or not..have to respect the linearity into the frequency, the current, the voltage, the gain, and obbeying that..if number 0o211 or o0122 do not mind... change nothing into audio..but sometimes i use the standard original schematic parts...there are "millions" of possible substitutes that will sound absolutelly the same!
I use to work with standard transistors....good and reliable...BC556, 547, 546,557...... BD139/140.... 2SC5200 and 2SA1943.... Sanken 2SC2922 and 2SA1216 (or other number, do not remember)...and those high voltage plastic ones i suggested to turbo version... 2SC4427 i think and it's complementary.
Why?..... to finish with that conversation designers use to say that transistors "sounds"..... this way, i will not turn crazy searching for hundreds of transistors...i use something standard to compare all amplifiers.... the best one with BD139 will be the best...as it is linear to the voltage i use...always 37 Volts...this allows me to compare two units...as they are using same transistors and same voltage...
If you do not reduce variables... parameters of judgment, amplifier designers will be saying...
-" sounded not good because..."
- You have not used my board
- You have not used my supply
- You have not used my capacitor
- You have not used the correct supply voltage
So.... the construction is always the same type...parts always the same...voltage the same and speaker the same....this way..compared "Elecktronix with Sounhisterix" the best will be the best...no conversations about parts.... those thing are stories to put babies to sleep....Myths!
I have made too much amplifiers and replaced too much transistors to believe in those things...negative!
regards,
Carlos
I have used for some monthes till i decide to not use them anymore...say.... those MJE15030 and 15031
The plastic ones, from Toshiba, the ones i have suggested to the high power unit,... are better, they have not too much gain....they are units not addicted to oscilations...even beeing able to work in very high frequencies.
BD139 is worst than TIP41 related oscilations....more addicted to...but better in audio, as it is able to work into higher frequencies... TIP41 and TIP42 selection was to avoid risk of oscilation...to make the amplifier more safe, more reliable...but off course have losses in sonics because of that...but less risk to receive complains back too.
Graham had many 2SC5200 fakes.... he discover that using a capacitor from base to colector made his units work fine...he used into his 200 Watts amplifier.... of course if underpowered fakes were your case.... it will burn to tell you they are fake.
Some fakes are only the units considered "junk" into the factory.... political and technical decisions were made:
For instance.... Dc gain lower than 80, than junk!
Those non accepted could be "deviated" from the trash box destiny .... and than entering the market with lower price...some of them can be original Toshibas that did not have passed into the quality control rules only...do not meaning exactly they are entirelly bad transistors..... TIP35 can be an option to replacement, at least to 8 ohms uses.... but also there are many fakes of TIP35... also 15004 and so on!
There are moments that i use the original parts the schematic indicates....more because the designer saying that his schematic was not followed exactly...reason why sounded not so good...in those moments i install the original to check and confirm...as i already know they do not make differences, if original or not..have to respect the linearity into the frequency, the current, the voltage, the gain, and obbeying that..if number 0o211 or o0122 do not mind... change nothing into audio..but sometimes i use the standard original schematic parts...there are "millions" of possible substitutes that will sound absolutelly the same!
I use to work with standard transistors....good and reliable...BC556, 547, 546,557...... BD139/140.... 2SC5200 and 2SA1943.... Sanken 2SC2922 and 2SA1216 (or other number, do not remember)...and those high voltage plastic ones i suggested to turbo version... 2SC4427 i think and it's complementary.
Why?..... to finish with that conversation designers use to say that transistors "sounds"..... this way, i will not turn crazy searching for hundreds of transistors...i use something standard to compare all amplifiers.... the best one with BD139 will be the best...as it is linear to the voltage i use...always 37 Volts...this allows me to compare two units...as they are using same transistors and same voltage...
If you do not reduce variables... parameters of judgment, amplifier designers will be saying...
-" sounded not good because..."
- You have not used my board
- You have not used my supply
- You have not used my capacitor
- You have not used the correct supply voltage
So.... the construction is always the same type...parts always the same...voltage the same and speaker the same....this way..compared "Elecktronix with Sounhisterix" the best will be the best...no conversations about parts.... those thing are stories to put babies to sleep....Myths!
I have made too much amplifiers and replaced too much transistors to believe in those things...negative!
regards,
Carlos
There still seem to be some confusion...
I wanted to swap
Fake 2sc5200 for real toshiba 2sc3281
and fairchild 2sa1943 for toshiba 2sa1302, specs look very much the same... with the latter being slightly lower max voltage...
But it is all good, appart from the wait, the toshiba 2sc5200 & 2sa1943 from e-bay worked out cheaper...
I was also thinking about just scratching that channel, and starting over... but hell man... it played niceley for hours, berore the crackleing, and then it played about an hour last night before blowing the fuses...
But maybe it is the sane thing to do...
I measured rails through bias resistors last night, after the blowout...
Bias stuck at 3A
0.1V on + and - rail, so somwhere I suspect on both sides of the circuit the transistors went closed circuit...
I wanted to swap
Fake 2sc5200 for real toshiba 2sc3281
and fairchild 2sa1943 for toshiba 2sa1302, specs look very much the same... with the latter being slightly lower max voltage...
But it is all good, appart from the wait, the toshiba 2sc5200 & 2sa1943 from e-bay worked out cheaper...
I was also thinking about just scratching that channel, and starting over... but hell man... it played niceley for hours, berore the crackleing, and then it played about an hour last night before blowing the fuses...
But maybe it is the sane thing to do...
I measured rails through bias resistors last night, after the blowout...
Bias stuck at 3A
0.1V on + and - rail, so somwhere I suspect on both sides of the circuit the transistors went closed circuit...
All rigth Nordic.... those ones you are saying are the old "2SC5200 and 2SC1943"
One is the development of the other.
The earlier models had problems related too much fakes in the market...was a relief when 2SC5200 come to life to help us to avoid fakes.
But the "fake industry" have already made the same to 2SC5200.
The ones you want are parents of 2SC5200 and 2SC1943... in the reality they are father and mother.
Data is almost the same because they are inside the same Toshiba family.
Good luck...but really enormous luck to find them not fake!
As i can remember...the PNP had a green case...the fake ones had pretty green case.... more beauty than the original ones.
regards,
Carlos
One is the development of the other.
The earlier models had problems related too much fakes in the market...was a relief when 2SC5200 come to life to help us to avoid fakes.
But the "fake industry" have already made the same to 2SC5200.
The ones you want are parents of 2SC5200 and 2SC1943... in the reality they are father and mother.
Data is almost the same because they are inside the same Toshiba family.
Good luck...but really enormous luck to find them not fake!
As i can remember...the PNP had a green case...the fake ones had pretty green case.... more beauty than the original ones.
regards,
Carlos
I think the most safe option, dear Nordic, could be the old 2N3055
Better the TIP3055 and TIP2955.
2 Pair of those ones will cost the same as 1 pair of the toshibas.
They can be nice.... why?
Has nice specifications to audio....not too much different from the drivers we are using...so..... a good solution too.... not really needed an output that can work into 27 Megahertz or more when your driver cannot!...the 2SC5200 is there, in the Dx amplifier because the power dissipation only.... because of power it was selected.
It will need 2 pairs in the place of a single transistor, because of power dissipation, than you will have 180 watts dissipation using two pairs...the price of 2 pairs will be the same as a single 2Sc5200 and 2SA1943 pair...and will be fine too.
Of course, board was not made for them...so...you will need to make some adaptations to use them.... emitter resistance to both of them and base resistances to both of them... well...this one do not need even the base resistance!
You can find those "guys" into plastic case, so.... the same construction you have into the 2SC5200... just one insulator and one screw... the amplifier will work great with those ones too!
regards,
Carlos
Better the TIP3055 and TIP2955.
2 Pair of those ones will cost the same as 1 pair of the toshibas.
They can be nice.... why?
Has nice specifications to audio....not too much different from the drivers we are using...so..... a good solution too.... not really needed an output that can work into 27 Megahertz or more when your driver cannot!...the 2SC5200 is there, in the Dx amplifier because the power dissipation only.... because of power it was selected.
It will need 2 pairs in the place of a single transistor, because of power dissipation, than you will have 180 watts dissipation using two pairs...the price of 2 pairs will be the same as a single 2Sc5200 and 2SA1943 pair...and will be fine too.
Of course, board was not made for them...so...you will need to make some adaptations to use them.... emitter resistance to both of them and base resistances to both of them... well...this one do not need even the base resistance!
You can find those "guys" into plastic case, so.... the same construction you have into the 2SC5200... just one insulator and one screw... the amplifier will work great with those ones too!
regards,
Carlos
Attachments
Those folks exist since the fifthies or sixthies.
And they continue to be used and factories supplying those units.
Why?
Because good...because simple, because cheap.
I do not believe transistor sounds....but if i could believe some unit will sound good....those would be the ones i will believe.
regards,
Carlos
And they continue to be used and factories supplying those units.
Why?
Because good...because simple, because cheap.
I do not believe transistor sounds....but if i could believe some unit will sound good....those would be the ones i will believe.
regards,
Carlos
Attachments
Nice folks those ones..... i use them into my prototypes construction.
Because they are huge.... i can inject a big DC on them...they can hold excesses.... strong and reliable.
Sometimes they are used as drivers when i am testing circuits... as errors can burn drivers and they are cheap...easy to find...and the special thing
- " there's no fakes of them here!"
regards,
Carlos
Because they are huge.... i can inject a big DC on them...they can hold excesses.... strong and reliable.
Sometimes they are used as drivers when i am testing circuits... as errors can burn drivers and they are cheap...easy to find...and the special thing
- " there's no fakes of them here!"
regards,
Carlos
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Yes dear Nordic... a shame for us...my home town turn this mess
I feel sorry because of that.
I do not thank you to remember me that.... yeah... i know you are kidding....no problem dear nephew.... you have this freedom to be kidding with me... no problems!
But those things are happening...they are real.
The image is a Military Police... searching for drugs up the hills.. sometimes battle and a lot of deaths.
Well, politics not allowable here...i will silent.
regards,
Carlos
I feel sorry because of that.
I do not thank you to remember me that.... yeah... i know you are kidding....no problem dear nephew.... you have this freedom to be kidding with me... no problems!
But those things are happening...they are real.
The image is a Military Police... searching for drugs up the hills.. sometimes battle and a lot of deaths.
Well, politics not allowable here...i will silent.
regards,
Carlos
Yes.... if we cannot find solution... if we have not power to produce the solution
Better is to keep the good mood!
You are right.... things that have not solution, already found solution = no solution!
Those TIP3055 do not hold the supply voltage from peak to peak.....will not be a problem, first because this value in not exact and not absolute...they can hold a little bit more voltage than guaranteed into specifications...also the supply will loose voltage during consumption moments..they will work fine, for sure!
regards,
Carlos
Better is to keep the good mood!
You are right.... things that have not solution, already found solution = no solution!
Those TIP3055 do not hold the supply voltage from peak to peak.....will not be a problem, first because this value in not exact and not absolute...they can hold a little bit more voltage than guaranteed into specifications...also the supply will loose voltage during consumption moments..they will work fine, for sure!
regards,
Carlos
I might get some 2955 and 3055 for testing purposes..., while I wait. I had 2 but used them in a preregulator... But I think they were numbered MJE2955 and MJE3055.
I was pretty impressed with my supplies dropping only about half a volt if I remember correctly when driven hard... otherwise they sit pretty at 35V.
I doudt I generaly even use 5W... benefit of a small brick house...
I was pretty impressed with my supplies dropping only about half a volt if I remember correctly when driven hard... otherwise they sit pretty at 35V.
I doudt I generaly even use 5W... benefit of a small brick house...
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