Are Discretes Better Than Chip Amps?

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"Any day, Any Time, the time honoured 2N3055 designs are better than chip amps." My friend tells me this; and people and prophets from the 70s seem to agree with this. How much of this is the prejudice of a generation? Do graphs, bode plotts, and all such instruemnts under the solar system corroborate? Is there some truth in this?

The cognoscenti are coaxed for a reply!?!!@@##$$%%^^&&**
 
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r_s_dhar said:
"Any day, Any Time, the time honoured 2N3055 designs are better than chip amps."

Having built more than a few SS amp and a couple of vaccum amps, and played with the stk's and tda of yesteryear, my experience is that the majority of chip amps suck, the stk's in particular, :).

with a SS amp, you have more freedom at its design, and you can easily add or subtract building blocks to suit your own needs: more power? higher voltage; want to drive low-impedence speakers? use more output devices or beefier transistors, etc.

you don't have that with a chip amp. for the most part anyway.

however, chip amps are a lot easier to build, and presummably have better internal consistencies: I rarely match my transistors for my SS amps.

so to me if your application doesn't call for high power and super high performance, go with a chip amp.
 
Halve a truth is of no use....

Konnichiwa,

r_s_dhar said:
"Any day, Any Time, the time honoured 2N3055 designs are better than chip amps." My friend tells me this; and people and prophets from the 70s seem to agree with this.

Well, even in the 1980's this was not any longer quite true. Chipamps have specific issues. Due to thermal issues they tend to be problematic if you really push power. On the good side, IF WELL IMPLEMENTED (LM3875 is a good example) they can offer perfomance comparable to ANY discrete, though power remains limted by the small case.

Given the choise between a "cooking" 2N3055 Amp or something with the LM3875 (and a few other qualifying chips) I would not even have to think, assuming the Chip was well implemented of course.

In the last decade at least for both small signal and medium power circuits I would be VERY HARD pressed to find an Audio application where I could materially (sonically and measured) better the best Chips with a discrete solid state circuit. It's possible, but increadably hard work, work IMHO better applied to get the best from the chips.... ;-)

I had a nice exchange with Walt Jung on this topic, around the time he was running his "Walts Tips" column in EDN and published on "Op-Amp" audio.... Worth a serious read.

Sayonara

BTW, most most monolithic integrated Amp's (op or power) when used for audio are utter dreck, as are most discrete circuits, but that should go without saying (STURGEON'S LAW: Ninety-five percent of everything is dreck.)
 
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Re: Halve a truth is of no use....

Kuei Yang Wang said:
BTW, most most monolithic integrated Amp's (op or power) when used for audio are utter dreck, as are most discrete circuits, but that should go without saying (STURGEON'S LAW: Ninety-five percent of everything is dreck.)


that especially goes for those early STK's (they are hybrid or thick film chip amps where the power devices are actually co-packaged transistors).

Not sure where they are today. I thought Sanyo made most of those STKs.
 
I own an old Technics amp with a STK???? module. I personally fried the module once by playing errr... too loud. :(
The modules were not available anymore. Now I don't care anymore, because I'll built a nice (and free!) gainclone with it. It has a 2x25 V transformer and a large heatsink. I have some old resistors, caps and OPA541's laying here. Let's see if I can build a good sounding amp under $10 :bigeyes:

'Love this hobby... :)

Fedde
 
I have 2 STK 4042`s sittin here...brand spankin new and I am going to waist my time building an amp with them and its going to sound terrible but what the Hell I`m deaf in one ear and can`t hear out of the other....I grew up with sub standard equipment and I thought it was good at the time..haha

DIRT®
 
One aspect is overload behaviour.
Chip amps like the 3875 series sound bad when driven into clip or current overload.

TDA chip amps are better in this respect.
STK modules are variable according to the model.
Discrete amps can be anywhere in between.

Most modern amplifiers are close enough to perfect at normal levels, but IMO it is overload behaviour that more strongly distinguishes different amplifiers.

Eric.
 
diyAudio Senior Member
Joined 2002
Hi,

Most modern amplifiers are close enough to perfect at normal levels, but IMO it is overload behaviour that more strongly distinguishes different amplifiers.

And that's precisely where valves really make all the difference...

Seriously, Erik, with your interest in live amplification and related fields you should consider this feature.

Just telling you as a friend with your best interest in mind...;)
 
Caring And Sharing.

Hi Frank,
Modern PA systems nowadays typically run oversize amplifiers such that clipping is avoided, or at least allowed to hit clip only momentarily.

It is considered very un-kosher to blow expensive high power drivers, and any live sound engineer who does usually has some explaining to do, and if it happens too often a bad professional reputation is the result.
Also nowadays many modern PA amplifiers incorporate internal soft limiting stages and this can help to idiot proof live systems.

Reasonable quality tube mic and instrument preamp stages are becoming more affordable and more available, and this is where tubes are most relevant for live sound.

FOH tube amplifiers are not an economic proposition for modern live music unfortunately - digital amplifiers are making quite strong inroads but I have heard differing opinions of these.

Perhaps tube amp mids/highs would be worth a try.
I can lend suitable 0.1% tube amps and Turbosound TMS-4's (105 dB/W) for the heck of it and try it out sometime.
The tube amp design that I speak of can be expanded out to 400 RMS - that might be some good loud fun.

Eric.
 
Sooner Or Later I'll Know.

350W version (sorry 400W info was wrong) has not been built and likely won't, but the design can be extended to this.
The existing version is conservatively rated at 60W RMS, but even this into 105dB/W will make a decent racket, but still not loud enough for serious PA usage.
400W RMS for mids and highs only would surely make it into earbleeding levels...
I thought the benefit of tube amplifiers was no ear bleeding ?.
In the near future (a month or two) I will be making new crossovers for a whole bunch of TMS-4's (the originals have been BURNT) so this will be a good opportunity to give them a go with with a nice tube amp - I'll let you know what the result is.

Eric.
 
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one thing I really liked about (some of) the STK chips is the separation of output stage from the rest of the chips. If you want, you can hook up your own output devices and use the input, vas and driver stages of the chip. I wish National can do the same with its class ab chips - not to integrate the output devices on the chips - much like their Class D offerings.

That way, you just go find your own power BJTs and you have one wonderful, versatile, and powerful amp.

we can all dream, cannot we?
 
summarizing...

Guys, I assume this thread was started with a domestic point of view.
50 watts RMS is more than enough for your room.

Anyway, thinking of an ideal amplifier (when are we going to have a wire with gain?:bawling: ), I will point out two main advantages of chip amps:

1. Short signal path.
2. Much less components.

These should theoretically make very hard for you to make a discrete design to be as good as the best chips.
In practice, since I first switched on the first GC I built, I've got a bug in my head.:devily:
My god, it's fantastic!
And it would be very hard for anyone to make a discrete design for a preamp with the technical specs and sonic excellence of an op-amp like the OPA627/37.


BTW, Kuei, your pre was reviewed in Hi-Fi World.:cool:
They say it's very good.:D
 
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