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Question to geeks -- Why do amps have so many parts?

Mystery

Mystery

constantly upgrading...
I'm not talking about modern receivers that have DD, DTS, HD etc... processing.
Simple stereo amplifier like BB275 or vintage 2-chanel amps have so many parts that it's really weird to look inside.
Can't there be just one transformer, couple of transistors and few capacitors?
Why in the hell they need 1000's and 1000's pieces of resistors, capacitors, transistors and all others thingies to amplify input signal?
Does each part do something that other can't do or smaller number of them can't do what a lot more of them can do?

This is a question, not a comment so thanks for informational replies.

An example below of BB275. It's a 2-channel 75wpc amp but look at the number of resistors, caps and transistors, they are everywhere.
I even see quite a few chips in there.:yikes:

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Everything to the right of the heat sink is power supply. A great amp is really all about the power supply design. Most of the little bits are to supply the correct bias and feedback to the "transistors" of whatever type they are using. Add voltage regulation, filtering, and protection circuits as a minimum. Hell the one above is nice and clean!

I think the fewer the number of parts, the more expensive the amp!
 
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:D

It takes that many to make the "magic".

The whole right side is the power supply. It turns AC into DC.
You need a positive DC and negative DC.

The left side is the amp, stereo needs 2 of everything.
To get to 75wpc, it takes a "gang" effort, and this amp uses banks of transistors to do that. The big things bolted to the heat sinks. You need "drivers" to send the signal to those "outputs", you need pre-drivers to send the signal to those transistors.

To take a small audio signal and ramp it to a loud set of speakers, you have to do it in stages, so there is a cascade of transistors to do that. They all work at different levels and need proper voltage to do it, so you need a bunch of parts to do all that.

You need to control the ramping, so there are feedback circuits to control that. There are heat sensors too that the control the amp. The amp is a "push-pull" so you need a push side and pull side and that doubles the parts. (so times 2 for stereo and times 2 for push pull).

Throw in a protection system and that brings in a bunch of parts.

Once you learn enough "geek" its all pretty simple.
 
Us circuit designers get paid by the part. Quit rocking the boat.

Seriously...check out Nelson Pass's First Watt amps. Very few parts in them, relatively speaking.
 
Let's put mice and rats aside.
I don't believe that the parts in there are just for show and not connected to anything.
Why waste parts as 99% of consumers never even open the case?

In any case, looks like amplification technology is little over my head. :headscrat
 
To the OP: consider that some people spend their entire lives learning to design amplifiers. I'm afraid you're not going to get a satisfactory answer to your question. There are several decent books on power amplifier design available through Amazon and elsewhere.
 
I don't think there are more than 300 parts in the amplifier shown. A far cry from
1000's and 1000's. You can build a circuit that will work on your bench with very few
parts, but a production unit that must perform reliably under varying conditions of
line voltage, ambient temperature and all that needs a lot of circuitry to achieve its
goal. Regards
 
Well, some don't seem to have a lot of parts inside. Conrad Johnson MF 2300A
 

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Mystery said:
Let's put mice and rats aside.
I don't believe that the parts in there are just for show and not connected to anything.
Why waste parts as 99% of consumers never even open the case?

In any case, looks like amplification technology is little over my head. :headscrat
Click to expand...

You're absolutely correct. They are not for show. Each and every part in there is doing a specific job. I am not sure what exactly those jobs and how often they are being done, all the parts are in use though. For example, if equipped the DC Protection Circuitry might never come into use unless the DC Offset floats too high and causes it to kick in, thus protection your potentially expensive speakers from harm.

It might be better if you were to look at a block diagram of an amplifier. Each block in the diagram represents a bunch of parts that are used to achieve that block's specific goal. All these blocks put together are the amplifier.

Here are some examples. These are from Kenwood integreated amplifiers, so they have a bit more "stages" than the amplifier pictured:

Kenwood KA-6100
http://i.imgur.com/Q3w8BwQ.png

Kenwood 500/600/650
http://i.imgur.com/tHxU6Ux.png

Each stage itself can be broken down into blocks as well. I don't have anything at that level but you get the basic concept.

I dont think a manufacturer is going to just waste parts, as popular as cost savings is these days.
 
?

Mystery said:
I'm not talking about modern receivers that have DD, DTS, HD etc... processing.
Simple stereo amplifier like BB275 or vintage 2-chanel amps have so many parts that it's really weird to look inside.
Can't there be just one transformer, couple of transistors and few capacitors?
Why in the hell they need 1000's and 1000's pieces of resistors, capacitors, transistors and all others thingies to amplify input signal?
Does each part do something that other can't do or smaller number of them can't do what a lot more of them can do?

This is a question, not a comment so thanks for informational replies.

An example below of BB275. It's a 2-channel 75wpc amp but look at the number of resistors, caps and transistors, they are everywhere.
I even see quite a few chips in there.:yikes:

attachment.php
Click to expand...

Same could be asked about our Body,yes?:scratch2:
 
All the parts are necessary, they were just joking.

However, there aren't any chips in that amp. I suspect that you're looking at the ouput transistors (parts that make the power).


Mystery said:
Let's put mice and rats aside.
I don't believe that the parts in there are just for show and not connected to anything.
Why waste parts as 99% of consumers never even open the case?

In any case, looks like amplification technology is little over my head. :headscrat
Click to expand...
 
fastbike said:
All the parts are necessary, they were just joking.

However, there aren't any chips in that amp. I suspect that you're looking at the ouput transistors (parts that make the power).
Click to expand...

Looks like an 8 pin DIP just in front of the inputs.
 
Mystery said:
Let's put mice and rats aside.
I don't believe that the parts in there are just for show and not connected to anything.
Why waste parts as 99% of consumers never even open the case?

In any case, looks like amplification technology is little over my head. :headscrat
Click to expand...

Kidding aside, blhagstrom pretty much summed up what the various clusters of components in the amp in your picture do. That looks pretty typical for a transistor amp.

Cheers,

Otto
 
Thanks for comments.

fastbike said:
All the parts are necessary, they were just joking.
However, there aren't any chips in that amp. I suspect that you're looking at the ouput transistors (parts that make the power).
Click to expand...

There are.

Jeffery said:
Looks like an 8 pin DIP just in front of the inputs.
Click to expand...
Yes and another 4-pin on the left next to orange capacitor.
At least those are visible.
I hope there isn't any board under that board.
I have seen few amps that have board under board under board and so on...
I opened the base cover of few receivers before and they had even more parts from the bottom. :yikes:
 
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