2n3055 amp claims 200 to 220 watt

[geraldfryjr]

My rig has two of those with a sunn 610 and a 215 cabinets and rocks to no end! jer

[jaycee]

I really dont see why people are still messing around with the 2N3055 when the MJ15003 or MJ15024 can be got so easily.

[geraldfryjr]

It is just that they can be had so cheaply and they are nostalgic as it was the very first work horse power transistor that started the whole thing.

They cost as much as 1/3 that of the MJ XXXXX and is much more readily available and that is a perfromance for the price.

A well designed circuit with the 2N3055 can rivil some but not all power amplifiers.
At least you can go done to the local parts store and get one but to get an MJxxxxxx you have to order it from mail and their are a ton of them out there yet to be used.

Yes I agree that the times have changed but when you can build a super power amp with 8 of them and a THD less than .1% for $.89 apiece is nothing to be shaking a stick at because it will just break it.

As the are very durable. jer

[jan.didden]

The max power supply you can use the 2N3055 with is 70V total or +/-35V. That is ignoring any serious SOA issues.
No way you get 200W from this device even massively paralleled.

jan didden

[lineup]

some, 2N3055, 2N3055A, 2N3055H are 60 VCE
other, 2N3055HV are 100 VCE
also TIP41C is 100 VCE

- circuit shows +-55V = 110 Volt
which is beyond safety margins, even if you use 100V 2N3055HV

[geraldfryjr]

Originally Posted by lineup

some, 2N3055, 2N3055A, 2N3055H are 60 VCE
other, 2N3055HV are 100 VCE
also TIP41C is 100 VCE

- circuit shows +-55V = 110 Volt
which is beyond safety margins, even if you use 100V 2N3055HV

what do you consider a safety margin?
As a 55v supply voltage is well below the maxium spec of 60V.
You have to remember that ,that was considered HV back in the day.
Not 80v on some of todays amplifiers and the problem back then as today is when it comes to a low ohm load is how much current can it handle at that voltage level this is Pd.
you guys can play around with your vas stage all you want but there are better methods for reducing THD even though the charcteristic curve is sloppy.
my favorite is the 2N3773 its big bother through the years I always wanted to get my hands on some MJxxxx transistor but they were very costly and the last ones I ever had were in a Sansui G 9000 (or was it 8000) the biggest stereo ever made .
Sadly enough I blew that one out too and then some idiot stole it Ha,Ha lucky for him!
It was an exceptional reciever and I miss it.
But my sunn amps still turn the test of time with the transformer drive stage.
The voltage across each transistor is set at 25v.
jer

[jaycee]

From Farnell's small order UK division CPC (prices are each):

2N3055H (Magnatec) - £1.00
2N3773 (probably Magnatec) - £1.85
MJ15003 (Onsemi) - £2.52
MJ15024G (Onsemi) - £2.52
MJ21194G (Onsemi) - £2.97 not much extra for a much superior part over the other MJ's

To me, the cost saving is hardly worth it. Where is the saving when the thing blows up and takes your speakers with it?

[jan.didden]

Originally Posted by geraldfryjr

what do you consider a safety margin?
As a 55v supply voltage is well below the maxium spec of 60V.
You have to remember that ,that was considered HV back in the day.
Not 80v on some of todays amplifiers and the problem back then as today is when it comes to a low ohm load is how much current can it handle at that voltage level this is Pd.
you guys can play around with your vas stage all you want but there are better methods for reducing THD even though the charcteristic curve is sloppy.
my favorite is the 2N3773 its big bother through the years I always wanted to get my hands on some MJxxxx transistor but they were very costly and the last ones I ever had were in a Sansui G 9000 (or was it 8000) the biggest stereo ever made .
Sadly enough I blew that one out too and then some idiot stole it Ha,Ha lucky for him!
It was an exceptional reciever and I miss it.
But my sunn amps still turn the test of time with the transformer drive stage.
The voltage across each transistor is set at 25v.
jer

Its + and - 55 so the max voltage across the device can be 110V....
I did build some amps with 3 ea 3773 parallel in the dim past, and it worked well.
But they are relatively slow so THD above a few kHz goes up quickly due to xover distortion.

jan didden

[geraldfryjr]

Well you are are right about that as I have seen specs claiming 3.5mhz and 1.7mhz but 350khz is the norm.
And when I tried to use them at those frequency's I gave up and that was in the 80's.
I have a crown DC300 and a BGW amp's from that era and they work flawlessly '
I have also had the Sunn coliseum slave which uses the 2N3773 for the output stage and have yet to see one blow!
It is a very simple circuit and uses those very common parts that every one claims that they are inferior.
Sorry but I love that old stuff and always have.

An other one was the randall amp and was not around for very long it used the TIS97 on the input stage it was a very clean and powerful amp but poeple didn't like it becuase it was too clean and did not consider it as a guitarist amp.
jer

[geraldfryjr]

I have a friend that had that randal amp and dup'ed it for stereo in a little box with some little heat sinks and that sucker ran hot but never broke down the whole night long at a wedding gig.
And it did sounded good the whole time.
I was even was able to touch with my hand on it and it was quite warm but it never quit at all'
shoot that was in 1981. jer