Here is A amplifier with 2n3055 transistors on its output for those of you that are looking at doing a bang for buck amplifier with all those 2n3055 lieing around that as most electronics guys think when they look in there junkbox there must be something i can do with this stuff?????? Well I really don't know for sure if this amp schematic is able to do what is says but even if it comes close thats one way to make use of of those 2n3055's lieing around for a pa type amp even. Can anyone have a look at this schematic and see if it is actually capable of producing what it claims???? I would appreciate it my maths says it would produce around 150 watts but iam not 100% sure. I would like another eye on it. It just looked like a good bang for buck amp. Thanks
Sweet!
That is what I like cheap simple high power design that does not use exotic parts.
I am sure it will do that kind of power as My sunn concert slave does 180 watts on just 4 of them and 120 watts clean. jer
There are lots of shiny (and dull aluminum) things called 2N3055. Some can take 55 volt rails but many can not. I bought a big box full of military surplus RCA transistors back in 1970. I still have some. The label on the box had a house number, a FSN (federal stock number) and writing that said similar to 2N3055 (no H).
The amplifiers that I made back then were crude totem pole designs with no protection circuits. They were used as guitar amps where the main design criteria was to be louder than the other guy. Some even ran directly from rectified line voltage.
Many of them blew up over time but as of the early 90's (last time I saw the guys) two of the big ones were still going. One used 8 of the mystery 2N3055's to make 300 watts into 4 ohms. The really big one used 24 of the mystery transistors to make a measured 1200 watts into a 2 ohm load. The guys were using it as a PA amp for outdoor rock concerts. I saw it used with about 6 speaker cabinets connected up to it (individual impedances unknown).
Assuming that the "2N3055" used can handle the voltage. 200 watts from 55 volt rails is possible. It only takes one transistor avalanche to blow them all up!
The amplifiers that I made back then were crude totem pole designs with no protection circuits. They were used as guitar amps where the main design criteria was to be louder than the other guy. Some even ran directly from rectified line voltage.
Many of them blew up over time but as of the early 90's (last time I saw the guys) two of the big ones were still going. One used 8 of the mystery 2N3055's to make 300 watts into 4 ohms. The really big one used 24 of the mystery transistors to make a measured 1200 watts into a 2 ohm load. The guys were using it as a PA amp for outdoor rock concerts. I saw it used with about 6 speaker cabinets connected up to it (individual impedances unknown).
Assuming that the "2N3055" used can handle the voltage. 200 watts from 55 volt rails is possible. It only takes one transistor avalanche to blow them all up!
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
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
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
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?
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?
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
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
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
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
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
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.