So I encounter various equipment. Often i see steel transistors (to-3 I believe) on
Old pioneers. Encapsulated in flat steel cylinder.
And new black or green colored semiconductor transistors. Rectangular shape
What are benefits of each type of output transistor. Ive heard to-3 steel type are unreliable and can leak .. easily stressed.
It's one major reason i am always selling or avoiding old amps with those to-3 types of transistors
And would prefer nakamichi pa-7 over threshold s300 or whichever one was copied by nakamichi. I think s300 used old steel output transistors
Old pioneers. Encapsulated in flat steel cylinder.
And new black or green colored semiconductor transistors. Rectangular shape
What are benefits of each type of output transistor. Ive heard to-3 steel type are unreliable and can leak .. easily stressed.
It's one major reason i am always selling or avoiding old amps with those to-3 types of transistors
And would prefer nakamichi pa-7 over threshold s300 or whichever one was copied by nakamichi. I think s300 used old steel output transistors
good transistor are good, whatever package they're put in
no need for further discussion
regarding leakage ..... maybe you heard something about oldest type of transistor - Germanium, but that is also having nothing with physical package
no need for further discussion
regarding leakage ..... maybe you heard something about oldest type of transistor - Germanium, but that is also having nothing with physical package
So steel encapsulation isn't really indicative of the material used Inside
Did they make rectangular output transistors with small heat sink of the same simiconductor type as those encapsulated in steel cylinders?
What's the purpose of steel encapsulation. Heat dissipation?
And why did industry moved from steel encapsulated transistors to rectangular . Rectangular with heat plate is easier to install looks like
Did they make rectangular output transistors with small heat sink of the same simiconductor type as those encapsulated in steel cylinders?
What's the purpose of steel encapsulation. Heat dissipation?
And why did industry moved from steel encapsulated transistors to rectangular . Rectangular with heat plate is easier to install looks like
in time of T0-3 (or TO-3) cans and similar, industry didn't had know how to make special plastic cases
simple as that
when that is invented, simpler and more practical packages are made...... also being cheaper in production
simple as that
when that is invented, simpler and more practical packages are made...... also being cheaper in production
I see.
Now the hot question.
Output transistor quality and reliability on threshold s300 vs on nakamichi pa-7
I really want to know truthful scientifically backed answer.
Without any patronizingly polite general statements that avoid the truth. I know it's pass labs forum so it's sort of a little tribe of passophiles who worship to nelson pass. This may be a slightly overblown metaphor. Just few times when I expressed my opinion about garbage adcom amplifiers(and this cannot be debated, as they are made from scrap metal, no dc relay+ long track record of these amps blowing speakers up)I often got retorts from few emotionally charged members trying to be hero and defend the papa nelson pass as if I am attacking him physically.
Stasis is a great idea. But implementation reliability and parts quality is different.
S300
Output MJ15012 and MJ15011
Drivers MJ15022 and MJ15023
Found this info online
"I since studied into the circuit and look at the transistors. The PA-7 uses 2SA1294 and 2SC3263 output transistor which are still up to date for modern design. They are faster(35MHz+)than most of the transistors used in today's amp. The Threshold S/300 uses MJ15022 and MJ15023 type of old transistors that is only 1/10 the speed of the transistors used in PA-7. PA-7 definitely have superior parts than the equal Threshold.
"
Source:
Audio Asylum Thread Printer
Now the hot question.
Output transistor quality and reliability on threshold s300 vs on nakamichi pa-7
I really want to know truthful scientifically backed answer.
Without any patronizingly polite general statements that avoid the truth. I know it's pass labs forum so it's sort of a little tribe of passophiles who worship to nelson pass. This may be a slightly overblown metaphor. Just few times when I expressed my opinion about garbage adcom amplifiers(and this cannot be debated, as they are made from scrap metal, no dc relay+ long track record of these amps blowing speakers up)I often got retorts from few emotionally charged members trying to be hero and defend the papa nelson pass as if I am attacking him physically.
Stasis is a great idea. But implementation reliability and parts quality is different.
S300
Output MJ15012 and MJ15011
Drivers MJ15022 and MJ15023
Found this info online
"I since studied into the circuit and look at the transistors. The PA-7 uses 2SA1294 and 2SC3263 output transistor which are still up to date for modern design. They are faster(35MHz+)than most of the transistors used in today's amp. The Threshold S/300 uses MJ15022 and MJ15023 type of old transistors that is only 1/10 the speed of the transistors used in PA-7. PA-7 definitely have superior parts than the equal Threshold.
"
Source:
Audio Asylum Thread Printer
Last edited:
well, Nelson didn't build Adcom amps, so why should I bother
regarding speed of transistors, besides historical facts - when amplifier was made and what were available types then (take in account that those were days of things happening fast) , I'm not overly concerned with that.......... once when transistor is fast enough for my needs, I don't care how much faster it can be ..... except in cases - that resulting in headache (problems)
in most cases people without damn clue how to make an amplifier are most productive in making myths
and, of those who are capable to make own amplifier, 9 of 10 are not having a damn clue what's needed to make a product and sell it
I can bet that there are more functional S300 than PA-7 ........
regarding speed of transistors, besides historical facts - when amplifier was made and what were available types then (take in account that those were days of things happening fast) , I'm not overly concerned with that.......... once when transistor is fast enough for my needs, I don't care how much faster it can be ..... except in cases - that resulting in headache (problems)
in most cases people without damn clue how to make an amplifier are most productive in making myths
and, of those who are capable to make own amplifier, 9 of 10 are not having a damn clue what's needed to make a product and sell it
I can bet that there are more functional S300 than PA-7 ........
I agree. Lots of myths on internet
This forum has lots of good legitimate posters. Reliable sources.
One other thing I've read online pa-7 runs hot and has reliability issues due to that heat
Pa-7 ii fixed the heat issue.. but then there is this another internet rumor to get the original pa-7 not the pa-7ii
I might want to get pa-7 or 5 down the line. Years ahead. So collecting information.
I don't blast music loud. But currently using polk sda-crs+. In future might want to run 4 of them for a more moving and impactful presentation of some classical pieces
Not sure if ta-4a will be enough to run them connected in series. Sda-crs+ tend to be power hungry. 2 6.5" drivers + 1 tweeter. 89-90db efficiency. 6ohm impedance
Now I use one pair with ta-4a and 9-10 o'clock volume level max
This forum has lots of good legitimate posters. Reliable sources.
One other thing I've read online pa-7 runs hot and has reliability issues due to that heat
Pa-7 ii fixed the heat issue.. but then there is this another internet rumor to get the original pa-7 not the pa-7ii
I might want to get pa-7 or 5 down the line. Years ahead. So collecting information.
I don't blast music loud. But currently using polk sda-crs+. In future might want to run 4 of them for a more moving and impactful presentation of some classical pieces
Not sure if ta-4a will be enough to run them connected in series. Sda-crs+ tend to be power hungry. 2 6.5" drivers + 1 tweeter. 89-90db efficiency. 6ohm impedance
Now I use one pair with ta-4a and 9-10 o'clock volume level max