Connecting STK hibryds...

[Tomom]

I am intending to start a project on building an amp of STK4048II power module and STK3152III preamp; I am not sure how to connect them. Can anyone help? Many thanks!

[danielwritesbac]

For STK4048II, you can use http://www.analog.com/static/importe...D8610_8620.pdf A Jfet input buffer That buffer wants regulators.

STK4048II wants a buffered potentiometer (not a preamp).
That's because STK4048II doesn't want increased gain.

STK4048II "K-series" should make a nice project.

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For STK1352, you can use a discrete section as listed in this STK datasheet: http://www.datasheetcatalog.org/data...yo/STK3122.pdf See the test circuit? Keep scrolling down and you'll see this chip is a "Driver Chip"

STK1352 contains a tiny scrap of a discrete amplifier and then you assemble the rest. . . from discontinued, fake, substitute and "OEM" remake parts. That doesn't really make much sense. Just a few minutes saved on soldering at the cost of an unstable amp?? I wouldn't do it.
Instead. . .
I'd use a new driver chip that doesn't take discontinued parts (just search for "Driver Chip," here on the forums)
-or-
I'd use a discrete solid state amplifier that comes in kit form so there's no frustrating shopping experience searching for the little bits. A few additional minutes of soldering later and you have the real deal.

[Tomom]

Thank you for reply...Daniel, I guess. Now, I am talking about STK3152, not 1352... and sorry if I called it "preamp", yes it is driver, or voltage amp. In regards to STK4048II, are you able to post diagram of what you ment as input buffered potentiometer and how it connects to 4048...the site you suggested I couldn't open, neede some particular reader that my pc don't support at the moment...
Regards Tom

[Tomom]

..one more question, what if I use bipolar buffer...

[danielwritesbac]

Sorry for the previous typo. I had meant to type 3152. . .

The datasheet listed above for 3122 is correct because its in the same family of chips. Your 3152 is the higher voltage version of the 3122 driver chip. The spot to post questions about driver chips is the "Solid State" forum, since the labor and parts to use a driver chip is 2/3rds of a discrete amp.

EDIT: I must assume that 3152, although intended as a driver chip, must also be able to operate as a phase split, an op-amp and a preamp; however, the term "driver chip" is simply more specific.
.

PDF reader software--its vital. . .

For opening PDF type files, popular readers include Adobe and Foxit. During installation, I'd personally choose "custom" and deny / disable the installation of any extraneous toolbars.

You will really really need to have a PDF reader installed in order to make use of electronics data-sheets. Its unnecessary to pay for that software, because some of it is available open source.

[danielwritesbac]

Originally Posted by Tomom

..one more question, what if I use bipolar buffer...

A buffer isn't required by non-inverting amplifiers like yours.
A bipolar buffer, in this case, is extraneous or redundant
A 6n3p buffer might be useful but its application specific
A jfet buffer is mostly likely to be useful in general purpose

The datasheet linked above, is AD8620, a quality jfet op-amp (specific mention of "buffer" by the manufacturer indicates Unity Stable), and there is some expectation to power it from regulators for clean operation. Perhaps a separate little enclosure would make it easier to apply. Many models of Unity Stable Jfet Op-Amp are available.

The main task of the buffer is to prevent audible problems in applying potentiometers. That's why I mentioned earlier to buffer the potentiometer. Its risky to say it this way, but here goes: The buffer is for the potentiometer, not for the amp.
More specific:
If Not using a Unity Stable Jfet Op-Amp, then don't add a buffer and don't add a preamp, because. . . non-specific add-ons would be extraneous.

P.S. See the Decibel Dungeon site and Rod Elliot's site for examples of jfet buffers and volume controls.

[Tomom]

Thank you for your reply again. I am now working on the design of PC board for 4048, using Protel. First time doing something like that but hope I will get there. As you mentioned that 4848 doesnt like preamps, what kind of signal level is acceptable on its input.
I did look a bit through the subject of buffers an I would like to try a tube aproach. There are tubes like ECC86, which can work on low ( 12 - 24V) voltage. Is it sensible aproach?

[danielwritesbac]

The STK4048 already specs considerable gain. Its not allergic to preamps.
However, a buffer is more suitable. . . because a buffer has zero gain.

I cannot answer your question about tubes for general purpose buffer use although I have used some tubes for application specific harmonic filters. For better information, see the tube section of diyaudio.com.

Again, please bear in mind that STK4048 doesn't require either a preamp or a buffer.

[Tomom]

Thanks for opinion. I am working on pcb now, but I noticed discrapencies between original SANYO schematic for 4048XI and PCB that they suggested. Would you be able to look at that and try clarify? On their PCB pin 9 is connected to C8, which is in series with C5 which goes to pin7. But on schematic joint point between C8 and C5 is also connected to pin10?

Also there are two unused pads, between R8 and C5...seams like possible link to cross the track, but that would actualy cause short between pins 7 and 14...

Thank you, Tom

[danielwritesbac]

Download | Datasheet Archive
and
Download | Datasheet Archive

Looking at "Application Circuit for STK4048II" schematic will be more accurate than any wordy description that I could provide.