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Old 21st March 2004, 07:10 AM   #1
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Default STK Choice

Hi guys

I am really confused, I have to choose between STK4192II and STK4191II.

And to choose between STK4191II and between STK4191V .

Each option is a stand alone one, ok .

Which

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Old 23rd March 2004, 10:19 AM   #2
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Hi There,

you can use any of the abovementioned ICs -

STK4191II - 4192II both are pin compatible 4191II's have a lower distortion - the 4192 is in a smaller casing
4191V is in the smaller casing - HiFi grade (lower distortion)

except the different casing from the 4191II all are identical in pinout and power rating (2x50W MIN)
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Old 14th April 2004, 08:15 PM   #3
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Default Datasheets or shematics

Well i`m geting my self a bunch of STk 4191II tommorow.
They are already ordered.

Anione have a good shematics for them?

I`m going to use the sheme from the 4192II data sheet if don`t find another one..
Any proposes?

PS.Sorry for my bad english.I don`t practice it to much..
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Old 18th April 2004, 03:31 PM   #4
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SOmeone please help me.

I`m not shure will it be OK.
So advise me please!
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Old 18th April 2004, 04:05 PM   #5
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Exclamation 4192II

Full Datasheet including pcb artwork performance curves, component tweaks

file too big to upload here - Email me w/ reply address

-Baily
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Old 18th April 2004, 08:54 PM   #6
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10x allot

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Old 19th April 2004, 12:01 PM   #7
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Default Convert STK 41XX circuit to Technics new class A

i have recently uncovered that the STK41XX series amplifiers can be upgraded to the (virtually) PIN compatible Technics SVI3000 series (SVI300-3004) the SVI ICS being COMPLIMENTARY SYMMETRY with new class A biasing... simply put IC in place of STK *** PINS 6,7 & 8 are NOT Connected for the SVI (remove components that connect to these pins) - the SVI has alot higher current drive (delivers more power at lower rail voltage)

further Questions - Email


- Baily
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Old 24th April 2004, 10:11 PM   #8
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I`ve just build a STK4191II amp.
It sounds good and it`s not overheating.
I`m very proud of it becouse it`s my first amp.


But got a question.

On the datasheet of the amp there is a diagram.
It says that if my supply voltage is + / - 45V and i use a 4Om speaker the output power will be 130W
130W x 2 or 130W x 1?

becose my curent supply voltage is + / - 46,4 V
and i use 4 om Speakers.
can you tell me your opinion on that question?

10x

ps.I`ve attached the data sheet of STK4191V(pin and power compatilble to STK4191II)
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Old 25th April 2004, 06:31 AM   #9
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BDW can someone explain me this one?


Quote:
Originally posted by rljones
It is interesting that you should make this post, as I was about to start a thread on these hybrid op amps.

A few months ago, I made a pcb for the STK4048XI. [As an aside, this device has full complementary outputs; the 'V' versions, as opposed to the 'XI' versions, are quasi-complementary. A smaller module, the STK4044XI, has 4 output devices and 15 pins; the STK4048XI, 6 output devices and 18 pins. You can ignore the last 3 pins on the '48 if you put a '44 into the same circuit, so design for the 18 pin versions and you can go with either unit.]

Anyhow, I had so many problems that I became frustrated and put them away: horrible oscillation that I could not stop despite trying all sorts of things with the grounding, etc. However, after a friend of mine fried one of my amps, I decided to attempt making a couple of STK modules to put into the damaged unit. This weekend, I finally figured out the problems, one of which is hinted at on the application docs by Sanyo, and another which I accidentally discovered and yet seems very important.

The main secret in stopping oscillation is to keep the gain at 40dB. I don't like amps with this much gain as the input sensitivity is around 0.4 V for full power. This kept me from getting rid of the oscillation as I had initially changed the input resistors from 1K/50K to 1K/20K, and never looked back.

Once you get the gain up, to the suggested 40 dB range, almost all oscillation stops. The amp then looks very good on the scope, except for a little bit of something on the sine waves. (BTW, I used all of the parts suggested on the app docs, various 100pF caps, etc to avoid oscillation as Sanyo warns.) This where the application docs stop. What I found was that there was still oscillation, but at VERY low levels, like 1 mW output into 8 ohms. [And I'm now wondering if this low level oscillation is what has given these guys a back name, particularly with respect to longevity. Any amp that oscillates will overheat and eventually burn-out the output devices.]

At these low levels, the oscillation took off again. I tried all sorts of stuff to fix it: bypassing the feedback resistor with small caps like 10 to 200 pF, changing the input blocking caps, but nothing helped--until the other evening. I was looking at th scope ready to go to bed when I started holding a 200 pF cap across the feedback resistor when the oscillation completely disappeared. But I'd made a mistake, it turns out I'd actually put this capacitor from the amp output side of the feedback resistor to pin 3 going to ground.

In other words, by placing a 200 pF cap from the amp output to ground (but at low current level location; I didn't use the output terminals), the remaining oscillation stopped. The amp then looked absolutely perfect and all distortion dropped 10 dB, especially at low levels. The heatsinks were now cold when idling; before they were warm but this was due to overlooked oscillation.

This STK4048XI produces, with a +/-55 V supply that sags to 50V at full output, 140 W into 8 ohms and 220 W into 4 ohms. Freq response is -0.4 dB at 10 Hz to -2 dB at 100 kHz (limits of my equipment). Distortion (THD) is 0.8mW is 0.08% at 1kHz, 0.025% at 1W, 0.007% at 10W. At 20 kHz and 10W it is 0.035% and only 0.1% at 10W at 50 kHz.

As for sound, it initially sounds very good, not as open or airy as my Rowland amp, but very good. The input needs adjustment: my initially listening was done with an input transformer, which I think may be a mistake on this amp (I was still trying to cut that incredible gain...). Once I get it going, and properly set up, I'll compare it to a Tripath 104, a Rowland, and a homebrew Aleph.

Will it be good if i put a 200pF cap from the amp output to the ground?And do i must to put a polarised cap or normal cap?
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Old 27th April 2004, 07:34 AM   #10
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Well i see that noone is replyng to my posts..

But i will continue to ask you.

What is the diference between STK 4191II and SKT 4191 ??
I think they are pin compatible but are they the same quality?

I have some STK4191 here and if someone says i may just put them on..

10x

PLS give mio some replays..
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