2N3055 How much audio power?
john pucovsky
Hello everyone. I have some surpluss 2N3055 power transistors that I
would like to experiment with in building a guitar amp. If I run it in
a Class A amp what would be the most realistic power I could run it
at? Is there some way I could run it as a Class B by perhaps inverting
the negative with an inverting op amp or do I have to get the
complementary power transistor? Just curious.
Thank you for your help.
Duncan Munro
On Thu, 15 May 1997 16:42:45 GMT, jpuc...@wwdc.com (john pucovsky)
wrote:
Hi John,
Suggest you check out the local library to get some schematics which
will help you with your amplifier. 2N3055's are normally run in class
B (or AB to be exact) rather than class A.
You can get a complementary transistor (2N2955) or you can run what's
called "quasi-complementary" where you have a complementary pair
driving the 2N3055's. I've seen many designs along these lines -
indeed, I have a stereo amplifier and a guitar amp at home using
exactly this principle. Again, go to the library and pull out a few
books on transistor amplifiers.
Regarding power, a pair of 2N3055's (and these are ball park figures)
will give 50W with 8 ohm speaker load. Careful design, a 4 ohm
speaker load, and good heatsinks can push this up nearer 100W.
The current gain, or Hfe, on 2N3055's is relatively low. Gut feeling
tells me that an op-amp will not have enough drive capability to feed
them directly.... It's also worth checking the op-amp voltage range -
to get high power out of your amp, you will need approaching 100V on
the 2N3055's - this will kill most op-amp's....
Duncan
-----
Duncan Munro
http://www.muffy.demon.co.uk/
Phillip R. Cline
john pucovsky wrote:
>
> Hello everyone. I have some surpluss 2N3055 power transistors that I
> would like to experiment with in building a guitar amp. If I run it in
> a Class A amp what would be the most realistic power I could run it
> at? Is there some way I could run it as a Class B by perhaps inverting
> the negative with an inverting op amp or do I have to get the
> complementary power transistor? Just curious.
> Thank you for your help.
The reply from Duncan Munro is accurate for the most part. If you can
find an old issue of Popular Electronics from around 1969 there was a 70
Watt amp in it that used an RCA no. that crossed directly with the
2N3055. This circuit was also in the RCA transistor manual. The only
parts that might be hard to find are the 1N3755 diodes. Any good silicon
diode should sub for it. 1N4002 up should get it. The heat sinking of
the output transistors is critical for higher power amps. You also might
consider paralleling more transistors. Just be sure to use a low value
(.22-.47 Ohm typically) in series with the emitters.
Good luck,
Phil Cline.
Bob Wilson
In article <5lf8h0$a...@van1s03.cyberion.com>, jpuc...@wwdc.com writes...
>
> Hello everyone. I have some surpluss 2N3055 power transistors that I
>would like to experiment with in building a guitar amp. If I run it in
>a Class A amp what would be the most realistic power I could run it
>at? Is there some way I could run it as a Class B by perhaps inverting
>the negative with an inverting op amp or do I have to get the
>complementary power transistor? Just curious.
>
Seems to me that this should be easy to estimate using the power handling
capability of the 2N3055 (see any data sheet) and applying the usual
amplifier design criteria.
As far as your "class B" question, the answer is that you use a
quasi-complimentary output topology. This has nothing to do with inverting op
amps or anything like that. It is simply the configuration of the output
transistor/driver transistor combination is different for the "upper" half of
the totempole than the "lower" half. See any amplifier design or schematic
from the 1970s. A good example is the Phase Linear 400 amps that used 2N3055
transistors (and had about the fidelity one would expect from a guitar amp).
By the way, attempting to build a Class A amp using bipolars requires a
*very* good understanding of amplifier design (and in particular, of thermal
stabilization). If you lack this knowledge, you an expect to blow up a *lot*
of transistors before you give up in disgust!
Bob.
Duncan Munro
In article <337B3E...@iquest.net>, "Phillip R. Cline" <pcl...@iquest.net> wrote:
>john pucovsky wrote:
>> Hello everyone. I have some surpluss 2N3055 power transistors that I
> Greetings,
> The reply from Duncan Munro is accurate for the most part. .......
Whoops! Did I say something inaccurate????
Duncan
----------------------------------------------------------------
Duncan Munro Work: duncan...@gecm.com
Business Systems Manager Home: dun...@muffy.demon.co.uk
Radar Systems Division
Mario Mitchell
I have a 2N3055 Power Transistor that I have been trying to turn into an
audio amp for quite some time. Can someone Please help me.
Also where can i get a data sheet on this transistor?
Thank you
Ma...@cport.com
Bob Wilson wrote:
>
> In article <5lf8h0$a...@van1s03.cyberion.com>, jpuc...@wwdc.com writes...
> >
> > Hello everyone. I have some surpluss 2N3055 power transistors that I
> >would like to experiment with in building a guitar amp. If I run it in
> >a Class A amp what would be the most realistic power I could run it
> >at? Is there some way I could run it as a Class B by perhaps inverting
> >the negative with an inverting op amp or do I have to get the
> >complementary power transistor? Just curious.
> >
>
> Seems to me that this should be easy to estimate using the power handling
> capability of the 2N3055 (see any data sheet) and applying the usual
> amplifier design criteria.
--
|-| ê |_ |_ † ® ¡ ><
http://www.geocities.com/BourbonStreet/4589/index2.html
Electronics - http://www.geocities.com/BourbonStreet/4589/index.html
David ROSSE
This transistor is quite spread and it should be very easy to find a
data sheet (the highest output current must be about 15A for an input
current of about 1A).
To use a 2N3055 as an audio amplifier, you must use a driver (a 2N2222
for example). The gain of 2N3055 is low : about 15 to 20.
But, if you want to build a cheap and performant amplifier, have a look
at integrated amplifiers like TDA2040.
Regards.
Mark Zenier
In article <33827D...@cport.com>, Mario Mitchell <Ma...@cport.com> wrote:
>I have a 2N3055 Power Transistor that I have been trying to turn into an
>audio amp for quite some time. Can someone Please help me.
>Also where can i get a data sheet on this transistor?
The first skill you need when you want to design something is digging
up the data books.
Places to look:
The web, at sites for commpanies that make power transistors.
Good bets would be Motorola (www.design-net.com), Philips
(www.semiconductors.philips.com) note: only 1 L in Philips, and
SGS-Thomson (www.st.com). (A whole bunch more people make 2N3055s,
down to some little 50 employee companies that you've never heard of,
but they may not have a web site yet). Or start with one of the web
directories like http://www.xs4all.nl/~ganswijk/chipdir or Grey Creagers
pages on www.scruznet.com/~gcreager. (Hope I got my spelling right on
all those URLs).
The sales rep, sales office, or company literature department. Look in
the phone book or on the web page for the phone number of a company
or their local/regional sale representative or office. Call them up
and ask. It's their job to provide customer support and if you sound
like you halfway know what you're doing (say you're a student works,
too) AND it doesn't cost them much (don't get greedy) they'll often be
more than willing to send you information. (These days, it might be a
CD-ROM of their whole product line. Cheap, but not that easy to use,
IMHO.) If they won't help you, ask them where there is someone who can.
Like the nearest distributor.
Electronics distributors. Larger ones often fill the same literature
distribution role as the sale rep. Other distributors like Jameco,
JDR Microdevices, Future Active sell databooks as a catlog item. Or
a local distributor that caters to the walk in trade will have a databook
shelf and allow (or have a nominial fee for) photocopies. (The big
distributors are closed operations, mostly using phone salesmen and
UPS for distribution, visitors aren't necessarily welcome.)
A good library. Like one at a university with an electrical engineering
program, or a large city library.
Used book stores, a big unselective "book dump" often will have a good
stock of old databooks. Ones that you can't get from the manufacturer
and more. Likewise, electronics surplus stores (most big cities should
still have one or two) often have them.
Mark Zenier mze...@eskimo.com mze...@netcom.com
Gerhard Lamprecht
A British company used to make 50W and 125W single amplifier units(Autona
modules) using the 2N3055. The 50W unit used 2 and the 125W unit used 4.
The older Elector magazines had plenty of circuits in, using this. A
company in South Africa (Ellies electronics) sold these units.
Greg J Szekeres
In article <01bc67c3$f699f5e0$461299ce@gerhard>,
I have the NAD 3130 rated about 30 watts at 8 ohms. Still pushing it a bit
a 30 watts. Perhaps some devices might have higher ratings. You'll have
to compare manufacturers spec sheets. Besides ordering data sheets,
you can probably get some off the Web.
greg